linux/drivers/iio/adc/stm32-adc.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * This file is part of STM32 ADC driver
   4 *
   5 * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
   6 * Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
   7 */
   8
   9#include <linux/clk.h>
  10#include <linux/delay.h>
  11#include <linux/dma-mapping.h>
  12#include <linux/dmaengine.h>
  13#include <linux/iio/iio.h>
  14#include <linux/iio/buffer.h>
  15#include <linux/iio/timer/stm32-lptim-trigger.h>
  16#include <linux/iio/timer/stm32-timer-trigger.h>
  17#include <linux/iio/trigger.h>
  18#include <linux/iio/trigger_consumer.h>
  19#include <linux/iio/triggered_buffer.h>
  20#include <linux/interrupt.h>
  21#include <linux/io.h>
  22#include <linux/iopoll.h>
  23#include <linux/module.h>
  24#include <linux/platform_device.h>
  25#include <linux/of.h>
  26#include <linux/of_device.h>
  27
  28#include "stm32-adc-core.h"
  29
  30/* STM32F4 - Registers for each ADC instance */
  31#define STM32F4_ADC_SR                  0x00
  32#define STM32F4_ADC_CR1                 0x04
  33#define STM32F4_ADC_CR2                 0x08
  34#define STM32F4_ADC_SMPR1               0x0C
  35#define STM32F4_ADC_SMPR2               0x10
  36#define STM32F4_ADC_HTR                 0x24
  37#define STM32F4_ADC_LTR                 0x28
  38#define STM32F4_ADC_SQR1                0x2C
  39#define STM32F4_ADC_SQR2                0x30
  40#define STM32F4_ADC_SQR3                0x34
  41#define STM32F4_ADC_JSQR                0x38
  42#define STM32F4_ADC_JDR1                0x3C
  43#define STM32F4_ADC_JDR2                0x40
  44#define STM32F4_ADC_JDR3                0x44
  45#define STM32F4_ADC_JDR4                0x48
  46#define STM32F4_ADC_DR                  0x4C
  47
  48/* STM32F4_ADC_SR - bit fields */
  49#define STM32F4_STRT                    BIT(4)
  50#define STM32F4_EOC                     BIT(1)
  51
  52/* STM32F4_ADC_CR1 - bit fields */
  53#define STM32F4_RES_SHIFT               24
  54#define STM32F4_RES_MASK                GENMASK(25, 24)
  55#define STM32F4_SCAN                    BIT(8)
  56#define STM32F4_EOCIE                   BIT(5)
  57
  58/* STM32F4_ADC_CR2 - bit fields */
  59#define STM32F4_SWSTART                 BIT(30)
  60#define STM32F4_EXTEN_SHIFT             28
  61#define STM32F4_EXTEN_MASK              GENMASK(29, 28)
  62#define STM32F4_EXTSEL_SHIFT            24
  63#define STM32F4_EXTSEL_MASK             GENMASK(27, 24)
  64#define STM32F4_EOCS                    BIT(10)
  65#define STM32F4_DDS                     BIT(9)
  66#define STM32F4_DMA                     BIT(8)
  67#define STM32F4_ADON                    BIT(0)
  68
  69/* STM32H7 - Registers for each ADC instance */
  70#define STM32H7_ADC_ISR                 0x00
  71#define STM32H7_ADC_IER                 0x04
  72#define STM32H7_ADC_CR                  0x08
  73#define STM32H7_ADC_CFGR                0x0C
  74#define STM32H7_ADC_SMPR1               0x14
  75#define STM32H7_ADC_SMPR2               0x18
  76#define STM32H7_ADC_PCSEL               0x1C
  77#define STM32H7_ADC_SQR1                0x30
  78#define STM32H7_ADC_SQR2                0x34
  79#define STM32H7_ADC_SQR3                0x38
  80#define STM32H7_ADC_SQR4                0x3C
  81#define STM32H7_ADC_DR                  0x40
  82#define STM32H7_ADC_DIFSEL              0xC0
  83#define STM32H7_ADC_CALFACT             0xC4
  84#define STM32H7_ADC_CALFACT2            0xC8
  85
  86/* STM32H7_ADC_ISR - bit fields */
  87#define STM32H7_EOC                     BIT(2)
  88#define STM32H7_ADRDY                   BIT(0)
  89
  90/* STM32H7_ADC_IER - bit fields */
  91#define STM32H7_EOCIE                   STM32H7_EOC
  92
  93/* STM32H7_ADC_CR - bit fields */
  94#define STM32H7_ADCAL                   BIT(31)
  95#define STM32H7_ADCALDIF                BIT(30)
  96#define STM32H7_DEEPPWD                 BIT(29)
  97#define STM32H7_ADVREGEN                BIT(28)
  98#define STM32H7_LINCALRDYW6             BIT(27)
  99#define STM32H7_LINCALRDYW5             BIT(26)
 100#define STM32H7_LINCALRDYW4             BIT(25)
 101#define STM32H7_LINCALRDYW3             BIT(24)
 102#define STM32H7_LINCALRDYW2             BIT(23)
 103#define STM32H7_LINCALRDYW1             BIT(22)
 104#define STM32H7_ADCALLIN                BIT(16)
 105#define STM32H7_BOOST                   BIT(8)
 106#define STM32H7_ADSTP                   BIT(4)
 107#define STM32H7_ADSTART                 BIT(2)
 108#define STM32H7_ADDIS                   BIT(1)
 109#define STM32H7_ADEN                    BIT(0)
 110
 111/* STM32H7_ADC_CFGR bit fields */
 112#define STM32H7_EXTEN_SHIFT             10
 113#define STM32H7_EXTEN_MASK              GENMASK(11, 10)
 114#define STM32H7_EXTSEL_SHIFT            5
 115#define STM32H7_EXTSEL_MASK             GENMASK(9, 5)
 116#define STM32H7_RES_SHIFT               2
 117#define STM32H7_RES_MASK                GENMASK(4, 2)
 118#define STM32H7_DMNGT_SHIFT             0
 119#define STM32H7_DMNGT_MASK              GENMASK(1, 0)
 120
 121enum stm32h7_adc_dmngt {
 122        STM32H7_DMNGT_DR_ONLY,          /* Regular data in DR only */
 123        STM32H7_DMNGT_DMA_ONESHOT,      /* DMA one shot mode */
 124        STM32H7_DMNGT_DFSDM,            /* DFSDM mode */
 125        STM32H7_DMNGT_DMA_CIRC,         /* DMA circular mode */
 126};
 127
 128/* STM32H7_ADC_CALFACT - bit fields */
 129#define STM32H7_CALFACT_D_SHIFT         16
 130#define STM32H7_CALFACT_D_MASK          GENMASK(26, 16)
 131#define STM32H7_CALFACT_S_SHIFT         0
 132#define STM32H7_CALFACT_S_MASK          GENMASK(10, 0)
 133
 134/* STM32H7_ADC_CALFACT2 - bit fields */
 135#define STM32H7_LINCALFACT_SHIFT        0
 136#define STM32H7_LINCALFACT_MASK         GENMASK(29, 0)
 137
 138/* Number of linear calibration shadow registers / LINCALRDYW control bits */
 139#define STM32H7_LINCALFACT_NUM          6
 140
 141/* BOOST bit must be set on STM32H7 when ADC clock is above 20MHz */
 142#define STM32H7_BOOST_CLKRATE           20000000UL
 143
 144#define STM32_ADC_CH_MAX                20      /* max number of channels */
 145#define STM32_ADC_CH_SZ                 10      /* max channel name size */
 146#define STM32_ADC_MAX_SQ                16      /* SQ1..SQ16 */
 147#define STM32_ADC_MAX_SMP               7       /* SMPx range is [0..7] */
 148#define STM32_ADC_TIMEOUT_US            100000
 149#define STM32_ADC_TIMEOUT       (msecs_to_jiffies(STM32_ADC_TIMEOUT_US / 1000))
 150
 151#define STM32_DMA_BUFFER_SIZE           PAGE_SIZE
 152
 153/* External trigger enable */
 154enum stm32_adc_exten {
 155        STM32_EXTEN_SWTRIG,
 156        STM32_EXTEN_HWTRIG_RISING_EDGE,
 157        STM32_EXTEN_HWTRIG_FALLING_EDGE,
 158        STM32_EXTEN_HWTRIG_BOTH_EDGES,
 159};
 160
 161/* extsel - trigger mux selection value */
 162enum stm32_adc_extsel {
 163        STM32_EXT0,
 164        STM32_EXT1,
 165        STM32_EXT2,
 166        STM32_EXT3,
 167        STM32_EXT4,
 168        STM32_EXT5,
 169        STM32_EXT6,
 170        STM32_EXT7,
 171        STM32_EXT8,
 172        STM32_EXT9,
 173        STM32_EXT10,
 174        STM32_EXT11,
 175        STM32_EXT12,
 176        STM32_EXT13,
 177        STM32_EXT14,
 178        STM32_EXT15,
 179        STM32_EXT16,
 180        STM32_EXT17,
 181        STM32_EXT18,
 182        STM32_EXT19,
 183        STM32_EXT20,
 184};
 185
 186/**
 187 * struct stm32_adc_trig_info - ADC trigger info
 188 * @name:               name of the trigger, corresponding to its source
 189 * @extsel:             trigger selection
 190 */
 191struct stm32_adc_trig_info {
 192        const char *name;
 193        enum stm32_adc_extsel extsel;
 194};
 195
 196/**
 197 * struct stm32_adc_calib - optional adc calibration data
 198 * @calfact_s: Calibration offset for single ended channels
 199 * @calfact_d: Calibration offset in differential
 200 * @lincalfact: Linearity calibration factor
 201 */
 202struct stm32_adc_calib {
 203        u32                     calfact_s;
 204        u32                     calfact_d;
 205        u32                     lincalfact[STM32H7_LINCALFACT_NUM];
 206};
 207
 208/**
 209 * stm32_adc_regs - stm32 ADC misc registers & bitfield desc
 210 * @reg:                register offset
 211 * @mask:               bitfield mask
 212 * @shift:              left shift
 213 */
 214struct stm32_adc_regs {
 215        int reg;
