[deliverable/linux.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

/* 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 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,
};

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;

	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;

	/* Set ramp delay */
	if (pdata->reg_init_data &&
			pdata->reg_init_data->constraints.ramp_delay) {
		if (pdata->reg_init_data->constraints.ramp_delay < 25000)
			control1 |= MAX8973_RAMP_12mV_PER_US;
		else if (pdata->reg_init_data->constraints.ramp_delay < 50000)
			control1 |= MAX8973_RAMP_25mV_PER_US;
		else if (pdata->reg_init_data->constraints.ramp_delay < 200000)
			control1 |= MAX8973_RAMP_50mV_PER_US;
		else
			control1 |= MAX8973_RAMP_200mV_PER_US;
	} else {
		control1 |= MAX8973_RAMP_12mV_PER_US;
		max->desc.ramp_delay = 12500;
	}

	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
	70
	71	/* MAX8973_CONTROL2 */
	72	#define MAX8973_WDTMR_ENABLE BIT(6)
	73	#define MAX8973_DISCH_ENBABLE BIT(5)
	74	#define MAX8973_FT_ENABLE BIT(4)
	75
	76	#define MAX8973_CKKADV_TRIP_DISABLE 0xC
	77	#define MAX8973_CKKADV_TRIP_75mV_PER_US 0x0
	78	#define MAX8973_CKKADV_TRIP_150mV_PER_US 0x4
	79	#define MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS 0x8
	80	#define MAX8973_CONTROL_CLKADV_TRIP_MASK 0x00030000
	81
	82	#define MAX8973_INDUCTOR_MIN_30_PER 0x0
	83	#define MAX8973_INDUCTOR_NOMINAL 0x1
	84	#define MAX8973_INDUCTOR_PLUS_30_PER 0x2
	85	#define MAX8973_INDUCTOR_PLUS_60_PER 0x3
	86	#define MAX8973_CONTROL_INDUCTOR_VALUE_MASK 0x00300000
	87
	88	#define MAX8973_MIN_VOLATGE 606250
	89	#define MAX8973_MAX_VOLATGE 1400000
	90	#define MAX8973_VOLATGE_STEP 6250
	91	#define MAX8973_BUCK_N_VOLTAGE 0x80
	92
	93	/* Maxim 8973 chip information */
	94	struct max8973_chip {
	95	struct device *dev;
	96	struct regulator_desc desc;
5928f538 LD	97	struct regmap *regmap;
5928f538 LD	98	bool enable_external_control;
69eb0980	99	int enable_gpio;
5928f538 LD	100	int dvs_gpio;
	101	int lru_index[MAX8973_MAX_VOUT_REG];
	102	int curr_vout_val[MAX8973_MAX_VOUT_REG];
	103	int curr_vout_reg;
	104	int curr_gpio_val;
db892ff6	105	struct regulator_ops ops;
5928f538 LD	106	};
	107
	108	/*
	109	* find_voltage_set_register: Find new voltage configuration register (VOUT).
	110	* The finding of the new VOUT register will be based on the LRU mechanism.
	111	* Each VOUT register will have different voltage configured . This
	112	* Function will look if any of the VOUT register have requested voltage set
	113	* or not.
	114	* - If it is already there then it will make that register as most
	115	* recently used and return as found so that caller need not to set
	116	* the VOUT register but need to set the proper gpios to select this
	117	* VOUT register.
	118	* - If requested voltage is not found then it will use the least
	119	* recently mechanism to get new VOUT register for new configuration
	120	* and will return not_found so that caller need to set new VOUT
	121	* register and then gpios (both).
