drivers/regulator/fan53555.c - kernel/msm.git - Git at Google

 /*
  * FAN53555 Fairchild Digitally Programmable TinyBuck Regulator Driver.
  *
  * Supported Part Numbers:
  * FAN53555UC00X/01X/03X/04X/05X
  *
  * Copyright (c) 2012 Marvell Technology Ltd.
  * Yunfan Zhang <yfzhang@marvell.com>
  *
  * This package is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  */
 #include <linux/module.h>
 #include <linux/param.h>
 #include <linux/err.h>
 #include <linux/gpio.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>
 #include <linux/regulator/of_regulator.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
 #include <linux/i2c.h>
 #include <linux/slab.h>
 #include <linux/regmap.h>
 #include <linux/debugfs.h>
 #include <linux/delay.h>
 #include <linux/regulator/fan53555.h>

 /* Voltage setting */
 #define FAN53555_VSEL0		0x00
 #define FAN53555_VSEL1		0x01
 /* Control register */
 #define FAN53555_CONTROL	0x02
 /* IC Type */
 #define FAN53555_ID1		0x03
 /* IC mask version */
 #define FAN53555_ID2		0x04
 /* Monitor register */
 #define FAN53555_MONITOR	0x05

 /* VSEL bit definitions */
 #define VSEL_BUCK_EN	(1 << 7)
 #define VSEL_MODE		(1 << 6)
 #define VSEL_NSEL_MASK	0x3F
 #define VSEL_FULL_MASK	0xFF
 /* Chip ID and Verison */
 #define DIE_ID		0x0F	/* ID1 */
 #define DIE_REV		0x0F	/* ID2 */
 #define DIE_13_REV	0x0F	/* DIE Revsion ID of 13 option */
 #define DIE_23_REV	0x0C	/* DIE Revision ID of 23 option */

 /* Control bit definitions */
 #define CTL_OUTPUT_DISCHG	(1 << 7)
 #define CTL_SLEW_MASK		(0x7 << 4)
 #define CTL_SLEW_SHIFT		4
 #define CTL_RESET			(1 << 2)

 #define FAN53555_NVOLTAGES	64	/* Numbers of voltages */

 /* IC Type */
 enum {
 	FAN53555_CHIP_ID_00 = 0,
 	FAN53555_CHIP_ID_01,
 	FAN53555_CHIP_ID_02,
 	FAN53555_CHIP_ID_03,
 	FAN53555_CHIP_ID_04,
 	FAN53555_CHIP_ID_05,
 };

 static const int slew_rate_plan[] = {
 	64000,
 	32000,
 	16000,
 	8000,
 	4000,
 	2000,
 	1000,
 	500
 };

 struct fan53555_device_info {
 	struct regmap *regmap;
 	struct device *dev;
 	struct regulator_desc desc;
 	struct regulator_dev *rdev;
 	struct regulator_init_data *regulator;
 	/* IC Type and Rev */
 	int chip_id;
 	int chip_rev;
 	/* Voltage setting register */
 	unsigned int vol_reg;
 	unsigned int sleep_reg;
 	/* Voltage range and step(linear) */
 	unsigned int vsel_min;
 	unsigned int vsel_step;
 	/* Voltage slew rate limiting */
 	unsigned int slew_rate;
 	/* Sleep voltage cache */
 	unsigned int sleep_vol_cache;
 	unsigned int peek_poke_address;

 	struct dentry *debug_root;

 	bool disable_suspend;
 };

 static int delay_array[] = {10, 20, 30, 40, 50};

 static int fan53555_read(struct fan53555_device_info *di, unsigned int reg,
 						unsigned int *val)
 {
 	int i = 0, rc = 0;

 	rc = regmap_read(di->regmap, reg, val);
 	for (i = 0; rc && i < ARRAY_SIZE(delay_array); i++) {
 		pr_debug("Failed reading reg=%u - retry(%d)\n", reg, i);
 		msleep(delay_array[i]);
 		rc = regmap_read(di->regmap, reg, val);
 	}

 	if (rc)
 		pr_err("Failed reading reg=%u rc=%d\n", reg, rc);

 	return rc;
 }

 static int fan53555_write(struct fan53555_device_info *di, unsigned int reg,
 						unsigned int val)
 {
 	int i = 0, rc = 0;

 	rc = regmap_write(di->regmap, reg, val);
 	for (i = 0; rc && i < ARRAY_SIZE(delay_array); i++) {
 		pr_debug("Failed writing reg=%u - retry(%d)\n", reg, i);
 		msleep(delay_array[i]);
 		rc = regmap_write(di->regmap, reg, val);
 	}

 	if (rc)
 		pr_err("Failed writing reg=%u rc=%d\n", reg, rc);

 	return rc;
 }

 static int fan53555_update_bits(struct fan53555_device_info *di,
 			unsigned int reg, unsigned int mask, unsigned int val)
 {
 	int i = 0, rc = 0;

 	rc = regmap_update_bits(di->regmap, reg, mask, val);
 	for (i = 0; rc && i < ARRAY_SIZE(delay_array); i++) {
 		pr_debug("Failed updating reg=%u - retry(%d)\n", reg, i);
 		msleep(delay_array[i]);
 		rc = regmap_update_bits(di->regmap, reg, mask, val);
 	}

 	if (rc)
 		pr_err("Failed updating reg=%u rc=%d\n", reg, rc);

 	return rc;
 }

 static int fan53555_set_suspend_voltage(struct regulator_dev *rdev, int uV)
 {
 	struct fan53555_device_info *di = rdev_get_drvdata(rdev);
 	int ret;

 	if (di->sleep_vol_cache == uV)
 		return 0;
 	ret = regulator_map_voltage_linear(rdev, uV, uV);
 	if (ret < 0)
 		return -EINVAL;
 	ret = fan53555_update_bits(di, di->sleep_reg,
 					VSEL_NSEL_MASK, ret);
 	if (ret < 0)
 		return -EINVAL;
 	/* Cache the sleep voltage setting.
 	 * Might not be the real voltage which is rounded */
 	di->sleep_vol_cache = uV;

