drivers/iio/dac/stm32-dac-core.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * This file is part of STM32 DAC driver
   4  *
   5  * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
   6  * Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
   7  *
   8  */
   9
  10 #include <linux/clk.h>
  11 #include <linux/delay.h>
  12 #include <linux/module.h>
  13 #include <linux/of_platform.h>
  14 #include <linux/pm_runtime.h>
  15 #include <linux/regulator/consumer.h>
  16 #include <linux/reset.h>
  17
  18 #include "stm32-dac-core.h"
  19
  20 /**
  21  * struct stm32_dac_priv - stm32 DAC core private data
  22  * @pclk:               peripheral clock common for all DACs
  23  * @vref:               regulator reference
  24  * @common:             Common data for all DAC instances
  25  */
  26 struct stm32_dac_priv {
  27         struct clk *pclk;
  28         struct regulator *vref;
  29         struct stm32_dac_common common;
  30 };
  31
  32 /**
  33  * struct stm32_dac_cfg - DAC configuration
  34  * @has_hfsel: DAC has high frequency control
  35  */
  36 struct stm32_dac_cfg {
  37         bool has_hfsel;
  38 };
  39
  40 static struct stm32_dac_priv *to_stm32_dac_priv(struct stm32_dac_common *com)
  41 {
  42         return container_of(com, struct stm32_dac_priv, common);
  43 }
  44
  45 static const struct regmap_config stm32_dac_regmap_cfg = {
  46         .reg_bits = 32,
  47         .val_bits = 32,
  48         .reg_stride = sizeof(u32),
  49         .max_register = 0x3fc,
  50 };
  51
  52 static int stm32_dac_core_hw_start(struct device *dev)
  53 {
  54         struct stm32_dac_common *common = dev_get_drvdata(dev);
  55         struct stm32_dac_priv *priv = to_stm32_dac_priv(common);
  56         int ret;
  57
  58         ret = regulator_enable(priv->vref);
  59         if (ret < 0) {
  60                 dev_err(dev, "vref enable failed: %d\n", ret);
  61                 return ret;
  62         }
  63
  64         ret = clk_prepare_enable(priv->pclk);
  65         if (ret < 0) {
  66                 dev_err(dev, "pclk enable failed: %d\n", ret);
  67                 goto err_regulator_disable;
  68         }
  69
  70         return 0;
  71
  72 err_regulator_disable:
  73         regulator_disable(priv->vref);
  74
  75         return ret;
  76 }
  77
  78 static void stm32_dac_core_hw_stop(struct device *dev)
  79 {
  80         struct stm32_dac_common *common = dev_get_drvdata(dev);
  81         struct stm32_dac_priv *priv = to_stm32_dac_priv(common);
  82
  83         clk_disable_unprepare(priv->pclk);
  84         regulator_disable(priv->vref);
  85 }
  86
  87 static int stm32_dac_probe(struct platform_device *pdev)
  88 {
  89         struct device *dev = &pdev->dev;
  90         const struct stm32_dac_cfg *cfg;
  91         struct stm32_dac_priv *priv;
  92         struct regmap *regmap;
  93         struct resource *res;
  94         void __iomem *mmio;
  95         struct reset_control *rst;
  96         int ret;
  97
  98         if (!dev->of_node)
  99                 return -ENODEV;
 100
 101         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 102         if (!priv)
 103                 return -ENOMEM;
 104         platform_set_drvdata(pdev, &priv->common);
 105
 106         cfg = (const struct stm32_dac_cfg *)
 107                 of_match_device(dev->driver->of_match_table, dev)->data;
 108
 109         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 110         mmio = devm_ioremap_resource(dev, res);
 111         if (IS_ERR(mmio))
 112                 return PTR_ERR(mmio);
 113
 114         regmap = devm_regmap_init_mmio_clk(dev, "pclk", mmio,
 115                                            &stm32_dac_regmap_cfg);
 116         if (IS_ERR(regmap))
 117                 return PTR_ERR(regmap);
 118         priv->common.regmap = regmap;
 119
 120         priv->pclk = devm_clk_get(dev, "pclk");
 121         if (IS_ERR(priv->pclk)) {
 122                 ret = PTR_ERR(priv->pclk);
 123                 dev_err(dev, "pclk get failed\n");
 124                 return ret;
 125         }
 126
 127         priv->vref = devm_regulator_get(dev, "vref");
 128         if (IS_ERR(priv->vref)) {
 129                 ret = PTR_ERR(priv->vref);
 130                 dev_err(dev, "vref get failed, %d\n", ret);
 131                 return ret;
 132         }
 133
 134         pm_runtime_get_noresume(dev);
 135         pm_runtime_set_active(dev);
 136         pm_runtime_enable(dev);
 137
 138         ret = stm32_dac_core_hw_start(dev);
 139         if (ret)
 140                 goto err_pm_stop;
 141
 142         ret = regulator_get_voltage(priv->vref);
 143         if (ret < 0) {
 144                 dev_err(dev, "vref get voltage failed, %d\n", ret);
 145                 goto err_hw_stop;
 146         }
 147         priv->common.vref_mv = ret / 1000;
 148         dev_dbg(dev, "vref+=%dmV\n", priv->common.vref_mv);
 149
 150         rst = devm_reset_control_get_optional_exclusive(dev, NULL);
 151         if (rst) {
 152                 if (IS_ERR(rst)) {
 153                         ret = dev_err_probe(dev, PTR_ERR(rst), "reset get failed\n");
 154                         goto err_hw_stop;
 155                 }
 156
 157                 reset_control_assert(rst);
 158                 udelay(2);
 159                 reset_control_deassert(rst);
 160         }
 161
 162         if (cfg && cfg->has_hfsel) {
 163                 /* When clock speed is higher than 80MHz, set HFSEL */
 164                 priv->common.hfsel = (clk_get_rate(priv->pclk) > 80000000UL);
 165                 ret = regmap_update_bits(regmap, STM32_DAC_CR,
 166                                          STM32H7_DAC_CR_HFSEL,
 167                                          priv->common.hfsel ?