	122	*/
	123	static bool find_voltage_set_register(struct max8973_chip *tps,
	124	int req_vsel, int vout_reg, int gpio_val)
	125	{
	126	int i;
	127	bool found = false;
	128	int new_vout_reg = tps->lru_index[MAX8973_MAX_VOUT_REG - 1];
	129	int found_index = MAX8973_MAX_VOUT_REG - 1;
	130
	131	for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) {
	132	if (tps->curr_vout_val[tps->lru_index[i]] == req_vsel) {
	133	new_vout_reg = tps->lru_index[i];
	134	found_index = i;
	135	found = true;
	136	goto update_lru_index;
	137	}
	138	}
	139
	140	update_lru_index:
	141	for (i = found_index; i > 0; i--)
	142	tps->lru_index[i] = tps->lru_index[i - 1];
	143
	144	tps->lru_index[0] = new_vout_reg;
	145	*gpio_val = new_vout_reg;
	146	*vout_reg = MAX8973_VOUT + new_vout_reg;
	147	return found;
	148	}
	149
	150	static int max8973_dcdc_get_voltage_sel(struct regulator_dev *rdev)
	151	{
	152	struct max8973_chip *max = rdev_get_drvdata(rdev);
	153	unsigned int data;
	154	int ret;
	155
	156	ret = regmap_read(max->regmap, max->curr_vout_reg, &data);
	157	if (ret < 0) {
	158	dev_err(max->dev, "register %d read failed, err = %d\n",
	159	max->curr_vout_reg, ret);
	160	return ret;
	161	}
	162	return data & MAX8973_VOUT_MASK;
	163	}
	164
	165	static int max8973_dcdc_set_voltage_sel(struct regulator_dev *rdev,
	166	unsigned vsel)
	167	{
	168	struct max8973_chip *max = rdev_get_drvdata(rdev);
	169	int ret;
170	bool found = false;
171	int vout_reg = max->curr_vout_reg;
172	int gpio_val = max->curr_gpio_val;
173
174	/*
175	* If gpios are available to select the VOUT register then least
176	* recently used register for new configuration.
177	*/
fa5f509f	178	if (gpio_is_valid(max->dvs_gpio))
5928f538 LD	179	found = find_voltage_set_register(max, vsel,
	180	&vout_reg, &gpio_val);
	181
	182	if (!found) {
	183	ret = regmap_update_bits(max->regmap, vout_reg,
	184	MAX8973_VOUT_MASK, vsel);
	185	if (ret < 0) {
	186	dev_err(max->dev, "register %d update failed, err %d\n",
	187	vout_reg, ret);
	188	return ret;
	189	}
	190	max->curr_vout_reg = vout_reg;
	191	max->curr_vout_val[gpio_val] = vsel;
	192	}
	193
	194	/* Select proper VOUT register vio gpios */
fa5f509f	195	if (gpio_is_valid(max->dvs_gpio)) {
5928f538 LD	196	gpio_set_value_cansleep(max->dvs_gpio, gpio_val & 0x1);
	197	max->curr_gpio_val = gpio_val;
	198	}
	199	return 0;
	200	}
	201
	202	static int max8973_dcdc_set_mode(struct regulator_dev *rdev, unsigned int mode)
	203	{
	204	struct max8973_chip *max = rdev_get_drvdata(rdev);
	205	int ret;
	206	int pwm;
	207
	208	/* Enable force PWM mode in FAST mode only. */
	209	switch (mode) {
	210	case REGULATOR_MODE_FAST:
	211	pwm = MAX8973_FPWM_EN_M;
	212	break;
	213
	214	case REGULATOR_MODE_NORMAL:
	215	pwm = 0;
	216	break;
	217
	218	default:
	219	return -EINVAL;
	220	}
	221
	222	ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
	223	MAX8973_FPWM_EN_M, pwm);
	224	if (ret < 0)
	225	dev_err(max->dev, "register %d update failed, err %d\n",
	226	MAX8973_CONTROL1, ret);
	227	return ret;
	228	}
	229
	230	static unsigned int max8973_dcdc_get_mode(struct regulator_dev *rdev)
	231	{
	232	struct max8973_chip *max = rdev_get_drvdata(rdev);
	233	unsigned int data;
	234	int ret;
	235
	236	ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
	237	if (ret < 0) {
	238	dev_err(max->dev, "register %d read failed, err %d\n",
	239	MAX8973_CONTROL1, ret);
	240	return ret;
	241	}
	242	return (data & MAX8973_FPWM_EN_M) ?