 216        int mask;
 217        int shift;
 218};
 219
 220/**
 221 * stm32_adc_regspec - stm32 registers definition, compatible dependent data
 222 * @dr:                 data register offset
 223 * @ier_eoc:            interrupt enable register & eocie bitfield
 224 * @isr_eoc:            interrupt status register & eoc bitfield
 225 * @sqr:                reference to sequence registers array
 226 * @exten:              trigger control register & bitfield
 227 * @extsel:             trigger selection register & bitfield
 228 * @res:                resolution selection register & bitfield
 229 * @smpr:               smpr1 & smpr2 registers offset array
 230 * @smp_bits:           smpr1 & smpr2 index and bitfields
 231 */
 232struct stm32_adc_regspec {
 233        const u32 dr;
 234        const struct stm32_adc_regs ier_eoc;
 235        const struct stm32_adc_regs isr_eoc;
 236        const struct stm32_adc_regs *sqr;
 237        const struct stm32_adc_regs exten;
 238        const struct stm32_adc_regs extsel;
 239        const struct stm32_adc_regs res;
 240        const u32 smpr[2];
 241        const struct stm32_adc_regs *smp_bits;
 242};
 243
 244struct stm32_adc;
 245
 246/**
 247 * stm32_adc_cfg - stm32 compatible configuration data
 248 * @regs:               registers descriptions
 249 * @adc_info:           per instance input channels definitions
 250 * @trigs:              external trigger sources
 251 * @clk_required:       clock is required
 252 * @selfcalib:          optional routine for self-calibration
 253 * @prepare:            optional prepare routine (power-up, enable)
 254 * @start_conv:         routine to start conversions
 255 * @stop_conv:          routine to stop conversions
 256 * @unprepare:          optional unprepare routine (disable, power-down)
 257 * @smp_cycles:         programmable sampling time (ADC clock cycles)
 258 */
 259struct stm32_adc_cfg {
 260        const struct stm32_adc_regspec  *regs;
 261        const struct stm32_adc_info     *adc_info;
 262        struct stm32_adc_trig_info      *trigs;
 263        bool clk_required;
 264        int (*selfcalib)(struct stm32_adc *);
 265        int (*prepare)(struct stm32_adc *);
 266        void (*start_conv)(struct stm32_adc *, bool dma);
 267        void (*stop_conv)(struct stm32_adc *);
 268        void (*unprepare)(struct stm32_adc *);
 269        const unsigned int *smp_cycles;
 270};
 271
 272/**
 273 * struct stm32_adc - private data of each ADC IIO instance
 274 * @common:             reference to ADC block common data
 275 * @offset:             ADC instance register offset in ADC block
 276 * @cfg:                compatible configuration data
 277 * @completion:         end of single conversion completion
 278 * @buffer:             data buffer
 279 * @clk:                clock for this adc instance
 280 * @irq:                interrupt for this adc instance
 281 * @lock:               spinlock
 282 * @bufi:               data buffer index
 283 * @num_conv:           expected number of scan conversions
 284 * @res:                data resolution (e.g. RES bitfield value)
 285 * @trigger_polarity:   external trigger polarity (e.g. exten)
 286 * @dma_chan:           dma channel
 287 * @rx_buf:             dma rx buffer cpu address
 288 * @rx_dma_buf:         dma rx buffer bus address
 289 * @rx_buf_sz:          dma rx buffer size
 290 * @difsel              bitmask to set single-ended/differential channel
 291 * @pcsel               bitmask to preselect channels on some devices
 292 * @smpr_val:           sampling time settings (e.g. smpr1 / smpr2)
 293 * @cal:                optional calibration data on some devices
 294 * @chan_name:          channel name array
 295 */
 296struct stm32_adc {
 297        struct stm32_adc_common *common;
 298        u32                     offset;
 299        const struct stm32_adc_cfg      *cfg;
 300        struct completion       completion;
 301        u16                     buffer[STM32_ADC_MAX_SQ];
 302        struct clk              *clk;
 303        int                     irq;
 304        spinlock_t              lock;           /* interrupt lock */
 305        unsigned int            bufi;
 306        unsigned int            num_conv;
 307        u32                     res;
 308        u32                     trigger_polarity;
 309        struct dma_chan         *dma_chan;
 310        u8                      *rx_buf;
 311        dma_addr_t              rx_dma_buf;
 312        unsigned int            rx_buf_sz;
 313        u32                     difsel;
 314        u32                     pcsel;
 315        u32                     smpr_val[2];
 316        struct stm32_adc_calib  cal;
 317        char                    chan_name[STM32_ADC_CH_MAX][STM32_ADC_CH_SZ];
 318};
 319
 320struct stm32_adc_diff_channel {
 321        u32 vinp;
 322        u32 vinn;
 323};
 324
 325/**
 326 * struct stm32_adc_info - stm32 ADC, per instance config data
 327 * @max_channels:       Number of channels
 328 * @resolutions:        available resolutions
 329 * @num_res:            number of available resolutions
 330 */
 331struct stm32_adc_info {
 332        int max_channels;
 333        const unsigned int *resolutions;
 334        const unsigned int num_res;
 335};
 336
 337static const unsigned int stm32f4_adc_resolutions[] = {
 338        /* sorted values so the index matches RES[1:0] in STM32F4_ADC_CR1 */
 339        12, 10, 8, 6,
 340};
 341
 342/* stm32f4 can have up to 16 channels */
 343static const struct stm32_adc_info stm32f4_adc_info = {
 344        .max_channels = 16,
 345        .resolutions = stm32f4_adc_resolutions,
 346        .num_res = ARRAY_SIZE(stm32f4_adc_resolutions),
 347};
 348
 349static const unsigned int stm32h7_adc_resolutions[] = {
 350        /* sorted values so the index matches RES[2:0] in STM32H7_ADC_CFGR */
 351        16, 14, 12, 10, 8,
 352};
 353
 354/* stm32h7 can have up to 20 channels */
 355static const struct stm32_adc_info stm32h7_adc_info = {
 356        .max_channels = STM32_ADC_CH_MAX,
 357        .resolutions = stm32h7_adc_resolutions,
 358        .num_res = ARRAY_SIZE(stm32h7_adc_resolutions),
 359};
 360
 361/**
 362 * stm32f4_sq - describe regular sequence registers
 363 * - L: sequence len (register & bit field)
 364 * - SQ1..SQ16: sequence entries (register & bit field)
 365 */
 366static const struct stm32_adc_regs stm32f4_sq[STM32_ADC_MAX_SQ + 1] = {
 367        /* L: len bit field description to be kept as first element */
 368        { STM32F4_ADC_SQR1, GENMASK(23, 20), 20 },
 369        /* SQ1..SQ16 registers & bit fields (reg, mask, shift) */
 370        { STM32F4_ADC_SQR3, GENMASK(4, 0), 0 },
 371        { STM32F4_ADC_SQR3, GENMASK(9, 5), 5 },
 372        { STM32F4_ADC_SQR3, GENMASK(14, 10), 10 },
 373        { STM32F4_ADC_SQR3, GENMASK(19, 15), 15 },
 374        { STM32F4_ADC_SQR3, GENMASK(24, 20), 20 },
 375        { STM32F4_ADC_SQR3, GENMASK(29, 25), 25 },
 376        { STM32F4_ADC_SQR2, GENMASK(4, 0), 0 },
 377        { STM32F4_ADC_SQR2, GENMASK(9, 5), 5 },
 378        { STM32F4_ADC_SQR2, GENMASK(14, 10), 10 },
 379        { STM32F4_ADC_SQR2, GENMASK(19, 15), 15 },
 380        { STM32F4_ADC_SQR2, GENMASK(24, 20), 20 },
 381        { STM32F4_ADC_SQR2, GENMASK(29, 25), 25 },
 382        { STM32F4_ADC_SQR1, GENMASK(4, 0), 0 },
 383        { STM32F4_ADC_SQR1, GENMASK(9, 5), 5 },
 384        { STM32F4_ADC_SQR1, GENMASK(14, 10), 10 },
 385        { STM32F4_ADC_SQR1, GENMASK(19, 15), 15 },
 386};
 387
 388/* STM32F4 external trigger sources for all instances */
 389static struct stm32_adc_trig_info stm32f4_adc_trigs[] = {
 390        { TIM1_CH1, STM32_EXT0 },
 391        { TIM1_CH2, STM32_EXT1 },
 392        { TIM1_CH3, STM32_EXT2 },
 393        { TIM2_CH2, STM32_EXT3 },
 394        { TIM2_CH3, STM32_EXT4 },
 395        { TIM2_CH4, STM32_EXT5 },
 396        { TIM2_TRGO, STM32_EXT6 },
 397        { TIM3_CH1, STM32_EXT7 },
 398        { TIM3_TRGO, STM32_EXT8 },
 399        { TIM4_CH4, STM32_EXT9 },
 400        { TIM5_CH1, STM32_EXT10 },
 401        { TIM5_CH2, STM32_EXT11 },
 402        { TIM5_CH3, STM32_EXT12 },
 403        { TIM8_CH1, STM32_EXT13 },
 404        { TIM8_TRGO, STM32_EXT14 },
 405        {}, /* sentinel */
 406};
 407
 408/**
 409 * stm32f4_smp_bits[] - describe sampling time register index & bit fields
 410 * Sorted so it can be indexed by channel number.
