drivers/iio/adc/rockchip_saradc.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Rockchip Successive Approximation Register (SAR) A/D Converter
   4  * Copyright (C) 2014 ROCKCHIP, Inc.
   5  */
   6
   7 #include <linux/bitfield.h>
   8 #include <linux/module.h>
   9 #include <linux/mutex.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/io.h>
  13 #include <linux/of.h>
  14 #include <linux/clk.h>
  15 #include <linux/completion.h>
  16 #include <linux/delay.h>
  17 #include <linux/reset.h>
  18 #include <linux/regulator/consumer.h>
  19 #include <linux/iio/buffer.h>
  20 #include <linux/iio/iio.h>
  21 #include <linux/iio/trigger_consumer.h>
  22 #include <linux/iio/triggered_buffer.h>
  23
  24 #define SARADC_DATA                     0x00
  25
  26 #define SARADC_STAS                     0x04
  27 #define SARADC_STAS_BUSY                BIT(0)
  28
  29 #define SARADC_CTRL                     0x08
  30 #define SARADC_CTRL_IRQ_STATUS          BIT(6)
  31 #define SARADC_CTRL_IRQ_ENABLE          BIT(5)
  32 #define SARADC_CTRL_POWER_CTRL          BIT(3)
  33 #define SARADC_CTRL_CHN_MASK            0x7
  34
  35 #define SARADC_DLY_PU_SOC               0x0c
  36 #define SARADC_DLY_PU_SOC_MASK          0x3f
  37
  38 #define SARADC_TIMEOUT                  msecs_to_jiffies(100)
  39 #define SARADC_MAX_CHANNELS             8
  40
  41 /* v2 registers */
  42 #define SARADC2_CONV_CON                0x000
  43 #define SARADC_T_PD_SOC                 0x004
  44 #define SARADC_T_DAS_SOC                0x00c
  45 #define SARADC2_END_INT_EN              0x104
  46 #define SARADC2_ST_CON                  0x108
  47 #define SARADC2_STATUS                  0x10c
  48 #define SARADC2_END_INT_ST              0x110
  49 #define SARADC2_DATA_BASE               0x120
  50
  51 #define SARADC2_EN_END_INT              BIT(0)
  52 #define SARADC2_START                   BIT(4)
  53 #define SARADC2_SINGLE_MODE             BIT(5)
  54
  55 #define SARADC2_CONV_CHANNELS GENMASK(3, 0)
  56
  57 struct rockchip_saradc;
  58
  59 struct rockchip_saradc_data {
  60         const struct iio_chan_spec      *channels;
  61         int                             num_channels;
  62         unsigned long                   clk_rate;
  63         void (*start)(struct rockchip_saradc *info, int chn);
  64         int (*read)(struct rockchip_saradc *info);
  65         void (*power_down)(struct rockchip_saradc *info);
  66 };
  67
  68 struct rockchip_saradc {
  69         void __iomem            *regs;
  70         struct clk              *pclk;
  71         struct clk              *clk;
  72         struct completion       completion;
  73         struct regulator        *vref;
  74         /* lock to protect against multiple access to the device */
  75         struct mutex            lock;
  76         int                     uv_vref;
  77         struct reset_control    *reset;
  78         const struct rockchip_saradc_data *data;
  79         u16                     last_val;
  80         const struct iio_chan_spec *last_chan;
  81         struct notifier_block nb;
  82 };
  83
  84 static void rockchip_saradc_reset_controller(struct reset_control *reset);
  85
  86 static void rockchip_saradc_start_v1(struct rockchip_saradc *info, int chn)
  87 {
  88         /* 8 clock periods as delay between power up and start cmd */
  89         writel_relaxed(8, info->regs + SARADC_DLY_PU_SOC);
  90         /* Select the channel to be used and trigger conversion */
  91         writel(SARADC_CTRL_POWER_CTRL | (chn & SARADC_CTRL_CHN_MASK) |
  92                SARADC_CTRL_IRQ_ENABLE, info->regs + SARADC_CTRL);
  93 }
  94
  95 static void rockchip_saradc_start_v2(struct rockchip_saradc *info, int chn)