	243	REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
	244	}
	245
db892ff6	246	static const struct regulator_ops max8973_dcdc_ops = {
5928f538 LD	247	.get_voltage_sel = max8973_dcdc_get_voltage_sel,
	248	.set_voltage_sel = max8973_dcdc_set_voltage_sel,
	249	.list_voltage = regulator_list_voltage_linear,
	250	.set_mode = max8973_dcdc_set_mode,
	251	.get_mode = max8973_dcdc_get_mode,
	252	};
	253
3d68dfe3 GKH	254	static int max8973_init_dcdc(struct max8973_chip *max,
3d68dfe3 GKH	255	struct max8973_regulator_platform_data *pdata)
5928f538 LD	256	{
	257	int ret;
	258	uint8_t control1 = 0;
	259	uint8_t control2 = 0;
	260
	261	if (pdata->control_flags & MAX8973_CONTROL_REMOTE_SENSE_ENABLE)
	262	control1 \|= MAX8973_SNS_ENABLE;
	263
	264	if (!(pdata->control_flags & MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE))
	265	control1 \|= MAX8973_NFSR_ENABLE;
	266
	267	if (pdata->control_flags & MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE)
	268	control1 \|= MAX8973_AD_ENABLE;
	269
dcd9ec6a	270	if (pdata->control_flags & MAX8973_CONTROL_BIAS_ENABLE) {
5928f538	271	control1 \|= MAX8973_BIAS_ENABLE;
dcd9ec6a LD	272	max->desc.enable_time = 20;
	273	} else {
	274	max->desc.enable_time = 240;
	275	}
5928f538 LD	276
	277	if (pdata->control_flags & MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE)
	278	control1 \|= MAX8973_FREQSHIFT_9PER;
	279
	280	/* Set ramp delay */
	281	if (pdata->reg_init_data &&
	282	pdata->reg_init_data->constraints.ramp_delay) {
	283	if (pdata->reg_init_data->constraints.ramp_delay < 25000)
b27032ca	284	control1 \|= MAX8973_RAMP_12mV_PER_US;
5928f538	285	else if (pdata->reg_init_data->constraints.ramp_delay < 50000)
b27032ca	286	control1 \|= MAX8973_RAMP_25mV_PER_US;
5928f538	287	else if (pdata->reg_init_data->constraints.ramp_delay < 200000)
b27032ca	288	control1 \|= MAX8973_RAMP_50mV_PER_US;
5928f538	289	else
b27032ca	290	control1 \|= MAX8973_RAMP_200mV_PER_US;
5928f538	291	} else {
b27032ca	292	control1 \|= MAX8973_RAMP_12mV_PER_US;
5928f538 LD	293	max->desc.ramp_delay = 12500;
	294	}
	295
	296	if (!(pdata->control_flags & MAX8973_CONTROL_PULL_DOWN_ENABLE))
	297	control2 \|= MAX8973_DISCH_ENBABLE;
	298
	299	/* Clock advance trip configuration */
	300	switch (pdata->control_flags & MAX8973_CONTROL_CLKADV_TRIP_MASK) {
	301	case MAX8973_CONTROL_CLKADV_TRIP_DISABLED:
	302	control2 \|= MAX8973_CKKADV_TRIP_DISABLE;
	303	break;
	304
	305	case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US:
	306	control2 \|= MAX8973_CKKADV_TRIP_75mV_PER_US;
	307	break;
	308
	309	case MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US:
	310	control2 \|= MAX8973_CKKADV_TRIP_150mV_PER_US;
	311	break;
	312
	313	case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US_HIST_DIS:
	314	control2 \|= MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS;
	315	break;
	316	}
	317
	318	/* Configure inductor value */
	319	switch (pdata->control_flags & MAX8973_CONTROL_INDUCTOR_VALUE_MASK) {
	320	case MAX8973_CONTROL_INDUCTOR_VALUE_NOMINAL:
	321	control2 \|= MAX8973_INDUCTOR_NOMINAL;
	322	break;
	323
	324	case MAX8973_CONTROL_INDUCTOR_VALUE_MINUS_30_PER:
	325	control2 \|= MAX8973_INDUCTOR_MIN_30_PER;
	326	break;
	327
	328	case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_30_PER:
	329	control2 \|= MAX8973_INDUCTOR_PLUS_30_PER;
	330	break;
	331
	332	case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_60_PER:
	333	control2 \|= MAX8973_INDUCTOR_PLUS_60_PER;
	334	break;
	335	}
	336
	337	ret = regmap_write(max->regmap, MAX8973_CONTROL1, control1);
	338	if (ret < 0) {
	339	dev_err(max->dev, "register %d write failed, err = %d",
	340	MAX8973_CONTROL1, ret);
	341	return ret;
	342	}
	343
	344	ret = regmap_write(max->regmap, MAX8973_CONTROL2, control2);
	345	if (ret < 0) {
	346	dev_err(max->dev, "register %d write failed, err = %d",
	347	MAX8973_CONTROL2, ret);
	348	return ret;
	349	}
	350
	351	/* If external control is enabled then disable EN bit */
	352	if (max->enable_external_control) {
	353	ret = regmap_update_bits(max->regmap, MAX8973_VOUT,
	354	MAX8973_VOUT_ENABLE, 0);
	355	if (ret < 0)
	356	dev_err(max->dev, "register %d update failed, err = %d",
357	MAX8973_VOUT, ret);
358	}
359	return ret;
360	}
361
362	static const struct regmap_config max8973_regmap_config = {
363	.reg_bits = 8,
364	.val_bits = 8,
