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