drivers/iio/adc/ti_am335x_adc.c

   1 /*
   2  * TI ADC MFD driver
   3  *
   4  * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation version 2.
   9  *
  10  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  11  * kind, whether express or implied; without even the implied warranty
  12  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/err.h>
  18 #include <linux/module.h>
  19 #include <linux/slab.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/io.h>
  23 #include <linux/iio/iio.h>
  24 #include <linux/of.h>
  25 #include <linux/of_device.h>
  26 #include <linux/iio/machine.h>
  27 #include <linux/iio/driver.h>
  28
  29 #include <linux/mfd/ti_am335x_tscadc.h>
  30 #include <linux/iio/buffer.h>
  31 #include <linux/iio/kfifo_buf.h>
  32
  33 struct tiadc_device {
  34         struct ti_tscadc_dev *mfd_tscadc;
  35         struct mutex fifo1_lock; /* to protect fifo access */
  36         int channels;
  37         u8 channel_line[8];
  38         u8 channel_step[8];
  39         int buffer_en_ch_steps;
  40         u16 data[8];
  41         u32 open_delay[8], sample_delay[8], step_avg[8];
  42 };
  43
  44 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
  45 {
  46         return readl(adc->mfd_tscadc->tscadc_base + reg);
  47 }
  48
  49 static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
  50                                         unsigned int val)
  51 {
  52         writel(val, adc->mfd_tscadc->tscadc_base + reg);
  53 }
  54
  55 static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
  56 {
  57         u32 step_en;
  58
  59         step_en = ((1 << adc_dev->channels) - 1);
  60         step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
  61         return step_en;
  62 }
  63
  64 static u32 get_adc_chan_step_mask(struct tiadc_device *adc_dev,
  65                 struct iio_chan_spec const *chan)
  66 {
  67         int i;
  68
  69         for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
  70                 if (chan->channel == adc_dev->channel_line[i]) {
  71                         u32 step;
  72
  73                         step = adc_dev->channel_step[i];
  74                         /* +1 for the charger */
  75                         return 1 << (step + 1);
  76                 }
  77         }
  78         WARN_ON(1);
  79         return 0;
  80 }
  81
  82 static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
  83 {
  84         return 1 << adc_dev->channel_step[chan];
  85 }
  86
  87 static void tiadc_step_config(struct iio_dev *indio_dev)
  88 {
  89         struct tiadc_device *adc_dev = iio_priv(indio_dev);
  90         struct device *dev = adc_dev->mfd_tscadc->dev;
  91         unsigned int stepconfig;
  92         int i, steps = 0;
  93
  94         /*
  95          * There are 16 configurable steps and 8 analog input
  96          * lines available which are shared between Touchscreen and ADC.
  97          *
  98          * Steps forwards i.e. from 0 towards 16 are used by ADC
  99          * depending on number of input lines needed.
 100          * Channel would represent which analog input
 101          * needs to be given to ADC to digitalize data.
 102          */
 103
 104
 105         for (i = 0; i < adc_dev->channels; i++) {
 106                 int chan;
 107
 108                 chan = adc_dev->channel_line[i];
 109
 110                 if (adc_dev->step_avg[i] > STEPCONFIG_AVG_16) {
 111                         dev_warn(dev, "chan %d step_avg truncating to %d\n",
 112                                  chan, STEPCONFIG_AVG_16);
 113                         adc_dev->step_avg[i] = STEPCONFIG_AVG_16;
 114                 }
 115
 116                 if (adc_dev->step_avg[i])
 117                         stepconfig =
 118                         STEPCONFIG_AVG(ffs(adc_dev->step_avg[i]) - 1) |
 119                         STEPCONFIG_FIFO1;
 120                 else
 121                         stepconfig = STEPCONFIG_FIFO1;
 122
 123                 if (iio_buffer_enabled(indio_dev))
 124                         stepconfig |= STEPCONFIG_MODE_SWCNT;
 125
 126                 tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
 127                                 stepconfig | STEPCONFIG_INP(chan));
 128
 129                 if (adc_dev->open_delay[i] > STEPDELAY_OPEN_MASK) {
 130                         dev_warn(dev, "chan %d open delay truncating to 0x3FFFF\n",
 131                                  chan);
 132                         adc_dev->open_delay[i] = STEPDELAY_OPEN_MASK;
 133                 }
 134
 135                 if (adc_dev->sample_delay[i] > 0xFF) {
 136                         dev_warn(dev, "chan %d sample delay truncating to 0xFF\n",
 137                                  chan);
 138                         adc_dev->sample_delay[i] = 0xFF;
 139                 }
 140
 141                 tiadc_writel(adc_dev, REG_STEPDELAY(steps),
 142                                 STEPDELAY_OPEN(adc_dev->open_delay[i]) |
 143                                 STEPDELAY_SAMPLE(adc_dev->sample_delay[i]));
 144
 145                 adc_dev->channel_step[i] = steps;
 146                 steps++;
 147         }
 148 }
 149
 150 static irqreturn_t tiadc_irq_h(int irq, void *private)
 151 {
 152         struct iio_dev *indio_dev = private;
 153         struct tiadc_device *adc_dev = iio_priv(indio_dev);
 154         unsigned int status, config;
 155         status = tiadc_readl(adc_dev, REG_IRQSTATUS);
 156
 157         /*
 158          * ADC and touchscreen share the IRQ line.
