regulator: MAX8997/8966 support

This patch supports PMIC/Regulator part of MAX8997/MAX8966 MFD.
In this initial release, selecting voltages or current-limit
and switching on/off the regulators are supported.

Controlling voltages for DVS with GPIOs is not implemented fully
and requires more considerations: it controls multiple bucks (selection
of 1, 2, and 5) at the same time with SET1~3 gpios. Thus, when DVS-GPIO
is activated, we lose the ability to control the voltage of a single
buck regulator independently; i.e., contolling a buck affects other two
bucks. Therefore, using the conventional regulator framework directly
might be problematic. However, in this driver, we try to choose
a setting without such side effect of affecting other regulators and
then try to choose a setting with the minimum side effect (the sum of
voltage changes in other regulators).

On the other hand, controlling all the three bucks simultenously based
on the voltage set table may help build cpufreq and similar system
more robust; i.e., all the three voltages are consistent every time
without glitches during transition.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

3 files changed, 1223 insertions, 0 deletions

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index e1d943619ab8..395d35941b84 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -108,6 +108,15 @@ config REGULATOR_MAX8952
 	  via I2C bus. Maxim 8952 has one voltage output and supports 4 DVS
 	  modes ranging from 0.77V to 1.40V by 0.01V steps.
 
+config REGULATOR_MAX8997
+	tristate "Maxim 8997/8966 regulator"
+	depends on MFD_MAX8997
+	help
+	  This driver controls a Maxim 8997/8966 regulator
+	  via I2C bus. The provided regulator is suitable for S5PC110,
+	  S5PV210, and Exynos-4 chips to control VCC_CORE and
+	  VCC_USIM voltages.
+
 config REGULATOR_MAX8998
 	tristate "Maxim 8998 voltage regulator"
 	depends on MFD_MAX8998
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 0b5e88c2b8d7..e43b8524871e 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_REGULATOR_MAX8649)	+= max8649.o
 obj-$(CONFIG_REGULATOR_MAX8660) += max8660.o
 obj-$(CONFIG_REGULATOR_MAX8925) += max8925-regulator.o
 obj-$(CONFIG_REGULATOR_MAX8952) += max8952.o
+obj-$(CONFIG_REGULATOR_MAX8997) += max8997.o
 obj-$(CONFIG_REGULATOR_MAX8998) += max8998.o
 obj-$(CONFIG_REGULATOR_WM831X) += wm831x-dcdc.o
 obj-$(CONFIG_REGULATOR_WM831X) += wm831x-isink.o
diff --git a/drivers/regulator/max8997.c b/drivers/regulator/max8997.c
new file mode 100644
index 000000000000..01ef7e9903bb
--- /dev/null
+++ b/drivers/regulator/max8997.c
@@ -0,0 +1,1213 @@
+/*
+ * max8997.c - Regulator driver for the Maxim 8997/8966
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ * MyungJoo Ham <myungjoo.ham@smasung.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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * This driver is based on max8998.c
+ */
+
+#include <linux/bug.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/mfd/max8997.h>
+#include <linux/mfd/max8997-private.h>
+
+struct max8997_data {
+	struct device *dev;
+	struct max8997_dev *iodev;
+	int num_regulators;
+	struct regulator_dev **rdev;
+	int ramp_delay; /* in mV/us */
+
+	u8 buck1_vol[8];
+	u8 buck2_vol[8];
+	u8 buck5_vol[8];
+	int buck125_gpioindex;
+
+	u8 saved_states[MAX8997_REG_MAX];
+};
+
+static inline void max8997_set_gpio(struct max8997_data *max8997)
+{
+	struct max8997_platform_data *pdata =
+		dev_get_platdata(max8997->iodev->dev);
+	int set3 = (max8997->buck125_gpioindex) & 0x1;
+	int set2 = ((max8997->buck125_gpioindex) >> 1) & 0x1;
+	int set1 = ((max8997->buck125_gpioindex) >> 2) & 0x1;
+
+	gpio_set_value(pdata->buck125_gpios[0], set1);
+	gpio_set_value(pdata->buck125_gpios[1], set2);
+	gpio_set_value(pdata->buck125_gpios[2], set3);
+}
+
+struct voltage_map_desc {
+	int min;
+	int max;
+	int step;
+	unsigned int n_bits;
+};
+
+/* Voltage maps in mV */
