drivers/iio/adc/stm32-dfsdm-adc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * This file is the ADC part of the STM32 DFSDM driver
   4  *
   5  * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
   6  * Author: Arnaud Pouliquen <arnaud.pouliquen@st.com>.
   7  */
   8
   9 #include <linux/dmaengine.h>
  10 #include <linux/dma-mapping.h>
  11 #include <linux/iio/adc/stm32-dfsdm-adc.h>
  12 #include <linux/iio/buffer.h>
  13 #include <linux/iio/hw-consumer.h>
  14 #include <linux/iio/sysfs.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/module.h>
  17 #include <linux/of_device.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/regmap.h>
  20 #include <linux/slab.h>
  21
  22 #include "stm32-dfsdm.h"
  23
  24 #define DFSDM_DMA_BUFFER_SIZE (4 * PAGE_SIZE)
  25
  26 /* Conversion timeout */
  27 #define DFSDM_TIMEOUT_US 100000
  28 #define DFSDM_TIMEOUT (msecs_to_jiffies(DFSDM_TIMEOUT_US / 1000))
  29
  30 /* Oversampling attribute default */
  31 #define DFSDM_DEFAULT_OVERSAMPLING  100
  32
  33 /* Oversampling max values */
  34 #define DFSDM_MAX_INT_OVERSAMPLING 256
  35 #define DFSDM_MAX_FL_OVERSAMPLING 1024
  36
  37 /* Max sample resolutions */
  38 #define DFSDM_MAX_RES BIT(31)
  39 #define DFSDM_DATA_RES BIT(23)
  40
  41 enum sd_converter_type {
  42         DFSDM_AUDIO,
  43         DFSDM_IIO,
  44 };
  45
  46 struct stm32_dfsdm_dev_data {
  47         int type;
  48         int (*init)(struct iio_dev *indio_dev);
  49         unsigned int num_channels;
  50         const struct regmap_config *regmap_cfg;
  51 };
  52
  53 struct stm32_dfsdm_adc {
  54         struct stm32_dfsdm *dfsdm;
  55         const struct stm32_dfsdm_dev_data *dev_data;
  56         unsigned int fl_id;
  57
  58         /* ADC specific */
  59         unsigned int oversamp;
  60         struct iio_hw_consumer *hwc;
  61         struct completion completion;
  62         u32 *buffer;
  63
  64         /* Audio specific */
  65         unsigned int spi_freq;  /* SPI bus clock frequency */
  66         unsigned int sample_freq; /* Sample frequency after filter decimation */
  67         int (*cb)(const void *data, size_t size, void *cb_priv);
  68         void *cb_priv;
  69
  70         /* DMA */
  71         u8 *rx_buf;
  72         unsigned int bufi; /* Buffer current position */
  73         unsigned int buf_sz; /* Buffer size */
  74         struct dma_chan *dma_chan;
  75         dma_addr_t dma_buf;
  76 };
  77
  78 struct stm32_dfsdm_str2field {
  79         const char      *name;
  80         unsigned int    val;
  81 };
  82
  83 /* DFSDM channel serial interface type */
  84 static const struct stm32_dfsdm_str2field stm32_dfsdm_chan_type[] = {
  85         { "SPI_R", 0 }, /* SPI with data on rising edge */
  86         { "SPI_F", 1 }, /* SPI with data on falling edge */
  87         { "MANCH_R", 2 }, /* Manchester codec, rising edge = logic 0 */
  88         { "MANCH_F", 3 }, /* Manchester codec, falling edge = logic 1 */
  89         {},
  90 };
  91
  92 /* DFSDM channel clock source */
  93 static const struct stm32_dfsdm_str2field stm32_dfsdm_chan_src[] = {
  94         /* External SPI clock (CLKIN x) */
  95         { "CLKIN", DFSDM_CHANNEL_SPI_CLOCK_EXTERNAL },
  96         /* Internal SPI clock (CLKOUT) */
  97         { "CLKOUT", DFSDM_CHANNEL_SPI_CLOCK_INTERNAL },
  98         /* Internal SPI clock divided by 2 (falling edge) */
  99         { "CLKOUT_F", DFSDM_CHANNEL_SPI_CLOCK_INTERNAL_DIV2_FALLING },
 100         /* Internal SPI clock divided by 2 (falling edge) */
 101         { "CLKOUT_R", DFSDM_CHANNEL_SPI_CLOCK_INTERNAL_DIV2_RISING },
 102         {},
 103 };
 104
 105 static int stm32_dfsdm_str2val(const char *str,
 106                                const struct stm32_dfsdm_str2field *list)
 107 {
 108         const struct stm32_dfsdm_str2field *p = list;
 109
 110         for (p = list; p && p->name; p++)
 111                 if (!strcmp(p->name, str))
 112                         return p->val;
 113
 114         return -EINVAL;
 115 }
 116
 117 static int stm32_dfsdm_set_osrs(struct stm32_dfsdm_filter *fl,
 118                                 unsigned int fast, unsigned int oversamp)
 119 {
 120         unsigned int i, d, fosr, iosr;
 121         u64 res;
 122         s64 delta;
 123         unsigned int m = 1;     /* multiplication factor */
 124         unsigned int p = fl->ford;      /* filter order (ford) */
 125
 126         pr_debug("%s: Requested oversampling: %d\n",  __func__, oversamp);
 127         /*
 128          * This function tries to compute filter oversampling and integrator
 129          * oversampling, base on oversampling ratio requested by user.
 130          *
 131          * Decimation d depends on the filter order and the oversampling ratios.
 132          * ford: filter order
 133          * fosr: filter over sampling ratio
 134          * iosr: integrator over sampling ratio
 135          */
 136         if (fl->ford == DFSDM_FASTSINC_ORDER) {
 137                 m = 2;
 138                 p = 2;
 139         }
 140
 141         /*
 142          * Look for filter and integrator oversampling ratios which allows
 143          * to reach 24 bits data output resolution.
 144          * Leave as soon as if exact resolution if reached.
 145          * Otherwise the higher resolution below 32 bits is kept.
