linux/sound/soc/bcm/bcm2835-i2s.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * ALSA SoC I2S Audio Layer for Broadcom BCM2835 SoC
   4 *
   5 * Author:      Florian Meier <florian.meier@koalo.de>
   6 *              Copyright 2013
   7 *
   8 * Based on
   9 *      Raspberry Pi PCM I2S ALSA Driver
  10 *      Copyright (c) by Phil Poole 2013
  11 *
  12 *      ALSA SoC I2S (McBSP) Audio Layer for TI DAVINCI processor
  13 *      Vladimir Barinov, <vbarinov@embeddedalley.com>
  14 *      Copyright (C) 2007 MontaVista Software, Inc., <source@mvista.com>
  15 *
  16 *      OMAP ALSA SoC DAI driver using McBSP port
  17 *      Copyright (C) 2008 Nokia Corporation
  18 *      Contact: Jarkko Nikula <jarkko.nikula@bitmer.com>
  19 *               Peter Ujfalusi <peter.ujfalusi@ti.com>
  20 *
  21 *      Freescale SSI ALSA SoC Digital Audio Interface (DAI) driver
  22 *      Author: Timur Tabi <timur@freescale.com>
  23 *      Copyright 2007-2010 Freescale Semiconductor, Inc.
  24 */
  25
  26#include <linux/bitops.h>
  27#include <linux/clk.h>
  28#include <linux/delay.h>
  29#include <linux/device.h>
  30#include <linux/init.h>
  31#include <linux/io.h>
  32#include <linux/module.h>
  33#include <linux/of_address.h>
  34#include <linux/slab.h>
  35
  36#include <sound/core.h>
  37#include <sound/dmaengine_pcm.h>
  38#include <sound/initval.h>
  39#include <sound/pcm.h>
  40#include <sound/pcm_params.h>
  41#include <sound/soc.h>
  42
  43/* I2S registers */
  44#define BCM2835_I2S_CS_A_REG            0x00
  45#define BCM2835_I2S_FIFO_A_REG          0x04
  46#define BCM2835_I2S_MODE_A_REG          0x08
  47#define BCM2835_I2S_RXC_A_REG           0x0c
  48#define BCM2835_I2S_TXC_A_REG           0x10
  49#define BCM2835_I2S_DREQ_A_REG          0x14
  50#define BCM2835_I2S_INTEN_A_REG 0x18
  51#define BCM2835_I2S_INTSTC_A_REG        0x1c
  52#define BCM2835_I2S_GRAY_REG            0x20
  53
  54/* I2S register settings */
  55#define BCM2835_I2S_STBY                BIT(25)
  56#define BCM2835_I2S_SYNC                BIT(24)
  57#define BCM2835_I2S_RXSEX               BIT(23)
  58#define BCM2835_I2S_RXF         BIT(22)
  59#define BCM2835_I2S_TXE         BIT(21)
  60#define BCM2835_I2S_RXD         BIT(20)
  61#define BCM2835_I2S_TXD         BIT(19)
  62#define BCM2835_I2S_RXR         BIT(18)
  63#define BCM2835_I2S_TXW         BIT(17)
  64#define BCM2835_I2S_CS_RXERR            BIT(16)
  65#define BCM2835_I2S_CS_TXERR            BIT(15)
  66#define BCM2835_I2S_RXSYNC              BIT(14)
  67#define BCM2835_I2S_TXSYNC              BIT(13)
  68#define BCM2835_I2S_DMAEN               BIT(9)
  69#define BCM2835_I2S_RXTHR(v)            ((v) << 7)
  70#define BCM2835_I2S_TXTHR(v)            ((v) << 5)
  71#define BCM2835_I2S_RXCLR               BIT(4)
  72#define BCM2835_I2S_TXCLR               BIT(3)
  73#define BCM2835_I2S_TXON                BIT(2)
  74#define BCM2835_I2S_RXON                BIT(1)
  75#define BCM2835_I2S_EN                  (1)
  76
  77#define BCM2835_I2S_CLKDIS              BIT(28)
  78#define BCM2835_I2S_PDMN                BIT(27)
  79#define BCM2835_I2S_PDME                BIT(26)
  80#define BCM2835_I2S_FRXP                BIT(25)
  81#define BCM2835_I2S_FTXP                BIT(24)
  82#define BCM2835_I2S_CLKM                BIT(23)
  83#define BCM2835_I2S_CLKI                BIT(22)
  84#define BCM2835_I2S_FSM         BIT(21)
  85#define BCM2835_I2S_FSI         BIT(20)
  86#define BCM2835_I2S_FLEN(v)             ((v) << 10)
  87#define BCM2835_I2S_FSLEN(v)            (v)
  88
  89#define BCM2835_I2S_CHWEX               BIT(15)
  90#define BCM2835_I2S_CHEN                BIT(14)
  91#define BCM2835_I2S_CHPOS(v)            ((v) << 4)
  92#define BCM2835_I2S_CHWID(v)            (v)
  93#define BCM2835_I2S_CH1(v)              ((v) << 16)
