[linux-block.git] / drivers / regulator / max8973-regulator.c

/*
 * max8973-regulator.c -- Maxim max8973
 *
 * Regulator driver for MAXIM 8973 DC-DC step-down switching regulator.
 *
 * Copyright (c) 2012, NVIDIA Corporation.
 *
 * Author: Laxman Dewangan <ldewangan@nvidia.com>
 *
 * 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 version 2.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
 * whether express or implied; 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/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/max8973-regulator.h>
#include <linux/regulator/of_regulator.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/regmap.h>

/* Register definitions */
#define MAX8973_VOUT					0x0
#define MAX8973_VOUT_DVS				0x1
#define MAX8973_CONTROL1				0x2
#define MAX8973_CONTROL2				0x3
#define MAX8973_CHIPID1					0x4
#define MAX8973_CHIPID2					0x5

#define MAX8973_MAX_VOUT_REG				2

/* MAX8973_VOUT */
#define MAX8973_VOUT_ENABLE				BIT(7)
#define MAX8973_VOUT_MASK				0x7F

/* MAX8973_VOUT_DVS */
#define MAX8973_DVS_VOUT_MASK				0x7F

/* MAX8973_CONTROL1 */
#define MAX8973_SNS_ENABLE				BIT(7)
#define MAX8973_FPWM_EN_M				BIT(6)
#define MAX8973_NFSR_ENABLE				BIT(5)
#define MAX8973_AD_ENABLE				BIT(4)
#define MAX8973_BIAS_ENABLE				BIT(3)
#define MAX8973_FREQSHIFT_9PER				BIT(2)

#define MAX8973_RAMP_12mV_PER_US			0x0
#define MAX8973_RAMP_25mV_PER_US			0x1
#define MAX8973_RAMP_50mV_PER_US			0x2
#define MAX8973_RAMP_200mV_PER_US			0x3
#define MAX8973_RAMP_MASK				0x3

/* MAX8973_CONTROL2 */
#define MAX8973_WDTMR_ENABLE				BIT(6)
#define MAX8973_DISCH_ENBABLE				BIT(5)
#define MAX8973_FT_ENABLE				BIT(4)

#define MAX8973_CKKADV_TRIP_DISABLE			0xC
#define MAX8973_CKKADV_TRIP_75mV_PER_US			0x0
#define MAX8973_CKKADV_TRIP_150mV_PER_US		0x4
#define MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS	0x8
#define MAX8973_CONTROL_CLKADV_TRIP_MASK		0x00030000

#define MAX8973_INDUCTOR_MIN_30_PER			0x0
#define MAX8973_INDUCTOR_NOMINAL			0x1
#define MAX8973_INDUCTOR_PLUS_30_PER			0x2
#define MAX8973_INDUCTOR_PLUS_60_PER			0x3
#define MAX8973_CONTROL_INDUCTOR_VALUE_MASK		0x00300000

#define MAX8973_MIN_VOLATGE				606250
#define MAX8973_MAX_VOLATGE				1400000
#define MAX8973_VOLATGE_STEP				6250
#define MAX8973_BUCK_N_VOLTAGE				0x80

/* Maxim 8973 chip information */
struct max8973_chip {
	struct device *dev;
	struct regulator_desc desc;
	struct regmap *regmap;
	bool enable_external_control;
	int enable_gpio;
	int dvs_gpio;
	int lru_index[MAX8973_MAX_VOUT_REG];
	int curr_vout_val[MAX8973_MAX_VOUT_REG];
	int curr_vout_reg;
	int curr_gpio_val;
	struct regulator_ops ops;
};

/*
 * find_voltage_set_register: Find new voltage configuration register (VOUT).
 * The finding of the new VOUT register will be based on the LRU mechanism.
 * Each VOUT register will have different voltage configured . This
 * Function will look if any of the VOUT register have requested voltage set
 * or not.
 *     - If it is already there then it will make that register as most
 *       recently used and return as found so that caller need not to set
 *       the VOUT register but need to set the proper gpios to select this
 *       VOUT register.
 *     - If requested voltage is not found then it will use the least
 *       recently mechanism to get new VOUT register for new configuration
 *       and will return not_found so that caller need to set new VOUT
 *       register and then gpios (both).
 */
static bool find_voltage_set_register(struct max8973_chip *tps,
		int req_vsel, int *vout_reg, int *gpio_val)
{
	int i;
	bool found = false;
	int new_vout_reg = tps->lru_index[MAX8973_MAX_VOUT_REG - 1];
	int found_index = MAX8973_MAX_VOUT_REG - 1;

	for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) {
		if (tps->curr_vout_val[tps->lru_index[i]] == req_vsel) {
			new_vout_reg = tps->lru_index[i];
			found_index = i;
			found = true;
			goto update_lru_index;
		}
	}

update_lru_index:
	for (i = found_index; i > 0; i--)
		tps->lru_index[i] = tps->lru_index[i - 1];

	tps->lru_index[0] = new_vout_reg;
	*gpio_val = new_vout_reg;
	*vout_reg = MAX8973_VOUT + new_vout_reg;
	return found;
}

static int max8973_dcdc_get_voltage_sel(struct regulator_dev *rdev)
{
	struct max8973_chip *max = rdev_get_drvdata(rdev);
	unsigned int data;
	int ret;

	ret = regmap_read(max->regmap, max->curr_vout_reg, &data);
	if (ret < 0) {
		dev_err(max->dev, "register %d read failed, err = %d\n",
			max->curr_vout_reg, ret);
		return ret;
	}
	return data & MAX8973_VOUT_MASK;
}

static int max8973_dcdc_set_voltage_sel(struct regulator_dev *rdev,
	     unsigned vsel)
{
	struct max8973_chip *max = rdev_get_drvdata(rdev);
	int ret;
	bool found = false;
	int vout_reg = max->curr_vout_reg;
	int gpio_val = max->curr_gpio_val;

