// 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,
 .fast_io = true,
};

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");