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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * This file is part the core part STM32 DFSDM driver
   4  *
   5  * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
   6  * Author(s): Arnaud Pouliquen <arnaud.pouliquen@st.com> for STMicroelectronics.
   7  */
   8
   9 #include <linux/clk.h>
  10 #include <linux/iio/iio.h>
  11 #include <linux/iio/sysfs.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/module.h>
  14 #include <linux/of_device.h>
  15 #include <linux/pinctrl/consumer.h>
  16 #include <linux/pm_runtime.h>
  17 #include <linux/regmap.h>
  18 #include <linux/slab.h>
  19
  20 #include "stm32-dfsdm.h"
  21
  22 struct stm32_dfsdm_dev_data {
  23         unsigned int num_filters;
  24         unsigned int num_channels;
  25         const struct regmap_config *regmap_cfg;
  26 };
  27
  28 #define STM32H7_DFSDM_NUM_FILTERS       4
  29 #define STM32H7_DFSDM_NUM_CHANNELS      8
  30 #define STM32MP1_DFSDM_NUM_FILTERS      6
  31 #define STM32MP1_DFSDM_NUM_CHANNELS     8
  32
  33 static bool stm32_dfsdm_volatile_reg(struct device *dev, unsigned int reg)
  34 {
  35         if (reg < DFSDM_FILTER_BASE_ADR)
  36                 return false;
  37
  38         /*
  39          * Mask is done on register to avoid to list registers of all
  40          * filter instances.
  41          */
  42         switch (reg & DFSDM_FILTER_REG_MASK) {
  43         case DFSDM_CR1(0) & DFSDM_FILTER_REG_MASK:
  44         case DFSDM_ISR(0) & DFSDM_FILTER_REG_MASK:
  45         case DFSDM_JDATAR(0) & DFSDM_FILTER_REG_MASK:
  46         case DFSDM_RDATAR(0) & DFSDM_FILTER_REG_MASK:
  47                 return true;
  48         }
  49
  50         return false;
  51 }
  52
  53 static const struct regmap_config stm32h7_dfsdm_regmap_cfg = {
  54         .reg_bits = 32,
  55         .val_bits = 32,
  56         .reg_stride = sizeof(u32),
  57         .max_register = 0x2B8,
  58         .volatile_reg = stm32_dfsdm_volatile_reg,
  59         .fast_io = true,
  60 };
  61
  62 static const struct stm32_dfsdm_dev_data stm32h7_dfsdm_data = {
  63         .num_filters = STM32H7_DFSDM_NUM_FILTERS,
  64         .num_channels = STM32H7_DFSDM_NUM_CHANNELS,
  65         .regmap_cfg = &stm32h7_dfsdm_regmap_cfg,
  66 };
  67
  68 static const struct regmap_config stm32mp1_dfsdm_regmap_cfg = {
  69         .reg_bits = 32,
  70         .val_bits = 32,
  71         .reg_stride = sizeof(u32),
  72         .max_register = 0x7fc,
  73         .volatile_reg = stm32_dfsdm_volatile_reg,
  74         .fast_io = true,
  75 };
  76
  77 static const struct stm32_dfsdm_dev_data stm32mp1_dfsdm_data = {
  78         .num_filters = STM32MP1_DFSDM_NUM_FILTERS,
  79         .num_channels = STM32MP1_DFSDM_NUM_CHANNELS,
  80         .regmap_cfg = &stm32mp1_dfsdm_regmap_cfg,
  81 };
  82
  83 struct dfsdm_priv {
  84         struct platform_device *pdev; /* platform device */
  85
  86         struct stm32_dfsdm dfsdm; /* common data exported for all instances */
  87
  88         unsigned int spi_clk_out_div; /* SPI clkout divider value */
  89         atomic_t n_active_ch;   /* number of current active channels */
  90
  91         struct clk *clk; /* DFSDM clock */
  92         struct clk *aclk; /* audio clock */
  93 };
  94
  95 static inline struct dfsdm_priv *to_stm32_dfsdm_priv(struct stm32_dfsdm *dfsdm)
  96 {
  97         return container_of(dfsdm, struct dfsdm_priv, dfsdm);
  98 }
  99
 100 static int stm32_dfsdm_clk_prepare_enable(struct stm32_dfsdm *dfsdm)
 101 {
 102         struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
 103         int ret;
 104
 105         ret = clk_prepare_enable(priv->clk);
 106         if (ret || !priv->aclk)
 107                 return ret;
 108
 109         ret = clk_prepare_enable(priv->aclk);
 110         if (ret)
 111                 clk_disable_unprepare(priv->clk);
 112
 113         return ret;
 114 }
 115
 116 static void stm32_dfsdm_clk_disable_unprepare(struct stm32_dfsdm *dfsdm)
 117 {
 118         struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
 119
 120         if (priv->aclk)
 121                 clk_disable_unprepare(priv->aclk);
 122         clk_disable_unprepare(priv->clk);
 123 }
 124
 125 /**
 126  * stm32_dfsdm_start_dfsdm - start global dfsdm interface.
