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