 146          */
 147         for (fosr = 1; fosr <= DFSDM_MAX_FL_OVERSAMPLING; fosr++) {
 148                 for (iosr = 1; iosr <= DFSDM_MAX_INT_OVERSAMPLING; iosr++) {
 149                         if (fast)
 150                                 d = fosr * iosr;
 151                         else if (fl->ford == DFSDM_FASTSINC_ORDER)
 152                                 d = fosr * (iosr + 3) + 2;
 153                         else
 154                                 d = fosr * (iosr - 1 + p) + p;
 155
 156                         if (d > oversamp)
 157                                 break;
 158                         else if (d != oversamp)
 159                                 continue;
 160                         /*
 161                          * Check resolution (limited to signed 32 bits)
 162                          *   res <= 2^31
 163                          * Sincx filters:
 164                          *   res = m * fosr^p x iosr (with m=1, p=ford)
 165                          * FastSinc filter
 166                          *   res = m * fosr^p x iosr (with m=2, p=2)
 167                          */
 168                         res = fosr;
 169                         for (i = p - 1; i > 0; i--) {
 170                                 res = res * (u64)fosr;
 171                                 if (res > DFSDM_MAX_RES)
 172                                         break;
 173                         }
 174                         if (res > DFSDM_MAX_RES)
 175                                 continue;
 176                         res = res * (u64)m * (u64)iosr;
 177                         if (res > DFSDM_MAX_RES)
 178                                 continue;
 179
 180                         delta = res - DFSDM_DATA_RES;
 181
 182                         if (res >= fl->res) {
 183                                 fl->res = res;
 184                                 fl->fosr = fosr;
 185                                 fl->iosr = iosr;
 186                                 fl->fast = fast;
 187                                 pr_debug("%s: fosr = %d, iosr = %d\n",
 188                                          __func__, fl->fosr, fl->iosr);
 189                         }
 190
 191                         if (!delta)
 192                                 return 0;
 193                 }
 194         }
 195
 196         if (!fl->fosr)
 197                 return -EINVAL;
 198
 199         return 0;
 200 }
 201
 202 static int stm32_dfsdm_start_channel(struct stm32_dfsdm *dfsdm,
 203                                      unsigned int ch_id)
 204 {
 205         return regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(ch_id),
 206                                   DFSDM_CHCFGR1_CHEN_MASK,
 207                                   DFSDM_CHCFGR1_CHEN(1));
 208 }
 209
 210 static void stm32_dfsdm_stop_channel(struct stm32_dfsdm *dfsdm,
 211                                      unsigned int ch_id)
 212 {
 213         regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(ch_id),
 214                            DFSDM_CHCFGR1_CHEN_MASK, DFSDM_CHCFGR1_CHEN(0));
 215 }
 216
 217 static int stm32_dfsdm_chan_configure(struct stm32_dfsdm *dfsdm,
 218                                       struct stm32_dfsdm_channel *ch)
 219 {
 220         unsigned int id = ch->id;
 221         struct regmap *regmap = dfsdm->regmap;
 222         int ret;
 223
 224         ret = regmap_update_bits(regmap, DFSDM_CHCFGR1(id),
 225                                  DFSDM_CHCFGR1_SITP_MASK,
 226                                  DFSDM_CHCFGR1_SITP(ch->type));
 227         if (ret < 0)
 228                 return ret;
 229         ret = regmap_update_bits(regmap, DFSDM_CHCFGR1(id),
 230                                  DFSDM_CHCFGR1_SPICKSEL_MASK,
 231                                  DFSDM_CHCFGR1_SPICKSEL(ch->src));
 232         if (ret < 0)
 233                 return ret;
 234         return regmap_update_bits(regmap, DFSDM_CHCFGR1(id),
 235                                   DFSDM_CHCFGR1_CHINSEL_MASK,
 236                                   DFSDM_CHCFGR1_CHINSEL(ch->alt_si));
 237 }
 238
 239 static int stm32_dfsdm_start_filter(struct stm32_dfsdm *dfsdm,
 240                                     unsigned int fl_id)
 241 {
 242         int ret;
 243
 244         /* Enable filter */
 245         ret = regmap_update_bits(dfsdm->regmap, DFSDM_CR1(fl_id),
 246                                  DFSDM_CR1_DFEN_MASK, DFSDM_CR1_DFEN(1));
 247         if (ret < 0)
 248                 return ret;
 249
 250         /* Start conversion */
 251         return regmap_update_bits(dfsdm->regmap, DFSDM_CR1(fl_id),
 252                                   DFSDM_CR1_RSWSTART_MASK,
 253                                   DFSDM_CR1_RSWSTART(1));
 254 }
 255
 256 static void stm32_dfsdm_stop_filter(struct stm32_dfsdm *dfsdm,
 257                                     unsigned int fl_id)
 258 {
 259         /* Disable conversion */
 260         regmap_update_bits(dfsdm->regmap, DFSDM_CR1(fl_id),
 261                            DFSDM_CR1_DFEN_MASK, DFSDM_CR1_DFEN(0));
 262 }
 263
 264 static int stm32_dfsdm_filter_configure(struct stm32_dfsdm *dfsdm,
 265                                         unsigned int fl_id, unsigned int ch_id)
 266 {
 267         struct regmap *regmap = dfsdm->regmap;
 268         struct stm32_dfsdm_filter *fl = &dfsdm->fl_list[fl_id];
 269         int ret;
 270
 271         /* Average integrator oversampling */
 272         ret = regmap_update_bits(regmap, DFSDM_FCR(fl_id), DFSDM_FCR_IOSR_MASK,
 273                                  DFSDM_FCR_IOSR(fl->iosr - 1));