 	return 0;
 }

 static int fan53555_set_mode(struct regulator_dev *rdev, unsigned int mode)
 {
 	struct fan53555_device_info *di = rdev_get_drvdata(rdev);

 	switch (mode) {
 	case REGULATOR_MODE_FAST:
 		fan53555_update_bits(di, di->vol_reg,
 				VSEL_MODE, VSEL_MODE);
 		break;
 	case REGULATOR_MODE_NORMAL:
 		fan53555_update_bits(di, di->vol_reg, VSEL_MODE, 0);
 		break;
 	default:
 		return -EINVAL;
 	}
 	return 0;
 }

 static unsigned int fan53555_get_mode(struct regulator_dev *rdev)
 {
 	struct fan53555_device_info *di = rdev_get_drvdata(rdev);
 	unsigned int val;
 	int ret = 0;

 	ret = fan53555_read(di, di->vol_reg, &val);
 	if (ret < 0)
 		return ret;
 	if (val & VSEL_MODE)
 		return REGULATOR_MODE_FAST;
 	else
 		return REGULATOR_MODE_NORMAL;
 }

 static struct regulator_ops fan53555_regulator_ops = {
 	.set_voltage_time_sel = regulator_set_voltage_time_sel,
 	.set_voltage_sel = regulator_set_voltage_sel_regmap,
 	.get_voltage_sel = regulator_get_voltage_sel_regmap,
 	.map_voltage = regulator_map_voltage_linear,
 	.list_voltage = regulator_list_voltage_linear,
 	.set_suspend_voltage = fan53555_set_suspend_voltage,
 	.enable = regulator_enable_regmap,
 	.disable = regulator_disable_regmap,
 	.is_enabled = regulator_is_enabled_regmap,
 	.set_mode = fan53555_set_mode,
 	.get_mode = fan53555_get_mode,
 };

 static struct regulator_ops fan53555_regulator_disable_suspend_ops = {
 	.set_voltage_time_sel = regulator_set_voltage_time_sel,
 	.set_voltage_sel = regulator_set_voltage_sel_regmap,
 	.get_voltage_sel = regulator_get_voltage_sel_regmap,
 	.map_voltage = regulator_map_voltage_linear,
 	.list_voltage = regulator_list_voltage_linear,
 	.enable = regulator_enable_regmap,
 	.disable = regulator_disable_regmap,
 	.is_enabled = regulator_is_enabled_regmap,
 	.set_mode = fan53555_set_mode,
 	.get_mode = fan53555_get_mode,
 };

 /*
  * The formula for calculating the actual slew rate is:
  * actual_slew_rate = 10mv_based_slew_rate * scaling_step_size_mv / 10mV
  */
 #define FAN53555_DVS_DEFAULT_STEP_SIZE_UV	10000
 static u32 fan53555_get_slew_rate_reg_value(struct fan53555_device_info *di,
 							u32 slew_rate)
 {
 	u32 index;
 	int scaled_slew_rate = slew_rate * FAN53555_DVS_DEFAULT_STEP_SIZE_UV /
 						di->vsel_step;

 	for (index = 0; index < ARRAY_SIZE(slew_rate_plan); index++)
 		if (scaled_slew_rate >= slew_rate_plan[index])
 			break;

 	if (index == ARRAY_SIZE(slew_rate_plan)) {
 		dev_err(di->dev, "invalid slew rate.\n");
 		index = FAN53555_SLEW_RATE_8MV;
 	}

 	return index;
 }

 /* For 00,01,03,05 options:
  * VOUT = 0.60V + NSELx * 10mV, from 0.60 to 1.23V.
  * For 04 option:
  * VOUT = 0.603V + NSELx * 12.826mV, from 0.603 to 1.411V.
  * For 13 option:
  * 13 option, its DIE ID is 0x00 and DIE_REV is 0x0F.
  * VOUT = 0.80V + NSELx * 10mV, from 0.80 to 1.43V.
  * For 23 option:
  * 23 option, its DIE ID is 0x00 and DIE_REV is 0x0C.
  * VOUT = 0.60V + NSELx * 12.5mV, from 0.60 to 1.3875V.
  * */
 static int fan53555_device_setup(struct fan53555_device_info *di,
 				struct fan53555_platform_data *pdata)
 {
 	unsigned int reg, data, mask;

 	/* Setup voltage control register */
 	switch (pdata->sleep_vsel_id) {
 	case FAN53555_VSEL_ID_0:
 		di->sleep_reg = FAN53555_VSEL0;
 		di->vol_reg = FAN53555_VSEL1;
 		break;
 	case FAN53555_VSEL_ID_1:
 		di->sleep_reg = FAN53555_VSEL1;
 		di->vol_reg = FAN53555_VSEL0;
 		break;
 	default:
 		dev_err(di->dev, "Invalid VSEL ID!\n");
 		return -EINVAL;
 	}
 	/* Init voltage range and step */
 	switch (di->chip_id) {
 	case FAN53555_CHIP_ID_00:
 		if (di->chip_rev == DIE_13_REV) {
 			di->vsel_min = 800000;
 			di->vsel_step = 10000;
 			break;
 		} else if (di->chip_rev == DIE_23_REV) {
 			di->vsel_min = 600000;
 			di->vsel_step = 12500;
 			break;
 		}
 	case FAN53555_CHIP_ID_01:
 	case FAN53555_CHIP_ID_03:
 	case FAN53555_CHIP_ID_05:
 		di->vsel_min = 600000;
 		di->vsel_step = 10000;
 		break;
 	case FAN53555_CHIP_ID_04:
 		di->vsel_min = 603000;
 		di->vsel_step = 12826;
 		break;
 	default:
 		dev_err(di->dev,
 			"Chip ID[%d]\n not supported!\n", di->chip_id);
 		return -EINVAL;
 	}
 	/* Init slew rate */
 	if (di->dev->of_node)
 		pdata->slew_rate = fan53555_get_slew_rate_reg_value(di,
 			pdata->regulator->constraints.ramp_delay);
 	else if (pdata->slew_rate & 0x7)
 		di->slew_rate = pdata->slew_rate;
 	else
 		di->slew_rate = FAN53555_SLEW_RATE_64MV;

