/*
 * This file is part of STM32 DAC driver
 *
 * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
 * Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
 *
 * License type: GPLv2
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/of_platform.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
 * @rst:                peripheral reset control
 * @vref:               regulator reference
 * @common:             Common data for all DAC instances
 */
struct stm32_dac_priv {
        struct clk *pclk;
        struct reset_control *rst;
        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_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        const struct stm32_dac_cfg *cfg;
        struct stm32_dac_priv *priv;
        struct regmap *regmap;
        struct resource *res;
        void __iomem *mmio;
        int ret;

        if (!dev->of_node)
                return -ENODEV;

        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;
        cfg = (const struct stm32_dac_cfg *)
                of_match_device(dev->driver->of_match_table, dev)->data;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        mmio = devm_ioremap_resource(dev, res);
        if (IS_ERR(mmio))
                return PTR_ERR(mmio);

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

        priv->vref = devm_regulator_get(dev, "vref");
        if (IS_ERR(priv->vref)) {
                ret = PTR_ERR(priv->vref);
                dev_err(dev, "vref get failed, %d\n", ret);
                return ret;
        }

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

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

        priv->pclk = devm_clk_get(dev, "pclk");
        if (IS_ERR(priv->pclk)) {
                ret = PTR_ERR(priv->pclk);
                dev_err(dev, "pclk get failed\n");
                goto err_vref;
        }

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

        priv->rst = devm_reset_control_get_exclusive(dev, NULL);
        if (!IS_ERR(priv->rst)) {
                reset_control_assert(priv->rst);
                udelay(2);
                reset_control_deassert(priv->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_pclk;
        }

        platform_set_drvdata(pdev, &priv->common);

        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_pclk;
        }

        return 0;

err_pclk:
        clk_disable_unprepare(priv->pclk);
err_vref:
        regulator_disable(priv->vref);

        return ret;
}

static int stm32_dac_remove(struct platform_device *pdev)
{
        struct stm32_dac_common *common = platform_get_drvdata(pdev);
        struct stm32_dac_priv *priv = to_stm32_dac_priv(common);

        of_platform_depopulate(&pdev->dev);
        clk_disable_unprepare(priv->pclk);
        regulator_disable(priv->vref);

        return 0;
}

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,
        },
};
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");