linux/drivers/iio/adc/at91_adc.c
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   1/*
   2 * Driver for the ADC present in the Atmel AT91 evaluation boards.
   3 *
   4 * Copyright 2011 Free Electrons
   5 *
   6 * Licensed under the GPLv2 or later.
   7 */
   8
   9#include <linux/bitmap.h>
  10#include <linux/bitops.h>
  11#include <linux/clk.h>
  12#include <linux/err.h>
  13#include <linux/io.h>
  14#include <linux/input.h>
  15#include <linux/interrupt.h>
  16#include <linux/jiffies.h>
  17#include <linux/kernel.h>
  18#include <linux/module.h>
  19#include <linux/of.h>
  20#include <linux/of_device.h>
  21#include <linux/platform_device.h>
  22#include <linux/sched.h>
  23#include <linux/slab.h>
  24#include <linux/wait.h>
  25
  26#include <linux/platform_data/at91_adc.h>
  27
  28#include <linux/iio/iio.h>
  29#include <linux/iio/buffer.h>
  30#include <linux/iio/trigger.h>
  31#include <linux/iio/trigger_consumer.h>
  32#include <linux/iio/triggered_buffer.h>
  33
  34#include <mach/at91_adc.h>
  35
  36#define AT91_ADC_CHAN(st, ch) \
  37        (st->registers->channel_base + (ch * 4))
  38#define at91_adc_readl(st, reg) \
  39        (readl_relaxed(st->reg_base + reg))
  40#define at91_adc_writel(st, reg, val) \
  41        (writel_relaxed(val, st->reg_base + reg))
  42
  43#define DRIVER_NAME             "at91_adc"
  44#define MAX_POS_BITS            12
  45
  46#define TOUCH_SAMPLE_PERIOD_US          2000    /* 2ms */
  47#define TOUCH_PEN_DETECT_DEBOUNCE_US    200
  48
  49struct at91_adc_caps {
  50        bool    has_ts;         /* Support touch screen */
  51        bool    has_tsmr;       /* only at91sam9x5, sama5d3 have TSMR reg */
  52        /*
  53         * Numbers of sampling data will be averaged. Can be 0~3.
  54         * Hardware can average (2 ^ ts_filter_average) sample data.
  55         */
  56        u8      ts_filter_average;
  57        /* Pen Detection input pull-up resistor, can be 0~3 */
  58        u8      ts_pen_detect_sensitivity;
  59
  60        /* startup time calculate function */
  61        u32 (*calc_startup_ticks)(u8 startup_time, u32 adc_clk_khz);
  62
  63        u8      num_channels;
  64        struct at91_adc_reg_desc registers;
  65};
  66
  67enum atmel_adc_ts_type {
  68        ATMEL_ADC_TOUCHSCREEN_NONE = 0,
  69        ATMEL_ADC_TOUCHSCREEN_4WIRE = 4,
  70        ATMEL_ADC_TOUCHSCREEN_5WIRE = 5,
  71};
  72
  73struct at91_adc_state {
  74        struct clk              *adc_clk;
  75        u16                     *buffer;
  76        unsigned long           channels_mask;
  77        struct clk              *clk;
  78        bool                    done;
  79        int                     irq;
  80        u16                     last_value;
  81        struct mutex            lock;
  82        u8                      num_channels;
  83        void __iomem            *reg_base;
  84        struct at91_adc_reg_desc *registers;
  85        u8                      startup_time;
  86        u8                      sample_hold_time;
  87        bool                    sleep_mode;
  88        struct iio_trigger      **trig;
  89        struct at91_adc_trigger *trigger_list;
  90        u32                     trigger_number;
  91        bool                    use_external;
  92        u32                     vref_mv;
  93        u32                     res;            /* resolution used for convertions */
  94        bool                    low_res;        /* the resolution corresponds to the lowest one */
  95        wait_queue_head_t       wq_data_avail;
  96        struct at91_adc_caps    *caps;
  97
  98        /*
  99         * Following ADC channels are shared by touchscreen:
 100         *
 101         * CH0 -- Touch screen XP/UL
 102         * CH1 -- Touch screen XM/UR
 103         * CH2 -- Touch screen YP/LL
 104         * CH3 -- Touch screen YM/Sense
 105         * CH4 -- Touch screen LR(5-wire only)
 106         *
 107         * The bitfields below represents the reserved channel in the
 108         * touchscreen mode.