+static const struct voltage_map_desc ldo_voltage_map_desc = {
+	.min = 800,	.max = 3950,	.step = 50,	.n_bits = 6,
+}; /* LDO1 ~ 18, 21 all */
+
+static const struct voltage_map_desc buck1245_voltage_map_desc = {
+	.min = 650,	.max = 2225,	.step = 25,	.n_bits = 6,
+}; /* Buck1, 2, 4, 5 */
+
+static const struct voltage_map_desc buck37_voltage_map_desc = {
+	.min = 750,	.max = 3900,	.step = 50,	.n_bits = 6,
+}; /* Buck3, 7 */
+
+/* current map in mA */
+static const struct voltage_map_desc charger_current_map_desc = {
+	.min = 200,	.max = 950,	.step = 50,	.n_bits = 4,
+};
+
+static const struct voltage_map_desc topoff_current_map_desc = {
+	.min = 50,	.max = 200,	.step = 10,	.n_bits = 4,
+};
+
+static const struct voltage_map_desc *reg_voltage_map[] = {
+	[MAX8997_LDO1] = &ldo_voltage_map_desc,
+	[MAX8997_LDO2] = &ldo_voltage_map_desc,
+	[MAX8997_LDO3] = &ldo_voltage_map_desc,
+	[MAX8997_LDO4] = &ldo_voltage_map_desc,
+	[MAX8997_LDO5] = &ldo_voltage_map_desc,
+	[MAX8997_LDO6] = &ldo_voltage_map_desc,
+	[MAX8997_LDO7] = &ldo_voltage_map_desc,
+	[MAX8997_LDO8] = &ldo_voltage_map_desc,
+	[MAX8997_LDO9] = &ldo_voltage_map_desc,
+	[MAX8997_LDO10] = &ldo_voltage_map_desc,
+	[MAX8997_LDO11] = &ldo_voltage_map_desc,
+	[MAX8997_LDO12] = &ldo_voltage_map_desc,
+	[MAX8997_LDO13] = &ldo_voltage_map_desc,
+	[MAX8997_LDO14] = &ldo_voltage_map_desc,
+	[MAX8997_LDO15] = &ldo_voltage_map_desc,
+	[MAX8997_LDO16] = &ldo_voltage_map_desc,
+	[MAX8997_LDO17] = &ldo_voltage_map_desc,
+	[MAX8997_LDO18] = &ldo_voltage_map_desc,
+	[MAX8997_LDO21] = &ldo_voltage_map_desc,
+	[MAX8997_BUCK1] = &buck1245_voltage_map_desc,
+	[MAX8997_BUCK2] = &buck1245_voltage_map_desc,
+	[MAX8997_BUCK3] = &buck37_voltage_map_desc,
+	[MAX8997_BUCK4] = &buck1245_voltage_map_desc,
+	[MAX8997_BUCK5] = &buck1245_voltage_map_desc,
+	[MAX8997_BUCK6] = NULL,
+	[MAX8997_BUCK7] = &buck37_voltage_map_desc,
+	[MAX8997_EN32KHZ_AP] = NULL,
+	[MAX8997_EN32KHZ_CP] = NULL,
+	[MAX8997_ENVICHG] = NULL,
+	[MAX8997_ESAFEOUT1] = NULL,
+	[MAX8997_ESAFEOUT2] = NULL,
+	[MAX8997_CHARGER_CV] = NULL,
+	[MAX8997_CHARGER] = &charger_current_map_desc,
+	[MAX8997_CHARGER_TOPOFF] = &topoff_current_map_desc,
+};
+
+static inline int max8997_get_rid(struct regulator_dev *rdev)
+{
+	return rdev_get_id(rdev);
+}
+
+static int max8997_list_voltage_safeout(struct regulator_dev *rdev,
+		unsigned int selector)
+{
+	int rid = max8997_get_rid(rdev);
+
+	if (rid == MAX8997_ESAFEOUT1 || rid == MAX8997_ESAFEOUT2) {
+		switch (selector) {
+		case 0:
+			return 4850000;
+		case 1:
+			return 4900000;
+		case 2:
+			return 4950000;
+		case 3:
+			return 3300000;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static int max8997_list_voltage_charger_cv(struct regulator_dev *rdev,
+		unsigned int selector)
+{
+	int rid = max8997_get_rid(rdev);
+
+	if (rid != MAX8997_CHARGER_CV)
+		goto err;
+
+	switch (selector) {
+	case 0x00:
+		return 4200000;
+	case 0x01 ... 0x0E:
+		return 4000000 + 20000 * (selector - 0x01);
+	case 0x0F:
+		return 4350000;
+	default:
+		return -EINVAL;
+	}
+err:
+	return -EINVAL;
+}
+
+static int max8997_list_voltage(struct regulator_dev *rdev,
+		unsigned int selector)
+{
+	const struct voltage_map_desc *desc;
+	int rid = max8997_get_rid(rdev);
+	int val;
+
+	if (rid >= ARRAY_SIZE(reg_voltage_map) ||
+			rid < 0)
+		return -EINVAL;
+
+	desc = reg_voltage_map[rid];
+	if (desc == NULL)
+		return -EINVAL;
+
+	val = desc->min + desc->step * selector;
+	if (val > desc->max)
+		return -EINVAL;
+
+	return val * 1000;
+}
+
+static int max8997_get_enable_register(struct regulator_dev *rdev,
+		int *reg, int *mask, int *pattern)
+{
+	int rid = max8997_get_rid(rdev);
+
+	switch (rid) {
+	case MAX8997_LDO1 ... MAX8997_LDO21:
+		*reg = MAX8997_REG_LDO1CTRL + (rid - MAX8997_LDO1);
+		*mask = 0xC0;
+		*pattern = 0xC0;
+		break;
+	case MAX8997_BUCK1:
+		*reg = MAX8997_REG_BUCK1CTRL;
+		*mask = 0x01;
+		*pattern = 0x01;
+		break;
+	case MAX8997_BUCK2:
+		*reg = MAX8997_REG_BUCK2CTRL;
+		*mask = 0x01;
+		*pattern = 0x01;
+		break;
+	case MAX8997_BUCK3:
+		*reg = MAX8997_REG_BUCK3CTRL;
+		*mask = 0x01;
+		*pattern = 0x01;
+		break;
+	case MAX8997_BUCK4:
+		*reg = MAX8997_REG_BUCK4CTRL;
+		*mask = 0x01;
+		*pattern = 0x01;
+		break;
+	case MAX8997_BUCK5:
+		*reg = MAX8997_REG_BUCK5CTRL;
+		*mask = 0x01;
+		*pattern = 0x01;
+		break;
+	case MAX8997_BUCK6:
+		*reg = MAX8997_REG_BUCK6CTRL;
+		*mask = 0x01;
+		*pattern = 0x01;
+		break;
+	case MAX8997_BUCK7:
+		*reg = MAX8997_REG_BUCK7CTRL;
+		*mask = 0x01;
+		*pattern = 0x01;
+		break;
+	case MAX8997_EN32KHZ_AP ... MAX8997_EN32KHZ_CP:
+		*reg = MAX8997_REG_MAINCON1;
+		*mask = 0x01 << (rid - MAX8997_EN32KHZ_AP);
+		*pattern = 0x01 << (rid - MAX8997_EN32KHZ_AP);
+		break;
+	case MAX8997_ENVICHG:
+		*reg = MAX8997_REG_MBCCTRL1;
+		*mask = 0x80;
+		*pattern = 0x80;
+		break;
+	case MAX8997_ESAFEOUT1 ... MAX8997_ESAFEOUT2:
+		*reg = MAX8997_REG_SAFEOUTCTRL;
+		*mask = 0x40 << (rid - MAX8997_ESAFEOUT1);
+		*pattern = 0x40 << (rid - MAX8997_ESAFEOUT1);
+		break;
+	case MAX8997_CHARGER:
+		*reg = MAX8997_REG_MBCCTRL2;
+		*mask = 0x40;
+		*pattern = 0x40;
+		break;
+	default:
+		/* Not controllable or not exists */
+		return -EINVAL;
+		break;
+	}
+
+	return 0;
+}
+
+static int max8997_reg_is_enabled(struct regulator_dev *rdev)
+{
+	struct max8997_data *max8997 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8997->iodev->i2c;
+	int ret, reg, mask, pattern;
+	u8 val;
+
+	ret = max8997_get_enable_register(rdev, &reg, &mask, &pattern);
+	if (ret == -EINVAL)
+		return 1; /* "not controllable" */
+	else if (ret)
+		return ret;
+
+	ret = max8997_read_reg(i2c, reg, &val);
+	if (ret)
+		return ret;
+
+	return (val & mask) == pattern;
+}
+
+static int max8997_reg_enable(struct regulator_dev *rdev)
+{
+	struct max8997_data *max8997 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8997->iodev->i2c;
+	int ret, reg, mask, pattern;
+
+	ret = max8997_get_enable_register(rdev, &reg, &mask, &pattern);
+	if (ret)
+		return ret;
+
+	return max8997_update_reg(i2c, reg, pattern, mask);
+}
+
+static int max8997_reg_disable(struct regulator_dev *rdev)
+{
+	struct max8997_data *max8997 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8997->iodev->i2c;
+	int ret, reg, mask, pattern;
+
+	ret = max8997_get_enable_register(rdev, &reg, &mask, &pattern);
+	if (ret)
+		return ret;
+
+	return max8997_update_reg(i2c, reg, ~pattern, mask);
+}
+
+static int max8997_get_voltage_register(struct regulator_dev *rdev,
+		int *_reg, int *_shift, int *_mask)
+{
+	int rid = max8997_get_rid(rdev);
+	int reg, shift = 0, mask = 0x3f;
+
+	switch (rid) {
+	case MAX8997_LDO1 ... MAX8997_LDO21:
+		reg = MAX8997_REG_LDO1CTRL + (rid - MAX8997_LDO1);
+		break;
+	case MAX8997_BUCK1:
+		reg = MAX8997_REG_BUCK1DVS1;
+		break;
+	case MAX8997_BUCK2:
+		reg = MAX8997_REG_BUCK2DVS1;
+		break;
+	case MAX8997_BUCK3:
+		reg = MAX8997_REG_BUCK3DVS;
+		break;
+	case MAX8997_BUCK4:
+		reg = MAX8997_REG_BUCK4DVS;
+		break;
+	case MAX8997_BUCK5:
+		reg = MAX8997_REG_BUCK5DVS1;
+		break;
+	case MAX8997_BUCK7:
+		reg = MAX8997_REG_BUCK7DVS;
+		break;
+	case MAX8997_ESAFEOUT1 ...  MAX8997_ESAFEOUT2:
+		reg = MAX8997_REG_SAFEOUTCTRL;
+		shift = (rid == MAX8997_ESAFEOUT2) ? 2 : 0;
+		mask = 0x3;
+		break;
+	case MAX8997_CHARGER_CV:
+		reg = MAX8997_REG_MBCCTRL3;
+		shift = 0;
+		mask = 0xf;
+		break;
+	case MAX8997_CHARGER:
+		reg = MAX8997_REG_MBCCTRL4;
+		shift = 0;
+		mask = 0xf;
+		break;
+	case MAX8997_CHARGER_TOPOFF:
+		reg = MAX8997_REG_MBCCTRL5;
+		shift = 0;
+		mask = 0xf;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	*_reg = reg;
+	*_shift = shift;
+	*_mask = mask;
+
+	return 0;
+}
+
+static int max8997_get_voltage(struct regulator_dev *rdev)
+{
+	struct max8997_data *max8997 = rdev_get_drvdata(rdev);
+	struct max8997_platform_data *pdata =
+		dev_get_platdata(max8997->iodev->dev);
+	struct i2c_client *i2c = max8997->iodev->i2c;