 411 */
 412static const struct stm32_adc_regs stm32f4_smp_bits[] = {
 413        /* STM32F4_ADC_SMPR2: smpr[] index, mask, shift for SMP0 to SMP9 */
 414        { 1, GENMASK(2, 0), 0 },
 415        { 1, GENMASK(5, 3), 3 },
 416        { 1, GENMASK(8, 6), 6 },
 417        { 1, GENMASK(11, 9), 9 },
 418        { 1, GENMASK(14, 12), 12 },
 419        { 1, GENMASK(17, 15), 15 },
 420        { 1, GENMASK(20, 18), 18 },
 421        { 1, GENMASK(23, 21), 21 },
 422        { 1, GENMASK(26, 24), 24 },
 423        { 1, GENMASK(29, 27), 27 },
 424        /* STM32F4_ADC_SMPR1, smpr[] index, mask, shift for SMP10 to SMP18 */
 425        { 0, GENMASK(2, 0), 0 },
 426        { 0, GENMASK(5, 3), 3 },
 427        { 0, GENMASK(8, 6), 6 },
 428        { 0, GENMASK(11, 9), 9 },
 429        { 0, GENMASK(14, 12), 12 },
 430        { 0, GENMASK(17, 15), 15 },
 431        { 0, GENMASK(20, 18), 18 },
 432        { 0, GENMASK(23, 21), 21 },
 433        { 0, GENMASK(26, 24), 24 },
 434};
 435
 436/* STM32F4 programmable sampling time (ADC clock cycles) */
 437static const unsigned int stm32f4_adc_smp_cycles[STM32_ADC_MAX_SMP + 1] = {
 438        3, 15, 28, 56, 84, 112, 144, 480,
 439};
 440
 441static const struct stm32_adc_regspec stm32f4_adc_regspec = {
 442        .dr = STM32F4_ADC_DR,
 443        .ier_eoc = { STM32F4_ADC_CR1, STM32F4_EOCIE },
 444        .isr_eoc = { STM32F4_ADC_SR, STM32F4_EOC },
 445        .sqr = stm32f4_sq,
 446        .exten = { STM32F4_ADC_CR2, STM32F4_EXTEN_MASK, STM32F4_EXTEN_SHIFT },
 447        .extsel = { STM32F4_ADC_CR2, STM32F4_EXTSEL_MASK,
 448                    STM32F4_EXTSEL_SHIFT },
 449        .res = { STM32F4_ADC_CR1, STM32F4_RES_MASK, STM32F4_RES_SHIFT },
 450        .smpr = { STM32F4_ADC_SMPR1, STM32F4_ADC_SMPR2 },
 451        .smp_bits = stm32f4_smp_bits,
 452};
 453
 454static const struct stm32_adc_regs stm32h7_sq[STM32_ADC_MAX_SQ + 1] = {
 455        /* L: len bit field description to be kept as first element */
 456        { STM32H7_ADC_SQR1, GENMASK(3, 0), 0 },
 457        /* SQ1..SQ16 registers & bit fields (reg, mask, shift) */
 458        { STM32H7_ADC_SQR1, GENMASK(10, 6), 6 },
 459        { STM32H7_ADC_SQR1, GENMASK(16, 12), 12 },
 460        { STM32H7_ADC_SQR1, GENMASK(22, 18), 18 },
 461        { STM32H7_ADC_SQR1, GENMASK(28, 24), 24 },
 462        { STM32H7_ADC_SQR2, GENMASK(4, 0), 0 },
 463        { STM32H7_ADC_SQR2, GENMASK(10, 6), 6 },
 464        { STM32H7_ADC_SQR2, GENMASK(16, 12), 12 },
 465        { STM32H7_ADC_SQR2, GENMASK(22, 18), 18 },
 466        { STM32H7_ADC_SQR2, GENMASK(28, 24), 24 },
 467        { STM32H7_ADC_SQR3, GENMASK(4, 0), 0 },
 468        { STM32H7_ADC_SQR3, GENMASK(10, 6), 6 },
 469        { STM32H7_ADC_SQR3, GENMASK(16, 12), 12 },
 470        { STM32H7_ADC_SQR3, GENMASK(22, 18), 18 },
 471        { STM32H7_ADC_SQR3, GENMASK(28, 24), 24 },
 472        { STM32H7_ADC_SQR4, GENMASK(4, 0), 0 },
 473        { STM32H7_ADC_SQR4, GENMASK(10, 6), 6 },
 474};
 475
 476/* STM32H7 external trigger sources for all instances */
 477static struct stm32_adc_trig_info stm32h7_adc_trigs[] = {
 478        { TIM1_CH1, STM32_EXT0 },
 479        { TIM1_CH2, STM32_EXT1 },
 480        { TIM1_CH3, STM32_EXT2 },
 481        { TIM2_CH2, STM32_EXT3 },
 482        { TIM3_TRGO, STM32_EXT4 },
 483        { TIM4_CH4, STM32_EXT5 },
 484        { TIM8_TRGO, STM32_EXT7 },
 485        { TIM8_TRGO2, STM32_EXT8 },
 486        { TIM1_TRGO, STM32_EXT9 },
 487        { TIM1_TRGO2, STM32_EXT10 },
 488        { TIM2_TRGO, STM32_EXT11 },
 489        { TIM4_TRGO, STM32_EXT12 },
 490        { TIM6_TRGO, STM32_EXT13 },
 491        { TIM15_TRGO, STM32_EXT14 },
 492        { TIM3_CH4, STM32_EXT15 },
 493        { LPTIM1_OUT, STM32_EXT18 },
 494        { LPTIM2_OUT, STM32_EXT19 },
 495        { LPTIM3_OUT, STM32_EXT20 },
 496        {},
 497};
 498
 499/**
 500 * stm32h7_smp_bits - describe sampling time register index & bit fields
 501 * Sorted so it can be indexed by channel number.
 502 */
 503static const struct stm32_adc_regs stm32h7_smp_bits[] = {
 504        /* STM32H7_ADC_SMPR1, smpr[] index, mask, shift for SMP0 to SMP9 */
 505        { 0, GENMASK(2, 0), 0 },
 506        { 0, GENMASK(5, 3), 3 },
 507        { 0, GENMASK(8, 6), 6 },
 508        { 0, GENMASK(11, 9), 9 },
 509        { 0, GENMASK(14, 12), 12 },
 510        { 0, GENMASK(17, 15), 15 },
 511        { 0, GENMASK(20, 18), 18 },
 512        { 0, GENMASK(23, 21), 21 },
 513        { 0, GENMASK(26, 24), 24 },
 514        { 0, GENMASK(29, 27), 27 },
 515        /* STM32H7_ADC_SMPR2, smpr[] index, mask, shift for SMP10 to SMP19 */
 516        { 1, GENMASK(2, 0), 0 },
 517        { 1, GENMASK(5, 3), 3 },
 518        { 1, GENMASK(8, 6), 6 },
 519        { 1, GENMASK(11, 9), 9 },
 520        { 1, GENMASK(14, 12), 12 },
 521        { 1, GENMASK(17, 15), 15 },
 522        { 1, GENMASK(20, 18), 18 },
 523        { 1, GENMASK(23, 21), 21 },
 524        { 1, GENMASK(26, 24), 24 },
 525        { 1, GENMASK(29, 27), 27 },
 526};
 527
 528/* STM32H7 programmable sampling time (ADC clock cycles, rounded down) */
 529static const unsigned int stm32h7_adc_smp_cycles[STM32_ADC_MAX_SMP + 1] = {
 530        1, 2, 8, 16, 32, 64, 387, 810,
 531};
 532
 533static const struct stm32_adc_regspec stm32h7_adc_regspec = {
 534        .dr = STM32H7_ADC_DR,
 535        .ier_eoc = { STM32H7_ADC_IER, STM32H7_EOCIE },
 536        .isr_eoc = { STM32H7_ADC_ISR, STM32H7_EOC },
 537        .sqr = stm32h7_sq,
 538        .exten = { STM32H7_ADC_CFGR, STM32H7_EXTEN_MASK, STM32H7_EXTEN_SHIFT },
 539        .extsel = { STM32H7_ADC_CFGR, STM32H7_EXTSEL_MASK,
 540                    STM32H7_EXTSEL_SHIFT },
 541        .res = { STM32H7_ADC_CFGR, STM32H7_RES_MASK, STM32H7_RES_SHIFT },
 542        .smpr = { STM32H7_ADC_SMPR1, STM32H7_ADC_SMPR2 },
 543        .smp_bits = stm32h7_smp_bits,
 544};
 545
 546/**
 547 * STM32 ADC registers access routines
 548 * @adc: stm32 adc instance
 549 * @reg: reg offset in adc instance
 550 *
 551 * Note: All instances share same base, with 0x0, 0x100 or 0x200 offset resp.
 552 * for adc1, adc2 and adc3.
 553 */
 554static u32 stm32_adc_readl(struct stm32_adc *adc, u32 reg)
 555{
 556        return readl_relaxed(adc->common->base + adc->offset + reg);
 557}
 558
 559#define stm32_adc_readl_addr(addr)      stm32_adc_readl(adc, addr)
 560
 561#define stm32_adc_readl_poll_timeout(reg, val, cond, sleep_us, timeout_us) \
 562        readx_poll_timeout(stm32_adc_readl_addr, reg, val, \
 563                           cond, sleep_us, timeout_us)
 564
 565static u16 stm32_adc_readw(struct stm32_adc *adc, u32 reg)
 566{
 567        return readw_relaxed(adc->common->base + adc->offset + reg);
 568}
 569
 570static void stm32_adc_writel(struct stm32_adc *adc, u32 reg, u32 val)
 571{
 572        writel_relaxed(val, adc->common->base + adc->offset + reg);
 573}
 574
 575static void stm32_adc_set_bits(struct stm32_adc *adc, u32 reg, u32 bits)
 576{
 577        unsigned long flags;
 578
 579        spin_lock_irqsave(&adc->lock, flags);
 580        stm32_adc_writel(adc, reg, stm32_adc_readl(adc, reg) | bits);
 581        spin_unlock_irqrestore(&adc->lock, flags);
 582}
 583
 584static void stm32_adc_clr_bits(struct stm32_adc *adc, u32 reg, u32 bits)
 585{
 586        unsigned long flags;
 587
 588        spin_lock_irqsave(&adc->lock, flags);
 589        stm32_adc_writel(adc, reg, stm32_adc_readl(adc, reg) & ~bits);
 590        spin_unlock_irqrestore(&adc->lock, flags);
 591}
 592
 593/**
 594 * stm32_adc_conv_irq_enable() - Enable end of conversion interrupt
 595 * @adc: stm32 adc instance
 596 */
 597static void stm32_adc_conv_irq_enable(struct stm32_adc *adc)
 598{
 599        stm32_adc_set_bits(adc, adc->cfg->regs->ier_eoc.reg,
 600                           adc->cfg->regs->ier_eoc.mask);
 601};
 602
 603/**
 604 * stm32_adc_conv_irq_disable() - Disable end of conversion interrupt
 605 * @adc: stm32 adc instance
 606 */
 607static void stm32_adc_conv_irq_disable(struct stm32_adc *adc)
 608{
 609        stm32_adc_clr_bits(adc, adc->cfg->regs->ier_eoc.reg,
 610                           adc->cfg->regs->ier_eoc.mask);
 611}
 612
 613static void stm32_adc_set_res(struct stm32_adc *adc)
 614{
 615        const struct stm32_adc_regs *res = &adc->cfg->regs->res;
 616        u32 val;
 617
 618        val = stm32_adc_readl(adc, res->reg);
 619        val = (val & ~res->mask) | (adc->res << res->shift);
 620        stm32_adc_writel(adc, res->reg, val);
 621}
 622
 623/**
 624 * stm32f4_adc_start_conv() - Start conversions for regular channels.
 625 * @adc: stm32 adc instance
 626 * @dma: use dma to transfer conversion result
 627 *
 628 * Start conversions for regular channels.
 629 * Also take care of normal or DMA mode. Circular DMA may be used for regular
 630 * conversions, in IIO buffer modes. Otherwise, use ADC interrupt with direct
 631 * DR read instead (e.g. read_raw, or triggered buffer mode without DMA).