  94#define BCM2835_I2S_CH2(v)              (v)
  95#define BCM2835_I2S_CH1_POS(v)          BCM2835_I2S_CH1(BCM2835_I2S_CHPOS(v))
  96#define BCM2835_I2S_CH2_POS(v)          BCM2835_I2S_CH2(BCM2835_I2S_CHPOS(v))
  97
  98#define BCM2835_I2S_TX_PANIC(v) ((v) << 24)
  99#define BCM2835_I2S_RX_PANIC(v) ((v) << 16)
 100#define BCM2835_I2S_TX(v)               ((v) << 8)
 101#define BCM2835_I2S_RX(v)               (v)
 102
 103#define BCM2835_I2S_INT_RXERR           BIT(3)
 104#define BCM2835_I2S_INT_TXERR           BIT(2)
 105#define BCM2835_I2S_INT_RXR             BIT(1)
 106#define BCM2835_I2S_INT_TXW             BIT(0)
 107
 108/* Frame length register is 10 bit, maximum length 1024 */
 109#define BCM2835_I2S_MAX_FRAME_LENGTH    1024
 110
 111/* General device struct */
 112struct bcm2835_i2s_dev {
 113        struct device                           *dev;
 114        struct snd_dmaengine_dai_dma_data       dma_data[2];
 115        unsigned int                            fmt;
 116        unsigned int                            tdm_slots;
 117        unsigned int                            rx_mask;
 118        unsigned int                            tx_mask;
 119        unsigned int                            slot_width;
 120        unsigned int                            frame_length;
 121
 122        struct regmap                           *i2s_regmap;
 123        struct clk                              *clk;
 124        bool                                    clk_prepared;
 125        int                                     clk_rate;
 126};
 127
 128static void bcm2835_i2s_start_clock(struct bcm2835_i2s_dev *dev)
 129{
 130        unsigned int master = dev->fmt & SND_SOC_DAIFMT_MASTER_MASK;
 131
 132        if (dev->clk_prepared)
 133                return;
 134
 135        switch (master) {
 136        case SND_SOC_DAIFMT_CBS_CFS:
 137        case SND_SOC_DAIFMT_CBS_CFM:
 138                clk_prepare_enable(dev->clk);
 139                dev->clk_prepared = true;
 140                break;
 141        default:
 142                break;
 143        }
 144}
 145
 146static void bcm2835_i2s_stop_clock(struct bcm2835_i2s_dev *dev)
 147{
 148        if (dev->clk_prepared)
 149                clk_disable_unprepare(dev->clk);
 150        dev->clk_prepared = false;
 151}
 152
 153static void bcm2835_i2s_clear_fifos(struct bcm2835_i2s_dev *dev,
 154                                    bool tx, bool rx)
 155{
 156        int timeout = 1000;
 157        uint32_t syncval;
 158        uint32_t csreg;
 159        uint32_t i2s_active_state;
 160        bool clk_was_prepared;
 161        uint32_t off;
 162        uint32_t clr;
 163
 164        off =  tx ? BCM2835_I2S_TXON : 0;
 165        off |= rx ? BCM2835_I2S_RXON : 0;
 166
 167        clr =  tx ? BCM2835_I2S_TXCLR : 0;
 168        clr |= rx ? BCM2835_I2S_RXCLR : 0;
 169
 170        /* Backup the current state */
 171        regmap_read(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, &csreg);
 172        i2s_active_state = csreg & (BCM2835_I2S_RXON | BCM2835_I2S_TXON);
 173
 174        /* Start clock if not running */
 175        clk_was_prepared = dev->clk_prepared;
 176        if (!clk_was_prepared)
 177                bcm2835_i2s_start_clock(dev);
 178
 179        /* Stop I2S module */
 180        regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, off, 0);
 181
 182        /*
 183         * Clear the FIFOs
 184         * Requires at least 2 PCM clock cycles to take effect
 185         */
 186        regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, clr, clr);
 187
 188        /* Wait for 2 PCM clock cycles */
 189
 190        /*
 191         * Toggle the SYNC flag. After 2 PCM clock cycles it can be read back
 192         * FIXME: This does not seem to work for slave mode!