 127  *
 128  * Enable interface if n_active_ch is not null.
 129  * @dfsdm: Handle used to retrieve dfsdm context.
 130  */
 131 int stm32_dfsdm_start_dfsdm(struct stm32_dfsdm *dfsdm)
 132 {
 133         struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
 134         struct device *dev = &priv->pdev->dev;
 135         unsigned int clk_div = priv->spi_clk_out_div, clk_src;
 136         int ret;
 137
 138         if (atomic_inc_return(&priv->n_active_ch) == 1) {
 139                 ret = pm_runtime_get_sync(dev);
 140                 if (ret < 0) {
 141                         pm_runtime_put_noidle(dev);
 142                         goto error_ret;
 143                 }
 144
 145                 /* select clock source, e.g. 0 for "dfsdm" or 1 for "audio" */
 146                 clk_src = priv->aclk ? 1 : 0;
 147                 ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
 148                                          DFSDM_CHCFGR1_CKOUTSRC_MASK,
 149                                          DFSDM_CHCFGR1_CKOUTSRC(clk_src));
 150                 if (ret < 0)
 151                         goto pm_put;
 152
 153                 /* Output the SPI CLKOUT (if clk_div == 0 clock if OFF) */
 154                 ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
 155                                          DFSDM_CHCFGR1_CKOUTDIV_MASK,
 156                                          DFSDM_CHCFGR1_CKOUTDIV(clk_div));
 157                 if (ret < 0)
 158                         goto pm_put;
 159
 160                 /* Global enable of DFSDM interface */
 161                 ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
 162                                          DFSDM_CHCFGR1_DFSDMEN_MASK,
 163                                          DFSDM_CHCFGR1_DFSDMEN(1));
 164                 if (ret < 0)
 165                         goto pm_put;
 166         }
 167
 168         dev_dbg(dev, "%s: n_active_ch %d\n", __func__,
 169                 atomic_read(&priv->n_active_ch));
 170
 171         return 0;
 172
 173 pm_put:
 174         pm_runtime_put_sync(dev);
 175 error_ret:
 176         atomic_dec(&priv->n_active_ch);
 177
 178         return ret;
 179 }
 180 EXPORT_SYMBOL_GPL(stm32_dfsdm_start_dfsdm);
 181
 182 /**
 183  * stm32_dfsdm_stop_dfsdm - stop global DFSDM interface.
 184  *
 185  * Disable interface if n_active_ch is null
 186  * @dfsdm: Handle used to retrieve dfsdm context.
 187  */
 188 int stm32_dfsdm_stop_dfsdm(struct stm32_dfsdm *dfsdm)
 189 {
 190         struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
 191         int ret;
 192
 193         if (atomic_dec_and_test(&priv->n_active_ch)) {
 194                 /* Global disable of DFSDM interface */
 195                 ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
 196                                          DFSDM_CHCFGR1_DFSDMEN_MASK,
 197                                          DFSDM_CHCFGR1_DFSDMEN(0));
 198                 if (ret < 0)
 199                         return ret;
 200
 201                 /* Stop SPI CLKOUT */
 202                 ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
 203                                          DFSDM_CHCFGR1_CKOUTDIV_MASK,
 204                                          DFSDM_CHCFGR1_CKOUTDIV(0));
 205                 if (ret < 0)
 206                         return ret;
 207
 208                 pm_runtime_put_sync(&priv->pdev->dev);
 209         }
 210         dev_dbg(&priv->pdev->dev, "%s: n_active_ch %d\n", __func__,
 211                 atomic_read(&priv->n_active_ch));
 212
 213         return 0;
 214 }
 215 EXPORT_SYMBOL_GPL(stm32_dfsdm_stop_dfsdm);
 216
 217 static int stm32_dfsdm_parse_of(struct platform_device *pdev,
 218                                 struct dfsdm_priv *priv)
 219 {
 220         struct device_node *node = pdev->dev.of_node;
 221         struct resource *res;
 222         unsigned long clk_freq, divider;
 223         unsigned int spi_freq, rem;
 224         int ret;
 225
 226         if (!node)
 227                 return -EINVAL;
 228
 229         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 230         if (!res) {
 231                 dev_err(&pdev->dev, "Failed to get memory resource\n");
 232                 return -ENODEV;
 233         }
 234         priv->dfsdm.phys_base = res->start;
 235         priv->dfsdm.base = devm_ioremap_resource(&pdev->dev, res);
 236
 237         /*
 238          * "dfsdm" clock is mandatory for DFSDM peripheral clocking.