 632 */
 633static void stm32f4_adc_start_conv(struct stm32_adc *adc, bool dma)
 634{
 635        stm32_adc_set_bits(adc, STM32F4_ADC_CR1, STM32F4_SCAN);
 636
 637        if (dma)
 638                stm32_adc_set_bits(adc, STM32F4_ADC_CR2,
 639                                   STM32F4_DMA | STM32F4_DDS);
 640
 641        stm32_adc_set_bits(adc, STM32F4_ADC_CR2, STM32F4_EOCS | STM32F4_ADON);
 642
 643        /* Wait for Power-up time (tSTAB from datasheet) */
 644        usleep_range(2, 3);
 645
 646        /* Software start ? (e.g. trigger detection disabled ?) */
 647        if (!(stm32_adc_readl(adc, STM32F4_ADC_CR2) & STM32F4_EXTEN_MASK))
 648                stm32_adc_set_bits(adc, STM32F4_ADC_CR2, STM32F4_SWSTART);
 649}
 650
 651static void stm32f4_adc_stop_conv(struct stm32_adc *adc)
 652{
 653        stm32_adc_clr_bits(adc, STM32F4_ADC_CR2, STM32F4_EXTEN_MASK);
 654        stm32_adc_clr_bits(adc, STM32F4_ADC_SR, STM32F4_STRT);
 655
 656        stm32_adc_clr_bits(adc, STM32F4_ADC_CR1, STM32F4_SCAN);
 657        stm32_adc_clr_bits(adc, STM32F4_ADC_CR2,
 658                           STM32F4_ADON | STM32F4_DMA | STM32F4_DDS);
 659}
 660
 661static void stm32h7_adc_start_conv(struct stm32_adc *adc, bool dma)
 662{
 663        enum stm32h7_adc_dmngt dmngt;
 664        unsigned long flags;
 665        u32 val;
 666
 667        if (dma)
 668                dmngt = STM32H7_DMNGT_DMA_CIRC;
 669        else
 670                dmngt = STM32H7_DMNGT_DR_ONLY;
 671
 672        spin_lock_irqsave(&adc->lock, flags);
 673        val = stm32_adc_readl(adc, STM32H7_ADC_CFGR);
 674        val = (val & ~STM32H7_DMNGT_MASK) | (dmngt << STM32H7_DMNGT_SHIFT);
 675        stm32_adc_writel(adc, STM32H7_ADC_CFGR, val);
 676        spin_unlock_irqrestore(&adc->lock, flags);
 677
 678        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADSTART);
 679}
 680
 681static void stm32h7_adc_stop_conv(struct stm32_adc *adc)
 682{
 683        struct iio_dev *indio_dev = iio_priv_to_dev(adc);
 684        int ret;
 685        u32 val;
 686
 687        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADSTP);
 688
 689        ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
 690                                           !(val & (STM32H7_ADSTART)),
 691                                           100, STM32_ADC_TIMEOUT_US);
 692        if (ret)
 693                dev_warn(&indio_dev->dev, "stop failed\n");
 694
 695        stm32_adc_clr_bits(adc, STM32H7_ADC_CFGR, STM32H7_DMNGT_MASK);
 696}
 697
 698static void stm32h7_adc_exit_pwr_down(struct stm32_adc *adc)
 699{
 700        /* Exit deep power down, then enable ADC voltage regulator */
 701        stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD);
 702        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADVREGEN);
 703
 704        if (adc->common->rate > STM32H7_BOOST_CLKRATE)
 705                stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_BOOST);
 706
 707        /* Wait for startup time */
 708        usleep_range(10, 20);
 709}
 710
 711static void stm32h7_adc_enter_pwr_down(struct stm32_adc *adc)
 712{
 713        stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_BOOST);
 714
 715        /* Setting DEEPPWD disables ADC vreg and clears ADVREGEN */
 716        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD);
 717}
 718
 719static int stm32h7_adc_enable(struct stm32_adc *adc)
 720{
 721        struct iio_dev *indio_dev = iio_priv_to_dev(adc);
 722        int ret;
 723        u32 val;
 724
 725        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADEN);
 726
 727        /* Poll for ADRDY to be set (after adc startup time) */
 728        ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_ISR, val,
 729                                           val & STM32H7_ADRDY,
 730                                           100, STM32_ADC_TIMEOUT_US);
 731        if (ret) {
 732                stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS);
 733                dev_err(&indio_dev->dev, "Failed to enable ADC\n");
 734        } else {
 735                /* Clear ADRDY by writing one */
 736                stm32_adc_set_bits(adc, STM32H7_ADC_ISR, STM32H7_ADRDY);
 737        }
 738
 739        return ret;
 740}
 741
 742static void stm32h7_adc_disable(struct stm32_adc *adc)
 743{
 744        struct iio_dev *indio_dev = iio_priv_to_dev(adc);
 745        int ret;
 746        u32 val;
 747
 748        /* Disable ADC and wait until it's effectively disabled */
 749        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS);
 750        ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
 751                                           !(val & STM32H7_ADEN), 100,
 752                                           STM32_ADC_TIMEOUT_US);
 753        if (ret)
 754                dev_warn(&indio_dev->dev, "Failed to disable\n");
 755}
 756
 757/**
 758 * stm32h7_adc_read_selfcalib() - read calibration shadow regs, save result
 759 * @adc: stm32 adc instance
 760 */
 761static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc)
 762{
 763        struct iio_dev *indio_dev = iio_priv_to_dev(adc);
 764        int i, ret;
 765        u32 lincalrdyw_mask, val;
 766
 767        /* Enable adc so LINCALRDYW1..6 bits are writable */
 768        ret = stm32h7_adc_enable(adc);
 769        if (ret)
 770                return ret;
 771
 772        /* Read linearity calibration */
 773        lincalrdyw_mask = STM32H7_LINCALRDYW6;
 774        for (i = STM32H7_LINCALFACT_NUM - 1; i >= 0; i--) {
 775                /* Clear STM32H7_LINCALRDYW[6..1]: transfer calib to CALFACT2 */
 776                stm32_adc_clr_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask);
 777
 778                /* Poll: wait calib data to be ready in CALFACT2 register */
 779                ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
 780                                                   !(val & lincalrdyw_mask),
 781                                                   100, STM32_ADC_TIMEOUT_US);
 782                if (ret) {
 783                        dev_err(&indio_dev->dev, "Failed to read calfact\n");
 784                        goto disable;
 785                }
 786
 787                val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT2);
 788                adc->cal.lincalfact[i] = (val & STM32H7_LINCALFACT_MASK);
 789                adc->cal.lincalfact[i] >>= STM32H7_LINCALFACT_SHIFT;
 790
 791                lincalrdyw_mask >>= 1;
 792        }
 793
 794        /* Read offset calibration */
 795        val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT);
 796        adc->cal.calfact_s = (val & STM32H7_CALFACT_S_MASK);
 797        adc->cal.calfact_s >>= STM32H7_CALFACT_S_SHIFT;
 798        adc->cal.calfact_d = (val & STM32H7_CALFACT_D_MASK);
 799        adc->cal.calfact_d >>= STM32H7_CALFACT_D_SHIFT;
 800
 801disable:
 802        stm32h7_adc_disable(adc);
 803
 804        return ret;
 805}
 806
 807/**
 808 * stm32h7_adc_restore_selfcalib() - Restore saved self-calibration result
 809 * @adc: stm32 adc instance
 810 * Note: ADC must be enabled, with no on-going conversions.
 811 */
 812static int stm32h7_adc_restore_selfcalib(struct stm32_adc *adc)
 813{
 814        struct iio_dev *indio_dev = iio_priv_to_dev(adc);
 815        int i, ret;
 816        u32 lincalrdyw_mask, val;
 817
 818        val = (adc->cal.calfact_s << STM32H7_CALFACT_S_SHIFT) |
 819                (adc->cal.calfact_d << STM32H7_CALFACT_D_SHIFT);
 820        stm32_adc_writel(adc, STM32H7_ADC_CALFACT, val);
 821
 822        lincalrdyw_mask = STM32H7_LINCALRDYW6;
 823        for (i = STM32H7_LINCALFACT_NUM - 1; i >= 0; i--) {
 824                /*
 825                 * Write saved calibration data to shadow registers:
 826                 * Write CALFACT2, and set LINCALRDYW[6..1] bit to trigger
 827                 * data write. Then poll to wait for complete transfer.
 828                 */
 829                val = adc->cal.lincalfact[i] << STM32H7_LINCALFACT_SHIFT;
 830                stm32_adc_writel(adc, STM32H7_ADC_CALFACT2, val);
 831                stm32_adc_set_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask);
 832                ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
 833                                                   val & lincalrdyw_mask,
 834                                                   100, STM32_ADC_TIMEOUT_US);
 835                if (ret) {
 836                        dev_err(&indio_dev->dev, "Failed to write calfact\n");
 837                        return ret;
 838                }
 839
 840                /*
 841                 * Read back calibration data, has two effects:
 842                 * - It ensures bits LINCALRDYW[6..1] are kept cleared
 843                 *   for next time calibration needs to be restored.
 844                 * - BTW, bit clear triggers a read, then check data has been
 845                 *   correctly written.
 846                 */
 847                stm32_adc_clr_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask);
 848                ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
 849                                                   !(val & lincalrdyw_mask),
 850                                                   100, STM32_ADC_TIMEOUT_US);
 851                if (ret) {
 852                        dev_err(&indio_dev->dev, "Failed to read calfact\n");
 853                        return ret;
 854                }
 855                val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT2);
 856                if (val != adc->cal.lincalfact[i] << STM32H7_LINCALFACT_SHIFT) {
 857                        dev_err(&indio_dev->dev, "calfact not consistent\n");
 858                        return -EIO;
 859                }
 860
 861                lincalrdyw_mask >>= 1;
 862        }
 863
 864        return 0;
 865}
 866
 867/**
 868 * Fixed timeout value for ADC calibration.
 869 * worst cases:
 870 * - low clock frequency
 871 * - maximum prescalers
 872 * Calibration requires:
 873 * - 131,072 ADC clock cycle for the linear calibration
 874 * - 20 ADC clock cycle for the offset calibration
 875 *
 876 * Set to 100ms for now
 877 */
 878#define STM32H7_ADC_CALIB_TIMEOUT_US            100000
 879
 880/**
 881 * stm32h7_adc_selfcalib() - Procedure to calibrate ADC (from power down)
 882 * @adc: stm32 adc instance
 883 * Exit from power down, calibrate ADC, then return to power down.