 193         */
 194        regmap_read(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, &syncval);
 195        syncval &= BCM2835_I2S_SYNC;
 196
 197        regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
 198                        BCM2835_I2S_SYNC, ~syncval);
 199
 200        /* Wait for the SYNC flag changing it's state */
 201        while (--timeout) {
 202                regmap_read(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, &csreg);
 203                if ((csreg & BCM2835_I2S_SYNC) != syncval)
 204                        break;
 205        }
 206
 207        if (!timeout)
 208                dev_err(dev->dev, "I2S SYNC error!\n");
 209
 210        /* Stop clock if it was not running before */
 211        if (!clk_was_prepared)
 212                bcm2835_i2s_stop_clock(dev);
 213
 214        /* Restore I2S state */
 215        regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
 216                        BCM2835_I2S_RXON | BCM2835_I2S_TXON, i2s_active_state);
 217}
 218
 219static int bcm2835_i2s_set_dai_fmt(struct snd_soc_dai *dai,
 220                                      unsigned int fmt)
 221{
 222        struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
 223        dev->fmt = fmt;
 224        return 0;
 225}
 226
 227static int bcm2835_i2s_set_dai_bclk_ratio(struct snd_soc_dai *dai,
 228                                      unsigned int ratio)
 229{
 230        struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
 231
 232        if (!ratio) {
 233                dev->tdm_slots = 0;
 234                return 0;
 235        }
 236
 237        if (ratio > BCM2835_I2S_MAX_FRAME_LENGTH)
 238                return -EINVAL;
 239
 240        dev->tdm_slots = 2;
 241        dev->rx_mask = 0x03;
 242        dev->tx_mask = 0x03;
 243        dev->slot_width = ratio / 2;
 244        dev->frame_length = ratio;
 245
 246        return 0;
 247}
 248
 249static int bcm2835_i2s_set_dai_tdm_slot(struct snd_soc_dai *dai,
 250        unsigned int tx_mask, unsigned int rx_mask,
 251        int slots, int width)
 252{
 253        struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
 254
 255        if (slots) {
 256                if (slots < 0 || width < 0)
 257                        return -EINVAL;
 258
 259                /* Limit masks to available slots */
 260                rx_mask &= GENMASK(slots - 1, 0);
 261                tx_mask &= GENMASK(slots - 1, 0);
 262
 263                /*
 264                 * The driver is limited to 2-channel setups.
 265                 * Check that exactly 2 bits are set in the masks.
 266                 */
 267                if (hweight_long((unsigned long) rx_mask) != 2
 268                    || hweight_long((unsigned long) tx_mask) != 2)
 269                        return -EINVAL;
 270
 271                if (slots * width > BCM2835_I2S_MAX_FRAME_LENGTH)
 272                        return -EINVAL;
 273        }
 274
 275        dev->tdm_slots = slots;
 276
 277        dev->rx_mask = rx_mask;
 278        dev->tx_mask = tx_mask;
 279        dev->slot_width = width;
 280        dev->frame_length = slots * width;
 281
 282        return 0;
 283}
 284
 285/*
 286 * Convert logical slot number into physical slot number.
 287 *
 288 * If odd_offset is 0 sequential number is identical to logical number.
 289 * This is used for DSP modes with slot numbering 0 1 2 3 ...
 290 *
 291 * Otherwise odd_offset defines the physical offset for odd numbered
 292 * slots. This is used for I2S and left/right justified modes to
 293 * translate from logical slot numbers 0 1 2 3 ... into physical slot
 294 * numbers 0 2 ... 3 4 ...
 295 */
 296static int bcm2835_i2s_convert_slot(unsigned int slot, unsigned int odd_offset)
 297{
 298        if (!odd_offset)
 299                return slot;
 300
 301        if (slot & 1)
 302                return (slot >> 1) + odd_offset;
 303
 304        return slot >> 1;
 305}
 306
 307/*
 308 * Calculate channel position from mask and slot width.
 309 *
 310 * Mask must contain exactly 2 set bits.
 311 * Lowest set bit is channel 1 position, highest set bit channel 2.
 312 * The constant offset is added to both channel positions.
 313 *
 314 * If odd_offset is > 0 slot positions are translated to
 315 * I2S-style TDM slot numbering ( 0 2 ... 3 4 ...) with odd
 316 * logical slot numbers starting at physical slot odd_offset.
 317 */
 318static void bcm2835_i2s_calc_channel_pos(
 319        unsigned int *ch1_pos, unsigned int *ch2_pos,
 320        unsigned int mask, unsigned int width,
 321        unsigned int bit_offset, unsigned int odd_offset)
 322{
 323        *ch1_pos = bcm2835_i2s_convert_slot((ffs(mask) - 1), odd_offset)
 324                        * width + bit_offset;
 325        *ch2_pos = bcm2835_i2s_convert_slot((fls(mask) - 1), odd_offset)
 326                        * width + bit_offset;
 327}
 328
 329static int bcm2835_i2s_hw_params(struct snd_pcm_substream *substream,
 330                                 struct snd_pcm_hw_params *params,
 331                                 struct snd_soc_dai *dai)
 332{
 333        struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
 334        unsigned int data_length, data_delay, framesync_length;
 335        unsigned int slots, slot_width, odd_slot_offset;
 336        int frame_length, bclk_rate;
 337        unsigned int rx_mask, tx_mask;
 338        unsigned int rx_ch1_pos, rx_ch2_pos, tx_ch1_pos, tx_ch2_pos;
 339        unsigned int mode, format;
 340        bool bit_clock_master = false;
 341        bool frame_sync_master = false;
 342        bool frame_start_falling_edge = false;
 343        uint32_t csreg;
 344        int ret = 0;
 345
 346        /*
 347         * If a stream is already enabled,
 348         * the registers are already set properly.