 	reg = FAN53555_CONTROL;
 	data = di->slew_rate << CTL_SLEW_SHIFT;
 	mask = CTL_SLEW_MASK;
 	return fan53555_update_bits(di, reg, mask, data);
 }

 static int fan53555_regulator_register(struct fan53555_device_info *di,
 			struct regulator_config *config)
 {
 	struct regulator_desc *rdesc = &di->desc;

 	rdesc->name = "fan53555-reg";
 	if (di->disable_suspend)
 		rdesc->ops = &fan53555_regulator_disable_suspend_ops;
 	else
 		rdesc->ops = &fan53555_regulator_ops;
 	rdesc->type = REGULATOR_VOLTAGE;
 	rdesc->n_voltages = FAN53555_NVOLTAGES;
 	rdesc->enable_reg = di->vol_reg;
 	rdesc->enable_mask = VSEL_BUCK_EN;
 	rdesc->min_uV = di->vsel_min;
 	rdesc->uV_step = di->vsel_step;
 	rdesc->vsel_reg = di->vol_reg;
 	rdesc->vsel_mask = VSEL_NSEL_MASK;
 	rdesc->owner = THIS_MODULE;

 	di->rdev = regulator_register(&di->desc, config);
 	return PTR_RET(di->rdev);

 }

 static struct regmap_config fan53555_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 };

 static int fan53555_parse_backup_reg(struct i2c_client *client, u32 *sleep_sel)
 {
 	int rc = -EINVAL;

 	rc = of_property_read_u32(client->dev.of_node, "fairchild,backup-vsel",
 				sleep_sel);
 	if (rc) {
 		dev_err(&client->dev, "fairchild,backup-vsel property missing\n");
 	} else {
 		switch (*sleep_sel) {
 		case FAN53555_VSEL_ID_0:
 		case FAN53555_VSEL_ID_1:
 			break;
 		default:
 			dev_err(&client->dev, "Invalid VSEL ID!\n");
 			rc = -EINVAL;
 		}
 	}

 	return rc;
 }


 static struct fan53555_platform_data *
 	fan53555_get_of_platform_data(struct i2c_client *client)
 {
 	struct fan53555_platform_data *pdata = NULL;
 	struct regulator_init_data *init_data;
 	u32 sleep_sel;

 	init_data = of_get_regulator_init_data(&client->dev,
 			client->dev.of_node);
 	if (!init_data) {
 		dev_err(&client->dev, "regulator init data is missing\n");
 		return pdata;
 	}

 	if (fan53555_parse_backup_reg(client, &sleep_sel))
 		return pdata;

 	pdata = devm_kzalloc(&client->dev,
 			sizeof(struct fan53555_platform_data), GFP_KERNEL);
 	if (!pdata) {
 		dev_err(&client->dev,
 			"fan53555_platform_data allocation failed.\n");
 		return pdata;
 	}

 	init_data->constraints.input_uV = init_data->constraints.max_uV;
 	init_data->constraints.valid_ops_mask |=
 		REGULATOR_CHANGE_STATUS	| REGULATOR_CHANGE_VOLTAGE |
 		REGULATOR_CHANGE_MODE;
 	init_data->constraints.valid_modes_mask =
 				REGULATOR_MODE_NORMAL |
 				REGULATOR_MODE_FAST;
 	init_data->constraints.initial_mode = REGULATOR_MODE_NORMAL;

 	pdata->regulator = init_data;
 	pdata->sleep_vsel_id = sleep_sel;

 	return pdata;
 }

 static int fan53555_restore_working_reg(struct device_node *node,
 			struct fan53555_device_info *di)
 {
 	int ret;
 	u32 val;

 	/* Restore register from back up register */
 	ret = fan53555_read(di, di->sleep_reg, &val);
 	if (ret < 0) {
 		dev_err(di->dev,
 			"Failed to get backup data from reg %d, ret = %d\n",
 			di->sleep_reg, ret);
 		return ret;
 	}

 	ret = fan53555_update_bits(di,
 		di->vol_reg, VSEL_FULL_MASK, val);
 	if (ret < 0) {
 		dev_err(di->dev,
 			"Failed to update working reg %d, ret = %d\n",
 			di->vol_reg, ret);
 		return ret;
 	}

 	return ret;
 }

 static int fan53555_of_init(struct device_node *node,
 			struct fan53555_device_info *di)
 {
 	int ret, gpio;
 	enum of_gpio_flags flags;

 	if (of_property_read_bool(node, "fairchild,restore-reg")) {
 		ret = fan53555_restore_working_reg(node, di);
 		if (ret)
 			return ret;
 	}

 	if (of_find_property(node, "fairchild,vsel-gpio", NULL)) {
 		gpio = of_get_named_gpio_flags(node, "fairchild,vsel-gpio", 0,
 						&flags);

 		if (!gpio_is_valid(gpio)) {
 			if (gpio != -EPROBE_DEFER)
 				dev_err(di->dev, "Could not get vsel, ret = %d\n",
 					gpio);
 			return gpio;
 		}

 		ret = devm_gpio_request(di->dev, gpio, "fan53555_vsel");
 		if (ret) {
 			dev_err(di->dev, "Failed to obtain gpio %d ret = %d\n",
 				gpio, ret);
 			return ret;
 		}

 		ret = gpio_direction_output(gpio, flags & OF_GPIO_ACTIVE_LOW ?
 							0 : 1);
 		if (ret) {
 			dev_err(di->dev,
 				"Failed to set GPIO %d to: %s, ret = %d",
 				gpio, flags & OF_GPIO_ACTIVE_LOW ?
 				"GPIO_LOW" : "GPIO_HIGH", ret);
 			return ret;
 		}
 	}