 884 */
 885static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
 886{
 887        struct iio_dev *indio_dev = iio_priv_to_dev(adc);
 888        int ret;
 889        u32 val;
 890
 891        stm32h7_adc_exit_pwr_down(adc);
 892
 893        /*
 894         * Select calibration mode:
 895         * - Offset calibration for single ended inputs
 896         * - No linearity calibration (do it later, before reading it)
 897         */
 898        stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_ADCALDIF);
 899        stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_ADCALLIN);
 900
 901        /* Start calibration, then wait for completion */
 902        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADCAL);
 903        ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
 904                                           !(val & STM32H7_ADCAL), 100,
 905                                           STM32H7_ADC_CALIB_TIMEOUT_US);
 906        if (ret) {
 907                dev_err(&indio_dev->dev, "calibration failed\n");
 908                goto pwr_dwn;
 909        }
 910
 911        /*
 912         * Select calibration mode, then start calibration:
 913         * - Offset calibration for differential input
 914         * - Linearity calibration (needs to be done only once for single/diff)
 915         *   will run simultaneously with offset calibration.
 916         */
 917        stm32_adc_set_bits(adc, STM32H7_ADC_CR,
 918                           STM32H7_ADCALDIF | STM32H7_ADCALLIN);
 919        stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADCAL);
 920        ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
 921                                           !(val & STM32H7_ADCAL), 100,
 922                                           STM32H7_ADC_CALIB_TIMEOUT_US);
 923        if (ret) {
 924                dev_err(&indio_dev->dev, "calibration failed\n");
 925                goto pwr_dwn;
 926        }
 927
 928        stm32_adc_clr_bits(adc, STM32H7_ADC_CR,
 929                           STM32H7_ADCALDIF | STM32H7_ADCALLIN);
 930
 931        /* Read calibration result for future reference */
 932        ret = stm32h7_adc_read_selfcalib(adc);
 933
 934pwr_dwn:
 935        stm32h7_adc_enter_pwr_down(adc);
 936
 937        return ret;
 938}
 939
 940/**
 941 * stm32h7_adc_prepare() - Leave power down mode to enable ADC.
 942 * @adc: stm32 adc instance
 943 * Leave power down mode.
 944 * Configure channels as single ended or differential before enabling ADC.
 945 * Enable ADC.
 946 * Restore calibration data.
 947 * Pre-select channels that may be used in PCSEL (required by input MUX / IO):
 948 * - Only one input is selected for single ended (e.g. 'vinp')
 949 * - Two inputs are selected for differential channels (e.g. 'vinp' & 'vinn')
 950 */
 951static int stm32h7_adc_prepare(struct stm32_adc *adc)
 952{
 953        int ret;
 954
 955        stm32h7_adc_exit_pwr_down(adc);
 956        stm32_adc_writel(adc, STM32H7_ADC_DIFSEL, adc->difsel);
 957
 958        ret = stm32h7_adc_enable(adc);
 959        if (ret)
 960                goto pwr_dwn;
 961
 962        ret = stm32h7_adc_restore_selfcalib(adc);
 963        if (ret)
 964                goto disable;
 965
 966        stm32_adc_writel(adc, STM32H7_ADC_PCSEL, adc->pcsel);
 967
 968        return 0;
 969
 970disable:
 971        stm32h7_adc_disable(adc);
 972pwr_dwn:
 973        stm32h7_adc_enter_pwr_down(adc);
 974
 975        return ret;
 976}
 977
 978static void stm32h7_adc_unprepare(struct stm32_adc *adc)
 979{
 980        stm32h7_adc_disable(adc);
 981        stm32h7_adc_enter_pwr_down(adc);
 982}
 983
 984/**
 985 * stm32_adc_conf_scan_seq() - Build regular channels scan sequence
 986 * @indio_dev: IIO device
 987 * @scan_mask: channels to be converted
 988 *
 989 * Conversion sequence :
 990 * Apply sampling time settings for all channels.
 991 * Configure ADC scan sequence based on selected channels in scan_mask.
 992 * Add channels to SQR registers, from scan_mask LSB to MSB, then
 993 * program sequence len.
 994 */
 995static int stm32_adc_conf_scan_seq(struct iio_dev *indio_dev,
 996                                   const unsigned long *scan_mask)
 997{
 998        struct stm32_adc *adc = iio_priv(indio_dev);
 999        const struct stm32_adc_regs *sqr = adc->cfg->regs->sqr;
1000        const struct iio_chan_spec *chan;
1001        u32 val, bit;
1002        int i = 0;
1003
1004        /* Apply sampling time settings */
1005        stm32_adc_writel(adc, adc->cfg->regs->smpr[0], adc->smpr_val[0]);
1006        stm32_adc_writel(adc, adc->cfg->regs->smpr[1], adc->smpr_val[1]);
1007
1008        for_each_set_bit(bit, scan_mask, indio_dev->masklength) {
1009                chan = indio_dev->channels + bit;
1010                /*
1011                 * Assign one channel per SQ entry in regular
1012                 * sequence, starting with SQ1.
1013                 */
1014                i++;
1015                if (i > STM32_ADC_MAX_SQ)
1016                        return -EINVAL;
1017
1018                dev_dbg(&indio_dev->dev, "%s chan %d to SQ%d\n",
1019                        __func__, chan->channel, i);
1020
1021                val = stm32_adc_readl(adc, sqr[i].reg);
1022                val &= ~sqr[i].mask;
1023                val |= chan->channel << sqr[i].shift;
1024                stm32_adc_writel(adc, sqr[i].reg, val);
1025        }
1026
1027        if (!i)
1028                return -EINVAL;
1029
1030        /* Sequence len */
1031        val = stm32_adc_readl(adc, sqr[0].reg);
1032        val &= ~sqr[0].mask;
1033        val |= ((i - 1) << sqr[0].shift);
1034        stm32_adc_writel(adc, sqr[0].reg, val);
1035
1036        return 0;
1037}
1038
1039/**
1040 * stm32_adc_get_trig_extsel() - Get external trigger selection
1041 * @trig: trigger
1042 *
1043 * Returns trigger extsel value, if trig matches, -EINVAL otherwise.
1044 */
1045static int stm32_adc_get_trig_extsel(struct iio_dev *indio_dev,
1046                                     struct iio_trigger *trig)
1047{
1048        struct stm32_adc *adc = iio_priv(indio_dev);
1049        int i;
1050
1051        /* lookup triggers registered by stm32 timer trigger driver */
1052        for (i = 0; adc->cfg->trigs[i].name; i++) {
1053                /**
1054                 * Checking both stm32 timer trigger type and trig name
1055                 * should be safe against arbitrary trigger names.
1056                 */
1057                if ((is_stm32_timer_trigger(trig) ||
1058                     is_stm32_lptim_trigger(trig)) &&
1059                    !strcmp(adc->cfg->trigs[i].name, trig->name)) {
1060                        return adc->cfg->trigs[i].extsel;
1061                }
1062        }
1063
1064        return -EINVAL;
1065}
1066
1067/**
1068 * stm32_adc_set_trig() - Set a regular trigger
1069 * @indio_dev: IIO device
1070 * @trig: IIO trigger
1071 *
1072 * Set trigger source/polarity (e.g. SW, or HW with polarity) :
1073 * - if HW trigger disabled (e.g. trig == NULL, conversion launched by sw)
1074 * - if HW trigger enabled, set source & polarity
1075 */
1076static int stm32_adc_set_trig(struct iio_dev *indio_dev,
1077                              struct iio_trigger *trig)
1078{
1079        struct stm32_adc *adc = iio_priv(indio_dev);
1080        u32 val, extsel = 0, exten = STM32_EXTEN_SWTRIG;
1081        unsigned long flags;
1082        int ret;
1083
1084        if (trig) {
1085                ret = stm32_adc_get_trig_extsel(indio_dev, trig);
1086                if (ret < 0)
1087                        return ret;
1088
1089                /* set trigger source and polarity (default to rising edge) */
1090                extsel = ret;
1091                exten = adc->trigger_polarity + STM32_EXTEN_HWTRIG_RISING_EDGE;
1092        }
1093
1094        spin_lock_irqsave(&adc->lock, flags);
1095        val = stm32_adc_readl(adc, adc->cfg->regs->exten.reg);
1096        val &= ~(adc->cfg->regs->exten.mask | adc->cfg->regs->extsel.mask);
1097        val |= exten << adc->cfg->regs->exten.shift;
1098        val |= extsel << adc->cfg->regs->extsel.shift;
1099        stm32_adc_writel(adc,  adc->cfg->regs->exten.reg, val);
1100        spin_unlock_irqrestore(&adc->lock, flags);
1101
1102        return 0;
1103}
1104
1105static int stm32_adc_set_trig_pol(struct iio_dev *indio_dev,
1106                                  const struct iio_chan_spec *chan,
1107                                  unsigned int type)
1108{
1109        struct stm32_adc *adc = iio_priv(indio_dev);
1110
1111        adc->trigger_polarity = type;
1112
1113        return 0;
1114}
1115
1116static int stm32_adc_get_trig_pol(struct iio_dev *indio_dev,
1117                                  const struct iio_chan_spec *chan)
1118{
1119        struct stm32_adc *adc = iio_priv(indio_dev);
1120
1121        return adc->trigger_polarity;
1122}
1123
1124static const char * const stm32_trig_pol_items[] = {
1125        "rising-edge", "falling-edge", "both-edges",
1126};
1127
1128static const struct iio_enum stm32_adc_trig_pol = {
1129        .items = stm32_trig_pol_items,
1130        .num_items = ARRAY_SIZE(stm32_trig_pol_items),
1131        .get = stm32_adc_get_trig_pol,
1132        .set = stm32_adc_set_trig_pol,
1133};
1134
1135/**
1136 * stm32_adc_single_conv() - Performs a single conversion
1137 * @indio_dev: IIO device
1138 * @chan: IIO channel
1139 * @res: conversion result
1140 *
1141 * The function performs a single conversion on a given channel:
1142 * - Apply sampling time settings
1143 * - Program sequencer with one channel (e.g. in SQ1 with len = 1)
1144 * - Use SW trigger
1145 * - Start conversion, then wait for interrupt completion.