  96 {
  97         int val;
  98
  99         if (info->reset)
 100                 rockchip_saradc_reset_controller(info->reset);
 101
 102         writel_relaxed(0xc, info->regs + SARADC_T_DAS_SOC);
 103         writel_relaxed(0x20, info->regs + SARADC_T_PD_SOC);
 104         val = FIELD_PREP(SARADC2_EN_END_INT, 1);
 105         val |= SARADC2_EN_END_INT << 16;
 106         writel_relaxed(val, info->regs + SARADC2_END_INT_EN);
 107         val = FIELD_PREP(SARADC2_START, 1) |
 108               FIELD_PREP(SARADC2_SINGLE_MODE, 1) |
 109               FIELD_PREP(SARADC2_CONV_CHANNELS, chn);
 110         val |= (SARADC2_START | SARADC2_SINGLE_MODE | SARADC2_CONV_CHANNELS) << 16;
 111         writel(val, info->regs + SARADC2_CONV_CON);
 112 }
 113
 114 static void rockchip_saradc_start(struct rockchip_saradc *info, int chn)
 115 {
 116         info->data->start(info, chn);
 117 }
 118
 119 static int rockchip_saradc_read_v1(struct rockchip_saradc *info)
 120 {
 121         return readl_relaxed(info->regs + SARADC_DATA);
 122 }
 123
 124 static int rockchip_saradc_read_v2(struct rockchip_saradc *info)
 125 {
 126         int offset;
 127
 128         /* Clear irq */
 129         writel_relaxed(0x1, info->regs + SARADC2_END_INT_ST);
 130
 131         offset = SARADC2_DATA_BASE + info->last_chan->channel * 0x4;
 132
 133         return readl_relaxed(info->regs + offset);
 134 }
 135
 136 static int rockchip_saradc_read(struct rockchip_saradc *info)
 137 {
 138         return info->data->read(info);
 139 }
 140
 141 static void rockchip_saradc_power_down_v1(struct rockchip_saradc *info)
 142 {
 143         writel_relaxed(0, info->regs + SARADC_CTRL);
 144 }
 145
 146 static void rockchip_saradc_power_down(struct rockchip_saradc *info)
 147 {
 148         if (info->data->power_down)
 149                 info->data->power_down(info);
 150 }
 151
 152 static int rockchip_saradc_conversion(struct rockchip_saradc *info,
 153                                       struct iio_chan_spec const *chan)
 154 {
 155         reinit_completion(&info->completion);
 156
 157         info->last_chan = chan;
 158         rockchip_saradc_start(info, chan->channel);
 159
 160         if (!wait_for_completion_timeout(&info->completion, SARADC_TIMEOUT))
 161                 return -ETIMEDOUT;
 162
 163         return 0;
 164 }
 165
 166 static int rockchip_saradc_read_raw(struct iio_dev *indio_dev,
 167                                     struct iio_chan_spec const *chan,
 168                                     int *val, int *val2, long mask)
 169 {
 170         struct rockchip_saradc *info = iio_priv(indio_dev);
 171         int ret;
 172
 173         switch (mask) {
 174         case IIO_CHAN_INFO_RAW:
 175                 mutex_lock(&info->lock);
 176
 177                 ret = rockchip_saradc_conversion(info, chan);
 178                 if (ret) {
 179                         rockchip_saradc_power_down(info);
 180                         mutex_unlock(&info->lock);
 181                         return ret;
 182                 }
 183
 184                 *val = info->last_val;
 185                 mutex_unlock(&info->lock);
 186                 return IIO_VAL_INT;
 187         case IIO_CHAN_INFO_SCALE:
 188                 *val = info->uv_vref / 1000;
 189                 *val2 = chan->scan_type.realbits;
 190                 return IIO_VAL_FRACTIONAL_LOG2;
 191         default:
 192                 return -EINVAL;
 193         }
 194 }
 195
 196 static irqreturn_t rockchip_saradc_isr(int irq, void *dev_id)
 197 {
 198         struct rockchip_saradc *info = dev_id;
 199
 200         /* Read value */