 	di->disable_suspend = of_property_read_bool(node,
 				"fairchild,disable-suspend");

 	return 0;
 }

 static int get_reg(void *data, u64 *val)
 {
 	struct fan53555_device_info *di = data;
 	int rc;
 	unsigned int temp = 0;

 	rc = fan53555_read(di, di->peek_poke_address, &temp);
 	if (rc < 0)
 		dev_err(di->dev, "Couldn't read reg %x rc = %d\n",
 				di->peek_poke_address, rc);
 	else
 		*val = temp;

 	return rc;
 }

 static int set_reg(void *data, u64 val)
 {
 	struct fan53555_device_info *di = data;
 	int rc;
 	unsigned int temp = 0;

 	temp = (unsigned int) val;
 	rc = fan53555_write(di, di->peek_poke_address, temp);
 	if (rc < 0)
 		dev_err(di->dev, "Couldn't write 0x%02x to 0x%02x rc= %d\n",
 			di->peek_poke_address, temp, rc);

 	return rc;
 }
 DEFINE_SIMPLE_ATTRIBUTE(poke_poke_debug_ops, get_reg, set_reg, "0x%02llx\n");

 static int fan53555_regulator_probe(struct i2c_client *client,
 				const struct i2c_device_id *id)
 {
 	struct fan53555_device_info *di;
 	struct fan53555_platform_data *pdata;
 	struct regulator_config config = { };
 	unsigned int val;
 	int ret;

 	if (client->dev.of_node)
 		pdata = fan53555_get_of_platform_data(client);
 	else
 		pdata = client->dev.platform_data;

 	if (!pdata || !pdata->regulator) {
 		dev_err(&client->dev, "Platform data not found!\n");
 		return -ENODEV;
 	}

 	di = devm_kzalloc(&client->dev, sizeof(struct fan53555_device_info),
 					GFP_KERNEL);
 	if (!di) {
 		dev_err(&client->dev, "Failed to allocate device info data!\n");
 		return -ENOMEM;
 	}
 	di->regmap = devm_regmap_init_i2c(client, &fan53555_regmap_config);
 	if (IS_ERR(di->regmap)) {
 		dev_err(&client->dev, "Failed to allocate regmap!\n");
 		return PTR_ERR(di->regmap);
 	}
 	di->dev = &client->dev;
 	di->regulator = pdata->regulator;
 	i2c_set_clientdata(client, di);
 	/* Get chip ID */
 	ret = fan53555_read(di, FAN53555_ID1, &val);
 	if (ret < 0) {
 		dev_err(&client->dev, "Failed to get chip ID!\n");
 		return -ENODEV;
 	}
 	di->chip_id = val & DIE_ID;
 	/* Get chip revision */
 	ret = fan53555_read(di, FAN53555_ID2, &val);
 	if (ret < 0) {
 		dev_err(&client->dev, "Failed to get chip Rev!\n");
 		return -ENODEV;
 	}
 	di->chip_rev = val & DIE_REV;
 	dev_info(&client->dev, "FAN53555 Option[%d] Rev[%d] Detected!\n",
 				di->chip_id, di->chip_rev);
 	/* Device init */
 	ret = fan53555_device_setup(di, pdata);
 	if (ret < 0) {
 		dev_err(&client->dev, "Failed to setup device!\n");
 		return ret;
 	}

 	/* Set up from device tree */
 	if (client->dev.of_node) {
 		ret = fan53555_of_init(client->dev.of_node, di);
 		if (ret)
 			return ret;
 	}
 	/* Register regulator */
 	config.dev = di->dev;
 	config.init_data = di->regulator;
 	config.regmap = di->regmap;
 	config.driver_data = di;
 	config.of_node = client->dev.of_node;

 	ret = fan53555_regulator_register(di, &config);
 	if (ret < 0)
 		dev_err(&client->dev, "Failed to register regulator!\n");

 	di->debug_root = debugfs_create_dir("fan53555", NULL);
 	if (!di->debug_root)
 		dev_err(&client->dev, "Couldn't create debug dir\n");

 	if (di->debug_root) {
 		struct dentry *ent;

 		ent = debugfs_create_x32("address", S_IFREG | S_IWUSR | S_IRUGO,
 					  di->debug_root,
 					  &(di->peek_poke_address));
 		if (!ent)
 			dev_err(&client->dev, "Couldn't create address debug file rc = %d\n",
 									ret);

 		ent = debugfs_create_file("data", S_IFREG | S_IWUSR | S_IRUGO,
 					  di->debug_root, di,
 					  &poke_poke_debug_ops);
 		if (!ent)
 			dev_err(&client->dev, "Couldn't create data debug file rc = %d\n",
 									ret);
 	}

 	return ret;

 }

 static int fan53555_regulator_remove(struct i2c_client *client)
 {
 	struct fan53555_device_info *di = i2c_get_clientdata(client);

 	regulator_unregister(di->rdev);

 	debugfs_remove_recursive(di->debug_root);

 	return 0;
 }

 static struct of_device_id fan53555_match_table[] = {
 	{ .compatible = "fairchild,fan53555-regulator",},
 	{},
 };
 MODULE_DEVICE_TABLE(of, fan53555_match_table);

 static const struct i2c_device_id fan53555_id[] = {
 	{"fan53555", -1},
 	{ },
 };

 static struct i2c_driver fan53555_regulator_driver = {
 	.driver = {
 		.name = "fan53555-regulator",
 		.owner = THIS_MODULE,
 		.of_match_table = fan53555_match_table,
 	},
 	.probe = fan53555_regulator_probe,
 	.remove = fan53555_regulator_remove,
 	.id_table = fan53555_id,
 };

 /**
  * fan53555_regulator_init() - initialized fan53555 regulator driver
  * This function registers the fan53555 regulator platform driver.
  *
  * Returns 0 on success or errno on failure.
  */
 int __init fan53555_regulator_init(void)
 {
 	static bool initialized;

 	if (initialized)
 		return 0;
 	else
 		initialized = true;

 	return i2c_add_driver(&fan53555_regulator_driver);
 }
 EXPORT_SYMBOL(fan53555_regulator_init);
 arch_initcall(fan53555_regulator_init);

 static void __exit fan53555_regulator_exit(void)
 {
 	i2c_del_driver(&fan53555_regulator_driver);
 }
 module_exit(fan53555_regulator_exit);