	/*
	 * If gpios are available to select the VOUT register then least
	 * recently used register for new configuration.
	 */
	if (gpio_is_valid(max->dvs_gpio))
		found = find_voltage_set_register(max, vsel,
					&vout_reg, &gpio_val);

	if (!found) {
		ret = regmap_update_bits(max->regmap, vout_reg,
					MAX8973_VOUT_MASK, vsel);
		if (ret < 0) {
			dev_err(max->dev, "register %d update failed, err %d\n",
				 vout_reg, ret);
			return ret;
		}
		max->curr_vout_reg = vout_reg;
		max->curr_vout_val[gpio_val] = vsel;
	}

	/* Select proper VOUT register vio gpios */
	if (gpio_is_valid(max->dvs_gpio)) {
		gpio_set_value_cansleep(max->dvs_gpio, gpio_val & 0x1);
		max->curr_gpio_val = gpio_val;
	}
	return 0;
}

static int max8973_dcdc_set_mode(struct regulator_dev *rdev, unsigned int mode)
{
	struct max8973_chip *max = rdev_get_drvdata(rdev);
	int ret;
	int pwm;

	/* Enable force PWM mode in FAST mode only. */
	switch (mode) {
	case REGULATOR_MODE_FAST:
		pwm = MAX8973_FPWM_EN_M;
		break;

	case REGULATOR_MODE_NORMAL:
		pwm = 0;
		break;

	default:
		return -EINVAL;
	}

	ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
				MAX8973_FPWM_EN_M, pwm);
	if (ret < 0)
		dev_err(max->dev, "register %d update failed, err %d\n",
				MAX8973_CONTROL1, ret);
	return ret;
}

static unsigned int max8973_dcdc_get_mode(struct regulator_dev *rdev)
{
	struct max8973_chip *max = rdev_get_drvdata(rdev);
	unsigned int data;
	int ret;

	ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
	if (ret < 0) {
		dev_err(max->dev, "register %d read failed, err %d\n",
				MAX8973_CONTROL1, ret);
		return ret;
	}
	return (data & MAX8973_FPWM_EN_M) ?
		REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
}

static int max8973_set_ramp_delay(struct regulator_dev *rdev,
		int ramp_delay)
{
	struct max8973_chip *max = rdev_get_drvdata(rdev);
	unsigned int control;
	int ret;
	int ret_val;

	/* Set ramp delay */
	if (ramp_delay < 25000) {
		control = MAX8973_RAMP_12mV_PER_US;
		ret_val = 12000;
	} else if (ramp_delay < 50000) {
		control = MAX8973_RAMP_25mV_PER_US;
		ret_val = 25000;
	} else if (ramp_delay < 200000) {
		control = MAX8973_RAMP_50mV_PER_US;
		ret_val = 50000;
	} else {
		control = MAX8973_RAMP_200mV_PER_US;
		ret_val = 200000;
	}

	ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
			MAX8973_RAMP_MASK, control);
	if (ret < 0)
		dev_err(max->dev, "register %d update failed, %d",
				MAX8973_CONTROL1, ret);
	return ret;
}

static const struct regulator_ops max8973_dcdc_ops = {
	.get_voltage_sel	= max8973_dcdc_get_voltage_sel,
	.set_voltage_sel	= max8973_dcdc_set_voltage_sel,
	.list_voltage		= regulator_list_voltage_linear,
	.set_mode		= max8973_dcdc_set_mode,
	.get_mode		= max8973_dcdc_get_mode,
	.set_voltage_time_sel	= regulator_set_voltage_time_sel,
	.set_ramp_delay		= max8973_set_ramp_delay,
};

static int max8973_init_dcdc(struct max8973_chip *max,
			     struct max8973_regulator_platform_data *pdata)
{
	int ret;
	uint8_t	control1 = 0;
	uint8_t control2 = 0;
	unsigned int data;

	ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
	if (ret < 0) {
		dev_err(max->dev, "register %d read failed, err = %d",
				MAX8973_CONTROL1, ret);
		return ret;
	}
	control1 = data & MAX8973_RAMP_MASK;
	switch (control1) {
	case MAX8973_RAMP_12mV_PER_US:
		max->desc.ramp_delay = 12000;
		break;
	case MAX8973_RAMP_25mV_PER_US:
		max->desc.ramp_delay = 252000;
		break;
	case MAX8973_RAMP_50mV_PER_US:
		max->desc.ramp_delay = 50000;
		break;
	case MAX8973_RAMP_200mV_PER_US:
		max->desc.ramp_delay = 200000;
		break;
	}

	if (pdata->control_flags & MAX8973_CONTROL_REMOTE_SENSE_ENABLE)
		control1 |= MAX8973_SNS_ENABLE;

	if (!(pdata->control_flags & MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE))
		control1 |= MAX8973_NFSR_ENABLE;

	if (pdata->control_flags & MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE)
		control1 |= MAX8973_AD_ENABLE;

	if (pdata->control_flags & MAX8973_CONTROL_BIAS_ENABLE) {
		control1 |= MAX8973_BIAS_ENABLE;
		max->desc.enable_time = 20;
	} else {
		max->desc.enable_time = 240;
	}

	if (pdata->control_flags & MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE)
		control1 |= MAX8973_FREQSHIFT_9PER;

	if (!(pdata->control_flags & MAX8973_CONTROL_PULL_DOWN_ENABLE))
		control2 |= MAX8973_DISCH_ENBABLE;

	/*  Clock advance trip configuration */
	switch (pdata->control_flags & MAX8973_CONTROL_CLKADV_TRIP_MASK) {
	case MAX8973_CONTROL_CLKADV_TRIP_DISABLED:
		control2 |= MAX8973_CKKADV_TRIP_DISABLE;
		break;

	case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US:
		control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US;
		break;

	case MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US:
		control2 |= MAX8973_CKKADV_TRIP_150mV_PER_US;
		break;

	case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US_HIST_DIS:
		control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS;
		break;
	}

