text: /*
   * max1586.c  --  Voltage and current regulation for the Maxim 1586
   *
   * Copyright (C) 2008 Robert Jarzmik
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * 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, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  #include <linux/module.h>
  #include <linux/err.h>
  #include <linux/i2c.h>
  #include <linux/platform_device.h>
  #include <linux/regulator/driver.h>
  #include <linux/slab.h>
  #include <linux/regulator/max1586.h>
  #include <linux/of_device.h>
  #include <linux/regulator/of_regulator.h>
  
  #define MAX1586_V3_MAX_VSEL 31
  #define MAX1586_V6_MAX_VSEL 3
  
  #define MAX1586_V3_MIN_UV   700000
  #define MAX1586_V3_MAX_UV  1475000
  
  #define MAX1586_V6_MIN_UV        0
  #define MAX1586_V6_MAX_UV  3000000
  
  #define I2C_V3_SELECT (0 << 5)
  #define I2C_V6_SELECT (1 << 5)
  
  struct max1586_data {
  	struct i2c_client *client;
  
  	/* min/max V3 voltage */
  	unsigned int min_uV;
  	unsigned int max_uV;
  
  	unsigned int v3_curr_sel;
  	unsigned int v6_curr_sel;
  };
  
  /*
   * V6 voltage
   * On I2C bus, sending a "x" byte to the max1586 means :
   *   set V6 to either 0V, 1.8V, 2.5V, 3V depending on (x & 0x3)
   * As regulator framework doesn't accept voltages to be 0V, we use 1uV.
   */
  static const unsigned int v6_voltages_uv[] = { 1, 1800000, 2500000, 3000000 };
  
  /*
   * V3 voltage
   * On I2C bus, sending a "x" byte to the max1586 means :
   *   set V3 to 0.700V + (x & 0x1f) * 0.025V
   * This voltage can be increased by external resistors
   * R24 and R25=100kOhm as described in the data sheet.
   * The gain is approximately: 1 + R24/R25 + R24/185.5kOhm
   */
  static int max1586_v3_get_voltage_sel(struct regulator_dev *rdev)
  {
  	struct max1586_data *max1586 = rdev_get_drvdata(rdev);
  
  	return max1586->v3_curr_sel;
  }
  
  static int max1586_v3_set_voltage_sel(struct regulator_dev *rdev,
  				      unsigned selector)
  {
  	struct max1586_data *max1586 = rdev_get_drvdata(rdev);
  	struct i2c_client *client = max1586->client;
  	int ret;
  	u8 v3_prog;
  
  	dev_dbg(&client->dev, "changing voltage v3 to %dmv\n",
  		regulator_list_voltage_linear(rdev, selector) / 1000);
  
  	v3_prog = I2C_V3_SELECT | (u8) selector;
  	ret = i2c_smbus_write_byte(client, v3_prog);
  	if (ret)
  		return ret;
  
  	max1586->v3_curr_sel = selector;
  
  	return 0;
  }
  
  static int max1586_v6_get_voltage_sel(struct regulator_dev *rdev)
  {
  	struct max1586_data *max1586 = rdev_get_drvdata(rdev);
  
  	return max1586->v6_curr_sel;
  }
  
  static int max1586_v6_set_voltage_sel(struct regulator_dev *rdev,
  				      unsigned int selector)
  {
  	struct max1586_data *max1586 = rdev_get_drvdata(rdev);
  	struct i2c_client *client = max1586->client;
  	u8 v6_prog;
  	int ret;
  
  	dev_dbg(&client->dev, "changing voltage v6 to %dmv\n",
  		rdev->desc->volt_table[selector] / 1000);
  
  	v6_prog = I2C_V6_SELECT | (u8) selector;
  	ret = i2c_smbus_write_byte(client, v6_prog);
  	if (ret)
  		return ret;
  
  	max1586->v6_curr_sel = selector;
  
  	return 0;
  }
  
  /*
   * The Maxim 1586 controls V3 and V6 voltages, but offers no way of reading back
   * the set up value.
   */
  static const struct regulator_ops max1586_v3_ops = {
  	.get_voltage_sel = max1586_v3_get_voltage_sel,
  	.set_voltage_sel = max1586_v3_set_voltage_sel,
  	.list_voltage = regulator_list_voltage_linear,
  	.map_voltage = regulator_map_voltage_linear,
  };
  
  static const struct regulator_ops max1586_v6_ops = {
  	.get_voltage_sel = max1586_v6_get_voltage_sel,
  	.set_voltage_sel = max1586_v6_set_voltage_sel,
  	.list_voltage = regulator_list_voltage_table,
  };
  
  static struct regulator_desc max1586_reg[] = {
  	{
  		.name = "Output_V3",
  		.id = MAX1586_V3,
  		.ops = &max1586_v3_ops,
  		.type = REGULATOR_VOLTAGE,
  		.n_voltages = MAX1586_V3_MAX_VSEL + 1,
  		.owner = THIS_MODULE,
  	},
  	{
  		.name = "Output_V6",
  		.id = MAX1586_V6,
  		.ops = &max1586_v6_ops,
  		.type = REGULATOR_VOLTAGE,
  		.n_voltages = MAX1586_V6_MAX_VSEL + 1,
  		.volt_table = v6_voltages_uv,
  		.owner = THIS_MODULE,
  	},
  };
  
  static int of_get_max1586_platform_data(struct device *dev,
  				 struct max1586_platform_data *pdata)
  {
  	struct max1586_subdev_data *sub;
  	struct of_regulator_match rmatch[ARRAY_SIZE(max1586_reg)] = { };
  	struct device_node *np = dev->of_node;
  	int i, matched;
  