 201         info->last_val = rockchip_saradc_read(info);
 202         info->last_val &= GENMASK(info->last_chan->scan_type.realbits - 1, 0);
 203
 204         rockchip_saradc_power_down(info);
 205
 206         complete(&info->completion);
 207
 208         return IRQ_HANDLED;
 209 }
 210
 211 static const struct iio_info rockchip_saradc_iio_info = {
 212         .read_raw = rockchip_saradc_read_raw,
 213 };
 214
 215 #define SARADC_CHANNEL(_index, _id, _res) {                     \
 216         .type = IIO_VOLTAGE,                                    \
 217         .indexed = 1,                                           \
 218         .channel = _index,                                      \
 219         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
 220         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
 221         .datasheet_name = _id,                                  \
 222         .scan_index = _index,                                   \
 223         .scan_type = {                                          \
 224                 .sign = 'u',                                    \
 225                 .realbits = _res,                               \
 226                 .storagebits = 16,                              \
 227                 .endianness = IIO_CPU,                          \
 228         },                                                      \
 229 }
 230
 231 static const struct iio_chan_spec rockchip_saradc_iio_channels[] = {
 232         SARADC_CHANNEL(0, "adc0", 10),
 233         SARADC_CHANNEL(1, "adc1", 10),
 234         SARADC_CHANNEL(2, "adc2", 10),
 235 };
 236
 237 static const struct rockchip_saradc_data saradc_data = {
 238         .channels = rockchip_saradc_iio_channels,
 239         .num_channels = ARRAY_SIZE(rockchip_saradc_iio_channels),
 240         .clk_rate = 1000000,
 241         .start = rockchip_saradc_start_v1,
 242         .read = rockchip_saradc_read_v1,
 243         .power_down = rockchip_saradc_power_down_v1,
 244 };
 245
 246 static const struct iio_chan_spec rockchip_rk3066_tsadc_iio_channels[] = {
 247         SARADC_CHANNEL(0, "adc0", 12),
 248         SARADC_CHANNEL(1, "adc1", 12),
 249 };
 250
 251 static const struct rockchip_saradc_data rk3066_tsadc_data = {
 252         .channels = rockchip_rk3066_tsadc_iio_channels,
 253         .num_channels = ARRAY_SIZE(rockchip_rk3066_tsadc_iio_channels),
 254         .clk_rate = 50000,
 255         .start = rockchip_saradc_start_v1,
 256         .read = rockchip_saradc_read_v1,
 257         .power_down = rockchip_saradc_power_down_v1,
 258 };
 259
 260 static const struct iio_chan_spec rockchip_rk3399_saradc_iio_channels[] = {
 261         SARADC_CHANNEL(0, "adc0", 10),
 262         SARADC_CHANNEL(1, "adc1", 10),
 263         SARADC_CHANNEL(2, "adc2", 10),
 264         SARADC_CHANNEL(3, "adc3", 10),
 265         SARADC_CHANNEL(4, "adc4", 10),
 266         SARADC_CHANNEL(5, "adc5", 10),
 267 };
 268
 269 static const struct rockchip_saradc_data rk3399_saradc_data = {
 270         .channels = rockchip_rk3399_saradc_iio_channels,
 271         .num_channels = ARRAY_SIZE(rockchip_rk3399_saradc_iio_channels),
 272         .clk_rate = 1000000,
 273         .start = rockchip_saradc_start_v1,
 274         .read = rockchip_saradc_read_v1,
 275         .power_down = rockchip_saradc_power_down_v1,
 276 };
 277
 278 static const struct iio_chan_spec rockchip_rk3568_saradc_iio_channels[] = {
 279         SARADC_CHANNEL(0, "adc0", 10),
 280         SARADC_CHANNEL(1, "adc1", 10),
 281         SARADC_CHANNEL(2, "adc2", 10),
 282         SARADC_CHANNEL(3, "adc3", 10),
 283         SARADC_CHANNEL(4, "adc4", 10),
 284         SARADC_CHANNEL(5, "adc5", 10),