	/* Configure inductor value */
	switch (pdata->control_flags & MAX8973_CONTROL_INDUCTOR_VALUE_MASK) {
	case MAX8973_CONTROL_INDUCTOR_VALUE_NOMINAL:
		control2 |= MAX8973_INDUCTOR_NOMINAL;
		break;

	case MAX8973_CONTROL_INDUCTOR_VALUE_MINUS_30_PER:
		control2 |= MAX8973_INDUCTOR_MIN_30_PER;
		break;

	case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_30_PER:
		control2 |= MAX8973_INDUCTOR_PLUS_30_PER;
		break;

	case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_60_PER:
		control2 |= MAX8973_INDUCTOR_PLUS_60_PER;
		break;
	}

	ret = regmap_write(max->regmap, MAX8973_CONTROL1, control1);
	if (ret < 0) {
		dev_err(max->dev, "register %d write failed, err = %d",
				MAX8973_CONTROL1, ret);
		return ret;
	}

	ret = regmap_write(max->regmap, MAX8973_CONTROL2, control2);
	if (ret < 0) {
		dev_err(max->dev, "register %d write failed, err = %d",
				MAX8973_CONTROL2, ret);
		return ret;
	}

	/* If external control is enabled then disable EN bit */
	if (max->enable_external_control) {
		ret = regmap_update_bits(max->regmap, MAX8973_VOUT,
						MAX8973_VOUT_ENABLE, 0);
		if (ret < 0)
			dev_err(max->dev, "register %d update failed, err = %d",
				MAX8973_VOUT, ret);
	}
	return ret;
}

static const struct regmap_config max8973_regmap_config = {
	.reg_bits		= 8,
	.val_bits		= 8,
	.max_register		= MAX8973_CHIPID2,
	.cache_type		= REGCACHE_RBTREE,
};

static struct max8973_regulator_platform_data *max8973_parse_dt(
		struct device *dev)
{
	struct max8973_regulator_platform_data *pdata;
	struct device_node *np = dev->of_node;
	int ret;
	u32 pval;

	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
	if (!pdata)
		return NULL;

	pdata->enable_ext_control = of_property_read_bool(np,
						"maxim,externally-enable");
	pdata->enable_gpio = of_get_named_gpio(np, "maxim,enable-gpio", 0);
	pdata->dvs_gpio = of_get_named_gpio(np, "maxim,dvs-gpio", 0);

	ret = of_property_read_u32(np, "maxim,dvs-default-state", &pval);
	if (!ret)
		pdata->dvs_def_state = pval;

	if (of_property_read_bool(np, "maxim,enable-remote-sense"))
		pdata->control_flags  |= MAX8973_CONTROL_REMOTE_SENSE_ENABLE;

	if (of_property_read_bool(np, "maxim,enable-falling-slew-rate"))
		pdata->control_flags  |=
				MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE;

	if (of_property_read_bool(np, "maxim,enable-active-discharge"))
		pdata->control_flags  |=
				MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE;

	if (of_property_read_bool(np, "maxim,enable-frequency-shift"))
		pdata->control_flags  |= MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE;

	if (of_property_read_bool(np, "maxim,enable-bias-control"))
		pdata->control_flags  |= MAX8973_BIAS_ENABLE;

	return pdata;
}

static int max8973_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct max8973_regulator_platform_data *pdata;
	struct regulator_init_data *ridata;
	struct regulator_config config = { };
	struct regulator_dev *rdev;
	struct max8973_chip *max;
	bool pdata_from_dt = false;
	int ret;

	pdata = dev_get_platdata(&client->dev);

	if (!pdata && client->dev.of_node) {
		pdata = max8973_parse_dt(&client->dev);
		pdata_from_dt = true;
	}

	if (!pdata) {
		dev_err(&client->dev, "No Platform data");
		return -EIO;
	}

	if ((pdata->dvs_gpio == -EPROBE_DEFER) ||
		(pdata->enable_gpio == -EPROBE_DEFER))
		return -EPROBE_DEFER;

	max = devm_kzalloc(&client->dev, sizeof(*max), GFP_KERNEL);
	if (!max)
		return -ENOMEM;

	max->regmap = devm_regmap_init_i2c(client, &max8973_regmap_config);
	if (IS_ERR(max->regmap)) {
		ret = PTR_ERR(max->regmap);
		dev_err(&client->dev, "regmap init failed, err %d\n", ret);
		return ret;
	}

	i2c_set_clientdata(client, max);
	max->ops = max8973_dcdc_ops;
	max->dev = &client->dev;
	max->desc.name = id->name;
	max->desc.id = 0;
	max->desc.ops = &max->ops;
	max->desc.type = REGULATOR_VOLTAGE;
	max->desc.owner = THIS_MODULE;
	max->desc.min_uV = MAX8973_MIN_VOLATGE;
	max->desc.uV_step = MAX8973_VOLATGE_STEP;
	max->desc.n_voltages = MAX8973_BUCK_N_VOLTAGE;

	max->dvs_gpio = (pdata->dvs_gpio) ? pdata->dvs_gpio : -EINVAL;
	max->enable_gpio = (pdata->enable_gpio) ? pdata->enable_gpio : -EINVAL;
	max->enable_external_control = pdata->enable_ext_control;
	max->curr_gpio_val = pdata->dvs_def_state;
	max->curr_vout_reg = MAX8973_VOUT + pdata->dvs_def_state;

	if (gpio_is_valid(max->enable_gpio))
		max->enable_external_control = true;

	if (!pdata->enable_ext_control) {
		max->desc.enable_reg = MAX8973_VOUT;
		max->desc.enable_mask = MAX8973_VOUT_ENABLE;
		max->ops.enable = regulator_enable_regmap;
		max->ops.disable = regulator_disable_regmap;
		max->ops.is_enabled = regulator_is_enabled_regmap;
	}

	max->lru_index[0] = max->curr_vout_reg;

	if (gpio_is_valid(max->dvs_gpio)) {
		int gpio_flags;
		int i;

		gpio_flags = (pdata->dvs_def_state) ?
				GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
		ret = devm_gpio_request_one(&client->dev, max->dvs_gpio,
				gpio_flags, "max8973-dvs");
		if (ret) {
			dev_err(&client->dev,
				"gpio_request for gpio %d failed, err = %d\n",
				max->dvs_gpio, ret);
			return ret;
		}

