// SPDX-License-Identifier: GPL-2.0+
  //
  // sy8106a-regulator.c - Regulator device driver for SY8106A
  //
  // Copyright (C) 2016 Ondřej Jirman <megous@megous.com>
  // Copyright (c) 2017-2018 Icenowy Zheng <icenowy@aosc.io>
  
  #include <linux/err.h>
  #include <linux/i2c.h>
  #include <linux/module.h>
  #include <linux/regmap.h>
  #include <linux/regulator/driver.h>
  #include <linux/regulator/of_regulator.h>
  
  #define SY8106A_REG_VOUT1_SEL		0x01
  #define SY8106A_REG_VOUT_COM		0x02
  #define SY8106A_REG_VOUT1_SEL_MASK	0x7f
  #define SY8106A_DISABLE_REG		BIT(0)
  /*
   * The I2C controlled voltage will only work when this bit is set; otherwise
   * it will behave like a fixed regulator.
   */
  #define SY8106A_GO_BIT			BIT(7)

  static const struct regmap_config sy8106a_regmap_config = {
  	.reg_bits = 8,
  	.val_bits = 8,
  };
  
  static const struct regulator_ops sy8106a_ops = {
  	.set_voltage_sel = regulator_set_voltage_sel_regmap,
  	.set_voltage_time_sel = regulator_set_voltage_time_sel,
  	.get_voltage_sel = regulator_get_voltage_sel_regmap,
  	.list_voltage = regulator_list_voltage_linear,
  	/* Enabling/disabling the regulator is not yet implemented */
  };
  
  /* Default limits measured in millivolts */
  #define SY8106A_MIN_MV		680
  #define SY8106A_MAX_MV		1950
  #define SY8106A_STEP_MV		10
  
  static const struct regulator_desc sy8106a_reg = {
  	.name = "SY8106A",
  	.id = 0,
  	.ops = &sy8106a_ops,
  	.type = REGULATOR_VOLTAGE,
  	.n_voltages = ((SY8106A_MAX_MV - SY8106A_MIN_MV) / SY8106A_STEP_MV) + 1,
  	.min_uV = (SY8106A_MIN_MV * 1000),
  	.uV_step = (SY8106A_STEP_MV * 1000),
  	.vsel_reg = SY8106A_REG_VOUT1_SEL,
  	.vsel_mask = SY8106A_REG_VOUT1_SEL_MASK,
  	/*
  	 * This ramp_delay is a conservative default value which works on
  	 * H3/H5 boards VDD-CPUX situations.
  	 */
  	.ramp_delay = 200,
  	.owner = THIS_MODULE,
  };
  
  /*
   * I2C driver interface functions
   */

  static int sy8106a_i2c_probe(struct i2c_client *i2c)

  {

  	struct device *dev = &i2c->dev;

  	struct regulator_dev *rdev;

  	struct regulator_config config = { };

  	struct regmap *regmap;

  	unsigned int reg, vsel;

  	u32 fixed_voltage;

  	int error;

  	error = of_property_read_u32(dev->of_node, "silergy,fixed-microvolt",

  				     &fixed_voltage);

  	if (error)
  		return error;

  	if (fixed_voltage < SY8106A_MIN_MV * 1000 ||
  	    fixed_voltage > SY8106A_MAX_MV * 1000)

  		return -EINVAL;

  	regmap = devm_regmap_init_i2c(i2c, &sy8106a_regmap_config);
  	if (IS_ERR(regmap)) {
  		error = PTR_ERR(regmap);

  		dev_err(dev, "Failed to allocate register map: %d
  ", error);
  		return error;
  	}
  
  	config.dev = &i2c->dev;

  	config.regmap = regmap;

  
  	config.of_node = dev->of_node;
  	config.init_data = of_get_regulator_init_data(dev, dev->of_node,
  						      &sy8106a_reg);
  
  	if (!config.init_data)
  		return -ENOMEM;
  
  	/* Ensure GO_BIT is enabled when probing */

  	error = regmap_read(regmap, SY8106A_REG_VOUT1_SEL, &reg);

  	if (error)
  		return error;
  
  	if (!(reg & SY8106A_GO_BIT)) {

  		vsel = (fixed_voltage / 1000 - SY8106A_MIN_MV) /

  		       SY8106A_STEP_MV;

  		error = regmap_write(regmap, SY8106A_REG_VOUT1_SEL,

  				     vsel | SY8106A_GO_BIT);
  		if (error)
  			return error;
  	}
  
  	/* Probe regulator */
  	rdev = devm_regulator_register(&i2c->dev, &sy8106a_reg, &config);
  	if (IS_ERR(rdev)) {
  		error = PTR_ERR(rdev);
  		dev_err(&i2c->dev, "Failed to register SY8106A regulator: %d
  ", error);
  		return error;
  	}

  	return 0;
  }
  
  static const struct of_device_id sy8106a_i2c_of_match[] = {
  	{ .compatible = "silergy,sy8106a" },
  	{ },
  };
  MODULE_DEVICE_TABLE(of, sy8106a_i2c_of_match);
  
  static const struct i2c_device_id sy8106a_i2c_id[] = {
  	{ "sy8106a", 0 },
  	{ },
  };
  MODULE_DEVICE_TABLE(i2c, sy8106a_i2c_id);
  
  static struct i2c_driver sy8106a_regulator_driver = {
  	.driver = {
  		.name = "sy8106a",
  		.of_match_table	= of_match_ptr(sy8106a_i2c_of_match),
  	},

  	.probe_new = sy8106a_i2c_probe,

  	.id_table = sy8106a_i2c_id,
  };
  
  module_i2c_driver(sy8106a_regulator_driver);
  
  MODULE_AUTHOR("Ondřej Jirman <megous@megous.com>");
  MODULE_AUTHOR("Icenowy Zheng <icenowy@aosc.io>");
  MODULE_DESCRIPTION("Regulator device driver for Silergy SY8106A");
  MODULE_LICENSE("GPL");