 109         */
 110#define CHAN_MASK_TOUCHSCREEN_4WIRE     (0xf << 0)
 111#define CHAN_MASK_TOUCHSCREEN_5WIRE     (0x1f << 0)
 112        enum atmel_adc_ts_type  touchscreen_type;
 113        struct input_dev        *ts_input;
 114
 115        u16                     ts_sample_period_val;
 116        u32                     ts_pressure_threshold;
 117};
 118
 119static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
 120{
 121        struct iio_poll_func *pf = p;
 122        struct iio_dev *idev = pf->indio_dev;
 123        struct at91_adc_state *st = iio_priv(idev);
 124        int i, j = 0;
 125
 126        for (i = 0; i < idev->masklength; i++) {
 127                if (!test_bit(i, idev->active_scan_mask))
 128                        continue;
 129                st->buffer[j] = at91_adc_readl(st, AT91_ADC_CHAN(st, i));
 130                j++;
 131        }
 132
 133        iio_push_to_buffers_with_timestamp(idev, st->buffer, pf->timestamp);
 134
 135        iio_trigger_notify_done(idev->trig);
 136
 137        /* Needed to ACK the DRDY interruption */
 138        at91_adc_readl(st, AT91_ADC_LCDR);
 139
 140        enable_irq(st->irq);
 141
 142        return IRQ_HANDLED;
 143}
 144
 145/* Handler for classic adc channel eoc trigger */
 146void handle_adc_eoc_trigger(int irq, struct iio_dev *idev)
 147{
 148        struct at91_adc_state *st = iio_priv(idev);
 149
 150        if (iio_buffer_enabled(idev)) {
 151                disable_irq_nosync(irq);
 152                iio_trigger_poll(idev->trig, iio_get_time_ns());
 153        } else {
 154                st->last_value = at91_adc_readl(st, AT91_ADC_LCDR);
 155                st->done = true;
 156                wake_up_interruptible(&st->wq_data_avail);
 157        }
 158}
 159
 160static int at91_ts_sample(struct at91_adc_state *st)
 161{
 162        unsigned int xscale, yscale, reg, z1, z2;
 163        unsigned int x, y, pres, xpos, ypos;
 164        unsigned int rxp = 1;
 165        unsigned int factor = 1000;
 166        struct iio_dev *idev = iio_priv_to_dev(st);
 167
 168        unsigned int xyz_mask_bits = st->res;
 169        unsigned int xyz_mask = (1 << xyz_mask_bits) - 1;
 170
 171        /* calculate position */
 172        /* x position = (x / xscale) * max, max = 2^MAX_POS_BITS - 1 */
 173        reg = at91_adc_readl(st, AT91_ADC_TSXPOSR);
 174        xpos = reg & xyz_mask;
 175        x = (xpos << MAX_POS_BITS) - xpos;
 176        xscale = (reg >> 16) & xyz_mask;
 177        if (xscale == 0) {
 178                dev_err(&idev->dev, "Error: xscale == 0!\n");
 179                return -1;
 180        }
 181        x /= xscale;
 182
 183        /* y position = (y / yscale) * max, max = 2^MAX_POS_BITS - 1 */
 184        reg = at91_adc_readl(st, AT91_ADC_TSYPOSR);
 185        ypos = reg & xyz_mask;
 186        y = (ypos << MAX_POS_BITS) - ypos;
 187        yscale = (reg >> 16) & xyz_mask;
 188        if (yscale == 0) {
 189                dev_err(&idev->dev, "Error: yscale == 0!\n");
 190                return -1;
 191        }
 192        y /= yscale;
 193
 194        /* calculate the pressure */
 195        reg = at91_adc_readl(st, AT91_ADC_TSPRESSR);
 196        z1 = reg & xyz_mask;
 197        z2 = (reg >> 16) & xyz_mask;
 198
 199        if (z1 != 0)
 200                pres = rxp * (x * factor / 1024) * (z2 * factor / z1 - factor)
 201                        / factor;
 202        else
 203                pres = st->ts_pressure_threshold;       /* no pen contacted */
 204
 205        dev_dbg(&idev->dev, "xpos = %d, xscale = %d, ypos = %d, yscale = %d, z1 = %d, z2 = %d, press = %d\n",
 206                                xpos, xscale, ypos, yscale, z1, z2, pres);
 207
 208        if (pres < st->ts_pressure_threshold) {
 209                dev_dbg(&idev->dev, "x = %d, y = %d, pressure = %d\n",
 210                                        x, y, pres / factor);
 211                input_report_abs(st->ts_input, ABS_X, x);
 212                input_report_abs(st->ts_input, ABS_Y, y);
 213                input_report_abs(st->ts_input, ABS_PRESSURE, pres);
 214                input_report_key(st->ts_input, BTN_TOUCH, 1);
 215                input_sync(st->ts_input);
 216        } else {
 217                dev_dbg(&idev->dev, "pressure too low: not reporting\n");
 218        }
 219
 220        return 0;
 221}
 222
 223static irqreturn_t at91_adc_interrupt(int irq, void *private)
 224{
 225        struct iio_dev *idev = private;
 226        struct at91_adc_state *st = iio_priv(idev);
 227        u32 status = at91_adc_readl(st, st->registers->status_register);
 228        const uint32_t ts_data_irq_mask =
 229                AT91_ADC_IER_XRDY |
 230                AT91_ADC_IER_YRDY |
 231                AT91_ADC_IER_PRDY;
 232
 233        if (status & st->registers->drdy_mask)
 234                handle_adc_eoc_trigger(irq, idev);
 235
 236        if (status & AT91_ADC_IER_PEN) {
 237                at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
 238                at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_NOPEN |
 239                        ts_data_irq_mask);
 240                /* Set up period trigger for sampling */
 241                at91_adc_writel(st, st->registers->trigger_register,
 242                        AT91_ADC_TRGR_MOD_PERIOD_TRIG |
 243                        AT91_ADC_TRGR_TRGPER_(st->ts_sample_period_val));
 244        } else if (status & AT91_ADC_IER_NOPEN) {
 245                at91_adc_writel(st, st->registers->trigger_register, 0);
 246                at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_NOPEN |
 247                        ts_data_irq_mask);
 248                at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
 249
 250                input_report_key(st->ts_input, BTN_TOUCH, 0);
 251                input_sync(st->ts_input);
 252        } else if ((status & ts_data_irq_mask) == ts_data_irq_mask) {
 253                /* Now all touchscreen data is ready */
 254
 255                if (status & AT91_ADC_ISR_PENS) {
 256                        /* validate data by pen contact */
 257                        at91_ts_sample(st);
 258                } else {
 259                        /* triggered by event that is no pen contact, just read
 260                         * them to clean the interrupt and discard all.
