// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   * max8952.c - Voltage and current regulation for the Maxim 8952
   *
   * Copyright (C) 2010 Samsung Electronics
   * MyungJoo Ham <myungjoo.ham@samsung.com>

   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/i2c.h>
  #include <linux/err.h>
  #include <linux/platform_device.h>
  #include <linux/regulator/driver.h>
  #include <linux/regulator/max8952.h>

  #include <linux/gpio/consumer.h>

  #include <linux/io.h>

  #include <linux/of.h>

  #include <linux/regulator/of_regulator.h>

  #include <linux/slab.h>
  
  /* Registers */
  enum {
  	MAX8952_REG_MODE0,
  	MAX8952_REG_MODE1,
  	MAX8952_REG_MODE2,
  	MAX8952_REG_MODE3,
  	MAX8952_REG_CONTROL,
  	MAX8952_REG_SYNC,
  	MAX8952_REG_RAMP,
  	MAX8952_REG_CHIP_ID1,
  	MAX8952_REG_CHIP_ID2,
  };
  
  struct max8952_data {
  	struct i2c_client	*client;

  	struct max8952_platform_data *pdata;

  	struct gpio_desc *vid0_gpiod;
  	struct gpio_desc *vid1_gpiod;

  	bool vid0;
  	bool vid1;

  };
  
  static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
  {
  	int ret = i2c_smbus_read_byte_data(max8952->client, reg);

  	if (ret > 0)
  		ret &= 0xff;
  
  	return ret;
  }
  
  static int max8952_write_reg(struct max8952_data *max8952,
  		u8 reg, u8 value)
  {
  	return i2c_smbus_write_byte_data(max8952->client, reg, value);
  }

  static int max8952_list_voltage(struct regulator_dev *rdev,
  		unsigned int selector)
  {
  	struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  
  	if (rdev_get_id(rdev) != 0)
  		return -EINVAL;

  	return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000;

  }

  static int max8952_get_voltage_sel(struct regulator_dev *rdev)

  {
  	struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  	u8 vid = 0;
  
  	if (max8952->vid0)
  		vid += 1;
  	if (max8952->vid1)
  		vid += 2;

  	return vid;

  }

  static int max8952_set_voltage_sel(struct regulator_dev *rdev,
  				   unsigned selector)

  {
  	struct max8952_data *max8952 = rdev_get_drvdata(rdev);

  	if (!max8952->vid0_gpiod || !max8952->vid1_gpiod) {

  		/* DVS not supported */
  		return -EPERM;
  	}

  	max8952->vid0 = selector & 0x1;
  	max8952->vid1 = (selector >> 1) & 0x1;

  	gpiod_set_value(max8952->vid0_gpiod, max8952->vid0);
  	gpiod_set_value(max8952->vid1_gpiod, max8952->vid1);

  
  	return 0;
  }

  static const struct regulator_ops max8952_ops = {

  	.list_voltage		= max8952_list_voltage,

  	.get_voltage_sel	= max8952_get_voltage_sel,

  	.set_voltage_sel	= max8952_set_voltage_sel,

  };

  static const struct regulator_desc regulator = {

  	.name		= "MAX8952_VOUT",
  	.id		= 0,
  	.n_voltages	= MAX8952_NUM_DVS_MODE,
  	.ops		= &max8952_ops,
  	.type		= REGULATOR_VOLTAGE,
  	.owner		= THIS_MODULE,
  };

  #ifdef CONFIG_OF

  static const struct of_device_id max8952_dt_match[] = {

  	{ .compatible = "maxim,max8952" },
  	{},
  };
  MODULE_DEVICE_TABLE(of, max8952_dt_match);
  
  static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
  {
  	struct max8952_platform_data *pd;
  	struct device_node *np = dev->of_node;
  	int ret;
  	int i;
  
