linux/drivers/iio/dac/stm32-dac-core.c
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   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 */
  26struct 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 */
  36struct stm32_dac_cfg {
  37        bool has_hfsel;
  38};
  39
  40static 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
  45static 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
  52static 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
  72err_regulator_disable:
  73        regulator_disable(priv->vref);
  74
  75        return ret;
  76}
  77
  78static 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
  87static 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
 184err_hw_stop:
 185        stm32_dac_core_hw_stop(dev);
 186err_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
 194static 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
 206static 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
 224static 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
 231static int __maybe_unused stm32_dac_core_runtime_resume(struct device *dev)
 232{
 233        return stm32_dac_core_hw_start(dev);
 234}
 235
 236static 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
 243static const struct stm32_dac_cfg stm32h7_dac_cfg = {
 244        .has_hfsel = true,
 245};
 246
 247static 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};
 256MODULE_DEVICE_TABLE(of, stm32_dac_of_match);
 257
 258static 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};
 267module_platform_driver(stm32_dac_driver);
 268
 269MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
 270MODULE_DESCRIPTION("STMicroelectronics STM32 DAC core driver");
 271MODULE_LICENSE("GPL v2");
 272MODULE_ALIAS("platform:stm32-dac-core");
 273