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