1146 */
1147static int stm32_adc_single_conv(struct iio_dev *indio_dev,
1148                                 const struct iio_chan_spec *chan,
1149                                 int *res)
1150{
1151        struct stm32_adc *adc = iio_priv(indio_dev);
1152        const struct stm32_adc_regspec *regs = adc->cfg->regs;
1153        long timeout;
1154        u32 val;
1155        int ret;
1156
1157        reinit_completion(&adc->completion);
1158
1159        adc->bufi = 0;
1160
1161        if (adc->cfg->prepare) {
1162                ret = adc->cfg->prepare(adc);
1163                if (ret)
1164                        return ret;
1165        }
1166
1167        /* Apply sampling time settings */
1168        stm32_adc_writel(adc, regs->smpr[0], adc->smpr_val[0]);
1169        stm32_adc_writel(adc, regs->smpr[1], adc->smpr_val[1]);
1170
1171        /* Program chan number in regular sequence (SQ1) */
1172        val = stm32_adc_readl(adc, regs->sqr[1].reg);
1173        val &= ~regs->sqr[1].mask;
1174        val |= chan->channel << regs->sqr[1].shift;
1175        stm32_adc_writel(adc, regs->sqr[1].reg, val);
1176
1177        /* Set regular sequence len (0 for 1 conversion) */
1178        stm32_adc_clr_bits(adc, regs->sqr[0].reg, regs->sqr[0].mask);
1179
1180        /* Trigger detection disabled (conversion can be launched in SW) */
1181        stm32_adc_clr_bits(adc, regs->exten.reg, regs->exten.mask);
1182
1183        stm32_adc_conv_irq_enable(adc);
1184
1185        adc->cfg->start_conv(adc, false);
1186
1187        timeout = wait_for_completion_interruptible_timeout(
1188                                        &adc->completion, STM32_ADC_TIMEOUT);
1189        if (timeout == 0) {
1190                ret = -ETIMEDOUT;
1191        } else if (timeout < 0) {
1192                ret = timeout;
1193        } else {
1194                *res = adc->buffer[0];
1195                ret = IIO_VAL_INT;
1196        }
1197
1198        adc->cfg->stop_conv(adc);
1199
1200        stm32_adc_conv_irq_disable(adc);
1201
1202        if (adc->cfg->unprepare)
1203                adc->cfg->unprepare(adc);
1204
1205        return ret;
1206}
1207
1208static int stm32_adc_read_raw(struct iio_dev *indio_dev,
1209                              struct iio_chan_spec const *chan,
1210                              int *val, int *val2, long mask)
1211{
1212        struct stm32_adc *adc = iio_priv(indio_dev);
1213        int ret;
1214
1215        switch (mask) {
1216        case IIO_CHAN_INFO_RAW:
1217                ret = iio_device_claim_direct_mode(indio_dev);
1218                if (ret)
1219                        return ret;
1220                if (chan->type == IIO_VOLTAGE)
1221                        ret = stm32_adc_single_conv(indio_dev, chan, val);
1222                else
1223                        ret = -EINVAL;
1224                iio_device_release_direct_mode(indio_dev);
1225                return ret;
1226
1227        case IIO_CHAN_INFO_SCALE:
1228                if (chan->differential) {
1229                        *val = adc->common->vref_mv * 2;
1230                        *val2 = chan->scan_type.realbits;
1231                } else {
1232                        *val = adc->common->vref_mv;
1233                        *val2 = chan->scan_type.realbits;
1234                }
1235                return IIO_VAL_FRACTIONAL_LOG2;
1236
1237        case IIO_CHAN_INFO_OFFSET:
1238                if (chan->differential)
1239                        /* ADC_full_scale / 2 */
1240                        *val = -((1 << chan->scan_type.realbits) / 2);
1241                else
1242                        *val = 0;
1243                return IIO_VAL_INT;
1244
1245        default:
1246                return -EINVAL;
1247        }
1248}
1249
1250static irqreturn_t stm32_adc_isr(int irq, void *data)
1251{
1252        struct stm32_adc *adc = data;
1253        struct iio_dev *indio_dev = iio_priv_to_dev(adc);
1254        const struct stm32_adc_regspec *regs = adc->cfg->regs;
1255        u32 status = stm32_adc_readl(adc, regs->isr_eoc.reg);
1256
1257        if (status & regs->isr_eoc.mask) {
1258                /* Reading DR also clears EOC status flag */
1259                adc->buffer[adc->bufi] = stm32_adc_readw(adc, regs->dr);
1260                if (iio_buffer_enabled(indio_dev)) {
1261                        adc->bufi++;
1262                        if (adc->bufi >= adc->num_conv) {
1263                                stm32_adc_conv_irq_disable(adc);
1264                                iio_trigger_poll(indio_dev->trig);
1265                        }
1266                } else {
1267                        complete(&adc->completion);
1268                }
1269                return IRQ_HANDLED;
1270        }
1271
1272        return IRQ_NONE;
1273}
1274
1275/**
1276 * stm32_adc_validate_trigger() - validate trigger for stm32 adc
1277 * @indio_dev: IIO device
1278 * @trig: new trigger
1279 *
1280 * Returns: 0 if trig matches one of the triggers registered by stm32 adc
1281 * driver, -EINVAL otherwise.
1282 */
1283static int stm32_adc_validate_trigger(struct iio_dev *indio_dev,
1284                                      struct iio_trigger *trig)
1285{
1286        return stm32_adc_get_trig_extsel(indio_dev, trig) < 0 ? -EINVAL : 0;
1287}
1288
1289static int stm32_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val)
1290{
1291        struct stm32_adc *adc = iio_priv(indio_dev);
1292        unsigned int watermark = STM32_DMA_BUFFER_SIZE / 2;
1293        unsigned int rx_buf_sz = STM32_DMA_BUFFER_SIZE;
1294
1295        /*
1296         * dma cyclic transfers are used, buffer is split into two periods.
1297         * There should be :
1298         * - always one buffer (period) dma is working on
1299         * - one buffer (period) driver can push with iio_trigger_poll().
1300         */
1301        watermark = min(watermark, val * (unsigned)(sizeof(u16)));
1302        adc->rx_buf_sz = min(rx_buf_sz, watermark * 2 * adc->num_conv);
1303
1304        return 0;
1305}
1306
1307static int stm32_adc_update_scan_mode(struct iio_dev *indio_dev,
1308                                      const unsigned long *scan_mask)
1309{
1310        struct stm32_adc *adc = iio_priv(indio_dev);
1311        int ret;
1312
1313        adc->num_conv = bitmap_weight(scan_mask, indio_dev->masklength);
1314
1315        ret = stm32_adc_conf_scan_seq(indio_dev, scan_mask);
1316        if (ret)
1317                return ret;
1318
1319        return 0;
1320}
1321
1322static int stm32_adc_of_xlate(struct iio_dev *indio_dev,
1323                              const struct of_phandle_args *iiospec)
1324{
1325        int i;
1326
1327        for (i = 0; i < indio_dev->num_channels; i++)
1328                if (indio_dev->channels[i].channel == iiospec->args[0])
1329                        return i;
1330
1331        return -EINVAL;
1332}
1333
1334/**
1335 * stm32_adc_debugfs_reg_access - read or write register value
1336 *
1337 * To read a value from an ADC register:
1338 *   echo [ADC reg offset] > direct_reg_access
1339 *   cat direct_reg_access
1340 *
1341 * To write a value in a ADC register:
1342 *   echo [ADC_reg_offset] [value] > direct_reg_access
1343 */
1344static int stm32_adc_debugfs_reg_access(struct iio_dev *indio_dev,
1345                                        unsigned reg, unsigned writeval,
1346                                        unsigned *readval)
1347{
1348        struct stm32_adc *adc = iio_priv(indio_dev);
1349
1350        if (!readval)
1351                stm32_adc_writel(adc, reg, writeval);
1352        else
1353                *readval = stm32_adc_readl(adc, reg);
1354
1355        return 0;
1356}
1357
1358static const struct iio_info stm32_adc_iio_info = {
1359        .read_raw = stm32_adc_read_raw,
1360        .validate_trigger = stm32_adc_validate_trigger,
1361        .hwfifo_set_watermark = stm32_adc_set_watermark,
1362        .update_scan_mode = stm32_adc_update_scan_mode,
1363        .debugfs_reg_access = stm32_adc_debugfs_reg_access,
1364        .of_xlate = stm32_adc_of_xlate,
1365};
1366
1367static unsigned int stm32_adc_dma_residue(struct stm32_adc *adc)
1368{
1369        struct dma_tx_state state;
1370        enum dma_status status;
1371
1372        status = dmaengine_tx_status(adc->dma_chan,
1373                                     adc->dma_chan->cookie,
1374                                     &state);
1375        if (status == DMA_IN_PROGRESS) {
1376                /* Residue is size in bytes from end of buffer */
1377                unsigned int i = adc->rx_buf_sz - state.residue;
1378                unsigned int size;
1379
1380                /* Return available bytes */
1381                if (i >= adc->bufi)
1382                        size = i - adc->bufi;
1383                else
1384                        size = adc->rx_buf_sz + i - adc->bufi;
1385
1386                return size;
1387        }
1388
1389        return 0;
1390}
1391
1392static void stm32_adc_dma_buffer_done(void *data)
1393{
1394        struct iio_dev *indio_dev = data;
1395
1396        iio_trigger_poll_chained(indio_dev->trig);
1397}
1398
1399static int stm32_adc_dma_start(struct iio_dev *indio_dev)
1400{
1401        struct stm32_adc *adc = iio_priv(indio_dev);
1402        struct dma_async_tx_descriptor *desc;
1403        dma_cookie_t cookie;
1404        int ret;
1405
1406        if (!adc->dma_chan)
1407                return 0;
1408
1409        dev_dbg(&indio_dev->dev, "%s size=%d watermark=%d\n", __func__,
1410                adc->rx_buf_sz, adc->rx_buf_sz / 2);
1411
1412        /* Prepare a DMA cyclic transaction */
1413        desc = dmaengine_prep_dma_cyclic(adc->dma_chan,
1414                                         adc->rx_dma_buf,
1415                                         adc->rx_buf_sz, adc->rx_buf_sz / 2,
1416                                         DMA_DEV_TO_MEM,
1417                                         DMA_PREP_INTERRUPT);
1418        if (!desc)
1419                return -EBUSY;
1420
1421        desc->callback = stm32_adc_dma_buffer_done;
1422        desc->callback_param = indio_dev;
1423
1424        cookie = dmaengine_submit(desc);
1425        ret = dma_submit_error(cookie);
1426        if (ret) {
1427                dmaengine_terminate_all(adc->dma_chan);
1428                return ret;
1429        }
1430
1431        /* Issue pending DMA requests */
1432        dma_async_issue_pending(adc->dma_chan);
1433
1434        return 0;
1435}
1436
1437static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
1438{
1439        struct stm32_adc *adc = iio_priv(indio_dev);
1440        int ret;
1441
1442        if (adc->cfg->prepare) {
1443                ret = adc->cfg->prepare(adc);
1444                if (ret)
1445                        return ret;
1446        }
1447
1448        ret = stm32_adc_set_trig(indio_dev, indio_dev->trig);
1449        if (ret) {
1450                dev_err(&indio_dev->dev, "Can't set trigger\n");
1451                goto err_unprepare;
1452        }
1453
1454        ret = stm32_adc_dma_start(indio_dev);
1455        if (ret) {
1456                dev_err(&indio_dev->dev, "Can't start dma\n");
1457                goto err_clr_trig;
1458        }
1459