 285         SARADC_CHANNEL(6, "adc6", 10),
 286         SARADC_CHANNEL(7, "adc7", 10),
 287 };
 288
 289 static const struct rockchip_saradc_data rk3568_saradc_data = {
 290         .channels = rockchip_rk3568_saradc_iio_channels,
 291         .num_channels = ARRAY_SIZE(rockchip_rk3568_saradc_iio_channels),
 292         .clk_rate = 1000000,
 293         .start = rockchip_saradc_start_v1,
 294         .read = rockchip_saradc_read_v1,
 295         .power_down = rockchip_saradc_power_down_v1,
 296 };
 297
 298 static const struct iio_chan_spec rockchip_rk3588_saradc_iio_channels[] = {
 299         SARADC_CHANNEL(0, "adc0", 12),
 300         SARADC_CHANNEL(1, "adc1", 12),
 301         SARADC_CHANNEL(2, "adc2", 12),
 302         SARADC_CHANNEL(3, "adc3", 12),
 303         SARADC_CHANNEL(4, "adc4", 12),
 304         SARADC_CHANNEL(5, "adc5", 12),
 305         SARADC_CHANNEL(6, "adc6", 12),
 306         SARADC_CHANNEL(7, "adc7", 12),
 307 };
 308
 309 static const struct rockchip_saradc_data rk3588_saradc_data = {
 310         .channels = rockchip_rk3588_saradc_iio_channels,
 311         .num_channels = ARRAY_SIZE(rockchip_rk3588_saradc_iio_channels),
 312         .clk_rate = 1000000,
 313         .start = rockchip_saradc_start_v2,
 314         .read = rockchip_saradc_read_v2,
 315 };
 316
 317 static const struct of_device_id rockchip_saradc_match[] = {
 318         {
 319                 .compatible = "rockchip,saradc",
 320                 .data = &saradc_data,
 321         }, {
 322                 .compatible = "rockchip,rk3066-tsadc",
 323                 .data = &rk3066_tsadc_data,
 324         }, {
 325                 .compatible = "rockchip,rk3399-saradc",
 326                 .data = &rk3399_saradc_data,
 327         }, {
 328                 .compatible = "rockchip,rk3568-saradc",
 329                 .data = &rk3568_saradc_data,
 330         }, {
 331                 .compatible = "rockchip,rk3588-saradc",
 332                 .data = &rk3588_saradc_data,
 333         },
 334         { }
 335 };
 336 MODULE_DEVICE_TABLE(of, rockchip_saradc_match);
 337
 338 /*
 339  * Reset SARADC Controller.
 340  */
 341 static void rockchip_saradc_reset_controller(struct reset_control *reset)
 342 {
 343         reset_control_assert(reset);
 344         usleep_range(10, 20);
 345         reset_control_deassert(reset);
 346 }
 347
 348 static void rockchip_saradc_regulator_disable(void *data)
 349 {
 350         struct rockchip_saradc *info = data;
 351
 352         regulator_disable(info->vref);
 353 }
 354
 355 static irqreturn_t rockchip_saradc_trigger_handler(int irq, void *p)
 356 {
 357         struct iio_poll_func *pf = p;
 358         struct iio_dev *i_dev = pf->indio_dev;
 359         struct rockchip_saradc *info = iio_priv(i_dev);
 360         /*
 361          * @values: each channel takes an u16 value
 362          * @timestamp: will be 8-byte aligned automatically
 363          */
 364         struct {
 365                 u16 values[SARADC_MAX_CHANNELS];
 366                 int64_t timestamp;
 367         } data;
 368         int ret;
 369         int i, j = 0;
 370
 371         mutex_lock(&info->lock);
 372
 373         iio_for_each_active_channel(i_dev, i) {
 374                 const struct iio_chan_spec *chan = &i_dev->channels[i];
 375
 376                 ret = rockchip_saradc_conversion(info, chan);
 377                 if (ret) {
 378                         rockchip_saradc_power_down(info);
 379                         goto out;
 380                 }
 381
 382                 data.values[j] = info->last_val;
 383                 j++;
 384         }
 385
 386         iio_push_to_buffers_with_timestamp(i_dev, &data, iio_get_time_ns(i_dev));