 349         */
 350        regmap_read(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, &csreg);
 351
 352        if (csreg & (BCM2835_I2S_TXON | BCM2835_I2S_RXON))
 353                return 0;
 354
 355        data_length = params_width(params);
 356        data_delay = 0;
 357        odd_slot_offset = 0;
 358        mode = 0;
 359
 360        if (dev->tdm_slots) {
 361                slots = dev->tdm_slots;
 362                slot_width = dev->slot_width;
 363                frame_length = dev->frame_length;
 364                rx_mask = dev->rx_mask;
 365                tx_mask = dev->tx_mask;
 366                bclk_rate = dev->frame_length * params_rate(params);
 367        } else {
 368                slots = 2;
 369                slot_width = params_width(params);
 370                rx_mask = 0x03;
 371                tx_mask = 0x03;
 372
 373                frame_length = snd_soc_params_to_frame_size(params);
 374                if (frame_length < 0)
 375                        return frame_length;
 376
 377                bclk_rate = snd_soc_params_to_bclk(params);
 378                if (bclk_rate < 0)
 379                        return bclk_rate;
 380        }
 381
 382        /* Check if data fits into slots */
 383        if (data_length > slot_width)
 384                return -EINVAL;
 385
 386        /* Check if CPU is bit clock master */
 387        switch (dev->fmt & SND_SOC_DAIFMT_MASTER_MASK) {
 388        case SND_SOC_DAIFMT_CBS_CFS:
 389        case SND_SOC_DAIFMT_CBS_CFM:
 390                bit_clock_master = true;
 391                break;
 392        case SND_SOC_DAIFMT_CBM_CFS:
 393        case SND_SOC_DAIFMT_CBM_CFM:
 394                bit_clock_master = false;
 395                break;
 396        default:
 397                return -EINVAL;
 398        }
 399
 400        /* Check if CPU is frame sync master */
 401        switch (dev->fmt & SND_SOC_DAIFMT_MASTER_MASK) {
 402        case SND_SOC_DAIFMT_CBS_CFS:
 403        case SND_SOC_DAIFMT_CBM_CFS:
 404                frame_sync_master = true;
 405                break;
 406        case SND_SOC_DAIFMT_CBS_CFM:
 407        case SND_SOC_DAIFMT_CBM_CFM:
 408                frame_sync_master = false;
 409                break;
 410        default:
 411                return -EINVAL;
 412        }
 413
 414        /* Clock should only be set up here if CPU is clock master */
 415        if (bit_clock_master &&
 416            (!dev->clk_prepared || dev->clk_rate != bclk_rate)) {
 417                if (dev->clk_prepared)
 418                        bcm2835_i2s_stop_clock(dev);
 419
 420                if (dev->clk_rate != bclk_rate) {
 421                        ret = clk_set_rate(dev->clk, bclk_rate);
 422                        if (ret)
 423                                return ret;
 424                        dev->clk_rate = bclk_rate;
 425                }
 426
 427                bcm2835_i2s_start_clock(dev);
 428        }
 429
 430        /* Setup the frame format */
 431        format = BCM2835_I2S_CHEN;
 432
 433        if (data_length >= 24)
 434                format |= BCM2835_I2S_CHWEX;
 435
 436        format |= BCM2835_I2S_CHWID((data_length-8)&0xf);
 437
 438        /* CH2 format is the same as for CH1 */
 439        format = BCM2835_I2S_CH1(format) | BCM2835_I2S_CH2(format);
 440
 441        switch (dev->fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
 442        case SND_SOC_DAIFMT_I2S:
 443                /* I2S mode needs an even number of slots */
 444                if (slots & 1)
 445                        return -EINVAL;
 446
 447                /*
 448                 * Use I2S-style logical slot numbering: even slots
 449                 * are in first half of frame, odd slots in second half.