+	int reg, shift, mask, ret;
+	int rid = max8997_get_rid(rdev);
+	u8 val;
+
+	ret = max8997_get_voltage_register(rdev, &reg, &shift, &mask);
+	if (ret)
+		return ret;
+
+	if ((rid == MAX8997_BUCK1 && pdata->buck1_gpiodvs) ||
+			(rid == MAX8997_BUCK2 && pdata->buck2_gpiodvs) ||
+			(rid == MAX8997_BUCK5 && pdata->buck5_gpiodvs))
+		reg += max8997->buck125_gpioindex;
+
+	ret = max8997_read_reg(i2c, reg, &val);
+	if (ret)
+		return ret;
+
+	val >>= shift;
+	val &= mask;
+
+	if (rdev->desc && rdev->desc->ops && rdev->desc->ops->list_voltage)
+		return rdev->desc->ops->list_voltage(rdev, val);
+
+	/*
+	 * max8997_list_voltage returns value for any rdev with voltage_map,
+	 * which works for "CHARGER" and "CHARGER TOPOFF" that do not have
+	 * list_voltage ops (they are current regulators).
+	 */
+	return max8997_list_voltage(rdev, val);
+}
+
+static inline int max8997_get_voltage_proper_val(
+		const struct voltage_map_desc *desc,
+		int min_vol, int max_vol)
+{
+	int i = 0;
+
+	if (desc == NULL)
+		return -EINVAL;
+
+	if (max_vol < desc->min || min_vol > desc->max)
+		return -EINVAL;
+
+	while (desc->min + desc->step * i < min_vol &&
+			desc->min + desc->step * i < desc->max)
+		i++;
+
+	if (desc->min + desc->step * i > max_vol)
+		return -EINVAL;
+
+	if (i >= (1 << desc->n_bits))
+		return -EINVAL;
+
+	return i;
+}
+
+static int max8997_set_voltage_charger_cv(struct regulator_dev *rdev,
+		int min_uV, int max_uV, unsigned *selector)
+{
+	struct max8997_data *max8997 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8997->iodev->i2c;
+	int rid = max8997_get_rid(rdev);
+	int lb, ub;
+	int reg, shift = 0, mask, ret = 0;
+	u8 val = 0x0;
+
+	if (rid != MAX8997_CHARGER_CV)
+		return -EINVAL;
+
+	ret = max8997_get_voltage_register(rdev, &reg, &shift, &mask);
+	if (ret)
+		return ret;
+
+	if (max_uV < 4000000 || min_uV > 4350000)
+		return -EINVAL;
+
+	if (min_uV <= 4000000) {
+		if (max_uV >= 4000000)
+			return -EINVAL;
+		else
+			val = 0x1;
+	} else if (min_uV <= 4200000 && max_uV >= 4200000)
+		val = 0x0;
+	else {
+		lb = (min_uV - 4000001) / 20000 + 2;
+		ub = (max_uV - 4000000) / 20000 + 1;
+
+		if (lb > ub)
+			return -EINVAL;
+
+		if (lb < 0xf)
+			val = lb;
+		else {
+			if (ub >= 0xf)
+				val = 0xf;
+			else
+				return -EINVAL;
+		}
+	}
+
+	*selector = val;
+
+	ret = max8997_update_reg(i2c, reg, val << shift, mask);
+
+	return ret;
+}
+
+/*
+ * For LDO1 ~ LDO21, BUCK1~5, BUCK7, CHARGER, CHARGER_TOPOFF
+ * BUCK1, 2, and 5 are available if they are not controlled by gpio
+ */
+static int max8997_set_voltage_ldobuck(struct regulator_dev *rdev,
+		int min_uV, int max_uV, unsigned *selector)
+{
+	struct max8997_data *max8997 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8997->iodev->i2c;
+	int min_vol = min_uV / 1000, max_vol = max_uV / 1000;
+	const struct voltage_map_desc *desc;
+	int rid = max8997_get_rid(rdev);
+	int reg, shift = 0, mask, ret;
+	int i;
+	u8 org;
+
+	switch (rid) {
+	case MAX8997_LDO1 ... MAX8997_LDO21:
+		break;
+	case MAX8997_BUCK1 ... MAX8997_BUCK5:
+		break;
+	case MAX8997_BUCK6:
+		return -EINVAL;
+	case MAX8997_BUCK7:
+		break;
+	case MAX8997_CHARGER:
+		break;
+	case MAX8997_CHARGER_TOPOFF:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	desc = reg_voltage_map[rid];
+
+	i = max8997_get_voltage_proper_val(desc, min_vol, max_vol);
+	if (i < 0)
+		return i;
+
+	ret = max8997_get_voltage_register(rdev, &reg, &shift, &mask);
+	if (ret)
+		return ret;
+
+	max8997_read_reg(i2c, reg, &org);
+	org = (org & mask) >> shift;
+
+	ret = max8997_update_reg(i2c, reg, i << shift, mask << shift);
+	*selector = i;
+
+	if (rid == MAX8997_BUCK1 || rid == MAX8997_BUCK2 ||
+			rid == MAX8997_BUCK4 || rid == MAX8997_BUCK5) {
+		/* If the voltage is increasing */
+		if (org < i)
+			udelay(desc->step * (i - org) / max8997->ramp_delay);
+	}
+
+	return ret;
+}
+
+/*
+ * Assess the damage on the voltage setting of BUCK1,2,5 by the change.