		/*
		 * Initialize the lru index with vout_reg id
		 * The index 0 will be most recently used and
		 * set with the max->curr_vout_reg */
		for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i)
			max->lru_index[i] = i;
		max->lru_index[0] = max->curr_vout_reg;
		max->lru_index[max->curr_vout_reg] = 0;
	}

	if (pdata_from_dt)
		pdata->reg_init_data = of_get_regulator_init_data(&client->dev,
					client->dev.of_node, &max->desc);

	ret = max8973_init_dcdc(max, pdata);
	if (ret < 0) {
		dev_err(max->dev, "Max8973 Init failed, err = %d\n", ret);
		return ret;
	}

	config.dev = &client->dev;
	config.init_data = pdata->reg_init_data;
	config.driver_data = max;
	config.of_node = client->dev.of_node;
	config.regmap = max->regmap;

	if (gpio_is_valid(max->enable_gpio)) {
		ridata = pdata->reg_init_data;
		config.ena_gpio_flags = GPIOF_OUT_INIT_LOW;
		if (ridata && (ridata->constraints.always_on ||
			ridata->constraints.boot_on))
			config.ena_gpio_flags = GPIOF_OUT_INIT_HIGH;
		config.ena_gpio = max->enable_gpio;
	}

	/* Register the regulators */
	rdev = devm_regulator_register(&client->dev, &max->desc, &config);
	if (IS_ERR(rdev)) {
		ret = PTR_ERR(rdev);
		dev_err(max->dev, "regulator register failed, err %d\n", ret);
		return ret;
	}

	return 0;
}

static const struct i2c_device_id max8973_id[] = {
	{.name = "max8973",},
	{},
};

MODULE_DEVICE_TABLE(i2c, max8973_id);

static struct i2c_driver max8973_i2c_driver = {
	.driver = {
		.name = "max8973",
		.owner = THIS_MODULE,
	},
	.probe = max8973_probe,
	.id_table = max8973_id,
};

static int __init max8973_init(void)
{
	return i2c_add_driver(&max8973_i2c_driver);
}
subsys_initcall(max8973_init);

static void __exit max8973_cleanup(void)
{
	i2c_del_driver(&max8973_i2c_driver);
}
module_exit(max8973_cleanup);

MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
MODULE_DESCRIPTION("MAX8973 voltage regulator driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
5928f538 LD	1	/*
	2	* max8973-regulator.c -- Maxim max8973
	3	*
	4	* Regulator driver for MAXIM 8973 DC-DC step-down switching regulator.
	5	*
	6	* Copyright (c) 2012, NVIDIA Corporation.
	7	*
	8	* Author: Laxman Dewangan <ldewangan@nvidia.com>
	9	*
	10	* This program is free software; you can redistribute it and/or
	11	* modify it under the terms of the GNU General Public License as
	12	* published by the Free Software Foundation version 2.
	13	*
	14	* This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
	15	* whether express or implied; without even the implied warranty of
	16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	17	* General Public License for more details.
	18	*
	19	* You should have received a copy of the GNU General Public License
	20	* along with this program; if not, write to the Free Software
	21	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
	22	* 02111-1307, USA
	23	*/
	24
	25	#include <linux/kernel.h>
	26	#include <linux/module.h>
	27	#include <linux/init.h>
	28	#include <linux/err.h>
42dc3023	29	#include <linux/of.h>
5928f538 LD	30	#include <linux/platform_device.h>
	31	#include <linux/regulator/driver.h>
	32	#include <linux/regulator/machine.h>
	33	#include <linux/regulator/max8973-regulator.h>
42dc3023	34	#include <linux/regulator/of_regulator.h>
5928f538	35	#include <linux/gpio.h>
c2ffa973	36	#include <linux/of_gpio.h>
5928f538 LD	37	#include <linux/i2c.h>
	38	#include <linux/slab.h>
	39	#include <linux/regmap.h>
	40
	41	/* Register definitions */
	42	#define MAX8973_VOUT 0x0
	43	#define MAX8973_VOUT_DVS 0x1
	44	#define MAX8973_CONTROL1 0x2
	45	#define MAX8973_CONTROL2 0x3
	46	#define MAX8973_CHIPID1 0x4
	47	#define MAX8973_CHIPID2 0x5
	48
	49	#define MAX8973_MAX_VOUT_REG 2
	50
	51	/* MAX8973_VOUT */
	52	#define MAX8973_VOUT_ENABLE BIT(7)
	53	#define MAX8973_VOUT_MASK 0x7F
	54
	55	/* MAX8973_VOUT_DVS */
	56	#define MAX8973_DVS_VOUT_MASK 0x7F
	57
	58	/* MAX8973_CONTROL1 */
	59	#define MAX8973_SNS_ENABLE BIT(7)
	60	#define MAX8973_FPWM_EN_M BIT(6)
	61	#define MAX8973_NFSR_ENABLE BIT(5)
	62	#define MAX8973_AD_ENABLE BIT(4)
	63	#define MAX8973_BIAS_ENABLE BIT(3)
	64	#define MAX8973_FREQSHIFT_9PER BIT(2)
	65
	66	#define MAX8973_RAMP_12mV_PER_US 0x0
	67	#define MAX8973_RAMP_25mV_PER_US 0x1
	68	#define MAX8973_RAMP_50mV_PER_US 0x2
	69	#define MAX8973_RAMP_200mV_PER_US 0x3
3064c1f3	70	#define MAX8973_RAMP_MASK 0x3
5928f538 LD	71
	72	/* MAX8973_CONTROL2 */
	73	#define MAX8973_WDTMR_ENABLE BIT(6)
	74	#define MAX8973_DISCH_ENBABLE BIT(5)
	75	#define MAX8973_FT_ENABLE BIT(4)
	76
	77	#define MAX8973_CKKADV_TRIP_DISABLE 0xC
	78	#define MAX8973_CKKADV_TRIP_75mV_PER_US 0x0
	79	#define MAX8973_CKKADV_TRIP_150mV_PER_US 0x4
	80	#define MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS 0x8
	81	#define MAX8973_CONTROL_CLKADV_TRIP_MASK 0x00030000
	82
	83	#define MAX8973_INDUCTOR_MIN_30_PER 0x0
	84	#define MAX8973_INDUCTOR_NOMINAL 0x1
	85	#define MAX8973_INDUCTOR_PLUS_30_PER 0x2
	86	#define MAX8973_INDUCTOR_PLUS_60_PER 0x3
	87	#define MAX8973_CONTROL_INDUCTOR_VALUE_MASK 0x00300000
	88
	89	#define MAX8973_MIN_VOLATGE 606250
	90	#define MAX8973_MAX_VOLATGE 1400000
	91	#define MAX8973_VOLATGE_STEP 6250
	92	#define MAX8973_BUCK_N_VOLTAGE 0x80
	93
	94	/* Maxim 8973 chip information */
	95	struct max8973_chip {
	96	struct device *dev;
	97	struct regulator_desc desc;
5928f538 LD	98	struct regmap *regmap;
5928f538 LD	99	bool enable_external_control;
69eb0980	100	int enable_gpio;
5928f538 LD	101	int dvs_gpio;
	102	int lru_index[MAX8973_MAX_VOUT_REG];
	103	int curr_vout_val[MAX8973_MAX_VOUT_REG];
	104	int curr_vout_reg;
	105	int curr_gpio_val;
db892ff6	106	struct regulator_ops ops;
5928f538 LD	107	};
	108
	109	/*
	110	* find_voltage_set_register: Find new voltage configuration register (VOUT).
	111	* The finding of the new VOUT register will be based on the LRU mechanism.
	112	* Each VOUT register will have different voltage configured . This
	113	* Function will look if any of the VOUT register have requested voltage set
	114	* or not.
	115	* - If it is already there then it will make that register as most
	116	* recently used and return as found so that caller need not to set
	117	* the VOUT register but need to set the proper gpios to select this
	118	* VOUT register.
	119	* - If requested voltage is not found then it will use the least
	120	* recently mechanism to get new VOUT register for new configuration
	121	* and will return not_found so that caller need to set new VOUT
	122	* register and then gpios (both).
	123	*/
	124	static bool find_voltage_set_register(struct max8973_chip *tps,
	125	int req_vsel, int vout_reg, int gpio_val)
	126	{
	127	int i;
	128	bool found = false;
	129	int new_vout_reg = tps->lru_index[MAX8973_MAX_VOUT_REG - 1];
	130	int found_index = MAX8973_MAX_VOUT_REG - 1;
	131
	132	for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) {
	133	if (tps->curr_vout_val[tps->lru_index[i]] == req_vsel) {