 159          * FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only
 160          */
 161         if (status & IRQENB_FIFO1OVRRUN) {
 162                 /* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */
 163                 config = tiadc_readl(adc_dev, REG_CTRL);
 164                 config &= ~(CNTRLREG_TSCSSENB);
 165                 tiadc_writel(adc_dev, REG_CTRL, config);
 166                 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN
 167                                 | IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES);
 168                 tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB));
 169                 return IRQ_HANDLED;
 170         } else if (status & IRQENB_FIFO1THRES) {
 171                 /* Disable irq and wake worker thread */
 172                 tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES);
 173                 return IRQ_WAKE_THREAD;
 174         }
 175
 176         return IRQ_NONE;
 177 }
 178
 179 static irqreturn_t tiadc_worker_h(int irq, void *private)
 180 {
 181         struct iio_dev *indio_dev = private;
 182         struct tiadc_device *adc_dev = iio_priv(indio_dev);
 183         int i, k, fifo1count, read;
 184         u16 *data = adc_dev->data;
 185
 186         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
 187         for (k = 0; k < fifo1count; k = k + i) {
 188                 for (i = 0; i < (indio_dev->scan_bytes)/2; i++) {
 189                         read = tiadc_readl(adc_dev, REG_FIFO1);
 190                         data[i] = read & FIFOREAD_DATA_MASK;
 191                 }
 192                 iio_push_to_buffers(indio_dev, (u8 *) data);
 193         }
 194
 195         tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES);
 196         tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES);
 197
 198         return IRQ_HANDLED;
 199 }
 200
 201 static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
 202 {
 203         struct tiadc_device *adc_dev = iio_priv(indio_dev);
 204         int i, fifo1count, read;
 205
 206         tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
 207                                 IRQENB_FIFO1OVRRUN |
 208                                 IRQENB_FIFO1UNDRFLW));
 209
 210         /* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */
 211         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
 212         for (i = 0; i < fifo1count; i++)
 213                 read = tiadc_readl(adc_dev, REG_FIFO1);
 214
 215         return 0;
 216 }
 217
 218 static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
 219 {
 220         struct tiadc_device *adc_dev = iio_priv(indio_dev);
 221         unsigned int enb = 0;
 222         u8 bit;
 223
 224         tiadc_step_config(indio_dev);
 225         for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels)
 226                 enb |= (get_adc_step_bit(adc_dev, bit) << 1);
 227         adc_dev->buffer_en_ch_steps = enb;
 228
 229         am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb);
 230
 231         tiadc_writel(adc_dev,  REG_IRQSTATUS, IRQENB_FIFO1THRES
 232                                 | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW);
 233         tiadc_writel(adc_dev,  REG_IRQENABLE, IRQENB_FIFO1THRES
 234                                 | IRQENB_FIFO1OVRRUN);
 235
 236         return 0;
 237 }
 238
 239 static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
 240 {
 241         struct tiadc_device *adc_dev = iio_priv(indio_dev);
 242         int fifo1count, i, read;
 243
 244         tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
 245                                 IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW));
 246         am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
 247         adc_dev->buffer_en_ch_steps = 0;
 248
 249         /* Flush FIFO of leftover data in the time it takes to disable adc */
 250         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
 251         for (i = 0; i < fifo1count; i++)
 252                 read = tiadc_readl(adc_dev, REG_FIFO1);