+ *
+ * When GPIO-DVS mode is used for multiple bucks, changing the voltage value
+ * of one of the bucks may affect that of another buck, which is the side
+ * effect of the change (set_voltage). This function examines the GPIO-DVS
+ * configurations and checks whether such side-effect exists.
+ */
+static int max8997_assess_side_effect(struct regulator_dev *rdev,
+		u8 new_val, int *best)
+{
+	struct max8997_data *max8997 = rdev_get_drvdata(rdev);
+	struct max8997_platform_data *pdata =
+		dev_get_platdata(max8997->iodev->dev);
+	int rid = max8997_get_rid(rdev);
+	u8 *buckx_val[3];
+	bool buckx_gpiodvs[3];
+	int side_effect[8];
+	int min_side_effect = INT_MAX;
+	int i;
+
+	*best = -1;
+
+	switch (rid) {
+	case MAX8997_BUCK1:
+		rid = 0;
+		break;
+	case MAX8997_BUCK2:
+		rid = 1;
+		break;
+	case MAX8997_BUCK5:
+		rid = 2;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	buckx_val[0] = max8997->buck1_vol;
+	buckx_val[1] = max8997->buck2_vol;
+	buckx_val[2] = max8997->buck5_vol;
+	buckx_gpiodvs[0] = pdata->buck1_gpiodvs;
+	buckx_gpiodvs[1] = pdata->buck2_gpiodvs;
+	buckx_gpiodvs[2] = pdata->buck5_gpiodvs;
+
+	for (i = 0; i < 8; i++) {
+		int others;
+
+		if (new_val != (buckx_val[rid])[i]) {
+			side_effect[i] = -1;
+			continue;
+		}
+
+		side_effect[i] = 0;
+		for (others = 0; others < 3; others++) {
+			int diff;
+
+			if (others == rid)
+				continue;
+			if (buckx_gpiodvs[others] == false)
+				continue; /* Not affected */
+			diff = (buckx_val[others])[i] -
+				(buckx_val[others])[max8997->buck125_gpioindex];
+			if (diff > 0)
+				side_effect[i] += diff;
+			else if (diff < 0)
+				side_effect[i] -= diff;
+		}
+		if (side_effect[i] == 0) {
+			*best = i;
+			return 0; /* NO SIDE EFFECT! Use This! */
+		}
+		if (side_effect[i] < min_side_effect) {
+			min_side_effect = side_effect[i];
+			*best = i;
+		}
+	}
+
+	if (*best == -1)
+		return -EINVAL;
+
+	return side_effect[*best];
+}
+
+/*
+ * For Buck 1 ~ 5 and 7. If it is not controlled by GPIO, this calls
+ * max8997_set_voltage_ldobuck to do the job.