 274         if (ret)
 275                 return ret;
 276
 277         /* Filter order and Oversampling */
 278         ret = regmap_update_bits(regmap, DFSDM_FCR(fl_id), DFSDM_FCR_FOSR_MASK,
 279                                  DFSDM_FCR_FOSR(fl->fosr - 1));
 280         if (ret)
 281                 return ret;
 282
 283         ret = regmap_update_bits(regmap, DFSDM_FCR(fl_id), DFSDM_FCR_FORD_MASK,
 284                                  DFSDM_FCR_FORD(fl->ford));
 285         if (ret)
 286                 return ret;
 287
 288         /* No scan mode supported for the moment */
 289         ret = regmap_update_bits(regmap, DFSDM_CR1(fl_id), DFSDM_CR1_RCH_MASK,
 290                                  DFSDM_CR1_RCH(ch_id));
 291         if (ret)
 292                 return ret;
 293
 294         return regmap_update_bits(regmap, DFSDM_CR1(fl_id),
 295                                   DFSDM_CR1_RSYNC_MASK,
 296                                   DFSDM_CR1_RSYNC(fl->sync_mode));
 297 }
 298
 299 static int stm32_dfsdm_channel_parse_of(struct stm32_dfsdm *dfsdm,
 300                                         struct iio_dev *indio_dev,
 301                                         struct iio_chan_spec *ch)
 302 {
 303         struct stm32_dfsdm_channel *df_ch;
 304         const char *of_str;
 305         int chan_idx = ch->scan_index;
 306         int ret, val;
 307
 308         ret = of_property_read_u32_index(indio_dev->dev.of_node,
 309                                          "st,adc-channels", chan_idx,
 310                                          &ch->channel);
 311         if (ret < 0) {
 312                 dev_err(&indio_dev->dev,
 313                         " Error parsing 'st,adc-channels' for idx %d\n",
 314                         chan_idx);
 315                 return ret;
 316         }
 317         if (ch->channel >= dfsdm->num_chs) {
 318                 dev_err(&indio_dev->dev,
 319                         " Error bad channel number %d (max = %d)\n",
 320                         ch->channel, dfsdm->num_chs);
 321                 return -EINVAL;
 322         }
 323
 324         ret = of_property_read_string_index(indio_dev->dev.of_node,
 325                                             "st,adc-channel-names", chan_idx,
 326                                             &ch->datasheet_name);
 327         if (ret < 0) {
 328                 dev_err(&indio_dev->dev,
 329                         " Error parsing 'st,adc-channel-names' for idx %d\n",
 330                         chan_idx);
 331                 return ret;
 332         }
 333
 334         df_ch =  &dfsdm->ch_list[ch->channel];
 335         df_ch->id = ch->channel;
 336
 337         ret = of_property_read_string_index(indio_dev->dev.of_node,
 338                                             "st,adc-channel-types", chan_idx,
 339                                             &of_str);
 340         if (!ret) {
 341                 val = stm32_dfsdm_str2val(of_str, stm32_dfsdm_chan_type);
 342                 if (val < 0)
 343                         return val;
 344         } else {
 345                 val = 0;
 346         }
 347         df_ch->type = val;
 348
 349         ret = of_property_read_string_index(indio_dev->dev.of_node,
 350                                             "st,adc-channel-clk-src", chan_idx,
 351                                             &of_str);
 352         if (!ret) {
 353                 val = stm32_dfsdm_str2val(of_str, stm32_dfsdm_chan_src);
 354                 if (val < 0)
 355                         return val;
 356         } else {
 357                 val = 0;
 358         }
 359         df_ch->src = val;
 360
 361         ret = of_property_read_u32_index(indio_dev->dev.of_node,
 362                                          "st,adc-alt-channel", chan_idx,
 363                                          &df_ch->alt_si);
 364         if (ret < 0)
 365                 df_ch->alt_si = 0;
 366
 367         return 0;
 368 }
 369
 370 static ssize_t dfsdm_adc_audio_get_spiclk(struct iio_dev *indio_dev,
 371                                           uintptr_t priv,
 372                                           const struct iio_chan_spec *chan,
 373                                           char *buf)
 374 {
 375         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 376
 377         return snprintf(buf, PAGE_SIZE, "%d\n", adc->spi_freq);
 378 }
 379
 380 static ssize_t dfsdm_adc_audio_set_spiclk(struct iio_dev *indio_dev,
 381                                           uintptr_t priv,
 382                                           const struct iio_chan_spec *chan,
 383                                           const char *buf, size_t len)
 384 {
 385         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 386         struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[adc->fl_id];
 387         struct stm32_dfsdm_channel *ch = &adc->dfsdm->ch_list[chan->channel];
 388         unsigned int sample_freq = adc->sample_freq;
 389         unsigned int spi_freq;
 390         int ret;
 391
 392         dev_err(&indio_dev->dev, "enter %s\n", __func__);
 393         /* If DFSDM is master on SPI, SPI freq can not be updated */
 394         if (ch->src != DFSDM_CHANNEL_SPI_CLOCK_EXTERNAL)
 395                 return -EPERM;
 396
 397         ret = kstrtoint(buf, 0, &spi_freq);
 398         if (ret)
 399                 return ret;
 400
 401         if (!spi_freq)
 402                 return -EINVAL;
 403
 404         if (sample_freq) {
 405                 if (spi_freq % sample_freq)