 MODULE_AUTHOR("Yunfan Zhang <yfzhang@marvell.com>");
 MODULE_DESCRIPTION("FAN53555 regulator driver");
 MODULE_LICENSE("GPL v2");
	/*
	* FAN53555 Fairchild Digitally Programmable TinyBuck Regulator Driver.
	*
	* Supported Part Numbers:
	* FAN53555UC00X/01X/03X/04X/05X
	*
	* Copyright (c) 2012 Marvell Technology Ltd.
	* Yunfan Zhang <yfzhang@marvell.com>
	*
	* This package is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	*/
	#include <linux/module.h>
	#include <linux/param.h>
	#include <linux/err.h>
	#include <linux/gpio.h>
	#include <linux/platform_device.h>
	#include <linux/regulator/driver.h>
	#include <linux/regulator/machine.h>
	#include <linux/regulator/of_regulator.h>
	#include <linux/of.h>
	#include <linux/of_gpio.h>
	#include <linux/i2c.h>
	#include <linux/slab.h>
	#include <linux/regmap.h>
	#include <linux/debugfs.h>
	#include <linux/delay.h>
	#include <linux/regulator/fan53555.h>

	/* Voltage setting */
	#define FAN53555_VSEL0 0x00
	#define FAN53555_VSEL1 0x01
	/* Control register */
	#define FAN53555_CONTROL 0x02
	/* IC Type */
	#define FAN53555_ID1 0x03
	/* IC mask version */
	#define FAN53555_ID2 0x04
	/* Monitor register */
	#define FAN53555_MONITOR 0x05

	/* VSEL bit definitions */
	#define VSEL_BUCK_EN (1 << 7)
	#define VSEL_MODE (1 << 6)
	#define VSEL_NSEL_MASK 0x3F
	#define VSEL_FULL_MASK 0xFF
	/* Chip ID and Verison */
	#define DIE_ID 0x0F /* ID1 */
	#define DIE_REV 0x0F /* ID2 */
	#define DIE_13_REV 0x0F /* DIE Revsion ID of 13 option */
	#define DIE_23_REV 0x0C /* DIE Revision ID of 23 option */

	/* Control bit definitions */
	#define CTL_OUTPUT_DISCHG (1 << 7)
	#define CTL_SLEW_MASK (0x7 << 4)
	#define CTL_SLEW_SHIFT 4
	#define CTL_RESET (1 << 2)

	#define FAN53555_NVOLTAGES 64 /* Numbers of voltages */

	/* IC Type */
	enum {
	FAN53555_CHIP_ID_00 = 0,
	FAN53555_CHIP_ID_01,
	FAN53555_CHIP_ID_02,
	FAN53555_CHIP_ID_03,
	FAN53555_CHIP_ID_04,
	FAN53555_CHIP_ID_05,
	};

	static const int slew_rate_plan[] = {
	64000,
	32000,
	16000,
	8000,
	4000,
	2000,
	1000,
	500
	};

	struct fan53555_device_info {
	struct regmap *regmap;
	struct device *dev;
	struct regulator_desc desc;
	struct regulator_dev *rdev;
	struct regulator_init_data *regulator;
	/* IC Type and Rev */
	int chip_id;
	int chip_rev;
	/* Voltage setting register */
	unsigned int vol_reg;
	unsigned int sleep_reg;
	/* Voltage range and step(linear) */
	unsigned int vsel_min;
	unsigned int vsel_step;
	/* Voltage slew rate limiting */
	unsigned int slew_rate;
	/* Sleep voltage cache */
	unsigned int sleep_vol_cache;
	unsigned int peek_poke_address;

	struct dentry *debug_root;

	bool disable_suspend;
	};

	static int delay_array[] = {10, 20, 30, 40, 50};

	static int fan53555_read(struct fan53555_device_info *di, unsigned int reg,
	unsigned int *val)
	{
	int i = 0, rc = 0;

	rc = regmap_read(di->regmap, reg, val);
	for (i = 0; rc && i < ARRAY_SIZE(delay_array); i++) {
	pr_debug("Failed reading reg=%u - retry(%d)\n", reg, i);
	msleep(delay_array[i]);
	rc = regmap_read(di->regmap, reg, val);
	}

	if (rc)
	pr_err("Failed reading reg=%u rc=%d\n", reg, rc);

	return rc;
	}

	static int fan53555_write(struct fan53555_device_info *di, unsigned int reg,
	unsigned int val)
	{
	int i = 0, rc = 0;

	rc = regmap_write(di->regmap, reg, val);
	for (i = 0; rc && i < ARRAY_SIZE(delay_array); i++) {
	pr_debug("Failed writing reg=%u - retry(%d)\n", reg, i);
	msleep(delay_array[i]);
	rc = regmap_write(di->regmap, reg, val);
	}

	if (rc)
	pr_err("Failed writing reg=%u rc=%d\n", reg, rc);

	return rc;
	}

	static int fan53555_update_bits(struct fan53555_device_info *di,
	unsigned int reg, unsigned int mask, unsigned int val)
	{
	int i = 0, rc = 0;

	rc = regmap_update_bits(di->regmap, reg, mask, val);
	for (i = 0; rc && i < ARRAY_SIZE(delay_array); i++) {
	pr_debug("Failed updating reg=%u - retry(%d)\n", reg, i);
	msleep(delay_array[i]);
	rc = regmap_update_bits(di->regmap, reg, mask, val);
	}

	if (rc)
	pr_err("Failed updating reg=%u rc=%d\n", reg, rc);

	return rc;
	}

	static int fan53555_set_suspend_voltage(struct regulator_dev *rdev, int uV)
	{
	struct fan53555_device_info *di = rdev_get_drvdata(rdev);
	int ret;

