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         void __iomem *mmio;
  94         struct reset_control *rst;
  95         int ret;
  96
  97         if (!dev->of_node)
  98                 return -ENODEV;
  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 = (const struct stm32_dac_cfg *)
 106                 of_match_device(dev->driver->of_match_table, dev)->data;
 107
 108         mmio = devm_platform_ioremap_resource(pdev, 0);
 109         if (IS_ERR(mmio))
 110                 return PTR_ERR(mmio);
 111
 112         regmap = devm_regmap_init_mmio_clk(dev, "pclk", mmio,
 113                                            &stm32_dac_regmap_cfg);
 114         if (IS_ERR(regmap))
 115                 return PTR_ERR(regmap);
 116         priv->common.regmap = regmap;
 117
 118         priv->pclk = devm_clk_get(dev, "pclk");
 119         if (IS_ERR(priv->pclk))
 120                 return dev_err_probe(dev, PTR_ERR(priv->pclk), "pclk get failed\n");
 121
 122         priv->vref = devm_regulator_get(dev, "vref");
 123         if (IS_ERR(priv->vref))
 124                 return dev_err_probe(dev, PTR_ERR(priv->vref), "vref get failed\n");
 125
 126         pm_runtime_get_noresume(dev);
 127         pm_runtime_set_active(dev);
 128         pm_runtime_enable(dev);
 129
 130         ret = stm32_dac_core_hw_start(dev);
 131         if (ret)
 132                 goto err_pm_stop;
 133
 134         ret = regulator_get_voltage(priv->vref);
 135         if (ret < 0) {
 136                 dev_err(dev, "vref get voltage failed, %d\n", ret);
 137                 goto err_hw_stop;
 138         }
 139         priv->common.vref_mv = ret / 1000;
 140         dev_dbg(dev, "vref+=%dmV\n", priv->common.vref_mv);
 141
 142         rst = devm_reset_control_get_optional_exclusive(dev, NULL);
 143         if (rst) {
 144                 if (IS_ERR(rst)) {
 145                         ret = dev_err_probe(dev, PTR_ERR(rst), "reset get failed\n");
 146                         goto err_hw_stop;
 147                 }
 148
 149                 reset_control_assert(rst);
 150                 udelay(2);
 151                 reset_control_deassert(rst);
 152         }
 153
 154         if (cfg && cfg->has_hfsel) {
 155                 /* When clock speed is higher than 80MHz, set HFSEL */
 156                 priv->common.hfsel = (clk_get_rate(priv->pclk) > 80000000UL);
 157                 ret = regmap_update_bits(regmap, STM32_DAC_CR,
 158                                          STM32H7_DAC_CR_HFSEL,
 159                                          priv->common.hfsel ?
 160                                          STM32H7_DAC_CR_HFSEL : 0);
 161                 if (ret)
 162                         goto err_hw_stop;
 163         }
 164
 165
 166         ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, dev);
 167         if (ret < 0) {
 168                 dev_err(dev, "failed to populate DT children\n");
 169                 goto err_hw_stop;
 170         }
 171
 172         pm_runtime_put(dev);
 173
 174         return 0;
 175
 176 err_hw_stop:
 177         stm32_dac_core_hw_stop(dev);
 178 err_pm_stop:
 179         pm_runtime_disable(dev);
 180         pm_runtime_set_suspended(dev);
 181         pm_runtime_put_noidle(dev);
 182
 183         return ret;
 184 }
 185
 186 static int stm32_dac_remove(struct platform_device *pdev)
 187 {
 188         pm_runtime_get_sync(&pdev->dev);
 189         of_platform_depopulate(&pdev->dev);
 190         stm32_dac_core_hw_stop(&pdev->dev);
 191         pm_runtime_disable(&pdev->dev);
 192         pm_runtime_set_suspended(&pdev->dev);
 193         pm_runtime_put_noidle(&pdev->dev);
 194
 195         return 0;
 196 }
 197
 198 static int stm32_dac_core_resume(struct device *dev)
 199 {
 200         struct stm32_dac_common *common = dev_get_drvdata(dev);
 201         struct stm32_dac_priv *priv = to_stm32_dac_priv(common);
 202         int ret;
 203
 204         if (priv->common.hfsel) {
 205                 /* restore hfsel (maybe lost under low power state) */
 206                 ret = regmap_update_bits(priv->common.regmap, STM32_DAC_CR,
 207                                          STM32H7_DAC_CR_HFSEL,
 208                                          STM32H7_DAC_CR_HFSEL);
 209                 if (ret)
 210                         return ret;
 211         }
 212
 213         return pm_runtime_force_resume(dev);
 214 }
 215
 216 static int stm32_dac_core_runtime_suspend(struct device *dev)
 217 {
 218         stm32_dac_core_hw_stop(dev);
 219
 220         return 0;
 221 }
 222
 223 static int stm32_dac_core_runtime_resume(struct device *dev)
 224 {
 225         return stm32_dac_core_hw_start(dev);
 226 }
 227
 228 static const struct dev_pm_ops stm32_dac_core_pm_ops = {
 229         SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, stm32_dac_core_resume)
 230         RUNTIME_PM_OPS(stm32_dac_core_runtime_suspend,
 231                        stm32_dac_core_runtime_resume,
 232                        NULL)
 233 };
 234
 235 static const struct stm32_dac_cfg stm32h7_dac_cfg = {
 236         .has_hfsel = true,
 237 };
 238
 239 static const struct of_device_id stm32_dac_of_match[] = {
 240         {
 241                 .compatible = "st,stm32f4-dac-core",
 242         }, {
 243                 .compatible = "st,stm32h7-dac-core",
 244                 .data = (void *)&stm32h7_dac_cfg,
 245         },
 246         {},
 247 };
 248 MODULE_DEVICE_TABLE(of, stm32_dac_of_match);
 249
 250 static struct platform_driver stm32_dac_driver = {
 251         .probe = stm32_dac_probe,
 252         .remove = stm32_dac_remove,
 253         .driver = {
 254                 .name = "stm32-dac-core",
 255                 .of_match_table = stm32_dac_of_match,
 256                 .pm = pm_ptr(&stm32_dac_core_pm_ops),
 257         },
 258 };
 259 module_platform_driver(stm32_dac_driver);
 260
 261 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
 262 MODULE_DESCRIPTION("STMicroelectronics STM32 DAC core driver");
 263 MODULE_LICENSE("GPL v2");
 264 MODULE_ALIAS("platform:stm32-dac-core");