 450                 */
 451                odd_slot_offset = slots >> 1;
 452
 453                /* MSB starts one cycle after frame start */
 454                data_delay = 1;
 455
 456                /* Setup frame sync signal for 50% duty cycle */
 457                framesync_length = frame_length / 2;
 458                frame_start_falling_edge = true;
 459                break;
 460        case SND_SOC_DAIFMT_LEFT_J:
 461                if (slots & 1)
 462                        return -EINVAL;
 463
 464                odd_slot_offset = slots >> 1;
 465                data_delay = 0;
 466                framesync_length = frame_length / 2;
 467                frame_start_falling_edge = false;
 468                break;
 469        case SND_SOC_DAIFMT_RIGHT_J:
 470                if (slots & 1)
 471                        return -EINVAL;
 472
 473                /* Odd frame lengths aren't supported */
 474                if (frame_length & 1)
 475                        return -EINVAL;
 476
 477                odd_slot_offset = slots >> 1;
 478                data_delay = slot_width - data_length;
 479                framesync_length = frame_length / 2;
 480                frame_start_falling_edge = false;
 481                break;
 482        case SND_SOC_DAIFMT_DSP_A:
 483                data_delay = 1;
 484                framesync_length = 1;
 485                frame_start_falling_edge = false;
 486                break;
 487        case SND_SOC_DAIFMT_DSP_B:
 488                data_delay = 0;
 489                framesync_length = 1;
 490                frame_start_falling_edge = false;
 491                break;
 492        default:
 493                return -EINVAL;
 494        }
 495
 496        bcm2835_i2s_calc_channel_pos(&rx_ch1_pos, &rx_ch2_pos,
 497                rx_mask, slot_width, data_delay, odd_slot_offset);
 498        bcm2835_i2s_calc_channel_pos(&tx_ch1_pos, &tx_ch2_pos,
 499                tx_mask, slot_width, data_delay, odd_slot_offset);
 500
 501        /*
 502         * Transmitting data immediately after frame start, eg
 503         * in left-justified or DSP mode A, only works stable
 504         * if bcm2835 is the frame clock master.
 505         */
 506        if ((!rx_ch1_pos || !tx_ch1_pos) && !frame_sync_master)
 507                dev_warn(dev->dev,
 508                        "Unstable slave config detected, L/R may be swapped");
 509
 510        /*
 511         * Set format for both streams.
 512         * We cannot set another frame length
 513         * (and therefore word length) anyway,
 514         * so the format will be the same.
 515         */
 516        regmap_write(dev->i2s_regmap, BCM2835_I2S_RXC_A_REG, 
 517                  format
 518                | BCM2835_I2S_CH1_POS(rx_ch1_pos)
 519                | BCM2835_I2S_CH2_POS(rx_ch2_pos));
 520        regmap_write(dev->i2s_regmap, BCM2835_I2S_TXC_A_REG, 
 521                  format
 522                | BCM2835_I2S_CH1_POS(tx_ch1_pos)
 523                | BCM2835_I2S_CH2_POS(tx_ch2_pos));
 524
 525        /* Setup the I2S mode */
 526
 527        if (data_length <= 16) {
 528                /*
 529                 * Use frame packed mode (2 channels per 32 bit word)
 530                 * We cannot set another frame length in the second stream
 531                 * (and therefore word length) anyway,
 532                 * so the format will be the same.
 533                 */
 534                mode |= BCM2835_I2S_FTXP | BCM2835_I2S_FRXP;
 535        }
 536
 537        mode |= BCM2835_I2S_FLEN(frame_length - 1);
 538        mode |= BCM2835_I2S_FSLEN(framesync_length);
 539
 540        /* CLKM selects bcm2835 clock slave mode */
 541        if (!bit_clock_master)
 542                mode |= BCM2835_I2S_CLKM;
 543
 544        /* FSM selects bcm2835 frame sync slave mode */
 545        if (!frame_sync_master)
 546                mode |= BCM2835_I2S_FSM;
 547
 548        /* CLKI selects normal clocking mode, sampling on rising edge */
 549        switch (dev->fmt & SND_SOC_DAIFMT_INV_MASK) {
 550        case SND_SOC_DAIFMT_NB_NF:
 551        case SND_SOC_DAIFMT_NB_IF:
 552                mode |= BCM2835_I2S_CLKI;
 553                break;
 554        case SND_SOC_DAIFMT_IB_NF:
 555        case SND_SOC_DAIFMT_IB_IF:
 556                break;
 557        default:
 558                return -EINVAL;
 559        }
 560
 561        /* FSI selects frame start on falling edge */
 562        switch (dev->fmt & SND_SOC_DAIFMT_INV_MASK) {
 563        case SND_SOC_DAIFMT_NB_NF:
 564        case SND_SOC_DAIFMT_IB_NF:
 565                if (frame_start_falling_edge)
 566                        mode |= BCM2835_I2S_FSI;
 567                break;
 568        case SND_SOC_DAIFMT_NB_IF:
 569        case SND_SOC_DAIFMT_IB_IF:
 570                if (!frame_start_falling_edge)
 571                        mode |= BCM2835_I2S_FSI;
 572                break;
 573        default:
 574                return -EINVAL;
 575        }
 576
 577        regmap_write(dev->i2s_regmap, BCM2835_I2S_MODE_A_REG, mode);
 578
 579        /* Setup the DMA parameters */