+ */
+static int max8997_set_voltage_buck(struct regulator_dev *rdev,
+		int min_uV, int max_uV, unsigned *selector)
+{
+	struct max8997_data *max8997 = rdev_get_drvdata(rdev);
+	struct max8997_platform_data *pdata =
+		dev_get_platdata(max8997->iodev->dev);
+	int rid = max8997_get_rid(rdev);
+	const struct voltage_map_desc *desc;
+	int new_val, new_idx, damage, tmp_val, tmp_idx, tmp_dmg;
+	bool gpio_dvs_mode = false;
+	int min_vol = min_uV / 1000, max_vol = max_uV / 1000;
+
+	if (rid < MAX8997_BUCK1 || rid > MAX8997_BUCK7)
+		return -EINVAL;
+
+	switch (rid) {
+	case MAX8997_BUCK1:
+		if (pdata->buck1_gpiodvs)
+			gpio_dvs_mode = true;
+		break;
+	case MAX8997_BUCK2:
+		if (pdata->buck2_gpiodvs)
+			gpio_dvs_mode = true;
+		break;
+	case MAX8997_BUCK5:
+		if (pdata->buck5_gpiodvs)
+			gpio_dvs_mode = true;
+		break;
+	}
+
+	if (!gpio_dvs_mode)
+		return max8997_set_voltage_ldobuck(rdev, min_uV, max_uV,
+						selector);
+
+	desc = reg_voltage_map[rid];
+	new_val = max8997_get_voltage_proper_val(desc, min_vol, max_vol);
+	if (new_val < 0)
+		return new_val;
+
+	tmp_dmg = INT_MAX;
+	tmp_idx = -1;
+	tmp_val = -1;
+	do {
+		damage = max8997_assess_side_effect(rdev, new_val, &new_idx);
+		if (damage == 0)
+			goto out;
+
+		if (tmp_dmg > damage) {
+			tmp_idx = new_idx;
+			tmp_val = new_val;
+			tmp_dmg = damage;
+		}
+
+		new_val++;
+	} while (desc->min + desc->step + new_val <= desc->max);
+
+	new_idx = tmp_idx;
+	new_val = tmp_val;
+
+	if (pdata->ignore_gpiodvs_side_effect == false)
+		return -EINVAL;
+
+	dev_warn(&rdev->dev, "MAX8997 GPIO-DVS Side Effect Warning: GPIO SET:"
+			" %d -> %d\n", max8997->buck125_gpioindex, tmp_idx);
+
+out:
+	if (new_idx < 0 || new_val < 0)
+		return -EINVAL;
+
+	max8997->buck125_gpioindex = new_idx;
+	max8997_set_gpio(max8997);
+	*selector = new_val;
+
+	return 0;
+}
+
+static const int safeoutvolt[] = {
+	3300000,
+	4850000,
+	4900000,
+	4950000,
+};
+
+/* For SAFEOUT1 and SAFEOUT2 */
+static int max8997_set_voltage_safeout(struct regulator_dev *rdev,
+		int min_uV, int max_uV, unsigned *selector)
+{
+	struct max8997_data *max8997 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8997->iodev->i2c;
+	int rid = max8997_get_rid(rdev);
+	int reg, shift = 0, mask, ret;
+	int i = 0;
+	u8 val;
+
+	if (rid != MAX8997_ESAFEOUT1 && rid != MAX8997_ESAFEOUT2)
+		return -EINVAL;
+
+	for (i = 0; i < ARRAY_SIZE(safeoutvolt); i++) {
+		if (min_uV <= safeoutvolt[i] &&
+				max_uV >= safeoutvolt[i])
+			break;
+	}
+
+	if (i >= ARRAY_SIZE(safeoutvolt))
+		return -EINVAL;
+
+	if (i == 0)
+		val = 0x3;
+	else
+		val = i - 1;
+
+	ret = max8997_get_voltage_register(rdev, &reg, &shift, &mask);
+	if (ret)
+		return ret;
+
+	ret = max8997_update_reg(i2c, reg, val << shift, mask << shift);
+	*selector = val;
+
+	return ret;
+}
+
+static int max8997_reg_enable_suspend(struct regulator_dev *rdev)
+{
+	return 0;
+}
+
+static int max8997_reg_disable_suspend(struct regulator_dev *rdev)
+{
+	struct max8997_data *max8997 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8997->iodev->i2c;
+	int ret, reg, mask, pattern;
+	int rid = max8997_get_rid(rdev);
+
+	ret = max8997_get_enable_register(rdev, &reg, &mask, &pattern);
+	if (ret)
+		return ret;
+
+	max8997_read_reg(i2c, reg, &max8997->saved_states[rid]);
+
+	if (rid == MAX8997_LDO1 ||
+			rid == MAX8997_LDO10 ||
+			rid == MAX8997_LDO21) {
+		dev_dbg(&rdev->dev, "Conditional Power-Off for %s\n",
+				rdev->desc->name);
+		return max8997_update_reg(i2c, reg, 0x40, mask);
+	}
+
+	dev_dbg(&rdev->dev, "Full Power-Off for %s (%xh -> %xh)\n",
+			rdev->desc->name, max8997->saved_states[rid] & mask,
+			(~pattern) & mask);
+	return max8997_update_reg(i2c, reg, ~pattern, mask);