 387 out:
 388         mutex_unlock(&info->lock);
 389
 390         iio_trigger_notify_done(i_dev->trig);
 391
 392         return IRQ_HANDLED;
 393 }
 394
 395 static int rockchip_saradc_volt_notify(struct notifier_block *nb,
 396                                        unsigned long event, void *data)
 397 {
 398         struct rockchip_saradc *info =
 399                         container_of(nb, struct rockchip_saradc, nb);
 400
 401         if (event & REGULATOR_EVENT_VOLTAGE_CHANGE)
 402                 info->uv_vref = (unsigned long)data;
 403
 404         return NOTIFY_OK;
 405 }
 406
 407 static void rockchip_saradc_regulator_unreg_notifier(void *data)
 408 {
 409         struct rockchip_saradc *info = data;
 410
 411         regulator_unregister_notifier(info->vref, &info->nb);
 412 }
 413
 414 static int rockchip_saradc_probe(struct platform_device *pdev)
 415 {
 416         const struct rockchip_saradc_data *match_data;
 417         struct rockchip_saradc *info = NULL;
 418         struct device_node *np = pdev->dev.of_node;
 419         struct iio_dev *indio_dev = NULL;
 420         int ret;
 421         int irq;
 422
 423         if (!np)
 424                 return -ENODEV;
 425
 426         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
 427         if (!indio_dev)
 428                 return dev_err_probe(&pdev->dev, -ENOMEM,
 429                                      "failed allocating iio device\n");
 430
 431         info = iio_priv(indio_dev);
 432
 433         match_data = of_device_get_match_data(&pdev->dev);
 434         if (!match_data)
 435                 return dev_err_probe(&pdev->dev, -ENODEV,
 436                                      "failed to match device\n");
 437
 438         info->data = match_data;
 439
 440         /* Sanity check for possible later IP variants with more channels */
 441         if (info->data->num_channels > SARADC_MAX_CHANNELS)
 442                 return dev_err_probe(&pdev->dev, -EINVAL,
 443                                      "max channels exceeded");
 444
 445         info->regs = devm_platform_ioremap_resource(pdev, 0);
 446         if (IS_ERR(info->regs))
 447                 return PTR_ERR(info->regs);
 448
 449         /*
 450          * The reset should be an optional property, as it should work
 451          * with old devicetrees as well
 452          */
 453         info->reset = devm_reset_control_get_optional_exclusive(&pdev->dev,
 454                                                                 "saradc-apb");
 455         if (IS_ERR(info->reset)) {
 456                 ret = PTR_ERR(info->reset);
 457                 return dev_err_probe(&pdev->dev, ret, "failed to get saradc-apb\n");
 458         }
 459
 460         init_completion(&info->completion);
 461
 462         irq = platform_get_irq(pdev, 0);
 463         if (irq < 0)
 464                 return irq;
 465
 466         ret = devm_request_irq(&pdev->dev, irq, rockchip_saradc_isr,
 467                                0, dev_name(&pdev->dev), info);
 468         if (ret < 0) {
 469                 dev_err(&pdev->dev, "failed requesting irq %d\n", irq);
 470                 return ret;
 471         }
 472
 473         info->vref = devm_regulator_get(&pdev->dev, "vref");
 474         if (IS_ERR(info->vref))
 475                 return dev_err_probe(&pdev->dev, PTR_ERR(info->vref),
 476                                      "failed to get regulator\n");
 477
 478         if (info->reset)
 479                 rockchip_saradc_reset_controller(info->reset);
 480
 481         /*
 482          * Use a default value for the converter clock.
 483          * This may become user-configurable in the future.