 168                                          STM32H7_DAC_CR_HFSEL : 0);
 169                 if (ret)
 170                         goto err_hw_stop;
 171         }
 172
 173
 174         ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, dev);
 175         if (ret < 0) {
 176                 dev_err(dev, "failed to populate DT children\n");
 177                 goto err_hw_stop;
 178         }
 179
 180         pm_runtime_put(dev);
 181
 182         return 0;
 183
 184 err_hw_stop:
 185         stm32_dac_core_hw_stop(dev);
 186 err_pm_stop:
 187         pm_runtime_disable(dev);
 188         pm_runtime_set_suspended(dev);
 189         pm_runtime_put_noidle(dev);
 190
 191         return ret;
 192 }
 193
 194 static int stm32_dac_remove(struct platform_device *pdev)
 195 {
 196         pm_runtime_get_sync(&pdev->dev);
 197         of_platform_depopulate(&pdev->dev);
 198         stm32_dac_core_hw_stop(&pdev->dev);
 199         pm_runtime_disable(&pdev->dev);
 200         pm_runtime_set_suspended(&pdev->dev);
 201         pm_runtime_put_noidle(&pdev->dev);
 202
 203         return 0;
 204 }
 205
 206 static int __maybe_unused stm32_dac_core_resume(struct device *dev)
 207 {
 208         struct stm32_dac_common *common = dev_get_drvdata(dev);
 209         struct stm32_dac_priv *priv = to_stm32_dac_priv(common);
 210         int ret;
 211
 212         if (priv->common.hfsel) {
 213                 /* restore hfsel (maybe lost under low power state) */
 214                 ret = regmap_update_bits(priv->common.regmap, STM32_DAC_CR,
 215                                          STM32H7_DAC_CR_HFSEL,
 216                                          STM32H7_DAC_CR_HFSEL);
 217                 if (ret)
 218                         return ret;
 219         }
 220
 221         return pm_runtime_force_resume(dev);
 222 }
 223
 224 static int __maybe_unused stm32_dac_core_runtime_suspend(struct device *dev)
 225 {
 226         stm32_dac_core_hw_stop(dev);
 227
 228         return 0;
 229 }
 230
 231 static int __maybe_unused stm32_dac_core_runtime_resume(struct device *dev)
 232 {
 233         return stm32_dac_core_hw_start(dev);
 234 }
 235
 236 static const struct dev_pm_ops stm32_dac_core_pm_ops = {
 237         SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, stm32_dac_core_resume)
 238         SET_RUNTIME_PM_OPS(stm32_dac_core_runtime_suspend,
 239                            stm32_dac_core_runtime_resume,
 240                            NULL)
 241 };
 242
 243 static const struct stm32_dac_cfg stm32h7_dac_cfg = {
 244         .has_hfsel = true,
 245 };
 246
 247 static const struct of_device_id stm32_dac_of_match[] = {
 248         {
 249                 .compatible = "st,stm32f4-dac-core",
 250         }, {
 251                 .compatible = "st,stm32h7-dac-core",
 252                 .data = (void *)&stm32h7_dac_cfg,
 253         },
 254         {},
 255 };
 256 MODULE_DEVICE_TABLE(of, stm32_dac_of_match);
 257
 258 static struct platform_driver stm32_dac_driver = {
 259         .probe = stm32_dac_probe,
 260         .remove = stm32_dac_remove,
 261         .driver = {
 262                 .name = "stm32-dac-core",
 263                 .of_match_table = stm32_dac_of_match,
 264                 .pm = &stm32_dac_core_pm_ops,
 265         },
 266 };
 267 module_platform_driver(stm32_dac_driver);
 268
 269 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
 270 MODULE_DESCRIPTION("STMicroelectronics STM32 DAC core driver");
 271 MODULE_LICENSE("GPL v2");
 272 MODULE_ALIAS("platform:stm32-dac-core");