365	.max_register = MAX8973_CHIPID2,
366	.cache_type = REGCACHE_RBTREE,
367	};
368
c2ffa973 LD	369	static struct max8973_regulator_platform_data *max8973_parse_dt(
	370	struct device *dev)
	371	{
	372	struct max8973_regulator_platform_data *pdata;
	373	struct device_node *np = dev->of_node;
	374	int ret;
	375	u32 pval;
	376
	377	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
	378	if (!pdata)
	379	return NULL;
	380
	381	pdata->enable_ext_control = of_property_read_bool(np,
	382	"maxim,externally-enable");
69eb0980	383	pdata->enable_gpio = of_get_named_gpio(np, "maxim,enable-gpio", 0);
c2ffa973 LD	384	pdata->dvs_gpio = of_get_named_gpio(np, "maxim,dvs-gpio", 0);
	385
	386	ret = of_property_read_u32(np, "maxim,dvs-default-state", &pval);
	387	if (!ret)
	388	pdata->dvs_def_state = pval;
	389
	390	if (of_property_read_bool(np, "maxim,enable-remote-sense"))
	391	pdata->control_flags \|= MAX8973_CONTROL_REMOTE_SENSE_ENABLE;
	392
	393	if (of_property_read_bool(np, "maxim,enable-falling-slew-rate"))
	394	pdata->control_flags \|=
	395	MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE;
	396
	397	if (of_property_read_bool(np, "maxim,enable-active-discharge"))
	398	pdata->control_flags \|=
	399	MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE;
	400
	401	if (of_property_read_bool(np, "maxim,enable-frequency-shift"))
	402	pdata->control_flags \|= MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE;
	403
	404	if (of_property_read_bool(np, "maxim,enable-bias-control"))
	405	pdata->control_flags \|= MAX8973_BIAS_ENABLE;
	406
	407	return pdata;
	408	}
	409
3d68dfe3 GKH	410	static int max8973_probe(struct i2c_client *client,
3d68dfe3 GKH	411	const struct i2c_device_id *id)
5928f538 LD	412	{
5928f538 LD	413	struct max8973_regulator_platform_data *pdata;
69eb0980	414	struct regulator_init_data *ridata;
5928f538 LD	415	struct regulator_config config = { };
	416	struct regulator_dev *rdev;
	417	struct max8973_chip *max;
c2ffa973	418	bool pdata_from_dt = false;
5928f538 LD	419	int ret;
5928f538 LD	420
dff91d0b	421	pdata = dev_get_platdata(&client->dev);
42dc3023	422
c2ffa973 LD	423	if (!pdata && client->dev.of_node) {
	424	pdata = max8973_parse_dt(&client->dev);
	425	pdata_from_dt = true;
	426	}
	427
	428	if (!pdata) {
5928f538 LD	429	dev_err(&client->dev, "No Platform data");
	430	return -EIO;
	431	}
	432
69eb0980 LD	433	if ((pdata->dvs_gpio == -EPROBE_DEFER) \|\|
69eb0980 LD	434	(pdata->enable_gpio == -EPROBE_DEFER))
c2ffa973 LD	435	return -EPROBE_DEFER;
c2ffa973 LD	436
5928f538	437	max = devm_kzalloc(&client->dev, sizeof(*max), GFP_KERNEL);
21024dee	438	if (!max)
5928f538	439	return -ENOMEM;
5928f538 LD	440
	441	max->regmap = devm_regmap_init_i2c(client, &max8973_regmap_config);
	442	if (IS_ERR(max->regmap)) {
	443	ret = PTR_ERR(max->regmap);
	444	dev_err(&client->dev, "regmap init failed, err %d\n", ret);
	445	return ret;
	446	}
	447
	448	i2c_set_clientdata(client, max);
db892ff6	449	max->ops = max8973_dcdc_ops;
5928f538 LD	450	max->dev = &client->dev;
	451	max->desc.name = id->name;
	452	max->desc.id = 0;
db892ff6	453	max->desc.ops = &max->ops;
5928f538 LD	454	max->desc.type = REGULATOR_VOLTAGE;
	455	max->desc.owner = THIS_MODULE;
	456	max->desc.min_uV = MAX8973_MIN_VOLATGE;
	457	max->desc.uV_step = MAX8973_VOLATGE_STEP;
	458	max->desc.n_voltages = MAX8973_BUCK_N_VOLTAGE;
	459
69eb0980 LD	460	max->dvs_gpio = (pdata->dvs_gpio) ? pdata->dvs_gpio : -EINVAL;
	461	max->enable_gpio = (pdata->enable_gpio) ? pdata->enable_gpio : -EINVAL;
	462	max->enable_external_control = pdata->enable_ext_control;
	463	max->curr_gpio_val = pdata->dvs_def_state;
	464	max->curr_vout_reg = MAX8973_VOUT + pdata->dvs_def_state;
	465
	466	if (gpio_is_valid(max->enable_gpio))
	467	max->enable_external_control = true;
	468
c2ffa973	469	if (!pdata->enable_ext_control) {
5928f538 LD	470	max->desc.enable_reg = MAX8973_VOUT;
5928f538 LD	471	max->desc.enable_mask = MAX8973_VOUT_ENABLE;
db892ff6 GL	472	max->ops.enable = regulator_enable_regmap;
	473	max->ops.disable = regulator_disable_regmap;
	474	max->ops.is_enabled = regulator_is_enabled_regmap;
5928f538 LD	475	}
5928f538 LD	476
5928f538	477	max->lru_index[0] = max->curr_vout_reg;
5928f538 LD	478
	479	if (gpio_is_valid(max->dvs_gpio)) {
	480	int gpio_flags;
	481	int i;
	482
	483	gpio_flags = (pdata->dvs_def_state) ?
