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