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/regulator/consumer.h>
  15#include <linux/reset.h>
  16
  17#include "stm32-dac-core.h"
  18
  19/**
  20 * struct stm32_dac_priv - stm32 DAC core private data
  21 * @pclk:               peripheral clock common for all DACs
  22 * @rst:                peripheral reset control
  23 * @vref:               regulator reference
  24 * @common:             Common data for all DAC instances
  25 */
  26struct stm32_dac_priv {
  27        struct clk *pclk;
  28        struct reset_control *rst;
  29        struct regulator *vref;
  30        struct stm32_dac_common common;
  31};
  32
  33/**
  34 * struct stm32_dac_cfg - DAC configuration
  35 * @has_hfsel: DAC has high frequency control
  36 */
  37struct stm32_dac_cfg {
  38        bool has_hfsel;
  39};
  40
  41static struct stm32_dac_priv *to_stm32_dac_priv(struct stm32_dac_common *com)
  42{
  43        return container_of(com, struct stm32_dac_priv, common);
  44}
  45
  46static const struct regmap_config stm32_dac_regmap_cfg = {
  47        .reg_bits = 32,
  48        .val_bits = 32,
  49        .reg_stride = sizeof(u32),
  50        .max_register = 0x3fc,
  51};
  52
  53static int stm32_dac_probe(struct platform_device *pdev)
  54{
  55        struct device *dev = &pdev->dev;
  56        const struct stm32_dac_cfg *cfg;
  57        struct stm32_dac_priv *priv;
  58        struct regmap *regmap;
  59        struct resource *res;
  60        void __iomem *mmio;
  61        int ret;
  62
  63        if (!dev->of_node)
  64                return -ENODEV;
  65
  66        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  67        if (!priv)
  68                return -ENOMEM;
  69        cfg = (const struct stm32_dac_cfg *)
  70                of_match_device(dev->driver->of_match_table, dev)->data;
  71
  72        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  73        mmio = devm_ioremap_resource(dev, res);
  74        if (IS_ERR(mmio))
  75                return PTR_ERR(mmio);
  76
  77        regmap = devm_regmap_init_mmio(dev, mmio, &stm32_dac_regmap_cfg);
  78        if (IS_ERR(regmap))
  79                return PTR_ERR(regmap);
  80        priv->common.regmap = regmap;
  81
  82        priv->vref = devm_regulator_get(dev, "vref");
  83        if (IS_ERR(priv->vref)) {
  84                ret = PTR_ERR(priv->vref);
  85                dev_err(dev, "vref get failed, %d\n", ret);
  86                return ret;
  87        }
  88
  89        ret = regulator_enable(priv->vref);
  90        if (ret < 0) {
  91                dev_err(dev, "vref enable failed\n");
  92                return ret;
  93        }
  94
  95        ret = regulator_get_voltage(priv->vref);
  96        if (ret < 0) {
  97                dev_err(dev, "vref get voltage failed, %d\n", ret);
  98                goto err_vref;
  99        }
 100        priv->common.vref_mv = ret / 1000;
 101        dev_dbg(dev, "vref+=%dmV\n", priv->common.vref_mv);
 102
 103        priv->pclk = devm_clk_get(dev, "pclk");
 104        if (IS_ERR(priv->pclk)) {
 105                ret = PTR_ERR(priv->pclk);
 106                dev_err(dev, "pclk get failed\n");
 107                goto err_vref;
 108        }
 109
 110        ret = clk_prepare_enable(priv->pclk);
 111        if (ret < 0) {
 112                dev_err(dev, "pclk enable failed\n");
 113                goto err_vref;
 114        }
 115
 116        priv->rst = devm_reset_control_get_exclusive(dev, NULL);
 117        if (!IS_ERR(priv->rst)) {
 118                reset_control_assert(priv->rst);
 119                udelay(2);
 120                reset_control_deassert(priv->rst);
 121        }
 122
 123        if (cfg && cfg->has_hfsel) {
 124                /* When clock speed is higher than 80MHz, set HFSEL */
 125                priv->common.hfsel = (clk_get_rate(priv->pclk) > 80000000UL);
 126                ret = regmap_update_bits(regmap, STM32_DAC_CR,
 127                                         STM32H7_DAC_CR_HFSEL,
 128                                         priv->common.hfsel ?
 129                                         STM32H7_DAC_CR_HFSEL : 0);
 130                if (ret)
 131                        goto err_pclk;
 132        }
 133
 134        platform_set_drvdata(pdev, &priv->common);
 135
 136        ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, dev);
 137        if (ret < 0) {
 138                dev_err(dev, "failed to populate DT children\n");
 139                goto err_pclk;
 140        }
 141
 142        return 0;
 143
 144err_pclk:
 145        clk_disable_unprepare(priv->pclk);
 146err_vref:
 147        regulator_disable(priv->vref);
 148
 149        return ret;
 150}
 151
 152static int stm32_dac_remove(struct platform_device *pdev)
 153{
 154        struct stm32_dac_common *common = platform_get_drvdata(pdev);
 155        struct stm32_dac_priv *priv = to_stm32_dac_priv(common);
 156
 157        of_platform_depopulate(&pdev->dev);
 158        clk_disable_unprepare(priv->pclk);
 159        regulator_disable(priv->vref);
 160
 161        return 0;
 162}
 163
 164static const struct stm32_dac_cfg stm32h7_dac_cfg = {
 165        .has_hfsel = true,
 166};
 167
 168static const struct of_device_id stm32_dac_of_match[] = {
 169        {
 170                .compatible = "st,stm32f4-dac-core",
 171        }, {
 172                .compatible = "st,stm32h7-dac-core",
 173                .data = (void *)&stm32h7_dac_cfg,
 174        },
 175        {},
 176};
 177MODULE_DEVICE_TABLE(of, stm32_dac_of_match);
 178
 179static struct platform_driver stm32_dac_driver = {
 180        .probe = stm32_dac_probe,
 181        .remove = stm32_dac_remove,
 182        .driver = {
 183                .name = "stm32-dac-core",
 184                .of_match_table = stm32_dac_of_match,
 185        },
 186};
 187module_platform_driver(stm32_dac_driver);
 188
 189MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
 190MODULE_DESCRIPTION("STMicroelectronics STM32 DAC core driver");
 191MODULE_LICENSE("GPL v2");
 192MODULE_ALIAS("platform:stm32-dac-core");
 193