 406                         dev_warn(&indio_dev->dev,
 407                                  "Sampling rate not accurate (%d)\n",
 408                                  spi_freq / (spi_freq / sample_freq));
 409
 410                 ret = stm32_dfsdm_set_osrs(fl, 0, (spi_freq / sample_freq));
 411                 if (ret < 0) {
 412                         dev_err(&indio_dev->dev,
 413                                 "No filter parameters that match!\n");
 414                         return ret;
 415                 }
 416         }
 417         adc->spi_freq = spi_freq;
 418
 419         return len;
 420 }
 421
 422 static int stm32_dfsdm_start_conv(struct stm32_dfsdm_adc *adc,
 423                                   const struct iio_chan_spec *chan,
 424                                   bool dma)
 425 {
 426         struct regmap *regmap = adc->dfsdm->regmap;
 427         int ret;
 428         unsigned int dma_en = 0, cont_en = 0;
 429
 430         ret = stm32_dfsdm_start_channel(adc->dfsdm, chan->channel);
 431         if (ret < 0)
 432                 return ret;
 433
 434         ret = stm32_dfsdm_filter_configure(adc->dfsdm, adc->fl_id,
 435                                            chan->channel);
 436         if (ret < 0)
 437                 goto stop_channels;
 438
 439         if (dma) {
 440                 /* Enable DMA transfer*/
 441                 dma_en =  DFSDM_CR1_RDMAEN(1);
 442                 /* Enable conversion triggered by SPI clock*/
 443                 cont_en = DFSDM_CR1_RCONT(1);
 444         }
 445         /* Enable DMA transfer*/
 446         ret = regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
 447                                  DFSDM_CR1_RDMAEN_MASK, dma_en);
 448         if (ret < 0)
 449                 goto stop_channels;
 450
 451         /* Enable conversion triggered by SPI clock*/
 452         ret = regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
 453                                  DFSDM_CR1_RCONT_MASK, cont_en);
 454         if (ret < 0)
 455                 goto stop_channels;
 456
 457         ret = stm32_dfsdm_start_filter(adc->dfsdm, adc->fl_id);
 458         if (ret < 0)
 459                 goto stop_channels;
 460
 461         return 0;
 462
 463 stop_channels:
 464         regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
 465                            DFSDM_CR1_RDMAEN_MASK, 0);
 466
 467         regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
 468                            DFSDM_CR1_RCONT_MASK, 0);
 469         stm32_dfsdm_stop_channel(adc->dfsdm, chan->channel);
 470
 471         return ret;
 472 }
 473
 474 static void stm32_dfsdm_stop_conv(struct stm32_dfsdm_adc *adc,
 475                                   const struct iio_chan_spec *chan)
 476 {
 477         struct regmap *regmap = adc->dfsdm->regmap;
 478
 479         stm32_dfsdm_stop_filter(adc->dfsdm, adc->fl_id);
 480
 481         /* Clean conversion options */
 482         regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
 483                            DFSDM_CR1_RDMAEN_MASK, 0);
 484
 485         regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
 486                            DFSDM_CR1_RCONT_MASK, 0);
 487
 488         stm32_dfsdm_stop_channel(adc->dfsdm, chan->channel);
 489 }
 490
 491 static int stm32_dfsdm_set_watermark(struct iio_dev *indio_dev,
 492                                      unsigned int val)
 493 {
 494         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 495         unsigned int watermark = DFSDM_DMA_BUFFER_SIZE / 2;
 496
 497         /*
 498          * DMA cyclic transfers are used, buffer is split into two periods.
 499          * There should be :
 500          * - always one buffer (period) DMA is working on
 501          * - one buffer (period) driver pushed to ASoC side.
 502          */
 503         watermark = min(watermark, val * (unsigned int)(sizeof(u32)));
 504         adc->buf_sz = watermark * 2;
 505
 506         return 0;
 507 }
 508
 509 static unsigned int stm32_dfsdm_adc_dma_residue(struct stm32_dfsdm_adc *adc)
 510 {
 511         struct dma_tx_state state;
 512         enum dma_status status;
 513
 514         status = dmaengine_tx_status(adc->dma_chan,
 515                                      adc->dma_chan->cookie,
 516                                      &state);
 517         if (status == DMA_IN_PROGRESS) {
 518                 /* Residue is size in bytes from end of buffer */
 519                 unsigned int i = adc->buf_sz - state.residue;
 520                 unsigned int size;
 521
 522                 /* Return available bytes */
 523                 if (i >= adc->bufi)
 524                         size = i - adc->bufi;
 525                 else
 526                         size = adc->buf_sz + i - adc->bufi;
 527
 528                 return size;
 529         }
 530
 531         return 0;
 532 }
 533
 534 static void stm32_dfsdm_audio_dma_buffer_done(void *data)
 535 {
 536         struct iio_dev *indio_dev = data;
 537         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 538         int available = stm32_dfsdm_adc_dma_residue(adc);
 539         size_t old_pos;
 540
 541         /*
 542          * FIXME: In Kernel interface does not support cyclic DMA buffer,and
 543          * offers only an interface to push data samples per samples.
 544          * For this reason IIO buffer interface is not used and interface is
 545          * bypassed using a private callback registered by ASoC.
 546          * This should be a temporary solution waiting a cyclic DMA engine
 547          * support in IIO.