	134	new_vout_reg = tps->lru_index[i];
	135	found_index = i;
	136	found = true;
	137	goto update_lru_index;
	138	}
	139	}
	140
	141	update_lru_index:
	142	for (i = found_index; i > 0; i--)
	143	tps->lru_index[i] = tps->lru_index[i - 1];
	144
	145	tps->lru_index[0] = new_vout_reg;
	146	*gpio_val = new_vout_reg;
	147	*vout_reg = MAX8973_VOUT + new_vout_reg;
	148	return found;
	149	}
	150
	151	static int max8973_dcdc_get_voltage_sel(struct regulator_dev *rdev)
	152	{
	153	struct max8973_chip *max = rdev_get_drvdata(rdev);
	154	unsigned int data;
	155	int ret;
	156
	157	ret = regmap_read(max->regmap, max->curr_vout_reg, &data);
	158	if (ret < 0) {
	159	dev_err(max->dev, "register %d read failed, err = %d\n",
	160	max->curr_vout_reg, ret);
	161	return ret;
	162	}
	163	return data & MAX8973_VOUT_MASK;
	164	}
	165
	166	static int max8973_dcdc_set_voltage_sel(struct regulator_dev *rdev,
	167	unsigned vsel)
	168	{
	169	struct max8973_chip *max = rdev_get_drvdata(rdev);
	170	int ret;
171	bool found = false;
172	int vout_reg = max->curr_vout_reg;
173	int gpio_val = max->curr_gpio_val;
174
175	/*
176	* If gpios are available to select the VOUT register then least
177	* recently used register for new configuration.
178	*/
fa5f509f	179	if (gpio_is_valid(max->dvs_gpio))
5928f538 LD	180	found = find_voltage_set_register(max, vsel,
	181	&vout_reg, &gpio_val);
	182
	183	if (!found) {
	184	ret = regmap_update_bits(max->regmap, vout_reg,
	185	MAX8973_VOUT_MASK, vsel);
	186	if (ret < 0) {
	187	dev_err(max->dev, "register %d update failed, err %d\n",
	188	vout_reg, ret);
	189	return ret;
	190	}
	191	max->curr_vout_reg = vout_reg;
	192	max->curr_vout_val[gpio_val] = vsel;
	193	}
	194
	195	/* Select proper VOUT register vio gpios */
fa5f509f	196	if (gpio_is_valid(max->dvs_gpio)) {
5928f538 LD	197	gpio_set_value_cansleep(max->dvs_gpio, gpio_val & 0x1);
	198	max->curr_gpio_val = gpio_val;
	199	}
	200	return 0;
	201	}
	202
	203	static int max8973_dcdc_set_mode(struct regulator_dev *rdev, unsigned int mode)
	204	{
	205	struct max8973_chip *max = rdev_get_drvdata(rdev);
	206	int ret;
	207	int pwm;
	208
	209	/* Enable force PWM mode in FAST mode only. */
	210	switch (mode) {
	211	case REGULATOR_MODE_FAST:
	212	pwm = MAX8973_FPWM_EN_M;
	213	break;
	214
	215	case REGULATOR_MODE_NORMAL:
	216	pwm = 0;
	217	break;
	218
	219	default:
	220	return -EINVAL;
	221	}
	222
	223	ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
	224	MAX8973_FPWM_EN_M, pwm);
	225	if (ret < 0)
	226	dev_err(max->dev, "register %d update failed, err %d\n",
	227	MAX8973_CONTROL1, ret);
	228	return ret;
	229	}
	230
	231	static unsigned int max8973_dcdc_get_mode(struct regulator_dev *rdev)
	232	{
	233	struct max8973_chip *max = rdev_get_drvdata(rdev);
	234	unsigned int data;
	235	int ret;
	236
	237	ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
	238	if (ret < 0) {
	239	dev_err(max->dev, "register %d read failed, err %d\n",
	240	MAX8973_CONTROL1, ret);
	241	return ret;
	242	}
	243	return (data & MAX8973_FPWM_EN_M) ?
	244	REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
	245	}
	246
3064c1f3 LD	247	static int max8973_set_ramp_delay(struct regulator_dev *rdev,
	248	int ramp_delay)
	249	{
	250	struct max8973_chip *max = rdev_get_drvdata(rdev);
	251	unsigned int control;
	252	int ret;
	253	int ret_val;
	254
	255	/* Set ramp delay */
	256	if (ramp_delay < 25000) {
	257	control = MAX8973_RAMP_12mV_PER_US;
	258	ret_val = 12000;
	259	} else if (ramp_delay < 50000) {
	260	control = MAX8973_RAMP_25mV_PER_US;
	261	ret_val = 25000;
	262	} else if (ramp_delay < 200000) {
	263	control = MAX8973_RAMP_50mV_PER_US;
	264	ret_val = 50000;
	265	} else {
	266	control = MAX8973_RAMP_200mV_PER_US;
	267	ret_val = 200000;
	268	}
	269
	270	ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
	271	MAX8973_RAMP_MASK, control);
	272	if (ret < 0)
	273	dev_err(max->dev, "register %d update failed, %d",
	274	MAX8973_CONTROL1, ret);
	275	return ret;
	276	}
	277
db892ff6	278	static const struct regulator_ops max8973_dcdc_ops = {
5928f538 LD	279	.get_voltage_sel = max8973_dcdc_get_voltage_sel,
	280	.set_voltage_sel = max8973_dcdc_set_voltage_sel,
	281	.list_voltage = regulator_list_voltage_linear,
	282	.set_mode = max8973_dcdc_set_mode,
	283	.get_mode = max8973_dcdc_get_mode,
3064c1f3 LD	284	.set_voltage_time_sel = regulator_set_voltage_time_sel,
3064c1f3 LD	285	.set_ramp_delay = max8973_set_ramp_delay,
5928f538 LD	286	};
5928f538 LD	287
3d68dfe3 GKH	288	static int max8973_init_dcdc(struct max8973_chip *max,
3d68dfe3 GKH	289	struct max8973_regulator_platform_data *pdata)
5928f538 LD	290	{
	291	int ret;
	292	uint8_t control1 = 0;
	293	uint8_t control2 = 0;
3064c1f3 LD	294	unsigned int data;
	295
	296	ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
	297	if (ret < 0) {
	298	dev_err(max->dev, "register %d read failed, err = %d",
	299	MAX8973_CONTROL1, ret);
	300	return ret;
	301	}
	302	control1 = data & MAX8973_RAMP_MASK;
	303	switch (control1) {
	304	case MAX8973_RAMP_12mV_PER_US:
	305	max->desc.ramp_delay = 12000;
	306	break;
	307	case MAX8973_RAMP_25mV_PER_US:
	308	max->desc.ramp_delay = 252000;