 261                         */
 262                        at91_adc_readl(st, AT91_ADC_TSXPOSR);
 263                        at91_adc_readl(st, AT91_ADC_TSYPOSR);
 264                        at91_adc_readl(st, AT91_ADC_TSPRESSR);
 265                }
 266        }
 267
 268        return IRQ_HANDLED;
 269}
 270
 271static int at91_adc_channel_init(struct iio_dev *idev)
 272{
 273        struct at91_adc_state *st = iio_priv(idev);
 274        struct iio_chan_spec *chan_array, *timestamp;
 275        int bit, idx = 0;
 276        unsigned long rsvd_mask = 0;
 277
 278        /* If touchscreen is enable, then reserve the adc channels */
 279        if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
 280                rsvd_mask = CHAN_MASK_TOUCHSCREEN_4WIRE;
 281        else if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_5WIRE)
 282                rsvd_mask = CHAN_MASK_TOUCHSCREEN_5WIRE;
 283
 284        /* set up the channel mask to reserve touchscreen channels */
 285        st->channels_mask &= ~rsvd_mask;
 286
 287        idev->num_channels = bitmap_weight(&st->channels_mask,
 288                                           st->num_channels) + 1;
 289
 290        chan_array = devm_kzalloc(&idev->dev,
 291                                  ((idev->num_channels + 1) *
 292                                        sizeof(struct iio_chan_spec)),
 293                                  GFP_KERNEL);
 294
 295        if (!chan_array)
 296                return -ENOMEM;
 297
 298        for_each_set_bit(bit, &st->channels_mask, st->num_channels) {
 299                struct iio_chan_spec *chan = chan_array + idx;
 300
 301                chan->type = IIO_VOLTAGE;
 302                chan->indexed = 1;
 303                chan->channel = bit;
 304                chan->scan_index = idx;
 305                chan->scan_type.sign = 'u';
 306                chan->scan_type.realbits = st->res;
 307                chan->scan_type.storagebits = 16;
 308                chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
 309                chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
 310                idx++;
 311        }
 312        timestamp = chan_array + idx;
 313
 314        timestamp->type = IIO_TIMESTAMP;
 315        timestamp->channel = -1;
 316        timestamp->scan_index = idx;
 317        timestamp->scan_type.sign = 's';
 318        timestamp->scan_type.realbits = 64;
 319        timestamp->scan_type.storagebits = 64;
 320
 321        idev->channels = chan_array;
 322        return idev->num_channels;
 323}
 324
 325static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
 326                                             struct at91_adc_trigger *triggers,
 327                                             const char *trigger_name)
 328{
 329        struct at91_adc_state *st = iio_priv(idev);
 330        u8 value = 0;
 331        int i;
 332
 333        for (i = 0; i < st->trigger_number; i++) {
 334                char *name = kasprintf(GFP_KERNEL,
 335                                "%s-dev%d-%s",
 336                                idev->name,
 337                                idev->id,
 338                                triggers[i].name);
 339                if (!name)
 340                        return -ENOMEM;
 341
 342                if (strcmp(trigger_name, name) == 0) {
 343                        value = triggers[i].value;
 344                        kfree(name);
 345                        break;
 346                }
 347
 348                kfree(name);
 349        }
 350
 351        return value;
 352}
 353
 354static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
 355{
 356        struct iio_dev *idev = iio_trigger_get_drvdata(trig);
 357        struct at91_adc_state *st = iio_priv(idev);
 358        struct iio_buffer *buffer = idev->buffer;
 359        struct at91_adc_reg_desc *reg = st->registers;
 360        u32 status = at91_adc_readl(st, reg->trigger_register);
 361        u8 value;
 362        u8 bit;
 363
 364        value = at91_adc_get_trigger_value_by_name(idev,
 365                                                   st->trigger_list,
 366                                                   idev->trig->name);
 367        if (value == 0)
 368                return -EINVAL;
 369
 370        if (state) {
 371                st->buffer = kmalloc(idev->scan_bytes, GFP_KERNEL);
 372                if (st->buffer == NULL)
 373                        return -ENOMEM;
 374
 375                at91_adc_writel(st, reg->trigger_register,
 376                                status | value);
 377
 378                for_each_set_bit(bit, buffer->scan_mask,
 379                                 st->num_channels) {
 380                        struct iio_chan_spec const *chan = idev->channels + bit;
 381                        at91_adc_writel(st, AT91_ADC_CHER,
 382                                        AT91_ADC_CH(chan->channel));
 383                }
 384
 385                at91_adc_writel(st, AT91_ADC_IER, reg->drdy_mask);
 386
 387        } else {
 388                at91_adc_writel(st, AT91_ADC_IDR, reg->drdy_mask);
 389
 390                at91_adc_writel(st, reg->trigger_register,
 391                                status & ~value);
 392
 393                for_each_set_bit(bit, buffer->scan_mask,
 394                                 st->num_channels) {
 395                        struct iio_chan_spec const *chan = idev->channels + bit;
 396                        at91_adc_writel(st, AT91_ADC_CHDR,
 397                                        AT91_ADC_CH(chan->channel));
 398                }
 399                kfree(st->buffer);
 400        }
 401
 402        return 0;
 403}
 404
 405static const struct iio_trigger_ops at91_adc_trigger_ops = {
 406        .owner = THIS_MODULE,