	484	GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
	485	ret = devm_gpio_request_one(&client->dev, max->dvs_gpio,
	486	gpio_flags, "max8973-dvs");
	487	if (ret) {
	488	dev_err(&client->dev,
	489	"gpio_request for gpio %d failed, err = %d\n",
	490	max->dvs_gpio, ret);
	491	return ret;
	492	}
5928f538 LD	493
	494	/*
	495	* Initialize the lru index with vout_reg id
	496	* The index 0 will be most recently used and
	497	* set with the max->curr_vout_reg */
	498	for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i)
	499	max->lru_index[i] = i;
	500	max->lru_index[0] = max->curr_vout_reg;
	501	max->lru_index[max->curr_vout_reg] = 0;
	502	}
	503
c2ffa973 LD	504	if (pdata_from_dt)
	505	pdata->reg_init_data = of_get_regulator_init_data(&client->dev,
	506	client->dev.of_node, &max->desc);
	507
	508	ret = max8973_init_dcdc(max, pdata);
	509	if (ret < 0) {
	510	dev_err(max->dev, "Max8973 Init failed, err = %d\n", ret);
	511	return ret;
5928f538 LD	512	}
	513
	514	config.dev = &client->dev;
c2ffa973	515	config.init_data = pdata->reg_init_data;
5928f538 LD	516	config.driver_data = max;
	517	config.of_node = client->dev.of_node;
	518	config.regmap = max->regmap;
	519
69eb0980 LD	520	if (gpio_is_valid(max->enable_gpio)) {
	521	ridata = pdata->reg_init_data;
	522	config.ena_gpio_flags = GPIOF_OUT_INIT_LOW;
	523	if (ridata && (ridata->constraints.always_on \|\|
	524	ridata->constraints.boot_on))
	525	config.ena_gpio_flags = GPIOF_OUT_INIT_HIGH;
	526	config.ena_gpio = max->enable_gpio;
	527	}
	528
5928f538	529	/* Register the regulators */
8d581fd0	530	rdev = devm_regulator_register(&client->dev, &max->desc, &config);
5928f538 LD	531	if (IS_ERR(rdev)) {
	532	ret = PTR_ERR(rdev);
	533	dev_err(max->dev, "regulator register failed, err %d\n", ret);
	534	return ret;
	535	}
	536
5928f538 LD	537	return 0;
	538	}
	539
5928f538 LD	540	static const struct i2c_device_id max8973_id[] = {
	541	{.name = "max8973",},
	542	{},
	543	};
	544
	545	MODULE_DEVICE_TABLE(i2c, max8973_id);
	546
	547	static struct i2c_driver max8973_i2c_driver = {
	548	.driver = {
	549	.name = "max8973",
	550	.owner = THIS_MODULE,
	551	},
	552	.probe = max8973_probe,
5928f538 LD	553	.id_table = max8973_id,
	554	};
	555
	556	static int __init max8973_init(void)
	557	{
	558	return i2c_add_driver(&max8973_i2c_driver);
	559	}
	560	subsys_initcall(max8973_init);
	561
	562	static void __exit max8973_cleanup(void)
	563	{
	564	i2c_del_driver(&max8973_i2c_driver);
	565	}
	566	module_exit(max8973_cleanup);
	567
	568	MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
	569	MODULE_DESCRIPTION("MAX8973 voltage regulator driver");
	570	MODULE_LICENSE("GPL v2");