 548          */
 549
 550         dev_dbg(&indio_dev->dev, "%s: pos = %d, available = %d\n", __func__,
 551                 adc->bufi, available);
 552         old_pos = adc->bufi;
 553
 554         while (available >= indio_dev->scan_bytes) {
 555                 u32 *buffer = (u32 *)&adc->rx_buf[adc->bufi];
 556
 557                 /* Mask 8 LSB that contains the channel ID */
 558                 *buffer = (*buffer & 0xFFFFFF00) << 8;
 559                 available -= indio_dev->scan_bytes;
 560                 adc->bufi += indio_dev->scan_bytes;
 561                 if (adc->bufi >= adc->buf_sz) {
 562                         if (adc->cb)
 563                                 adc->cb(&adc->rx_buf[old_pos],
 564                                          adc->buf_sz - old_pos, adc->cb_priv);
 565                         adc->bufi = 0;
 566                         old_pos = 0;
 567                 }
 568         }
 569         if (adc->cb)
 570                 adc->cb(&adc->rx_buf[old_pos], adc->bufi - old_pos,
 571                         adc->cb_priv);
 572 }
 573
 574 static int stm32_dfsdm_adc_dma_start(struct iio_dev *indio_dev)
 575 {
 576         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 577         struct dma_async_tx_descriptor *desc;
 578         dma_cookie_t cookie;
 579         int ret;
 580
 581         if (!adc->dma_chan)
 582                 return -EINVAL;
 583
 584         dev_dbg(&indio_dev->dev, "%s size=%d watermark=%d\n", __func__,
 585                 adc->buf_sz, adc->buf_sz / 2);
 586
 587         /* Prepare a DMA cyclic transaction */
 588         desc = dmaengine_prep_dma_cyclic(adc->dma_chan,
 589                                          adc->dma_buf,
 590                                          adc->buf_sz, adc->buf_sz / 2,
 591                                          DMA_DEV_TO_MEM,
 592                                          DMA_PREP_INTERRUPT);
 593         if (!desc)
 594                 return -EBUSY;
 595
 596         desc->callback = stm32_dfsdm_audio_dma_buffer_done;
 597         desc->callback_param = indio_dev;
 598
 599         cookie = dmaengine_submit(desc);
 600         ret = dma_submit_error(cookie);
 601         if (ret) {
 602                 dmaengine_terminate_all(adc->dma_chan);
 603                 return ret;
 604         }
 605
 606         /* Issue pending DMA requests */
 607         dma_async_issue_pending(adc->dma_chan);
 608
 609         return 0;
 610 }
 611
 612 static int stm32_dfsdm_postenable(struct iio_dev *indio_dev)
 613 {
 614         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 615         const struct iio_chan_spec *chan = &indio_dev->channels[0];
 616         int ret;
 617
 618         /* Reset adc buffer index */
 619         adc->bufi = 0;
 620
 621         ret = stm32_dfsdm_start_dfsdm(adc->dfsdm);
 622         if (ret < 0)
 623                 return ret;
 624
 625         ret = stm32_dfsdm_start_conv(adc, chan, true);
 626         if (ret) {
 627                 dev_err(&indio_dev->dev, "Can't start conversion\n");
 628                 goto stop_dfsdm;
 629         }
 630
 631         if (adc->dma_chan) {
 632                 ret = stm32_dfsdm_adc_dma_start(indio_dev);
 633                 if (ret) {
 634                         dev_err(&indio_dev->dev, "Can't start DMA\n");
 635                         goto err_stop_conv;
 636                 }
 637         }
 638
 639         return 0;
 640
 641 err_stop_conv:
 642         stm32_dfsdm_stop_conv(adc, chan);
 643 stop_dfsdm:
 644         stm32_dfsdm_stop_dfsdm(adc->dfsdm);
 645
 646         return ret;
 647 }
 648
 649 static int stm32_dfsdm_predisable(struct iio_dev *indio_dev)
 650 {
 651         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 652         const struct iio_chan_spec *chan = &indio_dev->channels[0];
 653
 654         if (adc->dma_chan)
 655                 dmaengine_terminate_all(adc->dma_chan);
 656
 657         stm32_dfsdm_stop_conv(adc, chan);
 658
 659         stm32_dfsdm_stop_dfsdm(adc->dfsdm);
 660
 661         return 0;
 662 }
 663
 664 static const struct iio_buffer_setup_ops stm32_dfsdm_buffer_setup_ops = {
 665         .postenable = &stm32_dfsdm_postenable,
 666         .predisable = &stm32_dfsdm_predisable,
 667 };
 668
 669 /**
 670  * stm32_dfsdm_get_buff_cb() - register a callback that will be called when
 671  *                             DMA transfer period is achieved.
 672  *
 673  * @iio_dev: Handle to IIO device.
 674  * @cb: Pointer to callback function:
 675  *      - data: pointer to data buffer
 676  *      - size: size in byte of the data buffer
 677  *      - private: pointer to consumer private structure.
 678  * @private: Pointer to consumer private structure.
 679  */
 680 int stm32_dfsdm_get_buff_cb(struct iio_dev *iio_dev,
 681                             int (*cb)(const void *data, size_t size,
 682                                       void *private),
 683                             void *private)
 684 {
 685         struct stm32_dfsdm_adc *adc;
 686
 687         if (!iio_dev)
 688                 return -EINVAL;
 689         adc = iio_priv(iio_dev);
 690
 691         adc->cb = cb;
 692         adc->cb_priv = private;
 693
 694         return 0;
 695 }
 696 EXPORT_SYMBOL_GPL(stm32_dfsdm_get_buff_cb);
 697
 698 /**
 699  * stm32_dfsdm_release_buff_cb - unregister buffer callback
 700  *
 701  * @iio_dev: Handle to IIO device.
 702  */
 703 int stm32_dfsdm_release_buff_cb(struct iio_dev *iio_dev)
 704 {
 705         struct stm32_dfsdm_adc *adc;
 706
 707         if (!iio_dev)
 708                 return -EINVAL;
 709         adc = iio_priv(iio_dev);
 710
 711         adc->cb = NULL;
 712         adc->cb_priv = NULL;
 713
 714         return 0;
 715 }
 716 EXPORT_SYMBOL_GPL(stm32_dfsdm_release_buff_cb);
 717
 718 static int stm32_dfsdm_single_conv(struct iio_dev *indio_dev,
 719                                    const struct iio_chan_spec *chan, int *res)
 720 {
 721         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 722         long timeout;
 723         int ret;
 724