 407        .set_trigger_state = &at91_adc_configure_trigger,
 408};
 409
 410static struct iio_trigger *at91_adc_allocate_trigger(struct iio_dev *idev,
 411                                                     struct at91_adc_trigger *trigger)
 412{
 413        struct iio_trigger *trig;
 414        int ret;
 415
 416        trig = iio_trigger_alloc("%s-dev%d-%s", idev->name,
 417                                 idev->id, trigger->name);
 418        if (trig == NULL)
 419                return NULL;
 420
 421        trig->dev.parent = idev->dev.parent;
 422        iio_trigger_set_drvdata(trig, idev);
 423        trig->ops = &at91_adc_trigger_ops;
 424
 425        ret = iio_trigger_register(trig);
 426        if (ret)
 427                return NULL;
 428
 429        return trig;
 430}
 431
 432static int at91_adc_trigger_init(struct iio_dev *idev)
 433{
 434        struct at91_adc_state *st = iio_priv(idev);
 435        int i, ret;
 436
 437        st->trig = devm_kzalloc(&idev->dev,
 438                                st->trigger_number * sizeof(*st->trig),
 439                                GFP_KERNEL);
 440
 441        if (st->trig == NULL) {
 442                ret = -ENOMEM;
 443                goto error_ret;
 444        }
 445
 446        for (i = 0; i < st->trigger_number; i++) {
 447                if (st->trigger_list[i].is_external && !(st->use_external))
 448                        continue;
 449
 450                st->trig[i] = at91_adc_allocate_trigger(idev,
 451                                                        st->trigger_list + i);
 452                if (st->trig[i] == NULL) {
 453                        dev_err(&idev->dev,
 454                                "Could not allocate trigger %d\n", i);
 455                        ret = -ENOMEM;
 456                        goto error_trigger;
 457                }
 458        }
 459
 460        return 0;
 461
 462error_trigger:
 463        for (i--; i >= 0; i--) {
 464                iio_trigger_unregister(st->trig[i]);
 465                iio_trigger_free(st->trig[i]);
 466        }
 467error_ret:
 468        return ret;
 469}
 470
 471static void at91_adc_trigger_remove(struct iio_dev *idev)
 472{
 473        struct at91_adc_state *st = iio_priv(idev);
 474        int i;
 475
 476        for (i = 0; i < st->trigger_number; i++) {
 477                iio_trigger_unregister(st->trig[i]);
 478                iio_trigger_free(st->trig[i]);
 479        }
 480}
 481
 482static int at91_adc_buffer_init(struct iio_dev *idev)
 483{
 484        return iio_triggered_buffer_setup(idev, &iio_pollfunc_store_time,
 485                &at91_adc_trigger_handler, NULL);
 486}
 487
 488static void at91_adc_buffer_remove(struct iio_dev *idev)
 489{
 490        iio_triggered_buffer_cleanup(idev);
 491}
 492
 493static int at91_adc_read_raw(struct iio_dev *idev,
 494                             struct iio_chan_spec const *chan,
 495                             int *val, int *val2, long mask)
 496{
 497        struct at91_adc_state *st = iio_priv(idev);
 498        int ret;
 499
 500        switch (mask) {
 501        case IIO_CHAN_INFO_RAW:
 502                mutex_lock(&st->lock);
 503
 504                at91_adc_writel(st, AT91_ADC_CHER,
 505                                AT91_ADC_CH(chan->channel));
 506                at91_adc_writel(st, AT91_ADC_IER, st->registers->drdy_mask);
 507                at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_START);
 508
 509                ret = wait_event_interruptible_timeout(st->wq_data_avail,
 510                                                       st->done,
 511                                                       msecs_to_jiffies(1000));
 512                if (ret == 0)
 513                        ret = -ETIMEDOUT;
 514                if (ret < 0) {
 515                        mutex_unlock(&st->lock);
 516                        return ret;
 517                }
 518
 519                *val = st->last_value;
 520
 521                at91_adc_writel(st, AT91_ADC_CHDR,
 522                                AT91_ADC_CH(chan->channel));
 523                at91_adc_writel(st, AT91_ADC_IDR, st->registers->drdy_mask);
 524
 525                st->last_value = 0;
 526                st->done = false;
 527                mutex_unlock(&st->lock);
 528                return IIO_VAL_INT;
 529
 530        case IIO_CHAN_INFO_SCALE:
 531                *val = st->vref_mv;
 532                *val2 = chan->scan_type.realbits;
 533                return IIO_VAL_FRACTIONAL_LOG2;
 534        default:
 535                break;
 536        }
 537        return -EINVAL;
 538}
 539
 540static int at91_adc_of_get_resolution(struct at91_adc_state *st,
 541                                      struct platform_device *pdev)
 542{
 543        struct iio_dev *idev = iio_priv_to_dev(st);
 544        struct device_node *np = pdev->dev.of_node;
 545        int count, i, ret = 0;
 546        char *res_name, *s;
 547        u32 *resolutions;
 548
 549        count = of_property_count_strings(np, "atmel,adc-res-names");
 550        if (count < 2) {
 551                dev_err(&idev->dev, "You must specified at least two resolution names for "
 552                                    "adc-res-names property in the DT\n");
 553                return count;
 554        }
 555
 556        resolutions = kmalloc(count * sizeof(*resolutions), GFP_KERNEL);
 557        if (!resolutions)
 558                return -ENOMEM;
 559
 560        if (of_property_read_u32_array(np, "atmel,adc-res", resolutions, count)) {
 561                dev_err(&idev->dev, "Missing adc-res property in the DT.\n");
 562                ret = -ENODEV;
 563                goto ret;
 564        }
 565
 566        if (of_property_read_string(np, "atmel,adc-use-res", (const char **)&res_name))