 580        regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
 581                        BCM2835_I2S_RXTHR(1)
 582                        | BCM2835_I2S_TXTHR(1)
 583                        | BCM2835_I2S_DMAEN, 0xffffffff);
 584
 585        regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_DREQ_A_REG,
 586                          BCM2835_I2S_TX_PANIC(0x10)
 587                        | BCM2835_I2S_RX_PANIC(0x30)
 588                        | BCM2835_I2S_TX(0x30)
 589                        | BCM2835_I2S_RX(0x20), 0xffffffff);
 590
 591        /* Clear FIFOs */
 592        bcm2835_i2s_clear_fifos(dev, true, true);
 593
 594        dev_dbg(dev->dev,
 595                "slots: %d width: %d rx mask: 0x%02x tx_mask: 0x%02x\n",
 596                slots, slot_width, rx_mask, tx_mask);
 597
 598        dev_dbg(dev->dev, "frame len: %d sync len: %d data len: %d\n",
 599                frame_length, framesync_length, data_length);
 600
 601        dev_dbg(dev->dev, "rx pos: %d,%d tx pos: %d,%d\n",
 602                rx_ch1_pos, rx_ch2_pos, tx_ch1_pos, tx_ch2_pos);
 603
 604        dev_dbg(dev->dev, "sampling rate: %d bclk rate: %d\n",
 605                params_rate(params), bclk_rate);
 606
 607        dev_dbg(dev->dev, "CLKM: %d CLKI: %d FSM: %d FSI: %d frame start: %s edge\n",
 608                !!(mode & BCM2835_I2S_CLKM),
 609                !!(mode & BCM2835_I2S_CLKI),
 610                !!(mode & BCM2835_I2S_FSM),
 611                !!(mode & BCM2835_I2S_FSI),
 612                (mode & BCM2835_I2S_FSI) ? "falling" : "rising");
 613
 614        return ret;
 615}
 616
 617static int bcm2835_i2s_prepare(struct snd_pcm_substream *substream,
 618                struct snd_soc_dai *dai)
 619{
 620        struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
 621        uint32_t cs_reg;
 622
 623        /*
 624         * Clear both FIFOs if the one that should be started
 625         * is not empty at the moment. This should only happen
 626         * after overrun. Otherwise, hw_params would have cleared
 627         * the FIFO.
 628         */
 629        regmap_read(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, &cs_reg);
 630
 631        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK
 632                        && !(cs_reg & BCM2835_I2S_TXE))
 633                bcm2835_i2s_clear_fifos(dev, true, false);
 634        else if (substream->stream == SNDRV_PCM_STREAM_CAPTURE
 635                        && (cs_reg & BCM2835_I2S_RXD))
 636                bcm2835_i2s_clear_fifos(dev, false, true);
 637
 638        return 0;
 639}
 640
 641static void bcm2835_i2s_stop(struct bcm2835_i2s_dev *dev,
 642                struct snd_pcm_substream *substream,
 643                struct snd_soc_dai *dai)
 644{
 645        uint32_t mask;
 646
 647        if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
 648                mask = BCM2835_I2S_RXON;
 649        else
 650                mask = BCM2835_I2S_TXON;
 651
 652        regmap_update_bits(dev->i2s_regmap,
 653                        BCM2835_I2S_CS_A_REG, mask, 0);
 654
 655        /* Stop also the clock when not SND_SOC_DAIFMT_CONT */
 656        if (!snd_soc_dai_active(dai) && !(dev->fmt & SND_SOC_DAIFMT_CONT))
 657                bcm2835_i2s_stop_clock(dev);
 658}
 659
 660static int bcm2835_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
 661                               struct snd_soc_dai *dai)
 662{
 663        struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
 664        uint32_t mask;
 665
 666        switch (cmd) {
 667        case SNDRV_PCM_TRIGGER_START:
 668        case SNDRV_PCM_TRIGGER_RESUME:
 669        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 670                bcm2835_i2s_start_clock(dev);
 671
 672                if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
 673                        mask = BCM2835_I2S_RXON;
 674                else
 675                        mask = BCM2835_I2S_TXON;
 676
 677                regmap_update_bits(dev->i2s_regmap,
 678                                BCM2835_I2S_CS_A_REG, mask, mask);
 679                break;
 680
 681        case SNDRV_PCM_TRIGGER_STOP:
 682        case SNDRV_PCM_TRIGGER_SUSPEND:
 683        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 684                bcm2835_i2s_stop(dev, substream, dai);
 685                break;
 686        default:
 687                return -EINVAL;
 688        }
 689
 690        return 0;
 691}
 692
 693static int bcm2835_i2s_startup(struct snd_pcm_substream *substream,
 694                               struct snd_soc_dai *dai)
 695{
 696        struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
 697
 698        if (snd_soc_dai_active(dai))
 699                return 0;
 700
 701        /* Should this still be running stop it */
 702        bcm2835_i2s_stop_clock(dev);
 703
 704        /* Enable PCM block */
 705        regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
 706                        BCM2835_I2S_EN, BCM2835_I2S_EN);
 707
 708        /*
 709         * Disable STBY.