1460        ret = iio_triggered_buffer_postenable(indio_dev);
1461        if (ret < 0)
1462                goto err_stop_dma;
1463
1464        /* Reset adc buffer index */
1465        adc->bufi = 0;
1466
1467        if (!adc->dma_chan)
1468                stm32_adc_conv_irq_enable(adc);
1469
1470        adc->cfg->start_conv(adc, !!adc->dma_chan);
1471
1472        return 0;
1473
1474err_stop_dma:
1475        if (adc->dma_chan)
1476                dmaengine_terminate_all(adc->dma_chan);
1477err_clr_trig:
1478        stm32_adc_set_trig(indio_dev, NULL);
1479err_unprepare:
1480        if (adc->cfg->unprepare)
1481                adc->cfg->unprepare(adc);
1482
1483        return ret;
1484}
1485
1486static int stm32_adc_buffer_predisable(struct iio_dev *indio_dev)
1487{
1488        struct stm32_adc *adc = iio_priv(indio_dev);
1489        int ret;
1490
1491        adc->cfg->stop_conv(adc);
1492        if (!adc->dma_chan)
1493                stm32_adc_conv_irq_disable(adc);
1494
1495        ret = iio_triggered_buffer_predisable(indio_dev);
1496        if (ret < 0)
1497                dev_err(&indio_dev->dev, "predisable failed\n");
1498
1499        if (adc->dma_chan)
1500                dmaengine_terminate_all(adc->dma_chan);
1501
1502        if (stm32_adc_set_trig(indio_dev, NULL))
1503                dev_err(&indio_dev->dev, "Can't clear trigger\n");
1504
1505        if (adc->cfg->unprepare)
1506                adc->cfg->unprepare(adc);
1507
1508        return ret;
1509}
1510
1511static const struct iio_buffer_setup_ops stm32_adc_buffer_setup_ops = {
1512        .postenable = &stm32_adc_buffer_postenable,
1513        .predisable = &stm32_adc_buffer_predisable,
1514};
1515
1516static irqreturn_t stm32_adc_trigger_handler(int irq, void *p)
1517{
1518        struct iio_poll_func *pf = p;
1519        struct iio_dev *indio_dev = pf->indio_dev;
1520        struct stm32_adc *adc = iio_priv(indio_dev);
1521
1522        dev_dbg(&indio_dev->dev, "%s bufi=%d\n", __func__, adc->bufi);
1523
1524        if (!adc->dma_chan) {
1525                /* reset buffer index */
1526                adc->bufi = 0;
1527                iio_push_to_buffers_with_timestamp(indio_dev, adc->buffer,
1528                                                   pf->timestamp);
1529        } else {
1530                int residue = stm32_adc_dma_residue(adc);
1531
1532                while (residue >= indio_dev->scan_bytes) {
1533                        u16 *buffer = (u16 *)&adc->rx_buf[adc->bufi];
1534
1535                        iio_push_to_buffers_with_timestamp(indio_dev, buffer,
1536                                                           pf->timestamp);
1537                        residue -= indio_dev->scan_bytes;
1538                        adc->bufi += indio_dev->scan_bytes;
1539                        if (adc->bufi >= adc->rx_buf_sz)
1540                                adc->bufi = 0;
1541                }
1542        }
1543
1544        iio_trigger_notify_done(indio_dev->trig);
1545
1546        /* re-enable eoc irq */
1547        if (!adc->dma_chan)
1548                stm32_adc_conv_irq_enable(adc);
1549
1550        return IRQ_HANDLED;
1551}
1552
1553static const struct iio_chan_spec_ext_info stm32_adc_ext_info[] = {
1554        IIO_ENUM("trigger_polarity", IIO_SHARED_BY_ALL, &stm32_adc_trig_pol),
1555        {
1556                .name = "trigger_polarity_available",
1557                .shared = IIO_SHARED_BY_ALL,
1558                .read = iio_enum_available_read,
1559                .private = (uintptr_t)&stm32_adc_trig_pol,
1560        },
1561        {},
1562};
1563
1564static int stm32_adc_of_get_resolution(struct iio_dev *indio_dev)
1565{
1566        struct device_node *node = indio_dev->dev.of_node;
1567        struct stm32_adc *adc = iio_priv(indio_dev);
1568        unsigned int i;
1569        u32 res;
1570
1571        if (of_property_read_u32(node, "assigned-resolution-bits", &res))
1572                res = adc->cfg->adc_info->resolutions[0];
1573
1574        for (i = 0; i < adc->cfg->adc_info->num_res; i++)
1575                if (res == adc->cfg->adc_info->resolutions[i])
1576                        break;
1577        if (i >= adc->cfg->adc_info->num_res) {
1578                dev_err(&indio_dev->dev, "Bad resolution: %u bits\n", res);
1579                return -EINVAL;
1580        }
1581
1582        dev_dbg(&indio_dev->dev, "Using %u bits resolution\n", res);
1583        adc->res = i;
1584
1585        return 0;
1586}
1587
1588static void stm32_adc_smpr_init(struct stm32_adc *adc, int channel, u32 smp_ns)
1589{
1590        const struct stm32_adc_regs *smpr = &adc->cfg->regs->smp_bits[channel];
1591        u32 period_ns, shift = smpr->shift, mask = smpr->mask;
1592        unsigned int smp, r = smpr->reg;
1593
1594        /* Determine sampling time (ADC clock cycles) */
1595        period_ns = NSEC_PER_SEC / adc->common->rate;
1596        for (smp = 0; smp <= STM32_ADC_MAX_SMP; smp++)
1597                if ((period_ns * adc->cfg->smp_cycles[smp]) >= smp_ns)
1598                        break;
1599        if (smp > STM32_ADC_MAX_SMP)
1600                smp = STM32_ADC_MAX_SMP;
1601
1602        /* pre-build sampling time registers (e.g. smpr1, smpr2) */
1603        adc->smpr_val[r] = (adc->smpr_val[r] & ~mask) | (smp << shift);
1604}
1605
1606static void stm32_adc_chan_init_one(struct iio_dev *indio_dev,
1607                                    struct iio_chan_spec *chan, u32 vinp,
1608                                    u32 vinn, int scan_index, bool differential)
1609{
1610        struct stm32_adc *adc = iio_priv(indio_dev);
1611        char *name = adc->chan_name[vinp];
1612
1613        chan->type = IIO_VOLTAGE;
1614        chan->channel = vinp;
1615        if (differential) {
1616                chan->differential = 1;
1617                chan->channel2 = vinn;
1618                snprintf(name, STM32_ADC_CH_SZ, "in%d-in%d", vinp, vinn);
1619        } else {
1620                snprintf(name, STM32_ADC_CH_SZ, "in%d", vinp);
1621        }
1622        chan->datasheet_name = name;
1623        chan->scan_index = scan_index;
1624        chan->indexed = 1;
1625        chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
1626        chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
1627                                         BIT(IIO_CHAN_INFO_OFFSET);
1628        chan->scan_type.sign = 'u';
1629        chan->scan_type.realbits = adc->cfg->adc_info->resolutions[adc->res];
1630        chan->scan_type.storagebits = 16;
1631        chan->ext_info = stm32_adc_ext_info;
1632
1633        /* pre-build selected channels mask */
1634        adc->pcsel |= BIT(chan->channel);
1635        if (differential) {
1636                /* pre-build diff channels mask */
1637                adc->difsel |= BIT(chan->channel);
1638                /* Also add negative input to pre-selected channels */
1639                adc->pcsel |= BIT(chan->channel2);
1640        }
1641}
1642
1643static int stm32_adc_chan_of_init(struct iio_dev *indio_dev)
1644{
1645        struct device_node *node = indio_dev->dev.of_node;
1646        struct stm32_adc *adc = iio_priv(indio_dev);
1647        const struct stm32_adc_info *adc_info = adc->cfg->adc_info;
1648        struct stm32_adc_diff_channel diff[STM32_ADC_CH_MAX];
1649        struct property *prop;
1650        const __be32 *cur;
1651        struct iio_chan_spec *channels;
1652        int scan_index = 0, num_channels = 0, num_diff = 0, ret, i;
1653        u32 val, smp = 0;
1654
1655        ret = of_property_count_u32_elems(node, "st,adc-channels");
1656        if (ret > adc_info->max_channels) {
1657                dev_err(&indio_dev->dev, "Bad st,adc-channels?\n");
1658                return -EINVAL;
1659        } else if (ret > 0) {
1660                num_channels += ret;
1661        }
1662
1663        ret = of_property_count_elems_of_size(node, "st,adc-diff-channels",
1664                                              sizeof(*diff));
1665        if (ret > adc_info->max_channels) {
1666                dev_err(&indio_dev->dev, "Bad st,adc-diff-channels?\n");
1667                return -EINVAL;
1668        } else if (ret > 0) {
1669                int size = ret * sizeof(*diff) / sizeof(u32);
1670
1671                num_diff = ret;
1672                num_channels += ret;
1673                ret = of_property_read_u32_array(node, "st,adc-diff-channels",
1674                                                 (u32 *)diff, size);
1675                if (ret)
1676                        return ret;
1677        }
1678
1679        if (!num_channels) {
1680                dev_err(&indio_dev->dev, "No channels configured\n");
1681                return -ENODATA;
1682        }
1683
1684        /* Optional sample time is provided either for each, or all channels */
1685        ret = of_property_count_u32_elems(node, "st,min-sample-time-nsecs");
1686        if (ret > 1 && ret != num_channels) {
1687                dev_err(&indio_dev->dev, "Invalid st,min-sample-time-nsecs\n");
1688                return -EINVAL;
1689        }
1690
1691        channels = devm_kcalloc(&indio_dev->dev, num_channels,
1692                                sizeof(struct iio_chan_spec), GFP_KERNEL);
1693        if (!channels)
1694                return -ENOMEM;
1695
1696        of_property_for_each_u32(node, "st,adc-channels", prop, cur, val) {
1697                if (val >= adc_info->max_channels) {
1698                        dev_err(&indio_dev->dev, "Invalid channel %d\n", val);
1699                        return -EINVAL;
1700                }
1701
1702                /* Channel can't be configured both as single-ended & diff */
1703                for (i = 0; i < num_diff; i++) {
1704                        if (val == diff[i].vinp) {
1705                                dev_err(&indio_dev->dev,
1706                                        "channel %d miss-configured\n", val);
1707                                return -EINVAL;
1708                        }
1709                }
1710                stm32_adc_chan_init_one(indio_dev, &channels[scan_index], val,
1711                                        0, scan_index, false);
1712                scan_index++;
1713        }
1714
1715        for (i = 0; i < num_diff; i++) {
1716                if (diff[i].vinp >= adc_info->max_channels ||
1717                    diff[i].vinn >= adc_info->max_channels) {
1718                        dev_err(&indio_dev->dev, "Invalid channel in%d-in%d\n",
1719                                diff[i].vinp, diff[i].vinn);
1720                        return -EINVAL;
1721                }
1722                stm32_adc_chan_init_one(indio_dev, &channels[scan_index],
1723                                        diff[i].vinp, diff[i].vinn, scan_index,
1724                                        true);
1725                scan_index++;
1726        }
1727
1728        for (i = 0; i < scan_index; i++) {
1729                /*
1730                 * Using of_property_read_u32_index(), smp value will only be
1731                 * modified if valid u32 value can be decoded. This allows to
1732                 * get either no value, 1 shared value for all indexes, or one
1733                 * value per channel.