 239          * "dfsdm" or "audio" clocks can be used as source clock for
 240          * the SPI clock out signal and internal processing, depending
 241          * on use case.
 242          */
 243         priv->clk = devm_clk_get(&pdev->dev, "dfsdm");
 244         if (IS_ERR(priv->clk)) {
 245                 dev_err(&pdev->dev, "No stm32_dfsdm_clk clock found\n");
 246                 return -EINVAL;
 247         }
 248
 249         priv->aclk = devm_clk_get(&pdev->dev, "audio");
 250         if (IS_ERR(priv->aclk))
 251                 priv->aclk = NULL;
 252
 253         if (priv->aclk)
 254                 clk_freq = clk_get_rate(priv->aclk);
 255         else
 256                 clk_freq = clk_get_rate(priv->clk);
 257
 258         /* SPI clock out frequency */
 259         ret = of_property_read_u32(pdev->dev.of_node, "spi-max-frequency",
 260                                    &spi_freq);
 261         if (ret < 0) {
 262                 /* No SPI master mode */
 263                 return 0;
 264         }
 265
 266         divider = div_u64_rem(clk_freq, spi_freq, &rem);
 267         /* Round up divider when ckout isn't precise, not to exceed spi_freq */
 268         if (rem)
 269                 divider++;
 270
 271         /* programmable divider is in range of [2:256] */
 272         if (divider < 2 || divider > 256) {
 273                 dev_err(&pdev->dev, "spi-max-frequency not achievable\n");
 274                 return -EINVAL;
 275         }
 276
 277         /* SPI clock output divider is: divider = CKOUTDIV + 1 */
 278         priv->spi_clk_out_div = divider - 1;
 279         priv->dfsdm.spi_master_freq = clk_freq / (priv->spi_clk_out_div + 1);
 280
 281         if (rem) {
 282                 dev_warn(&pdev->dev, "SPI clock not accurate\n");
 283                 dev_warn(&pdev->dev, "%ld = %d * %d + %d\n",
 284                          clk_freq, spi_freq, priv->spi_clk_out_div + 1, rem);
 285         }
 286
 287         return 0;
 288 };
 289
 290 static const struct of_device_id stm32_dfsdm_of_match[] = {
 291         {
 292                 .compatible = "st,stm32h7-dfsdm",
 293                 .data = &stm32h7_dfsdm_data,
 294         },
 295         {
 296                 .compatible = "st,stm32mp1-dfsdm",
 297                 .data = &stm32mp1_dfsdm_data,
 298         },
 299         {}
 300 };
 301 MODULE_DEVICE_TABLE(of, stm32_dfsdm_of_match);
 302
 303 static int stm32_dfsdm_probe(struct platform_device *pdev)
 304 {
 305         struct dfsdm_priv *priv;
 306         const struct stm32_dfsdm_dev_data *dev_data;
 307         struct stm32_dfsdm *dfsdm;
 308         int ret;
 309
 310         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 311         if (!priv)
 312                 return -ENOMEM;
 313
 314         priv->pdev = pdev;
 315
 316         dev_data = of_device_get_match_data(&pdev->dev);
 317
 318         dfsdm = &priv->dfsdm;
 319         dfsdm->fl_list = devm_kcalloc(&pdev->dev, dev_data->num_filters,
 320                                       sizeof(*dfsdm->fl_list), GFP_KERNEL);
 321         if (!dfsdm->fl_list)
 322                 return -ENOMEM;
 323
 324         dfsdm->num_fls = dev_data->num_filters;
 325         dfsdm->ch_list = devm_kcalloc(&pdev->dev, dev_data->num_channels,
 326                                       sizeof(*dfsdm->ch_list),
 327                                       GFP_KERNEL);
 328         if (!dfsdm->ch_list)
 329                 return -ENOMEM;
 330         dfsdm->num_chs = dev_data->num_channels;
 331
 332         ret = stm32_dfsdm_parse_of(pdev, priv);
 333         if (ret < 0)
 334                 return ret;
 335
 336         dfsdm->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "dfsdm",
 337                                                   dfsdm->base,
 338                                                   dev_data->regmap_cfg);
 339         if (IS_ERR(dfsdm->regmap)) {
 340                 ret = PTR_ERR(dfsdm->regmap);