  	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);

  	if (!pd)

  		return NULL;

  	if (of_property_read_u32(np, "max8952,default-mode", &pd->default_mode))
  		dev_warn(dev, "Default mode not specified, assuming 0
  ");
  
  	ret = of_property_read_u32_array(np, "max8952,dvs-mode-microvolt",
  					pd->dvs_mode, ARRAY_SIZE(pd->dvs_mode));
  	if (ret) {
  		dev_err(dev, "max8952,dvs-mode-microvolt property not specified");
  		return NULL;
  	}
  
  	for (i = 0; i < ARRAY_SIZE(pd->dvs_mode); ++i) {
  		if (pd->dvs_mode[i] < 770000 || pd->dvs_mode[i] > 1400000) {
  			dev_err(dev, "DVS voltage %d out of range
  ", i);
  			return NULL;
  		}
  		pd->dvs_mode[i] = (pd->dvs_mode[i] - 770000) / 10000;
  	}
  
  	if (of_property_read_u32(np, "max8952,sync-freq", &pd->sync_freq))
  		dev_warn(dev, "max8952,sync-freq property not specified, defaulting to 26MHz
  ");
  
  	if (of_property_read_u32(np, "max8952,ramp-speed", &pd->ramp_speed))
  		dev_warn(dev, "max8952,ramp-speed property not specified, defaulting to 32mV/us
  ");

  	pd->reg_data = of_get_regulator_init_data(dev, np, &regulator);

  	if (!pd->reg_data) {
  		dev_err(dev, "Failed to parse regulator init data
  ");
  		return NULL;
  	}
  
  	return pd;
  }
  #else
  static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
  {
  	return NULL;
  }
  #endif

  static int max8952_pmic_probe(struct i2c_client *client,

  		const struct i2c_device_id *i2c_id)
  {

  	struct i2c_adapter *adapter = client->adapter;

  	struct max8952_platform_data *pdata = dev_get_platdata(&client->dev);

  	struct regulator_config config = { };

  	struct max8952_data *max8952;

  	struct regulator_dev *rdev;

  	struct gpio_desc *gpiod;
  	enum gpiod_flags gflags;

  	int ret = 0;

  	if (client->dev.of_node)
  		pdata = max8952_parse_dt(&client->dev);

  	if (!pdata) {
  		dev_err(&client->dev, "Require the platform data
  ");
  		return -EINVAL;
  	}
  
  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
  		return -EIO;

  	max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data),
  			       GFP_KERNEL);

  	if (!max8952)
  		return -ENOMEM;
  
  	max8952->client = client;

  	max8952->pdata = pdata;

  	config.dev = &client->dev;

  	config.init_data = pdata->reg_data;

  	config.driver_data = max8952;

  	config.of_node = client->dev.of_node;

  	if (pdata->reg_data->constraints.boot_on)

  		gflags = GPIOD_OUT_HIGH;
  	else
  		gflags = GPIOD_OUT_LOW;

  	gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;

  	/*
  	 * Do not use devm* here: the regulator core takes over the
  	 * lifecycle management of the GPIO descriptor.
  	 */
  	gpiod = gpiod_get_optional(&client->dev,
  				   "max8952,en",
  				   gflags);

  	if (IS_ERR(gpiod))
  		return PTR_ERR(gpiod);
  	if (gpiod)
  		config.ena_gpiod = gpiod;

  	rdev = devm_regulator_register(&client->dev, &regulator, &config);

  	if (IS_ERR(rdev)) {
  		ret = PTR_ERR(rdev);
  		dev_err(&client->dev, "regulator init failed (%d)
  ", ret);

  		return ret;

  	}

  	max8952->vid0 = pdata->default_mode & 0x1;
  	max8952->vid1 = (pdata->default_mode >> 1) & 0x1;