 567                res_name = "highres";
 568
 569        for (i = 0; i < count; i++) {
 570                if (of_property_read_string_index(np, "atmel,adc-res-names", i, (const char **)&s))
 571                        continue;
 572
 573                if (strcmp(res_name, s))
 574                        continue;
 575
 576                st->res = resolutions[i];
 577                if (!strcmp(res_name, "lowres"))
 578                        st->low_res = true;
 579                else
 580                        st->low_res = false;
 581
 582                dev_info(&idev->dev, "Resolution used: %u bits\n", st->res);
 583                goto ret;
 584        }
 585
 586        dev_err(&idev->dev, "There is no resolution for %s\n", res_name);
 587
 588ret:
 589        kfree(resolutions);
 590        return ret;
 591}
 592
 593static u32 calc_startup_ticks_9260(u8 startup_time, u32 adc_clk_khz)
 594{
 595        /*
 596         * Number of ticks needed to cover the startup time of the ADC
 597         * as defined in the electrical characteristics of the board,
 598         * divided by 8. The formula thus is :
 599         *   Startup Time = (ticks + 1) * 8 / ADC Clock
 600         */
 601        return round_up((startup_time * adc_clk_khz / 1000) - 1, 8) / 8;
 602}
 603
 604static u32 calc_startup_ticks_9x5(u8 startup_time, u32 adc_clk_khz)
 605{
 606        /*
 607         * For sama5d3x and at91sam9x5, the formula changes to:
 608         * Startup Time = <lookup_table_value> / ADC Clock
 609         */
 610        const int startup_lookup[] = {
 611                0  , 8  , 16 , 24 ,
 612                64 , 80 , 96 , 112,
 613                512, 576, 640, 704,
 614                768, 832, 896, 960
 615                };
 616        int i, size = ARRAY_SIZE(startup_lookup);
 617        unsigned int ticks;
 618
 619        ticks = startup_time * adc_clk_khz / 1000;
 620        for (i = 0; i < size; i++)
 621                if (ticks < startup_lookup[i])
 622                        break;
 623
 624        ticks = i;
 625        if (ticks == size)
 626                /* Reach the end of lookup table */
 627                ticks = size - 1;
 628
 629        return ticks;
 630}
 631
 632static const struct of_device_id at91_adc_dt_ids[];
 633
 634static int at91_adc_probe_dt_ts(struct device_node *node,
 635        struct at91_adc_state *st, struct device *dev)
 636{
 637        int ret;
 638        u32 prop;
 639
 640        ret = of_property_read_u32(node, "atmel,adc-ts-wires", &prop);
 641        if (ret) {
 642                dev_info(dev, "ADC Touch screen is disabled.\n");
 643                return 0;
 644        }
 645
 646        switch (prop) {
 647        case 4:
 648        case 5:
 649                st->touchscreen_type = prop;
 650                break;
 651        default:
 652                dev_err(dev, "Unsupported number of touchscreen wires (%d). Should be 4 or 5.\n", prop);
 653                return -EINVAL;
 654        }
 655
 656        prop = 0;
 657        of_property_read_u32(node, "atmel,adc-ts-pressure-threshold", &prop);
 658        st->ts_pressure_threshold = prop;
 659        if (st->ts_pressure_threshold) {
 660                return 0;
 661        } else {
 662                dev_err(dev, "Invalid pressure threshold for the touchscreen\n");
 663                return -EINVAL;
 664        }
 665}
 666
 667static int at91_adc_probe_dt(struct at91_adc_state *st,
 668                             struct platform_device *pdev)
 669{
 670        struct iio_dev *idev = iio_priv_to_dev(st);
 671        struct device_node *node = pdev->dev.of_node;
 672        struct device_node *trig_node;
 673        int i = 0, ret;
 674        u32 prop;
 675
 676        if (!node)
 677                return -EINVAL;
 678
 679        st->caps = (struct at91_adc_caps *)
 680                of_match_device(at91_adc_dt_ids, &pdev->dev)->data;
 681
 682        st->use_external = of_property_read_bool(node, "atmel,adc-use-external-triggers");
 683
 684        if (of_property_read_u32(node, "atmel,adc-channels-used", &prop)) {
 685                dev_err(&idev->dev, "Missing adc-channels-used property in the DT.\n");
 686                ret = -EINVAL;
 687                goto error_ret;
 688        }
 689        st->channels_mask = prop;
 690
 691        st->sleep_mode = of_property_read_bool(node, "atmel,adc-sleep-mode");
 692
 693        if (of_property_read_u32(node, "atmel,adc-startup-time", &prop)) {
 694                dev_err(&idev->dev, "Missing adc-startup-time property in the DT.\n");
 695                ret = -EINVAL;
 696                goto error_ret;
 697        }
 698        st->startup_time = prop;
 699
 700        prop = 0;
 701        of_property_read_u32(node, "atmel,adc-sample-hold-time", &prop);
 702        st->sample_hold_time = prop;
 703
 704        if (of_property_read_u32(node, "atmel,adc-vref", &prop)) {
 705                dev_err(&idev->dev, "Missing adc-vref property in the DT.\n");
 706                ret = -EINVAL;
 707                goto error_ret;
 708        }
 709        st->vref_mv = prop;
 710
 711        ret = at91_adc_of_get_resolution(st, pdev);
 712        if (ret)
 713                goto error_ret;
 714
 715        st->registers = &st->caps->registers;
 716        st->num_channels = st->caps->num_channels;
 717        st->trigger_number = of_get_child_count(node);
 718        st->trigger_list = devm_kzalloc(&idev->dev, st->trigger_number *
 719                                        sizeof(struct at91_adc_trigger),
 720                                        GFP_KERNEL);
 721        if (!st->trigger_list) {
 722                dev_err(&idev->dev, "Could not allocate trigger list memory.\n");
 723                ret = -ENOMEM;
 724                goto error_ret;
 725        }
 726