+}
+
+static struct regulator_ops max8997_ldo_ops = {
+	.list_voltage		= max8997_list_voltage,
+	.is_enabled		= max8997_reg_is_enabled,
+	.enable			= max8997_reg_enable,
+	.disable		= max8997_reg_disable,
+	.get_voltage		= max8997_get_voltage,
+	.set_voltage		= max8997_set_voltage_ldobuck,
+	.set_suspend_enable	= max8997_reg_enable_suspend,
+	.set_suspend_disable	= max8997_reg_disable_suspend,
+};
+
+static struct regulator_ops max8997_buck_ops = {
+	.list_voltage		= max8997_list_voltage,
+	.is_enabled		= max8997_reg_is_enabled,
+	.enable			= max8997_reg_enable,
+	.disable		= max8997_reg_disable,
+	.get_voltage		= max8997_get_voltage,
+	.set_voltage		= max8997_set_voltage_buck,
+	.set_suspend_enable	= max8997_reg_enable_suspend,
+	.set_suspend_disable	= max8997_reg_disable_suspend,
+};
+
+static struct regulator_ops max8997_fixedvolt_ops = {
+	.list_voltage		= max8997_list_voltage,
+	.is_enabled		= max8997_reg_is_enabled,
+	.enable			= max8997_reg_enable,
+	.disable		= max8997_reg_disable,
+	.set_suspend_enable	= max8997_reg_enable_suspend,
+	.set_suspend_disable	= max8997_reg_disable_suspend,
+};
+
+static struct regulator_ops max8997_safeout_ops = {
+	.list_voltage		= max8997_list_voltage_safeout,
+	.is_enabled		= max8997_reg_is_enabled,
+	.enable			= max8997_reg_enable,
+	.disable		= max8997_reg_disable,
+	.get_voltage		= max8997_get_voltage,
+	.set_voltage		= max8997_set_voltage_safeout,
+	.set_suspend_enable	= max8997_reg_enable_suspend,
+	.set_suspend_disable	= max8997_reg_disable_suspend,
+};
+
+static struct regulator_ops max8997_fixedstate_ops = {
+	.list_voltage		= max8997_list_voltage_charger_cv,
+	.get_voltage		= max8997_get_voltage,
+	.set_voltage		= max8997_set_voltage_charger_cv,
+};
+
+static int max8997_set_voltage_ldobuck_wrap(struct regulator_dev *rdev,
+		int min_uV, int max_uV)
+{
+	unsigned dummy;
+
+	return max8997_set_voltage_ldobuck(rdev, min_uV, max_uV, &dummy);
+}
+
+
+static struct regulator_ops max8997_charger_ops = {
+	.is_enabled		= max8997_reg_is_enabled,
+	.enable			= max8997_reg_enable,
+	.disable		= max8997_reg_disable,
+	.get_current_limit	= max8997_get_voltage,
+	.set_current_limit	= max8997_set_voltage_ldobuck_wrap,
+};
+
+static struct regulator_ops max8997_charger_fixedstate_ops = {
+	.is_enabled		= max8997_reg_is_enabled,
+	.get_current_limit	= max8997_get_voltage,
+	.set_current_limit	= max8997_set_voltage_ldobuck_wrap,
+};
+
+#define regulator_desc_ldo(num)		{	\
+	.name		= "LDO"#num,		\
+	.id		= MAX8997_LDO##num,	\
+	.ops		= &max8997_ldo_ops,	\
+	.type		= REGULATOR_VOLTAGE,	\
+	.owner		= THIS_MODULE,		\
+}
+#define regulator_desc_buck(num)		{	\
+	.name		= "BUCK"#num,		\
+	.id		= MAX8997_BUCK##num,	\
+	.ops		= &max8997_buck_ops,	\
+	.type		= REGULATOR_VOLTAGE,	\
+	.owner		= THIS_MODULE,		\
+}
+
+static struct regulator_desc regulators[] = {
+	regulator_desc_ldo(1),
+	regulator_desc_ldo(2),
+	regulator_desc_ldo(3),
+	regulator_desc_ldo(4),
+	regulator_desc_ldo(5),
+	regulator_desc_ldo(6),
+	regulator_desc_ldo(7),
+	regulator_desc_ldo(8),
+	regulator_desc_ldo(9),
+	regulator_desc_ldo(10),
+	regulator_desc_ldo(11),
+	regulator_desc_ldo(12),
+	regulator_desc_ldo(13),
+	regulator_desc_ldo(14),
+	regulator_desc_ldo(15),
+	regulator_desc_ldo(16),
+	regulator_desc_ldo(17),
+	regulator_desc_ldo(18),
+	regulator_desc_ldo(21),
+	regulator_desc_buck(1),
+	regulator_desc_buck(2),
+	regulator_desc_buck(3),
+	regulator_desc_buck(4),
+	regulator_desc_buck(5),
+	{
+		.name	= "BUCK6",
+		.id	= MAX8997_BUCK6,
+		.ops	= &max8997_fixedvolt_ops,
+		.type	= REGULATOR_VOLTAGE,
+		.owner	= THIS_MODULE,
+	},
+	regulator_desc_buck(7),
+	{
+		.name	= "EN32KHz AP",
+		.id	= MAX8997_EN32KHZ_AP,