 710         * Requires at least 4 PCM clock cycles to take effect.
 711         */
 712        regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
 713                        BCM2835_I2S_STBY, BCM2835_I2S_STBY);
 714
 715        return 0;
 716}
 717
 718static void bcm2835_i2s_shutdown(struct snd_pcm_substream *substream,
 719                struct snd_soc_dai *dai)
 720{
 721        struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
 722
 723        bcm2835_i2s_stop(dev, substream, dai);
 724
 725        /* If both streams are stopped, disable module and clock */
 726        if (snd_soc_dai_active(dai))
 727                return;
 728
 729        /* Disable the module */
 730        regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
 731                        BCM2835_I2S_EN, 0);
 732
 733        /*
 734         * Stopping clock is necessary, because stop does
 735         * not stop the clock when SND_SOC_DAIFMT_CONT
 736         */
 737        bcm2835_i2s_stop_clock(dev);
 738}
 739
 740static const struct snd_soc_dai_ops bcm2835_i2s_dai_ops = {
 741        .startup        = bcm2835_i2s_startup,
 742        .shutdown       = bcm2835_i2s_shutdown,
 743        .prepare        = bcm2835_i2s_prepare,
 744        .trigger        = bcm2835_i2s_trigger,
 745        .hw_params      = bcm2835_i2s_hw_params,
 746        .set_fmt        = bcm2835_i2s_set_dai_fmt,
 747        .set_bclk_ratio = bcm2835_i2s_set_dai_bclk_ratio,
 748        .set_tdm_slot   = bcm2835_i2s_set_dai_tdm_slot,
 749};
 750
 751static int bcm2835_i2s_dai_probe(struct snd_soc_dai *dai)
 752{
 753        struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
 754
 755        snd_soc_dai_init_dma_data(dai,
 756                        &dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK],
 757                        &dev->dma_data[SNDRV_PCM_STREAM_CAPTURE]);
 758
 759        return 0;
 760}
 761
 762static struct snd_soc_dai_driver bcm2835_i2s_dai = {
 763        .name   = "bcm2835-i2s",
 764        .probe  = bcm2835_i2s_dai_probe,
 765        .playback = {
 766                .channels_min = 2,
 767                .channels_max = 2,
 768                .rates =        SNDRV_PCM_RATE_CONTINUOUS,
 769                .rate_min =     8000,
 770                .rate_max =     384000,
 771                .formats =      SNDRV_PCM_FMTBIT_S16_LE
 772                                | SNDRV_PCM_FMTBIT_S24_LE
 773                                | SNDRV_PCM_FMTBIT_S32_LE
 774                },
 775        .capture = {
 776                .channels_min = 2,
 777                .channels_max = 2,
 778                .rates =        SNDRV_PCM_RATE_CONTINUOUS,
 779                .rate_min =     8000,
 780                .rate_max =     384000,
 781                .formats =      SNDRV_PCM_FMTBIT_S16_LE
 782                                | SNDRV_PCM_FMTBIT_S24_LE
 783                                | SNDRV_PCM_FMTBIT_S32_LE
 784                },
 785        .ops = &bcm2835_i2s_dai_ops,
 786        .symmetric_rate = 1,
 787        .symmetric_sample_bits = 1,
 788};
 789
 790static bool bcm2835_i2s_volatile_reg(struct device *dev, unsigned int reg)
 791{
 792        switch (reg) {
 793        case BCM2835_I2S_CS_A_REG:
 794        case BCM2835_I2S_FIFO_A_REG:
 795        case BCM2835_I2S_INTSTC_A_REG:
 796        case BCM2835_I2S_GRAY_REG:
 797                return true;
 798        default:
 799                return false;
 800        }
 801}
 802
 803static bool bcm2835_i2s_precious_reg(struct device *dev, unsigned int reg)
 804{
 805        switch (reg) {
 806        case BCM2835_I2S_FIFO_A_REG:
 807                return true;
 808        default:
 809                return false;
 810        }
 811}
 812
 813static const struct regmap_config bcm2835_regmap_config = {
 814        .reg_bits = 32,
 815        .reg_stride = 4,
 816        .val_bits = 32,
 817        .max_register = BCM2835_I2S_GRAY_REG,
 818        .precious_reg = bcm2835_i2s_precious_reg,
 819        .volatile_reg = bcm2835_i2s_volatile_reg,
 820        .cache_type = REGCACHE_RBTREE,
 821};
 822
 823static const struct snd_soc_component_driver bcm2835_i2s_component = {