  	/* Fetch vid0 and vid1 GPIOs if available */
  	gflags = max8952->vid0 ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
  	max8952->vid0_gpiod = devm_gpiod_get_index_optional(&client->dev,
  							    "max8952,vid",
  							    0, gflags);
  	if (IS_ERR(max8952->vid0_gpiod))
  		return PTR_ERR(max8952->vid0_gpiod);
  	gflags = max8952->vid1 ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
  	max8952->vid1_gpiod = devm_gpiod_get_index_optional(&client->dev,
  							    "max8952,vid",
  							    1, gflags);
  	if (IS_ERR(max8952->vid1_gpiod))
  		return PTR_ERR(max8952->vid1_gpiod);
  
  	/* If either VID GPIO is missing just disable this */
  	if (!max8952->vid0_gpiod || !max8952->vid1_gpiod) {

  		dev_warn(&client->dev, "VID0/1 gpio invalid: "

  			 "DVS not available.
  ");

  		max8952->vid0 = 0;
  		max8952->vid1 = 0;

  		/* Make sure if we have any descriptors they get set to low */
  		if (max8952->vid0_gpiod)
  			gpiod_set_value(max8952->vid0_gpiod, 0);
  		if (max8952->vid1_gpiod)
  			gpiod_set_value(max8952->vid1_gpiod, 0);

  
  		/* Disable Pulldown of EN only */
  		max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);

  		dev_err(&client->dev, "DVS modes disabled because VID0 and VID1"

  				" do not have proper controls.
  ");
  	} else {
  		/*
  		 * Disable Pulldown on EN, VID0, VID1 to reduce
  		 * leakage current of MAX8952 assuming that MAX8952
  		 * is turned on (EN==1). Note that without having VID0/1
  		 * properly connected, turning pulldown off can be
  		 * problematic. Thus, turn this off only when they are
  		 * controllable by GPIO.
  		 */
  		max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
  	}
  
  	max8952_write_reg(max8952, MAX8952_REG_MODE0,
  			(max8952_read_reg(max8952,
  					  MAX8952_REG_MODE0) & 0xC0) |
  			(pdata->dvs_mode[0] & 0x3F));
  	max8952_write_reg(max8952, MAX8952_REG_MODE1,
  			(max8952_read_reg(max8952,
  					  MAX8952_REG_MODE1) & 0xC0) |
  			(pdata->dvs_mode[1] & 0x3F));
  	max8952_write_reg(max8952, MAX8952_REG_MODE2,
  			(max8952_read_reg(max8952,
  					  MAX8952_REG_MODE2) & 0xC0) |
  			(pdata->dvs_mode[2] & 0x3F));
  	max8952_write_reg(max8952, MAX8952_REG_MODE3,
  			(max8952_read_reg(max8952,
  					  MAX8952_REG_MODE3) & 0xC0) |
  			(pdata->dvs_mode[3] & 0x3F));
  
  	max8952_write_reg(max8952, MAX8952_REG_SYNC,
  			(max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
  			((pdata->sync_freq & 0x3) << 6));
  	max8952_write_reg(max8952, MAX8952_REG_RAMP,
  			(max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
  			((pdata->ramp_speed & 0x7) << 5));
  
  	i2c_set_clientdata(client, max8952);

  	return 0;

  }

  static const struct i2c_device_id max8952_ids[] = {
  	{ "max8952", 0 },
  	{ },
  };
  MODULE_DEVICE_TABLE(i2c, max8952_ids);
  
  static struct i2c_driver max8952_pmic_driver = {
  	.probe		= max8952_pmic_probe,

  	.driver		= {
  		.name	= "max8952",

  		.of_match_table = of_match_ptr(max8952_dt_match),

  	},
  	.id_table	= max8952_ids,
  };
  
  static int __init max8952_pmic_init(void)
  {
  	return i2c_add_driver(&max8952_pmic_driver);
  }
  subsys_initcall(max8952_pmic_init);
  
  static void __exit max8952_pmic_exit(void)
  {
  	i2c_del_driver(&max8952_pmic_driver);
  }
  module_exit(max8952_pmic_exit);
  
  MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
  MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
  MODULE_LICENSE("GPL");