 484          */
 485         ret = clk_set_rate(info->clk, info->data->clk_rate);
 486         if (ret < 0)
 487                 return dev_err_probe(&pdev->dev, ret,
 488                                      "failed to set adc clk rate\n");
 489
 490         ret = regulator_enable(info->vref);
 491         if (ret < 0)
 492                 return dev_err_probe(&pdev->dev, ret,
 493                                      "failed to enable vref regulator\n");
 494
 495         ret = devm_add_action_or_reset(&pdev->dev,
 496                                        rockchip_saradc_regulator_disable, info);
 497         if (ret)
 498                 return dev_err_probe(&pdev->dev, ret,
 499                                      "failed to register devm action\n");
 500
 501         ret = regulator_get_voltage(info->vref);
 502         if (ret < 0)
 503                 return ret;
 504
 505         info->uv_vref = ret;
 506
 507         info->pclk = devm_clk_get_enabled(&pdev->dev, "apb_pclk");
 508         if (IS_ERR(info->pclk))
 509                 return dev_err_probe(&pdev->dev, PTR_ERR(info->pclk),
 510                                      "failed to get pclk\n");
 511
 512         info->clk = devm_clk_get_enabled(&pdev->dev, "saradc");
 513         if (IS_ERR(info->clk))
 514                 return dev_err_probe(&pdev->dev, PTR_ERR(info->clk),
 515                                      "failed to get adc clock\n");
 516
 517         platform_set_drvdata(pdev, indio_dev);
 518
 519         indio_dev->name = dev_name(&pdev->dev);
 520         indio_dev->info = &rockchip_saradc_iio_info;
 521         indio_dev->modes = INDIO_DIRECT_MODE;
 522
 523         indio_dev->channels = info->data->channels;
 524         indio_dev->num_channels = info->data->num_channels;
 525         ret = devm_iio_triggered_buffer_setup(&indio_dev->dev, indio_dev, NULL,
 526                                               rockchip_saradc_trigger_handler,
 527                                               NULL);
 528         if (ret)
 529                 return ret;
 530
 531         info->nb.notifier_call = rockchip_saradc_volt_notify;
 532         ret = regulator_register_notifier(info->vref, &info->nb);
 533         if (ret)
 534                 return ret;
 535
 536         ret = devm_add_action_or_reset(&pdev->dev,
 537                                        rockchip_saradc_regulator_unreg_notifier,
 538                                        info);
 539         if (ret)
 540                 return ret;
 541
 542         mutex_init(&info->lock);
 543
 544         return devm_iio_device_register(&pdev->dev, indio_dev);
 545 }
 546
 547 static int rockchip_saradc_suspend(struct device *dev)
 548 {
 549         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 550         struct rockchip_saradc *info = iio_priv(indio_dev);
 551
 552         clk_disable_unprepare(info->clk);
 553         clk_disable_unprepare(info->pclk);
 554         regulator_disable(info->vref);
 555
 556         return 0;
 557 }
 558
 559 static int rockchip_saradc_resume(struct device *dev)
 560 {
 561         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 562         struct rockchip_saradc *info = iio_priv(indio_dev);
 563         int ret;
 564
 565         ret = regulator_enable(info->vref);
 566         if (ret)
 567                 return ret;
 568
 569         ret = clk_prepare_enable(info->pclk);
 570         if (ret)
 571                 return ret;
 572
 573         ret = clk_prepare_enable(info->clk);
 574         if (ret)
 575                 clk_disable_unprepare(info->pclk);
 576
 577         return ret;
 578 }
 579
 580 static DEFINE_SIMPLE_DEV_PM_OPS(rockchip_saradc_pm_ops,
 581                                 rockchip_saradc_suspend,
 582                                 rockchip_saradc_resume);
 583
 584 static struct platform_driver rockchip_saradc_driver = {
 585         .probe          = rockchip_saradc_probe,
 586         .driver         = {
 587                 .name   = "rockchip-saradc",
 588                 .of_match_table = rockchip_saradc_match,
 589                 .pm     = pm_sleep_ptr(&rockchip_saradc_pm_ops),
 590         },
 591 };
 592
 593 module_platform_driver(rockchip_saradc_driver);
 594
 595 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 596 MODULE_DESCRIPTION("Rockchip SARADC driver");
 597 MODULE_LICENSE("GPL v2");