 727        for_each_child_of_node(node, trig_node) {
 728                struct at91_adc_trigger *trig = st->trigger_list + i;
 729                const char *name;
 730
 731                if (of_property_read_string(trig_node, "trigger-name", &name)) {
 732                        dev_err(&idev->dev, "Missing trigger-name property in the DT.\n");
 733                        ret = -EINVAL;
 734                        goto error_ret;
 735                }
 736                trig->name = name;
 737
 738                if (of_property_read_u32(trig_node, "trigger-value", &prop)) {
 739                        dev_err(&idev->dev, "Missing trigger-value property in the DT.\n");
 740                        ret = -EINVAL;
 741                        goto error_ret;
 742                }
 743                trig->value = prop;
 744                trig->is_external = of_property_read_bool(trig_node, "trigger-external");
 745                i++;
 746        }
 747
 748        /* Check if touchscreen is supported. */
 749        if (st->caps->has_ts)
 750                return at91_adc_probe_dt_ts(node, st, &idev->dev);
 751        else
 752                dev_info(&idev->dev, "not support touchscreen in the adc compatible string.\n");
 753
 754        return 0;
 755
 756error_ret:
 757        return ret;
 758}
 759
 760static int at91_adc_probe_pdata(struct at91_adc_state *st,
 761                                struct platform_device *pdev)
 762{
 763        struct at91_adc_data *pdata = pdev->dev.platform_data;
 764
 765        if (!pdata)
 766                return -EINVAL;
 767
 768        st->use_external = pdata->use_external_triggers;
 769        st->vref_mv = pdata->vref;
 770        st->channels_mask = pdata->channels_used;
 771        st->num_channels = pdata->num_channels;
 772        st->startup_time = pdata->startup_time;
 773        st->trigger_number = pdata->trigger_number;
 774        st->trigger_list = pdata->trigger_list;
 775        st->registers = pdata->registers;
 776
 777        return 0;
 778}
 779
 780static const struct iio_info at91_adc_info = {
 781        .driver_module = THIS_MODULE,
 782        .read_raw = &at91_adc_read_raw,
 783};
 784
 785/* Touchscreen related functions */
 786static int atmel_ts_open(struct input_dev *dev)
 787{
 788        struct at91_adc_state *st = input_get_drvdata(dev);
 789
 790        at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
 791        return 0;
 792}
 793
 794static void atmel_ts_close(struct input_dev *dev)
 795{
 796        struct at91_adc_state *st = input_get_drvdata(dev);
 797
 798        at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
 799}
 800
 801static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz)
 802{
 803        u32 reg = 0, pendbc;
 804        int i = 0;
 805
 806        if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
 807                reg = AT91_ADC_TSMR_TSMODE_4WIRE_PRESS;
 808        else
 809                reg = AT91_ADC_TSMR_TSMODE_5WIRE;
 810
 811        /* a Pen Detect Debounce Time is necessary for the ADC Touch to avoid
 812         * pen detect noise.
 813         * The formula is : Pen Detect Debounce Time = (2 ^ pendbc) / ADCClock
 814         */
 815        pendbc = round_up(TOUCH_PEN_DETECT_DEBOUNCE_US * adc_clk_khz / 1000, 1);
 816
 817        while (pendbc >> ++i)
 818                ;       /* Empty! Find the shift offset */
 819        if (abs(pendbc - (1 << i)) < abs(pendbc - (1 << (i - 1))))
 820                pendbc = i;
 821        else
 822                pendbc = i - 1;
 823
 824        if (st->caps->has_tsmr) {
 825                reg |= AT91_ADC_TSMR_TSAV_(st->caps->ts_filter_average)
 826                                & AT91_ADC_TSMR_TSAV;
 827                reg |= AT91_ADC_TSMR_PENDBC_(pendbc) & AT91_ADC_TSMR_PENDBC;
 828                reg |= AT91_ADC_TSMR_NOTSDMA;
 829                reg |= AT91_ADC_TSMR_PENDET_ENA;
 830                reg |= 0x03 << 8;       /* TSFREQ, need bigger than TSAV */
 831
 832                at91_adc_writel(st, AT91_ADC_TSMR, reg);
 833        } else {
 834                /* TODO: for 9g45 which has no TSMR */
 835        }
 836
 837        /* Change adc internal resistor value for better pen detection,
 838         * default value is 100 kOhm.
 839         * 0 = 200 kOhm, 1 = 150 kOhm, 2 = 100 kOhm, 3 = 50 kOhm
 840         * option only available on ES2 and higher
 841         */
 842        at91_adc_writel(st, AT91_ADC_ACR, st->caps->ts_pen_detect_sensitivity
 843                        & AT91_ADC_ACR_PENDETSENS);
 844
 845        /* Sample Peroid Time = (TRGPER + 1) / ADCClock */
 846        st->ts_sample_period_val = round_up((TOUCH_SAMPLE_PERIOD_US *
 847                        adc_clk_khz / 1000) - 1, 1);
 848
 849        return 0;
 850}
 851
 852static int at91_ts_register(struct at91_adc_state *st,
 853                struct platform_device *pdev)
 854{
 855        struct input_dev *input;
 856        struct iio_dev *idev = iio_priv_to_dev(st);
 857        int ret;
 858
 859        input = input_allocate_device();
 860        if (!input) {
 861                dev_err(&idev->dev, "Failed to allocate TS device!\n");
 862                return -ENOMEM;
 863        }
 864
 865        input->name = DRIVER_NAME;
 866        input->id.bustype = BUS_HOST;
 867        input->dev.parent = &pdev->dev;
 868        input->open = atmel_ts_open;
 869        input->close = atmel_ts_close;
 870
 871        __set_bit(EV_ABS, input->evbit);
 872        __set_bit(EV_KEY, input->evbit);
 873        __set_bit(BTN_TOUCH, input->keybit);
 874        input_set_abs_params(input, ABS_X, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
 875        input_set_abs_params(input, ABS_Y, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
 876        input_set_abs_params(input, ABS_PRESSURE, 0, 0xffffff, 0, 0);