 341                 dev_err(&pdev->dev, "%s: Failed to allocate regmap: %d\n",
 342                         __func__, ret);
 343                 return ret;
 344         }
 345
 346         platform_set_drvdata(pdev, dfsdm);
 347
 348         ret = stm32_dfsdm_clk_prepare_enable(dfsdm);
 349         if (ret) {
 350                 dev_err(&pdev->dev, "Failed to start clock\n");
 351                 return ret;
 352         }
 353
 354         pm_runtime_get_noresume(&pdev->dev);
 355         pm_runtime_set_active(&pdev->dev);
 356         pm_runtime_enable(&pdev->dev);
 357
 358         ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
 359         if (ret)
 360                 goto pm_put;
 361
 362         pm_runtime_put(&pdev->dev);
 363
 364         return 0;
 365
 366 pm_put:
 367         pm_runtime_disable(&pdev->dev);
 368         pm_runtime_set_suspended(&pdev->dev);
 369         pm_runtime_put_noidle(&pdev->dev);
 370         stm32_dfsdm_clk_disable_unprepare(dfsdm);
 371
 372         return ret;
 373 }
 374
 375 static int stm32_dfsdm_core_remove(struct platform_device *pdev)
 376 {
 377         struct stm32_dfsdm *dfsdm = platform_get_drvdata(pdev);
 378
 379         pm_runtime_get_sync(&pdev->dev);
 380         of_platform_depopulate(&pdev->dev);
 381         pm_runtime_disable(&pdev->dev);
 382         pm_runtime_set_suspended(&pdev->dev);
 383         pm_runtime_put_noidle(&pdev->dev);
 384         stm32_dfsdm_clk_disable_unprepare(dfsdm);
 385
 386         return 0;
 387 }
 388
 389 static int __maybe_unused stm32_dfsdm_core_suspend(struct device *dev)
 390 {
 391         struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);
 392         struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
 393         int ret;
 394
 395         ret = pm_runtime_force_suspend(dev);
 396         if (ret)
 397                 return ret;
 398
 399         /* Balance devm_regmap_init_mmio_clk() clk_prepare() */
 400         clk_unprepare(priv->clk);
 401
 402         return pinctrl_pm_select_sleep_state(dev);
 403 }
 404
 405 static int __maybe_unused stm32_dfsdm_core_resume(struct device *dev)
 406 {
 407         struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);
 408         struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
 409         int ret;
 410
 411         ret = pinctrl_pm_select_default_state(dev);
 412         if (ret)
 413                 return ret;
 414
 415         ret = clk_prepare(priv->clk);
 416         if (ret)
 417                 return ret;
 418
 419         return pm_runtime_force_resume(dev);
 420 }
 421
 422 static int __maybe_unused stm32_dfsdm_core_runtime_suspend(struct device *dev)
 423 {
 424         struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);
 425
 426         stm32_dfsdm_clk_disable_unprepare(dfsdm);
 427
 428         return 0;
 429 }
 430
 431 static int __maybe_unused stm32_dfsdm_core_runtime_resume(struct device *dev)
 432 {
 433         struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);
 434
 435         return stm32_dfsdm_clk_prepare_enable(dfsdm);
 436 }
 437
 438 static const struct dev_pm_ops stm32_dfsdm_core_pm_ops = {
 439         SET_SYSTEM_SLEEP_PM_OPS(stm32_dfsdm_core_suspend,
 440                                 stm32_dfsdm_core_resume)
 441         SET_RUNTIME_PM_OPS(stm32_dfsdm_core_runtime_suspend,
 442                            stm32_dfsdm_core_runtime_resume,
 443                            NULL)
 444 };
 445
 446 static struct platform_driver stm32_dfsdm_driver = {
 447         .probe = stm32_dfsdm_probe,
 448         .remove = stm32_dfsdm_core_remove,
 449         .driver = {
 450                 .name = "stm32-dfsdm",
 451                 .of_match_table = stm32_dfsdm_of_match,
 452                 .pm = &stm32_dfsdm_core_pm_ops,
 453         },
 454 };
 455
 456 module_platform_driver(stm32_dfsdm_driver);
 457
 458 MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@st.com>");
 459 MODULE_DESCRIPTION("STMicroelectronics STM32 dfsdm driver");
 460 MODULE_LICENSE("GPL v2");