 725         reinit_completion(&adc->completion);
 726
 727         adc->buffer = res;
 728
 729         ret = stm32_dfsdm_start_dfsdm(adc->dfsdm);
 730         if (ret < 0)
 731                 return ret;
 732
 733         ret = regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR2(adc->fl_id),
 734                                  DFSDM_CR2_REOCIE_MASK, DFSDM_CR2_REOCIE(1));
 735         if (ret < 0)
 736                 goto stop_dfsdm;
 737
 738         ret = stm32_dfsdm_start_conv(adc, chan, false);
 739         if (ret < 0) {
 740                 regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR2(adc->fl_id),
 741                                    DFSDM_CR2_REOCIE_MASK, DFSDM_CR2_REOCIE(0));
 742                 goto stop_dfsdm;
 743         }
 744
 745         timeout = wait_for_completion_interruptible_timeout(&adc->completion,
 746                                                             DFSDM_TIMEOUT);
 747
 748         /* Mask IRQ for regular conversion achievement*/
 749         regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR2(adc->fl_id),
 750                            DFSDM_CR2_REOCIE_MASK, DFSDM_CR2_REOCIE(0));
 751
 752         if (timeout == 0)
 753                 ret = -ETIMEDOUT;
 754         else if (timeout < 0)
 755                 ret = timeout;
 756         else
 757                 ret = IIO_VAL_INT;
 758
 759         stm32_dfsdm_stop_conv(adc, chan);
 760
 761 stop_dfsdm:
 762         stm32_dfsdm_stop_dfsdm(adc->dfsdm);
 763
 764         return ret;
 765 }
 766
 767 static int stm32_dfsdm_write_raw(struct iio_dev *indio_dev,
 768                                  struct iio_chan_spec const *chan,
 769                                  int val, int val2, long mask)
 770 {
 771         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 772         struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[adc->fl_id];
 773         struct stm32_dfsdm_channel *ch = &adc->dfsdm->ch_list[chan->channel];
 774         unsigned int spi_freq = adc->spi_freq;
 775         int ret = -EINVAL;
 776
 777         switch (mask) {
 778         case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
 779                 ret = stm32_dfsdm_set_osrs(fl, 0, val);
 780                 if (!ret)
 781                         adc->oversamp = val;
 782
 783                 return ret;
 784
 785         case IIO_CHAN_INFO_SAMP_FREQ:
 786                 if (!val)
 787                         return -EINVAL;
 788                 if (ch->src != DFSDM_CHANNEL_SPI_CLOCK_EXTERNAL)
 789                         spi_freq = adc->dfsdm->spi_master_freq;
 790
 791                 if (spi_freq % val)
 792                         dev_warn(&indio_dev->dev,
 793                                  "Sampling rate not accurate (%d)\n",
 794                                  spi_freq / (spi_freq / val));
 795
 796                 ret = stm32_dfsdm_set_osrs(fl, 0, (spi_freq / val));
 797                 if (ret < 0) {
 798                         dev_err(&indio_dev->dev,
 799                                 "Not able to find parameter that match!\n");
 800                         return ret;
 801                 }
 802                 adc->sample_freq = val;
 803
 804                 return 0;
 805         }
 806
 807         return -EINVAL;
 808 }
 809
 810 static int stm32_dfsdm_read_raw(struct iio_dev *indio_dev,
 811                                 struct iio_chan_spec const *chan, int *val,
 812                                 int *val2, long mask)
 813 {
 814         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 815         int ret;
 816
 817         switch (mask) {
 818         case IIO_CHAN_INFO_RAW:
 819                 ret = iio_hw_consumer_enable(adc->hwc);
 820                 if (ret < 0) {
 821                         dev_err(&indio_dev->dev,
 822                                 "%s: IIO enable failed (channel %d)\n",
 823                                 __func__, chan->channel);
 824                         return ret;
 825                 }
 826                 ret = stm32_dfsdm_single_conv(indio_dev, chan, val);
 827                 iio_hw_consumer_disable(adc->hwc);
 828                 if (ret < 0) {
 829                         dev_err(&indio_dev->dev,
 830                                 "%s: Conversion failed (channel %d)\n",
 831                                 __func__, chan->channel);
 832                         return ret;
 833                 }
 834                 return IIO_VAL_INT;
 835
 836         case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
 837                 *val = adc->oversamp;
 838
 839                 return IIO_VAL_INT;
 840
 841         case IIO_CHAN_INFO_SAMP_FREQ:
 842                 *val = adc->sample_freq;
 843
 844                 return IIO_VAL_INT;
 845         }
 846
 847         return -EINVAL;
 848 }
 849
 850 static const struct iio_info stm32_dfsdm_info_audio = {
 851         .hwfifo_set_watermark = stm32_dfsdm_set_watermark,
 852         .read_raw = stm32_dfsdm_read_raw,
 853         .write_raw = stm32_dfsdm_write_raw,
 854 };
 855
 856 static const struct iio_info stm32_dfsdm_info_adc = {
 857         .read_raw = stm32_dfsdm_read_raw,
 858         .write_raw = stm32_dfsdm_write_raw,
 859 };
 860
 861 static irqreturn_t stm32_dfsdm_irq(int irq, void *arg)
 862 {
 863         struct stm32_dfsdm_adc *adc = arg;
 864         struct iio_dev *indio_dev = iio_priv_to_dev(adc);
 865         struct regmap *regmap = adc->dfsdm->regmap;
 866         unsigned int status, int_en;
 867
 868         regmap_read(regmap, DFSDM_ISR(adc->fl_id), &status);
 869         regmap_read(regmap, DFSDM_CR2(adc->fl_id), &int_en);
 870
 871         if (status & DFSDM_ISR_REOCF_MASK) {
 872                 /* Read the data register clean the IRQ status */
 873                 regmap_read(regmap, DFSDM_RDATAR(adc->fl_id), adc->buffer);
 874                 complete(&adc->completion);
 875         }
 876
 877         if (status & DFSDM_ISR_ROVRF_MASK) {
 878                 if (int_en & DFSDM_CR2_ROVRIE_MASK)
 879                         dev_warn(&indio_dev->dev, "Overrun detected\n");