 877
 878        st->ts_input = input;
 879        input_set_drvdata(input, st);
 880
 881        ret = input_register_device(input);
 882        if (ret)
 883                input_free_device(st->ts_input);
 884
 885        return ret;
 886}
 887
 888static void at91_ts_unregister(struct at91_adc_state *st)
 889{
 890        input_unregister_device(st->ts_input);
 891}
 892
 893static int at91_adc_probe(struct platform_device *pdev)
 894{
 895        unsigned int prsc, mstrclk, ticks, adc_clk, adc_clk_khz, shtim;
 896        int ret;
 897        struct iio_dev *idev;
 898        struct at91_adc_state *st;
 899        struct resource *res;
 900        u32 reg;
 901
 902        idev = devm_iio_device_alloc(&pdev->dev, sizeof(struct at91_adc_state));
 903        if (!idev)
 904                return -ENOMEM;
 905
 906        st = iio_priv(idev);
 907
 908        if (pdev->dev.of_node)
 909                ret = at91_adc_probe_dt(st, pdev);
 910        else
 911                ret = at91_adc_probe_pdata(st, pdev);
 912
 913        if (ret) {
 914                dev_err(&pdev->dev, "No platform data available.\n");
 915                return -EINVAL;
 916        }
 917
 918        platform_set_drvdata(pdev, idev);
 919
 920        idev->dev.parent = &pdev->dev;
 921        idev->name = dev_name(&pdev->dev);
 922        idev->modes = INDIO_DIRECT_MODE;
 923        idev->info = &at91_adc_info;
 924
 925        st->irq = platform_get_irq(pdev, 0);
 926        if (st->irq < 0) {
 927                dev_err(&pdev->dev, "No IRQ ID is designated\n");
 928                return -ENODEV;
 929        }
 930
 931        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 932
 933        st->reg_base = devm_ioremap_resource(&pdev->dev, res);
 934        if (IS_ERR(st->reg_base)) {
 935                return PTR_ERR(st->reg_base);
 936        }
 937
 938        /*
 939         * Disable all IRQs before setting up the handler
 940         */
 941        at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST);
 942        at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF);
 943        ret = request_irq(st->irq,
 944                          at91_adc_interrupt,
 945                          0,
 946                          pdev->dev.driver->name,
 947                          idev);
 948        if (ret) {
 949                dev_err(&pdev->dev, "Failed to allocate IRQ.\n");
 950                return ret;
 951        }
 952
 953        st->clk = devm_clk_get(&pdev->dev, "adc_clk");
 954        if (IS_ERR(st->clk)) {
 955                dev_err(&pdev->dev, "Failed to get the clock.\n");
 956                ret = PTR_ERR(st->clk);
 957                goto error_free_irq;
 958        }
 959
 960        ret = clk_prepare_enable(st->clk);
 961        if (ret) {
 962                dev_err(&pdev->dev,
 963                        "Could not prepare or enable the clock.\n");
 964                goto error_free_irq;
 965        }
 966
 967        st->adc_clk = devm_clk_get(&pdev->dev, "adc_op_clk");
 968        if (IS_ERR(st->adc_clk)) {
 969                dev_err(&pdev->dev, "Failed to get the ADC clock.\n");
 970                ret = PTR_ERR(st->adc_clk);
 971                goto error_disable_clk;
 972        }
 973
 974        ret = clk_prepare_enable(st->adc_clk);
 975        if (ret) {
 976                dev_err(&pdev->dev,
 977                        "Could not prepare or enable the ADC clock.\n");
 978                goto error_disable_clk;
 979        }
 980
 981        /*
 982         * Prescaler rate computation using the formula from the Atmel's
 983         * datasheet : ADC Clock = MCK / ((Prescaler + 1) * 2), ADC Clock being
 984         * specified by the electrical characteristics of the board.
 985         */
 986        mstrclk = clk_get_rate(st->clk);
 987        adc_clk = clk_get_rate(st->adc_clk);
 988        adc_clk_khz = adc_clk / 1000;
 989
 990        dev_dbg(&pdev->dev, "Master clock is set as: %d Hz, adc_clk should set as: %d Hz\n",
 991                mstrclk, adc_clk);
 992
 993        prsc = (mstrclk / (2 * adc_clk)) - 1;
 994
 995        if (!st->startup_time) {
 996                dev_err(&pdev->dev, "No startup time available.\n");
 997                ret = -EINVAL;
 998                goto error_disable_adc_clk;
 999        }
1000        ticks = (*st->caps->calc_startup_ticks)(st->startup_time, adc_clk_khz);
1001
1002        /*
1003         * a minimal Sample and Hold Time is necessary for the ADC to guarantee
1004         * the best converted final value between two channels selection
1005         * The formula thus is : Sample and Hold Time = (shtim + 1) / ADCClock
1006         */
1007        shtim = round_up((st->sample_hold_time * adc_clk_khz /
1008                          1000) - 1, 1);
1009
1010        reg = AT91_ADC_PRESCAL_(prsc) & st->registers->mr_prescal_mask;
1011        reg |= AT91_ADC_STARTUP_(ticks) & st->registers->mr_startup_mask;
1012        if (st->low_res)
1013                reg |= AT91_ADC_LOWRES;
1014        if (st->sleep_mode)
1015                reg |= AT91_ADC_SLEEP;
1016        reg |= AT91_ADC_SHTIM_(shtim) & AT91_ADC_SHTIM;
1017        at91_adc_writel(st, AT91_ADC_MR, reg);
1018
1019        /* Setup the ADC channels available on the board */
1020        ret = at91_adc_channel_init(idev);
1021        if (ret < 0) {
1022                dev_err(&pdev->dev, "Couldn't initialize the channels.\n");
1023                goto error_disable_adc_clk;
1024        }
1025
1026        init_waitqueue_head(&st->wq_data_avail);
1027        mutex_init(&st->lock);
1028
1029        /*
1030         * Since touch screen will set trigger register as period trigger. So
1031         * when touch screen is enabled, then we have to disable hardware
1032         * trigger for classic adc.