	if (di->sleep_vol_cache == uV)
	return 0;
	ret = regulator_map_voltage_linear(rdev, uV, uV);
	if (ret < 0)
	return -EINVAL;
	ret = fan53555_update_bits(di, di->sleep_reg,
	VSEL_NSEL_MASK, ret);
	if (ret < 0)
	return -EINVAL;
	/* Cache the sleep voltage setting.
	* Might not be the real voltage which is rounded */
	di->sleep_vol_cache = uV;

	return 0;
	}

	static int fan53555_set_mode(struct regulator_dev *rdev, unsigned int mode)
	{
	struct fan53555_device_info *di = rdev_get_drvdata(rdev);

	switch (mode) {
	case REGULATOR_MODE_FAST:
	fan53555_update_bits(di, di->vol_reg,
	VSEL_MODE, VSEL_MODE);
	break;
	case REGULATOR_MODE_NORMAL:
	fan53555_update_bits(di, di->vol_reg, VSEL_MODE, 0);
	break;
	default:
	return -EINVAL;
	}
	return 0;
	}

	static unsigned int fan53555_get_mode(struct regulator_dev *rdev)
	{
	struct fan53555_device_info *di = rdev_get_drvdata(rdev);
	unsigned int val;
	int ret = 0;

	ret = fan53555_read(di, di->vol_reg, &val);
	if (ret < 0)
	return ret;
	if (val & VSEL_MODE)
	return REGULATOR_MODE_FAST;
	else
	return REGULATOR_MODE_NORMAL;
	}

	static struct regulator_ops fan53555_regulator_ops = {
	.set_voltage_time_sel = regulator_set_voltage_time_sel,
	.set_voltage_sel = regulator_set_voltage_sel_regmap,
	.get_voltage_sel = regulator_get_voltage_sel_regmap,
	.map_voltage = regulator_map_voltage_linear,
	.list_voltage = regulator_list_voltage_linear,
	.set_suspend_voltage = fan53555_set_suspend_voltage,
	.enable = regulator_enable_regmap,
	.disable = regulator_disable_regmap,
	.is_enabled = regulator_is_enabled_regmap,
	.set_mode = fan53555_set_mode,
	.get_mode = fan53555_get_mode,
	};

	static struct regulator_ops fan53555_regulator_disable_suspend_ops = {
	.set_voltage_time_sel = regulator_set_voltage_time_sel,
	.set_voltage_sel = regulator_set_voltage_sel_regmap,
	.get_voltage_sel = regulator_get_voltage_sel_regmap,
	.map_voltage = regulator_map_voltage_linear,
	.list_voltage = regulator_list_voltage_linear,
	.enable = regulator_enable_regmap,
	.disable = regulator_disable_regmap,
	.is_enabled = regulator_is_enabled_regmap,
	.set_mode = fan53555_set_mode,
	.get_mode = fan53555_get_mode,
	};

	/*
	* The formula for calculating the actual slew rate is:
	* actual_slew_rate = 10mv_based_slew_rate * scaling_step_size_mv / 10mV
	*/
	#define FAN53555_DVS_DEFAULT_STEP_SIZE_UV 10000
	static u32 fan53555_get_slew_rate_reg_value(struct fan53555_device_info *di,
	u32 slew_rate)
	{
	u32 index;
	int scaled_slew_rate = slew_rate * FAN53555_DVS_DEFAULT_STEP_SIZE_UV /
	di->vsel_step;

	for (index = 0; index < ARRAY_SIZE(slew_rate_plan); index++)
	if (scaled_slew_rate >= slew_rate_plan[index])
	break;

	if (index == ARRAY_SIZE(slew_rate_plan)) {
	dev_err(di->dev, "invalid slew rate.\n");
	index = FAN53555_SLEW_RATE_8MV;
	}

	return index;
	}

	/* For 00,01,03,05 options:
	* VOUT = 0.60V + NSELx * 10mV, from 0.60 to 1.23V.
	* For 04 option:
	* VOUT = 0.603V + NSELx * 12.826mV, from 0.603 to 1.411V.
	* For 13 option:
	* 13 option, its DIE ID is 0x00 and DIE_REV is 0x0F.
	* VOUT = 0.80V + NSELx * 10mV, from 0.80 to 1.43V.
	* For 23 option:
	* 23 option, its DIE ID is 0x00 and DIE_REV is 0x0C.
	* VOUT = 0.60V + NSELx * 12.5mV, from 0.60 to 1.3875V.
	* */
	static int fan53555_device_setup(struct fan53555_device_info *di,
	struct fan53555_platform_data *pdata)
	{
	unsigned int reg, data, mask;

	/* Setup voltage control register */
	switch (pdata->sleep_vsel_id) {
	case FAN53555_VSEL_ID_0:
	di->sleep_reg = FAN53555_VSEL0;
	di->vol_reg = FAN53555_VSEL1;
	break;
	case FAN53555_VSEL_ID_1:
	di->sleep_reg = FAN53555_VSEL1;
	di->vol_reg = FAN53555_VSEL0;
	break;
	default:
	dev_err(di->dev, "Invalid VSEL ID!\n");
	return -EINVAL;
	}
	/* Init voltage range and step */
	switch (di->chip_id) {
	case FAN53555_CHIP_ID_00:
	if (di->chip_rev == DIE_13_REV) {
	di->vsel_min = 800000;
	di->vsel_step = 10000;
	break;
	} else if (di->chip_rev == DIE_23_REV) {
	di->vsel_min = 600000;
	di->vsel_step = 12500;
	break;
	}
	case FAN53555_CHIP_ID_01:
	case FAN53555_CHIP_ID_03:
	case FAN53555_CHIP_ID_05:
	di->vsel_min = 600000;
	di->vsel_step = 10000;
	break;
	case FAN53555_CHIP_ID_04:
	di->vsel_min = 603000;
	di->vsel_step = 12826;
	break;
	default:
	dev_err(di->dev,
	"Chip ID[%d]\n not supported!\n", di->chip_id);
	return -EINVAL;
	}
	/* Init slew rate */
	if (di->dev->of_node)
	pdata->slew_rate = fan53555_get_slew_rate_reg_value(di,
	pdata->regulator->constraints.ramp_delay);
	else if (pdata->slew_rate & 0x7)
	di->slew_rate = pdata->slew_rate;
	else
	di->slew_rate = FAN53555_SLEW_RATE_64MV;