	309	break;
	310	case MAX8973_RAMP_50mV_PER_US:
	311	max->desc.ramp_delay = 50000;
	312	break;
	313	case MAX8973_RAMP_200mV_PER_US:
	314	max->desc.ramp_delay = 200000;
	315	break;
	316	}
5928f538 LD	317
	318	if (pdata->control_flags & MAX8973_CONTROL_REMOTE_SENSE_ENABLE)
	319	control1 \|= MAX8973_SNS_ENABLE;
	320
	321	if (!(pdata->control_flags & MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE))
	322	control1 \|= MAX8973_NFSR_ENABLE;
	323
	324	if (pdata->control_flags & MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE)
	325	control1 \|= MAX8973_AD_ENABLE;
	326
dcd9ec6a	327	if (pdata->control_flags & MAX8973_CONTROL_BIAS_ENABLE) {
5928f538	328	control1 \|= MAX8973_BIAS_ENABLE;
dcd9ec6a LD	329	max->desc.enable_time = 20;
	330	} else {
	331	max->desc.enable_time = 240;
	332	}
5928f538 LD	333
	334	if (pdata->control_flags & MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE)
	335	control1 \|= MAX8973_FREQSHIFT_9PER;
	336
5928f538 LD	337	if (!(pdata->control_flags & MAX8973_CONTROL_PULL_DOWN_ENABLE))
	338	control2 \|= MAX8973_DISCH_ENBABLE;
	339
	340	/* Clock advance trip configuration */
	341	switch (pdata->control_flags & MAX8973_CONTROL_CLKADV_TRIP_MASK) {
	342	case MAX8973_CONTROL_CLKADV_TRIP_DISABLED:
	343	control2 \|= MAX8973_CKKADV_TRIP_DISABLE;
	344	break;
	345
	346	case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US:
	347	control2 \|= MAX8973_CKKADV_TRIP_75mV_PER_US;
	348	break;
	349
	350	case MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US:
	351	control2 \|= MAX8973_CKKADV_TRIP_150mV_PER_US;
	352	break;
	353
	354	case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US_HIST_DIS:
	355	control2 \|= MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS;
	356	break;
	357	}
	358
	359	/* Configure inductor value */
	360	switch (pdata->control_flags & MAX8973_CONTROL_INDUCTOR_VALUE_MASK) {
	361	case MAX8973_CONTROL_INDUCTOR_VALUE_NOMINAL:
	362	control2 \|= MAX8973_INDUCTOR_NOMINAL;
	363	break;
	364
	365	case MAX8973_CONTROL_INDUCTOR_VALUE_MINUS_30_PER:
	366	control2 \|= MAX8973_INDUCTOR_MIN_30_PER;
	367	break;
	368
	369	case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_30_PER:
	370	control2 \|= MAX8973_INDUCTOR_PLUS_30_PER;
	371	break;
	372
	373	case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_60_PER:
	374	control2 \|= MAX8973_INDUCTOR_PLUS_60_PER;
	375	break;
	376	}
	377
	378	ret = regmap_write(max->regmap, MAX8973_CONTROL1, control1);
	379	if (ret < 0) {
	380	dev_err(max->dev, "register %d write failed, err = %d",
	381	MAX8973_CONTROL1, ret);
	382	return ret;
	383	}
	384
	385	ret = regmap_write(max->regmap, MAX8973_CONTROL2, control2);
	386	if (ret < 0) {
	387	dev_err(max->dev, "register %d write failed, err = %d",
	388	MAX8973_CONTROL2, ret);
	389	return ret;
	390	}
	391
	392	/* If external control is enabled then disable EN bit */
	393	if (max->enable_external_control) {
	394	ret = regmap_update_bits(max->regmap, MAX8973_VOUT,
	395	MAX8973_VOUT_ENABLE, 0);
	396	if (ret < 0)
	397	dev_err(max->dev, "register %d update failed, err = %d",
	398	MAX8973_VOUT, ret);
	399	}
	400	return ret;
401	}
402
403	static const struct regmap_config max8973_regmap_config = {
404	.reg_bits = 8,
405	.val_bits = 8,
406	.max_register = MAX8973_CHIPID2,
407	.cache_type = REGCACHE_RBTREE,
408	};
409
c2ffa973 LD	410	static struct max8973_regulator_platform_data *max8973_parse_dt(
	411	struct device *dev)
	412	{
	413	struct max8973_regulator_platform_data *pdata;
	414	struct device_node *np = dev->of_node;
	415	int ret;
	416	u32 pval;
	417
	418	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
	419	if (!pdata)
	420	return NULL;
	421
	422	pdata->enable_ext_control = of_property_read_bool(np,
	423	"maxim,externally-enable");
69eb0980	424	pdata->enable_gpio = of_get_named_gpio(np, "maxim,enable-gpio", 0);
c2ffa973 LD	425	pdata->dvs_gpio = of_get_named_gpio(np, "maxim,dvs-gpio", 0);
	426
	427	ret = of_property_read_u32(np, "maxim,dvs-default-state", &pval);
	428	if (!ret)
	429	pdata->dvs_def_state = pval;
	430
	431	if (of_property_read_bool(np, "maxim,enable-remote-sense"))
	432	pdata->control_flags \|= MAX8973_CONTROL_REMOTE_SENSE_ENABLE;
	433
	434	if (of_property_read_bool(np, "maxim,enable-falling-slew-rate"))
	435	pdata->control_flags \|=
	436	MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE;
	437
	438	if (of_property_read_bool(np, "maxim,enable-active-discharge"))
	439	pdata->control_flags \|=
	440	MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE;
	441
	442	if (of_property_read_bool(np, "maxim,enable-frequency-shift"))
	443	pdata->control_flags \|= MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE;
	444
	445	if (of_property_read_bool(np, "maxim,enable-bias-control"))
	446	pdata->control_flags \|= MAX8973_BIAS_ENABLE;
	447
	448	return pdata;
	449	}
	450
3d68dfe3 GKH	451	static int max8973_probe(struct i2c_client *client,
3d68dfe3 GKH	452	const struct i2c_device_id *id)
5928f538 LD	453	{
5928f538 LD	454	struct max8973_regulator_platform_data *pdata;
69eb0980	455	struct regulator_init_data *ridata;
5928f538 LD	456	struct regulator_config config = { };