 253
 254         return 0;
 255 }
 256
 257 static int tiadc_buffer_postdisable(struct iio_dev *indio_dev)
 258 {
 259         tiadc_step_config(indio_dev);
 260
 261         return 0;
 262 }
 263
 264 static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = {
 265         .preenable = &tiadc_buffer_preenable,
 266         .postenable = &tiadc_buffer_postenable,
 267         .predisable = &tiadc_buffer_predisable,
 268         .postdisable = &tiadc_buffer_postdisable,
 269 };
 270
 271 static int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev,
 272         irqreturn_t (*pollfunc_bh)(int irq, void *p),
 273         irqreturn_t (*pollfunc_th)(int irq, void *p),
 274         int irq,
 275         unsigned long flags,
 276         const struct iio_buffer_setup_ops *setup_ops)
 277 {
 278         struct iio_buffer *buffer;
 279         int ret;
 280
 281         buffer = iio_kfifo_allocate();
 282         if (!buffer)
 283                 return -ENOMEM;
 284
 285         iio_device_attach_buffer(indio_dev, buffer);
 286
 287         ret = request_threaded_irq(irq, pollfunc_th, pollfunc_bh,
 288                                 flags, indio_dev->name, indio_dev);
 289         if (ret)
 290                 goto error_kfifo_free;
 291
 292         indio_dev->setup_ops = setup_ops;
 293         indio_dev->modes |= INDIO_BUFFER_SOFTWARE;
 294
 295         return 0;
 296
 297 error_kfifo_free:
 298         iio_kfifo_free(indio_dev->buffer);
 299         return ret;
 300 }
 301
 302 static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev)
 303 {
 304         struct tiadc_device *adc_dev = iio_priv(indio_dev);
 305
 306         free_irq(adc_dev->mfd_tscadc->irq, indio_dev);
 307         iio_kfifo_free(indio_dev->buffer);
 308 }
 309
 310
 311 static const char * const chan_name_ain[] = {
 312         "AIN0",
 313         "AIN1",
 314         "AIN2",
 315         "AIN3",
 316         "AIN4",
 317         "AIN5",
 318         "AIN6",
 319         "AIN7",
 320 };
 321
 322 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
 323 {
 324         struct tiadc_device *adc_dev = iio_priv(indio_dev);
 325         struct iio_chan_spec *chan_array;
 326         struct iio_chan_spec *chan;
 327         int i;
 328
 329         indio_dev->num_channels = channels;
 330         chan_array = kcalloc(channels, sizeof(*chan_array), GFP_KERNEL);
 331         if (chan_array == NULL)
 332                 return -ENOMEM;
 333
 334         chan = chan_array;
 335         for (i = 0; i < channels; i++, chan++) {
 336
 337                 chan->type = IIO_VOLTAGE;
 338                 chan->indexed = 1;
 339                 chan->channel = adc_dev->channel_line[i];
 340                 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
 341                 chan->datasheet_name = chan_name_ain[chan->channel];
 342                 chan->scan_index = i;
 343                 chan->scan_type.sign = 'u';
 344                 chan->scan_type.realbits = 12;
 345                 chan->scan_type.storagebits = 16;
 346         }
 347
 348         indio_dev->channels = chan_array;
 349
 350         return 0;
 351 }
 352
 353 static void tiadc_channels_remove(struct iio_dev *indio_dev)
 354 {
 355         kfree(indio_dev->channels);
 356 }
 357
 358 static int tiadc_read_raw(struct iio_dev *indio_dev,
 359                 struct iio_chan_spec const *chan,
 360                 int *val, int *val2, long mask)
 361 {
 362         struct tiadc_device *adc_dev = iio_priv(indio_dev);
 363         int ret = IIO_VAL_INT;
 364         int i, map_val;
 365         unsigned int fifo1count, read, stepid;
 366         bool found = false;
 367         u32 step_en;
 368         unsigned long timeout;
 369
 370         if (iio_buffer_enabled(indio_dev))
 371                 return -EBUSY;
 372
 373         step_en = get_adc_chan_step_mask(adc_dev, chan);
 374         if (!step_en)
 375                 return -EINVAL;
 376
 377         mutex_lock(&adc_dev->fifo1_lock);
 378         fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