 880                 regmap_update_bits(regmap, DFSDM_ICR(adc->fl_id),
 881                                    DFSDM_ICR_CLRROVRF_MASK,
 882                                    DFSDM_ICR_CLRROVRF_MASK);
 883         }
 884
 885         return IRQ_HANDLED;
 886 }
 887
 888 /*
 889  * Define external info for SPI Frequency and audio sampling rate that can be
 890  * configured by ASoC driver through consumer.h API
 891  */
 892 static const struct iio_chan_spec_ext_info dfsdm_adc_audio_ext_info[] = {
 893         /* spi_clk_freq : clock freq on SPI/manchester bus used by channel */
 894         {
 895                 .name = "spi_clk_freq",
 896                 .shared = IIO_SHARED_BY_TYPE,
 897                 .read = dfsdm_adc_audio_get_spiclk,
 898                 .write = dfsdm_adc_audio_set_spiclk,
 899         },
 900         {},
 901 };
 902
 903 static void stm32_dfsdm_dma_release(struct iio_dev *indio_dev)
 904 {
 905         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 906
 907         if (adc->dma_chan) {
 908                 dma_free_coherent(adc->dma_chan->device->dev,
 909                                   DFSDM_DMA_BUFFER_SIZE,
 910                                   adc->rx_buf, adc->dma_buf);
 911                 dma_release_channel(adc->dma_chan);
 912         }
 913 }
 914
 915 static int stm32_dfsdm_dma_request(struct iio_dev *indio_dev)
 916 {
 917         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 918         struct dma_slave_config config = {
 919                 .src_addr = (dma_addr_t)adc->dfsdm->phys_base +
 920                         DFSDM_RDATAR(adc->fl_id),
 921                 .src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
 922         };
 923         int ret;
 924
 925         adc->dma_chan = dma_request_slave_channel(&indio_dev->dev, "rx");
 926         if (!adc->dma_chan)
 927                 return -EINVAL;
 928
 929         adc->rx_buf = dma_alloc_coherent(adc->dma_chan->device->dev,
 930                                          DFSDM_DMA_BUFFER_SIZE,
 931                                          &adc->dma_buf, GFP_KERNEL);
 932         if (!adc->rx_buf) {
 933                 ret = -ENOMEM;
 934                 goto err_release;
 935         }
 936
 937         ret = dmaengine_slave_config(adc->dma_chan, &config);
 938         if (ret)
 939                 goto err_free;
 940
 941         return 0;
 942
 943 err_free:
 944         dma_free_coherent(adc->dma_chan->device->dev, DFSDM_DMA_BUFFER_SIZE,
 945                           adc->rx_buf, adc->dma_buf);
 946 err_release:
 947         dma_release_channel(adc->dma_chan);
 948
 949         return ret;
 950 }
 951
 952 static int stm32_dfsdm_adc_chan_init_one(struct iio_dev *indio_dev,
 953                                          struct iio_chan_spec *ch)
 954 {
 955         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 956         int ret;
 957
 958         ret = stm32_dfsdm_channel_parse_of(adc->dfsdm, indio_dev, ch);
 959         if (ret < 0)
 960                 return ret;
 961
 962         ch->type = IIO_VOLTAGE;
 963         ch->indexed = 1;
 964
 965         /*
 966          * IIO_CHAN_INFO_RAW: used to compute regular conversion
 967          * IIO_CHAN_INFO_OVERSAMPLING_RATIO: used to set oversampling
 968          */
 969         ch->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
 970         ch->info_mask_shared_by_all = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO);
 971
 972         if (adc->dev_data->type == DFSDM_AUDIO) {
 973                 ch->scan_type.sign = 's';
 974                 ch->ext_info = dfsdm_adc_audio_ext_info;
 975         } else {
 976                 ch->scan_type.sign = 'u';
 977         }
 978         ch->scan_type.realbits = 24;
 979         ch->scan_type.storagebits = 32;
 980
 981         return stm32_dfsdm_chan_configure(adc->dfsdm,
 982                                           &adc->dfsdm->ch_list[ch->channel]);
 983 }
 984
 985 static int stm32_dfsdm_audio_init(struct iio_dev *indio_dev)
 986 {
 987         struct iio_chan_spec *ch;
 988         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 989         struct stm32_dfsdm_channel *d_ch;
 990         int ret;
 991
 992         indio_dev->modes |= INDIO_BUFFER_SOFTWARE;
 993         indio_dev->setup_ops = &stm32_dfsdm_buffer_setup_ops;
 994
 995         ch = devm_kzalloc(&indio_dev->dev, sizeof(*ch), GFP_KERNEL);
 996         if (!ch)
 997                 return -ENOMEM;
 998
 999         ch->scan_index = 0;
1000
1001         ret = stm32_dfsdm_adc_chan_init_one(indio_dev, ch);
1002         if (ret < 0) {
1003                 dev_err(&indio_dev->dev, "Channels init failed\n");
1004                 return ret;
1005         }
1006         ch->info_mask_separate = BIT(IIO_CHAN_INFO_SAMP_FREQ);
1007
1008         d_ch = &adc->dfsdm->ch_list[ch->channel];
1009         if (d_ch->src != DFSDM_CHANNEL_SPI_CLOCK_EXTERNAL)
1010                 adc->spi_freq = adc->dfsdm->spi_master_freq;
1011
1012         indio_dev->num_channels = 1;
1013         indio_dev->channels = ch;
1014
1015         return stm32_dfsdm_dma_request(indio_dev);
1016 }
1017
1018 static int stm32_dfsdm_adc_init(struct iio_dev *indio_dev)
1019 {
1020         struct iio_chan_spec *ch;
1021         struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
1022         int num_ch;
1023         int ret, chan_idx;
1024
1025         adc->oversamp = DFSDM_DEFAULT_OVERSAMPLING;
1026         ret = stm32_dfsdm_set_osrs(&adc->dfsdm->fl_list[adc->fl_id], 0,
1027                                    adc->oversamp);
1028         if (ret < 0)
1029                 return ret;
1030
1031         num_ch = of_property_count_u32_elems(indio_dev->dev.of_node,
1032                                              "st,adc-channels");
1033         if (num_ch < 0 || num_ch > adc->dfsdm->num_chs) {
1034                 dev_err(&indio_dev->dev, "Bad st,adc-channels\n");
1035                 return num_ch < 0 ? num_ch : -EINVAL;
1036         }
1037
1038         /* Bind to SD modulator IIO device */