	reg = FAN53555_CONTROL;
	data = di->slew_rate << CTL_SLEW_SHIFT;
	mask = CTL_SLEW_MASK;
	return fan53555_update_bits(di, reg, mask, data);
	}

	static int fan53555_regulator_register(struct fan53555_device_info *di,
	struct regulator_config *config)
	{
	struct regulator_desc *rdesc = &di->desc;

	rdesc->name = "fan53555-reg";
	if (di->disable_suspend)
	rdesc->ops = &fan53555_regulator_disable_suspend_ops;
	else
	rdesc->ops = &fan53555_regulator_ops;
	rdesc->type = REGULATOR_VOLTAGE;
	rdesc->n_voltages = FAN53555_NVOLTAGES;
	rdesc->enable_reg = di->vol_reg;
	rdesc->enable_mask = VSEL_BUCK_EN;
	rdesc->min_uV = di->vsel_min;
	rdesc->uV_step = di->vsel_step;
	rdesc->vsel_reg = di->vol_reg;
	rdesc->vsel_mask = VSEL_NSEL_MASK;
	rdesc->owner = THIS_MODULE;

	di->rdev = regulator_register(&di->desc, config);
	return PTR_RET(di->rdev);

	}

	static struct regmap_config fan53555_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	};

	static int fan53555_parse_backup_reg(struct i2c_client client, u32 sleep_sel)
	{
	int rc = -EINVAL;

	rc = of_property_read_u32(client->dev.of_node, "fairchild,backup-vsel",
	sleep_sel);
	if (rc) {
	dev_err(&client->dev, "fairchild,backup-vsel property missing\n");
	} else {
	switch (*sleep_sel) {
	case FAN53555_VSEL_ID_0:
	case FAN53555_VSEL_ID_1:
	break;
	default:
	dev_err(&client->dev, "Invalid VSEL ID!\n");
	rc = -EINVAL;
	}
	}

	return rc;
	}


	static struct fan53555_platform_data *
	fan53555_get_of_platform_data(struct i2c_client *client)
	{
	struct fan53555_platform_data *pdata = NULL;
	struct regulator_init_data *init_data;
	u32 sleep_sel;

	init_data = of_get_regulator_init_data(&client->dev,
	client->dev.of_node);
	if (!init_data) {
	dev_err(&client->dev, "regulator init data is missing\n");
	return pdata;
	}

	if (fan53555_parse_backup_reg(client, &sleep_sel))
	return pdata;

	pdata = devm_kzalloc(&client->dev,
	sizeof(struct fan53555_platform_data), GFP_KERNEL);
	if (!pdata) {
	dev_err(&client->dev,
	"fan53555_platform_data allocation failed.\n");
	return pdata;
	}

	init_data->constraints.input_uV = init_data->constraints.max_uV;
	init_data->constraints.valid_ops_mask \|=
	REGULATOR_CHANGE_STATUS \| REGULATOR_CHANGE_VOLTAGE \|
	REGULATOR_CHANGE_MODE;
	init_data->constraints.valid_modes_mask =
	REGULATOR_MODE_NORMAL \|
	REGULATOR_MODE_FAST;
	init_data->constraints.initial_mode = REGULATOR_MODE_NORMAL;

	pdata->regulator = init_data;
	pdata->sleep_vsel_id = sleep_sel;

	return pdata;
	}

	static int fan53555_restore_working_reg(struct device_node *node,
	struct fan53555_device_info *di)
	{
	int ret;
	u32 val;

	/* Restore register from back up register */
	ret = fan53555_read(di, di->sleep_reg, &val);
	if (ret < 0) {
	dev_err(di->dev,
	"Failed to get backup data from reg %d, ret = %d\n",
	di->sleep_reg, ret);
	return ret;
	}

	ret = fan53555_update_bits(di,
	di->vol_reg, VSEL_FULL_MASK, val);
	if (ret < 0) {
	dev_err(di->dev,
	"Failed to update working reg %d, ret = %d\n",
	di->vol_reg, ret);
	return ret;
	}

	return ret;
	}

	static int fan53555_of_init(struct device_node *node,
	struct fan53555_device_info *di)
	{
	int ret, gpio;
	enum of_gpio_flags flags;

	if (of_property_read_bool(node, "fairchild,restore-reg")) {
	ret = fan53555_restore_working_reg(node, di);
	if (ret)
	return ret;
	}

	if (of_find_property(node, "fairchild,vsel-gpio", NULL)) {
	gpio = of_get_named_gpio_flags(node, "fairchild,vsel-gpio", 0,
	&flags);

	if (!gpio_is_valid(gpio)) {
	if (gpio != -EPROBE_DEFER)
	dev_err(di->dev, "Could not get vsel, ret = %d\n",
	gpio);
	return gpio;
	}

	ret = devm_gpio_request(di->dev, gpio, "fan53555_vsel");
	if (ret) {
	dev_err(di->dev, "Failed to obtain gpio %d ret = %d\n",
	gpio, ret);
	return ret;
	}

	ret = gpio_direction_output(gpio, flags & OF_GPIO_ACTIVE_LOW ?
	0 : 1);
	if (ret) {
	dev_err(di->dev,
	"Failed to set GPIO %d to: %s, ret = %d",
	gpio, flags & OF_GPIO_ACTIVE_LOW ?
	"GPIO_LOW" : "GPIO_HIGH", ret);
	return ret;
	}
	}

	di->disable_suspend = of_property_read_bool(node,
	"fairchild,disable-suspend");