 379         while (fifo1count--)
 380                 tiadc_readl(adc_dev, REG_FIFO1);
 381
 382         am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en);
 383
 384         timeout = jiffies + msecs_to_jiffies
 385                                 (IDLE_TIMEOUT * adc_dev->channels);
 386         /* Wait for Fifo threshold interrupt */
 387         while (1) {
 388                 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
 389                 if (fifo1count)
 390                         break;
 391
 392                 if (time_after(jiffies, timeout)) {
 393                         am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
 394                         ret = -EAGAIN;
 395                         goto err_unlock;
 396                 }
 397         }
 398         map_val = adc_dev->channel_step[chan->scan_index];
 399
 400         /*
 401          * We check the complete FIFO. We programmed just one entry but in case
 402          * something went wrong we left empty handed (-EAGAIN previously) and
 403          * then the value apeared somehow in the FIFO we would have two entries.
 404          * Therefore we read every item and keep only the latest version of the
 405          * requested channel.
 406          */
 407         for (i = 0; i < fifo1count; i++) {
 408                 read = tiadc_readl(adc_dev, REG_FIFO1);
 409                 stepid = read & FIFOREAD_CHNLID_MASK;
 410                 stepid = stepid >> 0x10;
 411
 412                 if (stepid == map_val) {
 413                         read = read & FIFOREAD_DATA_MASK;
 414                         found = true;
 415                         *val = (u16) read;
 416                 }
 417         }
 418         am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
 419
 420         if (found == false)
 421                 ret =  -EBUSY;
 422
 423 err_unlock:
 424         mutex_unlock(&adc_dev->fifo1_lock);
 425         return ret;
 426 }
 427
 428 static const struct iio_info tiadc_info = {
 429         .read_raw = &tiadc_read_raw,
 430         .driver_module = THIS_MODULE,
 431 };
 432
 433 static int tiadc_parse_dt(struct platform_device *pdev,
 434                           struct tiadc_device *adc_dev)
 435 {
 436         struct device_node *node = pdev->dev.of_node;
 437         struct property *prop;
 438         const __be32 *cur;
 439         int channels = 0;
 440         u32 val;
 441
 442         of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
 443                 adc_dev->channel_line[channels] = val;
 444
 445                 /* Set Default values for optional DT parameters */
 446                 adc_dev->open_delay[channels] = STEPCONFIG_OPENDLY;
 447                 adc_dev->sample_delay[channels] = STEPCONFIG_SAMPLEDLY;
 448                 adc_dev->step_avg[channels] = 16;
 449
 450                 channels++;
 451         }
 452
 453         of_property_read_u32_array(node, "ti,chan-step-avg",
 454                                    adc_dev->step_avg, channels);
 455         of_property_read_u32_array(node, "ti,chan-step-opendelay",
 456                                    adc_dev->open_delay, channels);
 457         of_property_read_u32_array(node, "ti,chan-step-sampledelay",
 458                                    adc_dev->sample_delay, channels);
 459
 460         adc_dev->channels = channels;
 461         return 0;
 462 }
 463
 464 static int tiadc_probe(struct platform_device *pdev)
 465 {
 466         struct iio_dev          *indio_dev;
 467         struct tiadc_device     *adc_dev;
 468         struct device_node      *node = pdev->dev.of_node;
 469         int                     err;
 470
 471         if (!node) {
 472                 dev_err(&pdev->dev, "Could not find valid DT data.\n");
 473                 return -EINVAL;
 474         }
 475
 476         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*indio_dev));
 477         if (indio_dev == NULL) {
 478                 dev_err(&pdev->dev, "failed to allocate iio device\n");
 479                 return -ENOMEM;
 480         }