1039         adc->hwc = devm_iio_hw_consumer_alloc(&indio_dev->dev);
1040         if (IS_ERR(adc->hwc))
1041                 return -EPROBE_DEFER;
1042
1043         ch = devm_kcalloc(&indio_dev->dev, num_ch, sizeof(*ch),
1044                           GFP_KERNEL);
1045         if (!ch)
1046                 return -ENOMEM;
1047
1048         for (chan_idx = 0; chan_idx < num_ch; chan_idx++) {
1049                 ch[chan_idx].scan_index = chan_idx;
1050                 ret = stm32_dfsdm_adc_chan_init_one(indio_dev, &ch[chan_idx]);
1051                 if (ret < 0) {
1052                         dev_err(&indio_dev->dev, "Channels init failed\n");
1053                         return ret;
1054                 }
1055         }
1056
1057         indio_dev->num_channels = num_ch;
1058         indio_dev->channels = ch;
1059
1060         init_completion(&adc->completion);
1061
1062         return 0;
1063 }
1064
1065 static const struct stm32_dfsdm_dev_data stm32h7_dfsdm_adc_data = {
1066         .type = DFSDM_IIO,
1067         .init = stm32_dfsdm_adc_init,
1068 };
1069
1070 static const struct stm32_dfsdm_dev_data stm32h7_dfsdm_audio_data = {
1071         .type = DFSDM_AUDIO,
1072         .init = stm32_dfsdm_audio_init,
1073 };
1074
1075 static const struct of_device_id stm32_dfsdm_adc_match[] = {
1076         {
1077                 .compatible = "st,stm32-dfsdm-adc",
1078                 .data = &stm32h7_dfsdm_adc_data,
1079         },
1080         {
1081                 .compatible = "st,stm32-dfsdm-dmic",
1082                 .data = &stm32h7_dfsdm_audio_data,
1083         },
1084         {}
1085 };
1086
1087 static int stm32_dfsdm_adc_probe(struct platform_device *pdev)
1088 {
1089         struct device *dev = &pdev->dev;
1090         struct stm32_dfsdm_adc *adc;
1091         struct device_node *np = dev->of_node;
1092         const struct stm32_dfsdm_dev_data *dev_data;
1093         struct iio_dev *iio;
1094         char *name;
1095         int ret, irq, val;
1096
1097         dev_data = of_device_get_match_data(dev);
1098         iio = devm_iio_device_alloc(dev, sizeof(*adc));
1099         if (!iio) {
1100                 dev_err(dev, "%s: Failed to allocate IIO\n", __func__);
1101                 return -ENOMEM;
1102         }
1103
1104         adc = iio_priv(iio);
1105         adc->dfsdm = dev_get_drvdata(dev->parent);
1106
1107         iio->dev.parent = dev;
1108         iio->dev.of_node = np;
1109         iio->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
1110
1111         platform_set_drvdata(pdev, adc);
1112
1113         ret = of_property_read_u32(dev->of_node, "reg", &adc->fl_id);
1114         if (ret != 0 || adc->fl_id >= adc->dfsdm->num_fls) {
1115                 dev_err(dev, "Missing or bad reg property\n");
1116                 return -EINVAL;
1117         }
1118
1119         name = devm_kzalloc(dev, sizeof("dfsdm-adc0"), GFP_KERNEL);
1120         if (!name)
1121                 return -ENOMEM;
1122         if (dev_data->type == DFSDM_AUDIO) {
1123                 iio->info = &stm32_dfsdm_info_audio;
1124                 snprintf(name, sizeof("dfsdm-pdm0"), "dfsdm-pdm%d", adc->fl_id);
1125         } else {
1126                 iio->info = &stm32_dfsdm_info_adc;
1127                 snprintf(name, sizeof("dfsdm-adc0"), "dfsdm-adc%d", adc->fl_id);
1128         }
1129         iio->name = name;
1130
1131         /*
1132          * In a first step IRQs generated for channels are not treated.
1133          * So IRQ associated to filter instance 0 is dedicated to the Filter 0.
1134          */
1135         irq = platform_get_irq(pdev, 0);
1136         ret = devm_request_irq(dev, irq, stm32_dfsdm_irq,
1137                                0, pdev->name, adc);
1138         if (ret < 0) {
1139                 dev_err(dev, "Failed to request IRQ\n");
1140                 return ret;
1141         }
1142
1143         ret = of_property_read_u32(dev->of_node, "st,filter-order", &val);
1144         if (ret < 0) {
1145                 dev_err(dev, "Failed to set filter order\n");
1146                 return ret;
1147         }
1148
1149         adc->dfsdm->fl_list[adc->fl_id].ford = val;
1150
1151         ret = of_property_read_u32(dev->of_node, "st,filter0-sync", &val);
1152         if (!ret)
1153                 adc->dfsdm->fl_list[adc->fl_id].sync_mode = val;
1154
1155         adc->dev_data = dev_data;
1156         ret = dev_data->init(iio);
1157         if (ret < 0)
1158                 return ret;
1159
1160         ret = iio_device_register(iio);
1161         if (ret < 0)
1162                 goto err_cleanup;
1163
1164         if (dev_data->type == DFSDM_AUDIO) {
1165                 ret = of_platform_populate(np, NULL, NULL, dev);
1166                 if (ret < 0) {
1167                         dev_err(dev, "Failed to find an audio DAI\n");
1168                         goto err_unregister;
1169                 }
1170         }
1171
1172         return 0;
1173
1174 err_unregister:
1175         iio_device_unregister(iio);
1176 err_cleanup:
1177         stm32_dfsdm_dma_release(iio);
1178
1179         return ret;
1180 }
1181
1182 static int stm32_dfsdm_adc_remove(struct platform_device *pdev)
1183 {
1184         struct stm32_dfsdm_adc *adc = platform_get_drvdata(pdev);
1185         struct iio_dev *indio_dev = iio_priv_to_dev(adc);
1186
1187         if (adc->dev_data->type == DFSDM_AUDIO)
1188                 of_platform_depopulate(&pdev->dev);
1189         iio_device_unregister(indio_dev);
1190         stm32_dfsdm_dma_release(indio_dev);
1191
1192         return 0;
1193 }
1194
1195 static struct platform_driver stm32_dfsdm_adc_driver = {
1196         .driver = {
1197                 .name = "stm32-dfsdm-adc",
1198                 .of_match_table = stm32_dfsdm_adc_match,
1199         },
1200         .probe = stm32_dfsdm_adc_probe,
1201         .remove = stm32_dfsdm_adc_remove,
1202 };
1203 module_platform_driver(stm32_dfsdm_adc_driver);
1204
1205 MODULE_DESCRIPTION("STM32 sigma delta ADC");
1206 MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@st.com>");
1207 MODULE_LICENSE("GPL v2");