	457	struct regulator_dev *rdev;
	458	struct max8973_chip *max;
c2ffa973	459	bool pdata_from_dt = false;
5928f538 LD	460	int ret;
5928f538 LD	461
dff91d0b	462	pdata = dev_get_platdata(&client->dev);
42dc3023	463
c2ffa973 LD	464	if (!pdata && client->dev.of_node) {
	465	pdata = max8973_parse_dt(&client->dev);
	466	pdata_from_dt = true;
	467	}
	468
	469	if (!pdata) {
5928f538 LD	470	dev_err(&client->dev, "No Platform data");
	471	return -EIO;
	472	}
	473
69eb0980 LD	474	if ((pdata->dvs_gpio == -EPROBE_DEFER) \|\|
69eb0980 LD	475	(pdata->enable_gpio == -EPROBE_DEFER))
c2ffa973 LD	476	return -EPROBE_DEFER;
c2ffa973 LD	477
5928f538	478	max = devm_kzalloc(&client->dev, sizeof(*max), GFP_KERNEL);
21024dee	479	if (!max)
5928f538	480	return -ENOMEM;
5928f538 LD	481
	482	max->regmap = devm_regmap_init_i2c(client, &max8973_regmap_config);
	483	if (IS_ERR(max->regmap)) {
	484	ret = PTR_ERR(max->regmap);
	485	dev_err(&client->dev, "regmap init failed, err %d\n", ret);
	486	return ret;
	487	}
	488
	489	i2c_set_clientdata(client, max);
db892ff6	490	max->ops = max8973_dcdc_ops;
5928f538 LD	491	max->dev = &client->dev;
	492	max->desc.name = id->name;
	493	max->desc.id = 0;
db892ff6	494	max->desc.ops = &max->ops;
5928f538 LD	495	max->desc.type = REGULATOR_VOLTAGE;
	496	max->desc.owner = THIS_MODULE;
	497	max->desc.min_uV = MAX8973_MIN_VOLATGE;
	498	max->desc.uV_step = MAX8973_VOLATGE_STEP;
	499	max->desc.n_voltages = MAX8973_BUCK_N_VOLTAGE;
	500
69eb0980 LD	501	max->dvs_gpio = (pdata->dvs_gpio) ? pdata->dvs_gpio : -EINVAL;
	502	max->enable_gpio = (pdata->enable_gpio) ? pdata->enable_gpio : -EINVAL;
	503	max->enable_external_control = pdata->enable_ext_control;
	504	max->curr_gpio_val = pdata->dvs_def_state;
	505	max->curr_vout_reg = MAX8973_VOUT + pdata->dvs_def_state;
	506
	507	if (gpio_is_valid(max->enable_gpio))
	508	max->enable_external_control = true;
	509
c2ffa973	510	if (!pdata->enable_ext_control) {
5928f538 LD	511	max->desc.enable_reg = MAX8973_VOUT;
5928f538 LD	512	max->desc.enable_mask = MAX8973_VOUT_ENABLE;
db892ff6 GL	513	max->ops.enable = regulator_enable_regmap;
	514	max->ops.disable = regulator_disable_regmap;
	515	max->ops.is_enabled = regulator_is_enabled_regmap;
5928f538 LD	516	}
5928f538 LD	517
5928f538	518	max->lru_index[0] = max->curr_vout_reg;
5928f538 LD	519
	520	if (gpio_is_valid(max->dvs_gpio)) {
	521	int gpio_flags;
	522	int i;
	523
	524	gpio_flags = (pdata->dvs_def_state) ?
	525	GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
	526	ret = devm_gpio_request_one(&client->dev, max->dvs_gpio,
	527	gpio_flags, "max8973-dvs");
	528	if (ret) {
	529	dev_err(&client->dev,
	530	"gpio_request for gpio %d failed, err = %d\n",
	531	max->dvs_gpio, ret);
	532	return ret;
	533	}
5928f538 LD	534
	535	/*
	536	* Initialize the lru index with vout_reg id
	537	* The index 0 will be most recently used and
	538	* set with the max->curr_vout_reg */
	539	for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i)
	540	max->lru_index[i] = i;
	541	max->lru_index[0] = max->curr_vout_reg;
	542	max->lru_index[max->curr_vout_reg] = 0;
	543	}
	544
c2ffa973 LD	545	if (pdata_from_dt)
	546	pdata->reg_init_data = of_get_regulator_init_data(&client->dev,
	547	client->dev.of_node, &max->desc);
	548
	549	ret = max8973_init_dcdc(max, pdata);
	550	if (ret < 0) {
	551	dev_err(max->dev, "Max8973 Init failed, err = %d\n", ret);
	552	return ret;
5928f538 LD	553	}
	554
	555	config.dev = &client->dev;
c2ffa973	556	config.init_data = pdata->reg_init_data;
5928f538 LD	557	config.driver_data = max;
	558	config.of_node = client->dev.of_node;
	559	config.regmap = max->regmap;
	560
69eb0980 LD	561	if (gpio_is_valid(max->enable_gpio)) {
	562	ridata = pdata->reg_init_data;
	563	config.ena_gpio_flags = GPIOF_OUT_INIT_LOW;
	564	if (ridata && (ridata->constraints.always_on \|\|
	565	ridata->constraints.boot_on))
	566	config.ena_gpio_flags = GPIOF_OUT_INIT_HIGH;
	567	config.ena_gpio = max->enable_gpio;
	568	}
	569
5928f538	570	/* Register the regulators */
8d581fd0	571	rdev = devm_regulator_register(&client->dev, &max->desc, &config);
5928f538 LD	572	if (IS_ERR(rdev)) {
	573	ret = PTR_ERR(rdev);
	574	dev_err(max->dev, "regulator register failed, err %d\n", ret);
	575	return ret;
	576	}
	577
5928f538 LD	578	return 0;
	579	}
	580
5928f538 LD	581	static const struct i2c_device_id max8973_id[] = {
	582	{.name = "max8973",},
	583	{},
	584	};
	585
	586	MODULE_DEVICE_TABLE(i2c, max8973_id);
	587
	588	static struct i2c_driver max8973_i2c_driver = {
	589	.driver = {
	590	.name = "max8973",
	591	.owner = THIS_MODULE,
	592	},
	593	.probe = max8973_probe,
5928f538 LD	594	.id_table = max8973_id,
	595	};
	596
	597	static int __init max8973_init(void)
	598	{
	599	return i2c_add_driver(&max8973_i2c_driver);
	600	}
	601	subsys_initcall(max8973_init);
	602
	603	static void __exit max8973_cleanup(void)
	604	{
	605	i2c_del_driver(&max8973_i2c_driver);
	606	}
	607	module_exit(max8973_cleanup);
	608
	609	MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
	610	MODULE_DESCRIPTION("MAX8973 voltage regulator driver");
	611	MODULE_LICENSE("GPL v2");