 481         adc_dev = iio_priv(indio_dev);
 482
 483         adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
 484         tiadc_parse_dt(pdev, adc_dev);
 485
 486         indio_dev->dev.parent = &pdev->dev;
 487         indio_dev->name = dev_name(&pdev->dev);
 488         indio_dev->modes = INDIO_DIRECT_MODE;
 489         indio_dev->info = &tiadc_info;
 490
 491         tiadc_step_config(indio_dev);
 492         tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
 493         mutex_init(&adc_dev->fifo1_lock);
 494
 495         err = tiadc_channel_init(indio_dev, adc_dev->channels);
 496         if (err < 0)
 497                 return err;
 498
 499         err = tiadc_iio_buffered_hardware_setup(indio_dev,
 500                 &tiadc_worker_h,
 501                 &tiadc_irq_h,
 502                 adc_dev->mfd_tscadc->irq,
 503                 IRQF_SHARED,
 504                 &tiadc_buffer_setup_ops);
 505
 506         if (err)
 507                 goto err_free_channels;
 508
 509         err = iio_device_register(indio_dev);
 510         if (err)
 511                 goto err_buffer_unregister;
 512
 513         platform_set_drvdata(pdev, indio_dev);
 514
 515         return 0;
 516
 517 err_buffer_unregister:
 518         tiadc_iio_buffered_hardware_remove(indio_dev);
 519 err_free_channels:
 520         tiadc_channels_remove(indio_dev);
 521         return err;
 522 }
 523
 524 static int tiadc_remove(struct platform_device *pdev)
 525 {
 526         struct iio_dev *indio_dev = platform_get_drvdata(pdev);
 527         struct tiadc_device *adc_dev = iio_priv(indio_dev);
 528         u32 step_en;
 529
 530         iio_device_unregister(indio_dev);
 531         tiadc_iio_buffered_hardware_remove(indio_dev);
 532         tiadc_channels_remove(indio_dev);
 533
 534         step_en = get_adc_step_mask(adc_dev);
 535         am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
 536
 537         return 0;
 538 }
 539
 540 static int __maybe_unused tiadc_suspend(struct device *dev)
 541 {
 542         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 543         struct tiadc_device *adc_dev = iio_priv(indio_dev);
 544         struct ti_tscadc_dev *tscadc_dev;
 545         unsigned int idle;
 546
 547         tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
 548         if (!device_may_wakeup(tscadc_dev->dev)) {
 549                 idle = tiadc_readl(adc_dev, REG_CTRL);
 550                 idle &= ~(CNTRLREG_TSCSSENB);
 551                 tiadc_writel(adc_dev, REG_CTRL, (idle |
 552                                 CNTRLREG_POWERDOWN));
 553         }
 554
 555         return 0;
 556 }
 557
 558 static int __maybe_unused tiadc_resume(struct device *dev)
 559 {
 560         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 561         struct tiadc_device *adc_dev = iio_priv(indio_dev);
 562         unsigned int restore;
 563
 564         /* Make sure ADC is powered up */
 565         restore = tiadc_readl(adc_dev, REG_CTRL);
 566         restore &= ~(CNTRLREG_POWERDOWN);
 567         tiadc_writel(adc_dev, REG_CTRL, restore);
 568
 569         tiadc_step_config(indio_dev);
 570         am335x_tsc_se_set_cache(adc_dev->mfd_tscadc,
 571                         adc_dev->buffer_en_ch_steps);
 572         return 0;
 573 }
 574
 575 static SIMPLE_DEV_PM_OPS(tiadc_pm_ops, tiadc_suspend, tiadc_resume);
 576
 577 static const struct of_device_id ti_adc_dt_ids[] = {
 578         { .compatible = "ti,am3359-adc", },
 579         { }
 580 };
 581 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
 582
 583 static struct platform_driver tiadc_driver = {
 584         .driver = {
 585                 .name   = "TI-am335x-adc",
 586                 .pm     = &tiadc_pm_ops,
 587                 .of_match_table = ti_adc_dt_ids,
 588         },
 589         .probe  = tiadc_probe,
 590         .remove = tiadc_remove,
 591 };
 592 module_platform_driver(tiadc_driver);
 593
 594 MODULE_DESCRIPTION("TI ADC controller driver");
 595 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 596 MODULE_LICENSE("GPL");