	return 0;
	}

	static int get_reg(void data, u64 val)
	{
	struct fan53555_device_info *di = data;
	int rc;
	unsigned int temp = 0;

	rc = fan53555_read(di, di->peek_poke_address, &temp);
	if (rc < 0)
	dev_err(di->dev, "Couldn't read reg %x rc = %d\n",
	di->peek_poke_address, rc);
	else
	*val = temp;

	return rc;
	}

	static int set_reg(void *data, u64 val)
	{
	struct fan53555_device_info *di = data;
	int rc;
	unsigned int temp = 0;

	temp = (unsigned int) val;
	rc = fan53555_write(di, di->peek_poke_address, temp);
	if (rc < 0)
	dev_err(di->dev, "Couldn't write 0x%02x to 0x%02x rc= %d\n",
	di->peek_poke_address, temp, rc);

	return rc;
	}
	DEFINE_SIMPLE_ATTRIBUTE(poke_poke_debug_ops, get_reg, set_reg, "0x%02llx\n");

	static int fan53555_regulator_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct fan53555_device_info *di;
	struct fan53555_platform_data *pdata;
	struct regulator_config config = { };
	unsigned int val;
	int ret;

	if (client->dev.of_node)
	pdata = fan53555_get_of_platform_data(client);
	else
	pdata = client->dev.platform_data;

	if (!pdata \|\| !pdata->regulator) {
	dev_err(&client->dev, "Platform data not found!\n");
	return -ENODEV;
	}

	di = devm_kzalloc(&client->dev, sizeof(struct fan53555_device_info),
	GFP_KERNEL);
	if (!di) {
	dev_err(&client->dev, "Failed to allocate device info data!\n");
	return -ENOMEM;
	}
	di->regmap = devm_regmap_init_i2c(client, &fan53555_regmap_config);
	if (IS_ERR(di->regmap)) {
	dev_err(&client->dev, "Failed to allocate regmap!\n");
	return PTR_ERR(di->regmap);
	}
	di->dev = &client->dev;
	di->regulator = pdata->regulator;
	i2c_set_clientdata(client, di);
	/* Get chip ID */
	ret = fan53555_read(di, FAN53555_ID1, &val);
	if (ret < 0) {
	dev_err(&client->dev, "Failed to get chip ID!\n");
	return -ENODEV;
	}
	di->chip_id = val & DIE_ID;
	/* Get chip revision */
	ret = fan53555_read(di, FAN53555_ID2, &val);
	if (ret < 0) {
	dev_err(&client->dev, "Failed to get chip Rev!\n");
	return -ENODEV;
	}
	di->chip_rev = val & DIE_REV;
	dev_info(&client->dev, "FAN53555 Option[%d] Rev[%d] Detected!\n",
	di->chip_id, di->chip_rev);
	/* Device init */
	ret = fan53555_device_setup(di, pdata);
	if (ret < 0) {
	dev_err(&client->dev, "Failed to setup device!\n");
	return ret;
	}

	/* Set up from device tree */
	if (client->dev.of_node) {
	ret = fan53555_of_init(client->dev.of_node, di);
	if (ret)
	return ret;
	}
	/* Register regulator */
	config.dev = di->dev;
	config.init_data = di->regulator;
	config.regmap = di->regmap;
	config.driver_data = di;
	config.of_node = client->dev.of_node;

	ret = fan53555_regulator_register(di, &config);
	if (ret < 0)
	dev_err(&client->dev, "Failed to register regulator!\n");

	di->debug_root = debugfs_create_dir("fan53555", NULL);
	if (!di->debug_root)
	dev_err(&client->dev, "Couldn't create debug dir\n");

	if (di->debug_root) {
	struct dentry *ent;

	ent = debugfs_create_x32("address", S_IFREG \| S_IWUSR \| S_IRUGO,
	di->debug_root,
	&(di->peek_poke_address));
	if (!ent)
	dev_err(&client->dev, "Couldn't create address debug file rc = %d\n",
	ret);

	ent = debugfs_create_file("data", S_IFREG \| S_IWUSR \| S_IRUGO,
	di->debug_root, di,
	&poke_poke_debug_ops);
	if (!ent)
	dev_err(&client->dev, "Couldn't create data debug file rc = %d\n",
	ret);
	}

	return ret;

	}

	static int fan53555_regulator_remove(struct i2c_client *client)
	{
	struct fan53555_device_info *di = i2c_get_clientdata(client);

	regulator_unregister(di->rdev);

	debugfs_remove_recursive(di->debug_root);

	return 0;
	}

	static struct of_device_id fan53555_match_table[] = {
	{ .compatible = "fairchild,fan53555-regulator",},
	{},
	};
	MODULE_DEVICE_TABLE(of, fan53555_match_table);

	static const struct i2c_device_id fan53555_id[] = {
	{"fan53555", -1},
	{ },
	};

	static struct i2c_driver fan53555_regulator_driver = {
	.driver = {
	.name = "fan53555-regulator",
	.owner = THIS_MODULE,
	.of_match_table = fan53555_match_table,
	},
	.probe = fan53555_regulator_probe,
	.remove = fan53555_regulator_remove,
	.id_table = fan53555_id,
	};

	/**
	* fan53555_regulator_init() - initialized fan53555 regulator driver
	* This function registers the fan53555 regulator platform driver.
	*
	* Returns 0 on success or errno on failure.
	*/
	int __init fan53555_regulator_init(void)
	{
	static bool initialized;

	if (initialized)
	return 0;
	else
	initialized = true;

	return i2c_add_driver(&fan53555_regulator_driver);
	}
	EXPORT_SYMBOL(fan53555_regulator_init);
	arch_initcall(fan53555_regulator_init);

	static void __exit fan53555_regulator_exit(void)
	{
	i2c_del_driver(&fan53555_regulator_driver);
	}
	module_exit(fan53555_regulator_exit);

	MODULE_AUTHOR("Yunfan Zhang <yfzhang@marvell.com>");
	MODULE_DESCRIPTION("FAN53555 regulator driver");
	MODULE_LICENSE("GPL v2");