1033         */
1034        if (!st->touchscreen_type) {
1035                ret = at91_adc_buffer_init(idev);
1036                if (ret < 0) {
1037                        dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
1038                        goto error_disable_adc_clk;
1039                }
1040
1041                ret = at91_adc_trigger_init(idev);
1042                if (ret < 0) {
1043                        dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
1044                        at91_adc_buffer_remove(idev);
1045                        goto error_disable_adc_clk;
1046                }
1047        } else {
1048                if (!st->caps->has_tsmr) {
1049                        dev_err(&pdev->dev, "We don't support non-TSMR adc\n");
1050                        ret = -ENODEV;
1051                        goto error_disable_adc_clk;
1052                }
1053
1054                ret = at91_ts_register(st, pdev);
1055                if (ret)
1056                        goto error_disable_adc_clk;
1057
1058                at91_ts_hw_init(st, adc_clk_khz);
1059        }
1060
1061        ret = iio_device_register(idev);
1062        if (ret < 0) {
1063                dev_err(&pdev->dev, "Couldn't register the device.\n");
1064                goto error_iio_device_register;
1065        }
1066
1067        return 0;
1068
1069error_iio_device_register:
1070        if (!st->touchscreen_type) {
1071                at91_adc_trigger_remove(idev);
1072                at91_adc_buffer_remove(idev);
1073        } else {
1074                at91_ts_unregister(st);
1075        }
1076error_disable_adc_clk:
1077        clk_disable_unprepare(st->adc_clk);
1078error_disable_clk:
1079        clk_disable_unprepare(st->clk);
1080error_free_irq:
1081        free_irq(st->irq, idev);
1082        return ret;
1083}
1084
1085static int at91_adc_remove(struct platform_device *pdev)
1086{
1087        struct iio_dev *idev = platform_get_drvdata(pdev);
1088        struct at91_adc_state *st = iio_priv(idev);
1089
1090        iio_device_unregister(idev);
1091        if (!st->touchscreen_type) {
1092                at91_adc_trigger_remove(idev);
1093                at91_adc_buffer_remove(idev);
1094        } else {
1095                at91_ts_unregister(st);
1096        }
1097        clk_disable_unprepare(st->adc_clk);
1098        clk_disable_unprepare(st->clk);
1099        free_irq(st->irq, idev);
1100
1101        return 0;
1102}
1103
1104#ifdef CONFIG_OF
1105static struct at91_adc_caps at91sam9260_caps = {
1106        .calc_startup_ticks = calc_startup_ticks_9260,
1107        .num_channels = 4,
1108        .registers = {
1109                .channel_base = AT91_ADC_CHR(0),
1110                .drdy_mask = AT91_ADC_DRDY,
1111                .status_register = AT91_ADC_SR,
1112                .trigger_register = AT91_ADC_TRGR_9260,
1113                .mr_prescal_mask = AT91_ADC_PRESCAL_9260,
1114                .mr_startup_mask = AT91_ADC_STARTUP_9260,
1115        },
1116};
1117
1118static struct at91_adc_caps at91sam9g45_caps = {
1119        .has_ts = true,
1120        .calc_startup_ticks = calc_startup_ticks_9260,  /* same as 9260 */
1121        .num_channels = 8,
1122        .registers = {
1123                .channel_base = AT91_ADC_CHR(0),
1124                .drdy_mask = AT91_ADC_DRDY,
1125                .status_register = AT91_ADC_SR,
1126                .trigger_register = AT91_ADC_TRGR_9G45,
1127                .mr_prescal_mask = AT91_ADC_PRESCAL_9G45,
1128                .mr_startup_mask = AT91_ADC_STARTUP_9G45,
1129        },
1130};
1131
1132static struct at91_adc_caps at91sam9x5_caps = {
1133        .has_ts = true,
1134        .has_tsmr = true,
1135        .ts_filter_average = 3,
1136        .ts_pen_detect_sensitivity = 2,
1137        .calc_startup_ticks = calc_startup_ticks_9x5,
1138        .num_channels = 12,
1139        .registers = {
1140                .channel_base = AT91_ADC_CDR0_9X5,
1141                .drdy_mask = AT91_ADC_SR_DRDY_9X5,
1142                .status_register = AT91_ADC_SR_9X5,
1143                .trigger_register = AT91_ADC_TRGR_9X5,
1144                /* prescal mask is same as 9G45 */
1145                .mr_prescal_mask = AT91_ADC_PRESCAL_9G45,
1146                .mr_startup_mask = AT91_ADC_STARTUP_9X5,
1147        },
1148};
1149
1150static const struct of_device_id at91_adc_dt_ids[] = {
1151        { .compatible = "atmel,at91sam9260-adc", .data = &at91sam9260_caps },
1152        { .compatible = "atmel,at91sam9g45-adc", .data = &at91sam9g45_caps },
1153        { .compatible = "atmel,at91sam9x5-adc", .data = &at91sam9x5_caps },
1154        {},
1155};
1156MODULE_DEVICE_TABLE(of, at91_adc_dt_ids);
1157#endif
1158
1159static struct platform_driver at91_adc_driver = {
1160        .probe = at91_adc_probe,
1161        .remove = at91_adc_remove,
1162        .driver = {
1163                   .name = DRIVER_NAME,
1164                   .of_match_table = of_match_ptr(at91_adc_dt_ids),
1165        },
1166};
1167
1168module_platform_driver(at91_adc_driver);
1169
1170MODULE_LICENSE("GPL");
1171MODULE_DESCRIPTION("Atmel AT91 ADC Driver");
1172MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
1173