root/drivers/iio/dac/stm32-dac-core.c
// SPDX-License-Identifier: GPL-2.0
/*
 * This file is part of STM32 DAC driver
 *
 * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
 * Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
 *
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#include <linux/reset.h>

#include "stm32-dac-core.h"

/**
 * struct stm32_dac_priv - stm32 DAC core private data
 * @pclk:               peripheral clock common for all DACs
 * @vref:               regulator reference
 * @common:             Common data for all DAC instances
 */
struct stm32_dac_priv {
        struct clk *pclk;
        struct regulator *vref;
        struct stm32_dac_common common;
};

/**
 * struct stm32_dac_cfg - DAC configuration
 * @has_hfsel: DAC has high frequency control
 */
struct stm32_dac_cfg {
        bool has_hfsel;
};

static struct stm32_dac_priv *to_stm32_dac_priv(struct stm32_dac_common *com)
{
        return container_of(com, struct stm32_dac_priv, common);
}

static const struct regmap_config stm32_dac_regmap_cfg = {
        .reg_bits = 32,
        .val_bits = 32,
        .reg_stride = sizeof(u32),
        .max_register = 0x3fc,
};

static int stm32_dac_core_hw_start(struct device *dev)
{
        struct stm32_dac_common *common = dev_get_drvdata(dev);
        struct stm32_dac_priv *priv = to_stm32_dac_priv(common);
        int ret;

        ret = regulator_enable(priv->vref);
        if (ret < 0) {
                dev_err(dev, "vref enable failed: %d\n", ret);
                return ret;
        }

        ret = clk_prepare_enable(priv->pclk);
        if (ret < 0) {
                dev_err(dev, "pclk enable failed: %d\n", ret);
                goto err_regulator_disable;
        }

        return 0;

err_regulator_disable:
        regulator_disable(priv->vref);

        return ret;
}

static void stm32_dac_core_hw_stop(struct device *dev)
{
        struct stm32_dac_common *common = dev_get_drvdata(dev);
        struct stm32_dac_priv *priv = to_stm32_dac_priv(common);

        clk_disable_unprepare(priv->pclk);
        regulator_disable(priv->vref);
}

static int stm32_dac_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        const struct stm32_dac_cfg *cfg;
        struct stm32_dac_priv *priv;
        struct regmap *regmap;
        void __iomem *mmio;
        struct reset_control *rst;
        int ret;

        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;
        platform_set_drvdata(pdev, &priv->common);

        cfg = device_get_match_data(dev);

        mmio = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(mmio))
                return PTR_ERR(mmio);

        regmap = devm_regmap_init_mmio_clk(dev, "pclk", mmio,
                                           &stm32_dac_regmap_cfg);
        if (IS_ERR(regmap))
                return PTR_ERR(regmap);
        priv->common.regmap = regmap;

        priv->pclk = devm_clk_get(dev, "pclk");
        if (IS_ERR(priv->pclk))
                return dev_err_probe(dev, PTR_ERR(priv->pclk), "pclk get failed\n");

        priv->vref = devm_regulator_get(dev, "vref");
        if (IS_ERR(priv->vref))
                return dev_err_probe(dev, PTR_ERR(priv->vref), "vref get failed\n");

        pm_runtime_get_noresume(dev);
        pm_runtime_set_active(dev);
        pm_runtime_enable(dev);

        ret = stm32_dac_core_hw_start(dev);
        if (ret)
                goto err_pm_stop;

        ret = regulator_get_voltage(priv->vref);
        if (ret < 0) {
                dev_err(dev, "vref get voltage failed, %d\n", ret);
                goto err_hw_stop;
        }
        priv->common.vref_mv = ret / 1000;
        dev_dbg(dev, "vref+=%dmV\n", priv->common.vref_mv);

        rst = devm_reset_control_get_optional_exclusive(dev, NULL);
        if (rst) {
                if (IS_ERR(rst)) {
                        ret = dev_err_probe(dev, PTR_ERR(rst), "reset get failed\n");
                        goto err_hw_stop;
                }

                reset_control_assert(rst);
                udelay(2);
                reset_control_deassert(rst);
        }

        if (cfg && cfg->has_hfsel) {
                /* When clock speed is higher than 80MHz, set HFSEL */
                priv->common.hfsel = (clk_get_rate(priv->pclk) > 80000000UL);
                ret = regmap_update_bits(regmap, STM32_DAC_CR,
                                         STM32H7_DAC_CR_HFSEL,
                                         priv->common.hfsel ?
                                         STM32H7_DAC_CR_HFSEL : 0);
                if (ret)
                        goto err_hw_stop;
        }


        ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, dev);
        if (ret < 0) {
                dev_err(dev, "failed to populate DT children\n");
                goto err_hw_stop;
        }

        pm_runtime_put(dev);

        return 0;

err_hw_stop:
        stm32_dac_core_hw_stop(dev);
err_pm_stop:
        pm_runtime_disable(dev);
        pm_runtime_set_suspended(dev);
        pm_runtime_put_noidle(dev);

        return ret;
}

static void stm32_dac_remove(struct platform_device *pdev)
{
        pm_runtime_get_sync(&pdev->dev);
        of_platform_depopulate(&pdev->dev);
        stm32_dac_core_hw_stop(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
        pm_runtime_set_suspended(&pdev->dev);
        pm_runtime_put_noidle(&pdev->dev);
}

static int stm32_dac_core_resume(struct device *dev)
{
        struct stm32_dac_common *common = dev_get_drvdata(dev);
        struct stm32_dac_priv *priv = to_stm32_dac_priv(common);
        int ret;

        if (priv->common.hfsel) {
                /* restore hfsel (maybe lost under low power state) */
                ret = regmap_set_bits(priv->common.regmap, STM32_DAC_CR,
                                      STM32H7_DAC_CR_HFSEL);
                if (ret)
                        return ret;
        }

        return pm_runtime_force_resume(dev);
}

static int stm32_dac_core_runtime_suspend(struct device *dev)
{
        stm32_dac_core_hw_stop(dev);

        return 0;
}

static int stm32_dac_core_runtime_resume(struct device *dev)
{
        return stm32_dac_core_hw_start(dev);
}

static const struct dev_pm_ops stm32_dac_core_pm_ops = {
        SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, stm32_dac_core_resume)
        RUNTIME_PM_OPS(stm32_dac_core_runtime_suspend,
                       stm32_dac_core_runtime_resume,
                       NULL)
};

static const struct stm32_dac_cfg stm32h7_dac_cfg = {
        .has_hfsel = true,
};

static const struct of_device_id stm32_dac_of_match[] = {
        {
                .compatible = "st,stm32f4-dac-core",
        }, {
                .compatible = "st,stm32h7-dac-core",
                .data = (void *)&stm32h7_dac_cfg,
        },
        { }
};
MODULE_DEVICE_TABLE(of, stm32_dac_of_match);

static struct platform_driver stm32_dac_driver = {
        .probe = stm32_dac_probe,
        .remove = stm32_dac_remove,
        .driver = {
                .name = "stm32-dac-core",
                .of_match_table = stm32_dac_of_match,
                .pm = pm_ptr(&stm32_dac_core_pm_ops),
        },
};
module_platform_driver(stm32_dac_driver);

MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
MODULE_DESCRIPTION("STMicroelectronics STM32 DAC core driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:stm32-dac-core");