  	if (of_property_read_u32(np, "v3-gain",
  				 &pdata->v3_gain) < 0) {
  		dev_err(dev, "%pOF has no 'v3-gain' property\n", np);
  		return -EINVAL;
  	}
  
  	np = of_get_child_by_name(np, "regulators");
  	if (!np) {
  		dev_err(dev, "missing 'regulators' subnode in DT\n");
  		return -EINVAL;
  	}
  
  	for (i = 0; i < ARRAY_SIZE(rmatch); i++)
  		rmatch[i].name = max1586_reg[i].name;
  
  	matched = of_regulator_match(dev, np, rmatch, ARRAY_SIZE(rmatch));
  	of_node_put(np);
  	/*
  	 * If matched is 0, ie. neither Output_V3 nor Output_V6 have been found,
  	 * return 0, which signals the normal situation where no subregulator is
  	 * available. This is normal because the max1586 doesn't provide any
  	 * readback support, so the subregulators can't report any status
  	 * anyway.  If matched < 0, return the error.
  	 */
  	if (matched <= 0)
  		return matched;
  
  	pdata->subdevs = devm_kzalloc(dev, sizeof(struct max1586_subdev_data) *
  						matched, GFP_KERNEL);
  	if (!pdata->subdevs)
  		return -ENOMEM;
  
  	pdata->num_subdevs = matched;
  	sub = pdata->subdevs;
  
  	for (i = 0; i < matched; i++) {
  		sub->id = i;
  		sub->name = rmatch[i].of_node->name;
  		sub->platform_data = rmatch[i].init_data;
  		sub++;
  	}
  
  	return 0;
  }
  
  static const struct of_device_id max1586_of_match[] = {
  	{ .compatible = "maxim,max1586", },
  	{},
  };
  MODULE_DEVICE_TABLE(of, max1586_of_match);
  
  static int max1586_pmic_probe(struct i2c_client *client,
  					const struct i2c_device_id *i2c_id)
  {
  	struct max1586_platform_data *pdata, pdata_of;
  	struct regulator_config config = { };
  	struct max1586_data *max1586;
  	int i, id, ret;
  	const struct of_device_id *match;
  
  	pdata = dev_get_platdata(&client->dev);
  	if (client->dev.of_node && !pdata) {
  		match = of_match_device(of_match_ptr(max1586_of_match),
  					&client->dev);
  		if (!match) {
  			dev_err(&client->dev, "Error: No device match found\n");
  			return -ENODEV;
  		}
  		ret = of_get_max1586_platform_data(&client->dev, &pdata_of);
  		if (ret < 0)
  			return ret;
  		pdata = &pdata_of;
  	}
  
  	max1586 = devm_kzalloc(&client->dev, sizeof(struct max1586_data),
  			GFP_KERNEL);
  	if (!max1586)
  		return -ENOMEM;
  
  	max1586->client = client;
  
  	if (!pdata->v3_gain)
  		return -EINVAL;
  
  	max1586->min_uV = MAX1586_V3_MIN_UV / 1000 * pdata->v3_gain / 1000;
  	max1586->max_uV = MAX1586_V3_MAX_UV / 1000 * pdata->v3_gain / 1000;
  
  	/* Set curr_sel to default voltage on power-up */
  	max1586->v3_curr_sel = 24; /* 1.3V */
  	max1586->v6_curr_sel = 0;
  
  	for (i = 0; i < pdata->num_subdevs && i <= MAX1586_V6; i++) {
  		struct regulator_dev *rdev;
  
  		id = pdata->subdevs[i].id;
  		if (!pdata->subdevs[i].platform_data)
  			continue;
  		if (id < MAX1586_V3 || id > MAX1586_V6) {
  			dev_err(&client->dev, "invalid regulator id %d\n", id);
  			return -EINVAL;
  		}
  
  		if (id == MAX1586_V3) {
  			max1586_reg[id].min_uV = max1586->min_uV;
  			max1586_reg[id].uV_step =
  					(max1586->max_uV - max1586->min_uV) /
  					MAX1586_V3_MAX_VSEL;
  		}
  
  		config.dev = &client->dev;
  		config.init_data = pdata->subdevs[i].platform_data;
  		config.driver_data = max1586;
  
  		rdev = devm_regulator_register(&client->dev,
  						  &max1586_reg[id], &config);
  		if (IS_ERR(rdev)) {
  			dev_err(&client->dev, "failed to register %s\n",
  				max1586_reg[id].name);
  			return PTR_ERR(rdev);
  		}
  	}
  
  	i2c_set_clientdata(client, max1586);
  	dev_info(&client->dev, "Maxim 1586 regulator driver loaded\n");
  	return 0;
  }
  
  static const struct i2c_device_id max1586_id[] = {
  	{ "max1586", 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, max1586_id);
  
  static struct i2c_driver max1586_pmic_driver = {
  	.probe = max1586_pmic_probe,
  	.driver		= {
  		.name	= "max1586",
  		.of_match_table = of_match_ptr(max1586_of_match),
  	},
  	.id_table	= max1586_id,
  };
  
  static int __init max1586_pmic_init(void)
  {
  	return i2c_add_driver(&max1586_pmic_driver);
  }
  subsys_initcall(max1586_pmic_init);
  
  static void __exit max1586_pmic_exit(void)
  {
  	i2c_del_driver(&max1586_pmic_driver);
  }
  module_exit(max1586_pmic_exit);
  
  /* Module information */
  MODULE_DESCRIPTION("MAXIM 1586 voltage regulator driver");
  MODULE_AUTHOR("Robert Jarzmik");
  MODULE_LICENSE("GPL");
  