 824        .name           = "bcm2835-i2s-comp",
 825};
 826
 827static int bcm2835_i2s_probe(struct platform_device *pdev)
 828{
 829        struct bcm2835_i2s_dev *dev;
 830        int ret;
 831        void __iomem *base;
 832        const __be32 *addr;
 833        dma_addr_t dma_base;
 834
 835        dev = devm_kzalloc(&pdev->dev, sizeof(*dev),
 836                           GFP_KERNEL);
 837        if (!dev)
 838                return -ENOMEM;
 839
 840        /* get the clock */
 841        dev->clk_prepared = false;
 842        dev->clk = devm_clk_get(&pdev->dev, NULL);
 843        if (IS_ERR(dev->clk)) {
 844                ret = PTR_ERR(dev->clk);
 845                if (ret == -EPROBE_DEFER)
 846                        dev_dbg(&pdev->dev, "could not get clk: %d\n", ret);
 847                else
 848                        dev_err(&pdev->dev, "could not get clk: %d\n", ret);
 849                return ret;
 850        }
 851
 852        /* Request ioarea */
 853        base = devm_platform_ioremap_resource(pdev, 0);
 854        if (IS_ERR(base))
 855                return PTR_ERR(base);
 856
 857        dev->i2s_regmap = devm_regmap_init_mmio(&pdev->dev, base,
 858                                &bcm2835_regmap_config);
 859        if (IS_ERR(dev->i2s_regmap))
 860                return PTR_ERR(dev->i2s_regmap);
 861
 862        /* Set the DMA address - we have to parse DT ourselves */
 863        addr = of_get_address(pdev->dev.of_node, 0, NULL, NULL);
 864        if (!addr) {
 865                dev_err(&pdev->dev, "could not get DMA-register address\n");
 866                return -EINVAL;
 867        }
 868        dma_base = be32_to_cpup(addr);
 869
 870        dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].addr =
 871                dma_base + BCM2835_I2S_FIFO_A_REG;
 872
 873        dev->dma_data[SNDRV_PCM_STREAM_CAPTURE].addr =
 874                dma_base + BCM2835_I2S_FIFO_A_REG;
 875
 876        /* Set the bus width */
 877        dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].addr_width =
 878                DMA_SLAVE_BUSWIDTH_4_BYTES;
 879        dev->dma_data[SNDRV_PCM_STREAM_CAPTURE].addr_width =
 880                DMA_SLAVE_BUSWIDTH_4_BYTES;
 881
 882        /* Set burst */
 883        dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].maxburst = 2;
 884        dev->dma_data[SNDRV_PCM_STREAM_CAPTURE].maxburst = 2;
 885
 886        /*
 887         * Set the PACK flag to enable S16_LE support (2 S16_LE values
 888         * packed into 32-bit transfers).
 889         */
 890        dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].flags =
 891                SND_DMAENGINE_PCM_DAI_FLAG_PACK;
 892        dev->dma_data[SNDRV_PCM_STREAM_CAPTURE].flags =
 893                SND_DMAENGINE_PCM_DAI_FLAG_PACK;
 894
 895        /* Store the pdev */
 896        dev->dev = &pdev->dev;
 897        dev_set_drvdata(&pdev->dev, dev);
 898
 899        ret = devm_snd_soc_register_component(&pdev->dev,
 900                        &bcm2835_i2s_component, &bcm2835_i2s_dai, 1);
 901        if (ret) {
 902                dev_err(&pdev->dev, "Could not register DAI: %d\n", ret);
 903                return ret;
 904        }
 905
 906        ret = devm_snd_dmaengine_pcm_register(&pdev->dev, NULL, 0);
 907        if (ret) {
 908                dev_err(&pdev->dev, "Could not register PCM: %d\n", ret);
 909                return ret;
 910        }
 911
 912        return 0;
 913}
 914
 915static const struct of_device_id bcm2835_i2s_of_match[] = {
 916        { .compatible = "brcm,bcm2835-i2s", },
 917        {},
 918};
 919
 920MODULE_DEVICE_TABLE(of, bcm2835_i2s_of_match);
 921
 922static struct platform_driver bcm2835_i2s_driver = {
 923        .probe          = bcm2835_i2s_probe,
 924        .driver         = {
 925                .name   = "bcm2835-i2s",
 926                .of_match_table = bcm2835_i2s_of_match,
 927        },
 928};
 929
 930module_platform_driver(bcm2835_i2s_driver);
 931
 932MODULE_ALIAS("platform:bcm2835-i2s");
 933MODULE_DESCRIPTION("BCM2835 I2S interface");
 934MODULE_AUTHOR("Florian Meier <florian.meier@koalo.de>");
 935MODULE_LICENSE("GPL v2");
 936