1734                 */
1735                of_property_read_u32_index(node, "st,min-sample-time-nsecs",
1736                                           i, &smp);
1737                /* Prepare sampling time settings */
1738                stm32_adc_smpr_init(adc, channels[i].channel, smp);
1739        }
1740
1741        indio_dev->num_channels = scan_index;
1742        indio_dev->channels = channels;
1743
1744        return 0;
1745}
1746
1747static int stm32_adc_dma_request(struct iio_dev *indio_dev)
1748{
1749        struct stm32_adc *adc = iio_priv(indio_dev);
1750        struct dma_slave_config config;
1751        int ret;
1752
1753        adc->dma_chan = dma_request_slave_channel(&indio_dev->dev, "rx");
1754        if (!adc->dma_chan)
1755                return 0;
1756
1757        adc->rx_buf = dma_alloc_coherent(adc->dma_chan->device->dev,
1758                                         STM32_DMA_BUFFER_SIZE,
1759                                         &adc->rx_dma_buf, GFP_KERNEL);
1760        if (!adc->rx_buf) {
1761                ret = -ENOMEM;
1762                goto err_release;
1763        }
1764
1765        /* Configure DMA channel to read data register */
1766        memset(&config, 0, sizeof(config));
1767        config.src_addr = (dma_addr_t)adc->common->phys_base;
1768        config.src_addr += adc->offset + adc->cfg->regs->dr;
1769        config.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
1770
1771        ret = dmaengine_slave_config(adc->dma_chan, &config);
1772        if (ret)
1773                goto err_free;
1774
1775        return 0;
1776
1777err_free:
1778        dma_free_coherent(adc->dma_chan->device->dev, STM32_DMA_BUFFER_SIZE,
1779                          adc->rx_buf, adc->rx_dma_buf);
1780err_release:
1781        dma_release_channel(adc->dma_chan);
1782
1783        return ret;
1784}
1785
1786static int stm32_adc_probe(struct platform_device *pdev)
1787{
1788        struct iio_dev *indio_dev;
1789        struct device *dev = &pdev->dev;
1790        struct stm32_adc *adc;
1791        int ret;
1792
1793        if (!pdev->dev.of_node)
1794                return -ENODEV;
1795
1796        indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
1797        if (!indio_dev)
1798                return -ENOMEM;
1799
1800        adc = iio_priv(indio_dev);
1801        adc->common = dev_get_drvdata(pdev->dev.parent);
1802        spin_lock_init(&adc->lock);
1803        init_completion(&adc->completion);
1804        adc->cfg = (const struct stm32_adc_cfg *)
1805                of_match_device(dev->driver->of_match_table, dev)->data;
1806
1807        indio_dev->name = dev_name(&pdev->dev);
1808        indio_dev->dev.parent = &pdev->dev;
1809        indio_dev->dev.of_node = pdev->dev.of_node;
1810        indio_dev->info = &stm32_adc_iio_info;
1811        indio_dev->modes = INDIO_DIRECT_MODE | INDIO_HARDWARE_TRIGGERED;
1812
1813        platform_set_drvdata(pdev, adc);
1814
1815        ret = of_property_read_u32(pdev->dev.of_node, "reg", &adc->offset);
1816        if (ret != 0) {
1817                dev_err(&pdev->dev, "missing reg property\n");
1818                return -EINVAL;
1819        }
1820
1821        adc->irq = platform_get_irq(pdev, 0);
1822        if (adc->irq < 0) {
1823                dev_err(&pdev->dev, "failed to get irq\n");
1824                return adc->irq;
1825        }
1826
1827        ret = devm_request_irq(&pdev->dev, adc->irq, stm32_adc_isr,
1828                               0, pdev->name, adc);
1829        if (ret) {
1830                dev_err(&pdev->dev, "failed to request IRQ\n");
1831                return ret;
1832        }
1833
1834        adc->clk = devm_clk_get(&pdev->dev, NULL);
1835        if (IS_ERR(adc->clk)) {
1836                ret = PTR_ERR(adc->clk);
1837                if (ret == -ENOENT && !adc->cfg->clk_required) {
1838                        adc->clk = NULL;
1839                } else {
1840                        dev_err(&pdev->dev, "Can't get clock\n");
1841                        return ret;
1842                }
1843        }
1844
1845        if (adc->clk) {
1846                ret = clk_prepare_enable(adc->clk);
1847                if (ret < 0) {
1848                        dev_err(&pdev->dev, "clk enable failed\n");
1849                        return ret;
1850                }
1851        }
1852
1853        ret = stm32_adc_of_get_resolution(indio_dev);
1854        if (ret < 0)
1855                goto err_clk_disable;
1856        stm32_adc_set_res(adc);
1857
1858        if (adc->cfg->selfcalib) {
1859                ret = adc->cfg->selfcalib(adc);
1860                if (ret)
1861                        goto err_clk_disable;
1862        }
1863
1864        ret = stm32_adc_chan_of_init(indio_dev);
1865        if (ret < 0)
1866                goto err_clk_disable;
1867
1868        ret = stm32_adc_dma_request(indio_dev);
1869        if (ret < 0)
1870                goto err_clk_disable;
1871
1872        ret = iio_triggered_buffer_setup(indio_dev,
1873                                         &iio_pollfunc_store_time,
1874                                         &stm32_adc_trigger_handler,
1875                                         &stm32_adc_buffer_setup_ops);
1876        if (ret) {
1877                dev_err(&pdev->dev, "buffer setup failed\n");
1878                goto err_dma_disable;
1879        }
1880
1881        ret = iio_device_register(indio_dev);
1882        if (ret) {
1883                dev_err(&pdev->dev, "iio dev register failed\n");
1884                goto err_buffer_cleanup;
1885        }
1886
1887        return 0;
1888
1889err_buffer_cleanup:
1890        iio_triggered_buffer_cleanup(indio_dev);
1891
1892err_dma_disable:
1893        if (adc->dma_chan) {
1894                dma_free_coherent(adc->dma_chan->device->dev,
1895                                  STM32_DMA_BUFFER_SIZE,
1896                                  adc->rx_buf, adc->rx_dma_buf);
1897                dma_release_channel(adc->dma_chan);
1898        }
1899err_clk_disable:
1900        if (adc->clk)
1901                clk_disable_unprepare(adc->clk);
1902
1903        return ret;
1904}
1905
1906static int stm32_adc_remove(struct platform_device *pdev)
1907{
1908        struct stm32_adc *adc = platform_get_drvdata(pdev);
1909        struct iio_dev *indio_dev = iio_priv_to_dev(adc);
1910
1911        iio_device_unregister(indio_dev);
1912        iio_triggered_buffer_cleanup(indio_dev);
1913        if (adc->dma_chan) {
1914                dma_free_coherent(adc->dma_chan->device->dev,
1915                                  STM32_DMA_BUFFER_SIZE,
1916                                  adc->rx_buf, adc->rx_dma_buf);
1917                dma_release_channel(adc->dma_chan);
1918        }
1919        if (adc->clk)
1920                clk_disable_unprepare(adc->clk);
1921
1922        return 0;
1923}
1924
1925static const struct stm32_adc_cfg stm32f4_adc_cfg = {
1926        .regs = &stm32f4_adc_regspec,
1927        .adc_info = &stm32f4_adc_info,
1928        .trigs = stm32f4_adc_trigs,
1929        .clk_required = true,
1930        .start_conv = stm32f4_adc_start_conv,
1931        .stop_conv = stm32f4_adc_stop_conv,
1932        .smp_cycles = stm32f4_adc_smp_cycles,
1933};
1934
1935static const struct stm32_adc_cfg stm32h7_adc_cfg = {
1936        .regs = &stm32h7_adc_regspec,
1937        .adc_info = &stm32h7_adc_info,
1938        .trigs = stm32h7_adc_trigs,
1939        .selfcalib = stm32h7_adc_selfcalib,
1940        .start_conv = stm32h7_adc_start_conv,
1941        .stop_conv = stm32h7_adc_stop_conv,
1942        .prepare = stm32h7_adc_prepare,
1943        .unprepare = stm32h7_adc_unprepare,
1944        .smp_cycles = stm32h7_adc_smp_cycles,
1945};
1946
1947static const struct of_device_id stm32_adc_of_match[] = {
1948        { .compatible = "st,stm32f4-adc", .data = (void *)&stm32f4_adc_cfg },
1949        { .compatible = "st,stm32h7-adc", .data = (void *)&stm32h7_adc_cfg },
1950        {},
1951};
1952MODULE_DEVICE_TABLE(of, stm32_adc_of_match);
1953
1954static struct platform_driver stm32_adc_driver = {
1955        .probe = stm32_adc_probe,
1956        .remove = stm32_adc_remove,
1957        .driver = {
1958                .name = "stm32-adc",
1959                .of_match_table = stm32_adc_of_match,
1960        },
1961};
1962module_platform_driver(stm32_adc_driver);
1963
1964MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
1965MODULE_DESCRIPTION("STMicroelectronics STM32 ADC IIO driver");
1966MODULE_LICENSE("GPL v2");
1967MODULE_ALIAS("platform:stm32-adc");
1968