// SPDX-License-Identifier: GPL-2.0-only
// Copyright (c) 2017, 2019-2020, The Linux Foundation. All rights reserved.
// Copyright (c) 2023, Linaro Limited

#include <linux/bitfield.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/of_regulator.h>

#define REFGEN_REG_BIAS_EN              0x08
#define REFGEN_BIAS_EN_MASK             GENMASK(2, 0)
 #define REFGEN_BIAS_EN_ENABLE          0x7
 #define REFGEN_BIAS_EN_DISABLE         0x6

#define REFGEN_REG_BG_CTRL              0x14
#define REFGEN_BG_CTRL_MASK             GENMASK(2, 1)
 #define REFGEN_BG_CTRL_ENABLE          0x3
 #define REFGEN_BG_CTRL_DISABLE         0x2

#define REFGEN_REG_PWRDWN_CTRL5         0x80
#define REFGEN_PWRDWN_CTRL5_MASK        BIT(0)
 #define REFGEN_PWRDWN_CTRL5_ENABLE     0x1

static int qcom_sdm845_refgen_enable(struct regulator_dev *rdev)
{
        regmap_update_bits(rdev->regmap, REFGEN_REG_BG_CTRL, REFGEN_BG_CTRL_MASK,
                           FIELD_PREP(REFGEN_BG_CTRL_MASK, REFGEN_BG_CTRL_ENABLE));

        regmap_write(rdev->regmap, REFGEN_REG_BIAS_EN,
                     FIELD_PREP(REFGEN_BIAS_EN_MASK, REFGEN_BIAS_EN_ENABLE));

        return 0;
}

static int qcom_sdm845_refgen_disable(struct regulator_dev *rdev)
{
        regmap_write(rdev->regmap, REFGEN_REG_BIAS_EN,
                     FIELD_PREP(REFGEN_BIAS_EN_MASK, REFGEN_BIAS_EN_DISABLE));

        regmap_update_bits(rdev->regmap, REFGEN_REG_BG_CTRL, REFGEN_BG_CTRL_MASK,
                           FIELD_PREP(REFGEN_BG_CTRL_MASK, REFGEN_BG_CTRL_DISABLE));

        return 0;
}

static int qcom_sdm845_refgen_is_enabled(struct regulator_dev *rdev)
{
        u32 val;

        regmap_read(rdev->regmap, REFGEN_REG_BG_CTRL, &val);
        if (FIELD_GET(REFGEN_BG_CTRL_MASK, val) != REFGEN_BG_CTRL_ENABLE)
                return 0;

        regmap_read(rdev->regmap, REFGEN_REG_BIAS_EN, &val);
        if (FIELD_GET(REFGEN_BIAS_EN_MASK, val) != REFGEN_BIAS_EN_ENABLE)
                return 0;

        return 1;
}

static const struct regulator_desc sdm845_refgen_desc = {
        .enable_time = 5,
        .name = "refgen",
        .owner = THIS_MODULE,
        .type = REGULATOR_VOLTAGE,
        .ops = &(const struct regulator_ops) {
                .enable         = qcom_sdm845_refgen_enable,
                .disable        = qcom_sdm845_refgen_disable,
                .is_enabled     = qcom_sdm845_refgen_is_enabled,
        },
};

static const struct regulator_desc sm8250_refgen_desc = {
        .enable_reg = REFGEN_REG_PWRDWN_CTRL5,
        .enable_mask = REFGEN_PWRDWN_CTRL5_MASK,
        .enable_val = REFGEN_PWRDWN_CTRL5_ENABLE,
        .disable_val = 0,
        .enable_time = 5,
        .name = "refgen",
        .owner = THIS_MODULE,
        .type = REGULATOR_VOLTAGE,
        .ops = &(const struct regulator_ops) {
                .enable         = regulator_enable_regmap,
                .disable        = regulator_disable_regmap,
                .is_enabled     = regulator_is_enabled_regmap,
        },
};

static const struct regmap_config qcom_refgen_regmap_config = {
        .reg_bits = 32,
        .reg_stride = 4,
        .val_bits = 32,
};

static int qcom_refgen_probe(struct platform_device *pdev)
{
        struct regulator_init_data *init_data;
        struct regulator_config config = {};
        const struct regulator_desc *rdesc;
        struct device *dev = &pdev->dev;
        struct regulator_dev *rdev;
        struct regmap *regmap;
        void __iomem *base;

        rdesc = of_device_get_match_data(dev);
        if (!rdesc)
                return -ENODATA;

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

        regmap = devm_regmap_init_mmio(dev, base, &qcom_refgen_regmap_config);
        if (IS_ERR(regmap))
                return PTR_ERR(regmap);

        init_data = of_get_regulator_init_data(dev, dev->of_node, rdesc);
        if (!init_data)
                return -ENOMEM;

        config.dev = dev;
        config.init_data = init_data;
        config.of_node = dev->of_node;
        config.regmap = regmap;

        rdev = devm_regulator_register(dev, rdesc, &config);
        if (IS_ERR(rdev))
                return PTR_ERR(rdev);

        return 0;
}

static const struct of_device_id qcom_refgen_match_table[] = {
        { .compatible = "qcom,sdm845-refgen-regulator", .data = &sdm845_refgen_desc },
        { .compatible = "qcom,sm8250-refgen-regulator", .data = &sm8250_refgen_desc },
        { }
};
MODULE_DEVICE_TABLE(of, qcom_refgen_match_table);

static struct platform_driver qcom_refgen_driver = {
        .probe = qcom_refgen_probe,
        .driver = {
                .name = "qcom-refgen-regulator",
                .of_match_table = qcom_refgen_match_table,
        },
};
module_platform_driver(qcom_refgen_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Qualcomm REFGEN regulator driver");