+		.ops	= &max8997_fixedvolt_ops,
+		.type	= REGULATOR_VOLTAGE,
+		.owner	= THIS_MODULE,
+	}, {
+		.name	= "EN32KHz CP",
+		.id	= MAX8997_EN32KHZ_CP,
+		.ops	= &max8997_fixedvolt_ops,
+		.type	= REGULATOR_VOLTAGE,
+		.owner	= THIS_MODULE,
+	}, {
+		.name	= "ENVICHG",
+		.id	= MAX8997_ENVICHG,
+		.ops	= &max8997_fixedvolt_ops,
+		.type	= REGULATOR_VOLTAGE,
+		.owner	= THIS_MODULE,
+	}, {
+		.name	= "ESAFEOUT1",
+		.id	= MAX8997_ESAFEOUT1,
+		.ops	= &max8997_safeout_ops,
+		.type	= REGULATOR_VOLTAGE,
+		.owner	 = THIS_MODULE,
+	}, {
+		.name	= "ESAFEOUT2",
+		.id	= MAX8997_ESAFEOUT2,
+		.ops	= &max8997_safeout_ops,
+		.type	= REGULATOR_VOLTAGE,
+		.owner	 = THIS_MODULE,
+	}, {
+		.name	= "CHARGER CV",
+		.id	= MAX8997_CHARGER_CV,
+		.ops	= &max8997_fixedstate_ops,
+		.type	= REGULATOR_VOLTAGE,
+		.owner	 = THIS_MODULE,
+	}, {
+		.name	= "CHARGER",
+		.id	= MAX8997_CHARGER,
+		.ops	= &max8997_charger_ops,
+		.type	= REGULATOR_CURRENT,
+		.owner	 = THIS_MODULE,
+	}, {
+		.name	= "CHARGER TOPOFF",
+		.id	= MAX8997_CHARGER_TOPOFF,
+		.ops	= &max8997_charger_fixedstate_ops,
+		.type	= REGULATOR_CURRENT,
+		.owner	 = THIS_MODULE,
+	},
+};
+
+static __devinit int max8997_pmic_probe(struct platform_device *pdev)
+{
+	struct max8997_dev *iodev = dev_get_drvdata(pdev->dev.parent);
+	struct max8997_platform_data *pdata = dev_get_platdata(iodev->dev);
+	struct regulator_dev **rdev;
+	struct max8997_data *max8997;
+	struct i2c_client *i2c;
+	int i, ret, size;
+	u8 max_buck1 = 0, max_buck2 = 0, max_buck5 = 0;
+
+	if (!pdata) {
+		dev_err(pdev->dev.parent, "No platform init data supplied.\n");
+		return -ENODEV;
+	}
+
+	max8997 = kzalloc(sizeof(struct max8997_data), GFP_KERNEL);
+	if (!max8997)
+		return -ENOMEM;
+
+	size = sizeof(struct regulator_dev *) * pdata->num_regulators;
+	max8997->rdev = kzalloc(size, GFP_KERNEL);
+	if (!max8997->rdev) {
+		kfree(max8997);
+		return -ENOMEM;
+	}
+
+	rdev = max8997->rdev;
+	max8997->dev = &pdev->dev;
+	max8997->iodev = iodev;
+	max8997->num_regulators = pdata->num_regulators;
+	platform_set_drvdata(pdev, max8997);
+	i2c = max8997->iodev->i2c;
+
+	max8997->buck125_gpioindex = pdata->buck125_default_idx;
+
+	for (i = 0; i < 8; i++) {
+		max8997->buck1_vol[i] = ret =
+			max8997_get_voltage_proper_val(
+					&buck1245_voltage_map_desc,
+					pdata->buck1_voltage[i] / 1000,
+					pdata->buck1_voltage[i] / 1000 +
+					buck1245_voltage_map_desc.step);
+		if (ret < 0)
+			goto err_alloc;
+
+		max8997->buck2_vol[i] = ret =
+			max8997_get_voltage_proper_val(
+					&buck1245_voltage_map_desc,
+					pdata->buck2_voltage[i] / 1000,
+					pdata->buck2_voltage[i] / 1000 +
+					buck1245_voltage_map_desc.step);
+		if (ret < 0)
+			goto err_alloc;
+
+		max8997->buck5_vol[i] = ret =
+			max8997_get_voltage_proper_val(
+					&buck1245_voltage_map_desc,
+					pdata->buck5_voltage[i] / 1000,
+					pdata->buck5_voltage[i] / 1000 +
+					buck1245_voltage_map_desc.step);
+		if (ret < 0)
+			goto err_alloc;
+
+		if (max_buck1 < max8997->buck1_vol[i])
+			max_buck1 = max8997->buck1_vol[i];
+		if (max_buck2 < max8997->buck2_vol[i])
+			max_buck2 = max8997->buck2_vol[i];
+		if (max_buck5 < max8997->buck5_vol[i])
+			max_buck5 = max8997->buck5_vol[i];
+	}
+
+	/* For the safety, set max voltage before setting up */
+	for (i = 0; i < 8; i++) {
+		max8997_update_reg(i2c, MAX8997_REG_BUCK1DVS(i + 1),
+				max_buck1, 0x3f);
+		max8997_update_reg(i2c, MAX8997_REG_BUCK2DVS(i + 1),
+				max_buck2, 0x3f);
+		max8997_update_reg(i2c, MAX8997_REG_BUCK5DVS(i + 1),
+				max_buck5, 0x3f);
+	}
+
+	/*
+	 * If buck 1, 2, and 5 do not care DVS GPIO settings, ignore them.
+	 * If at least one of them cares, set gpios.
+	 */
+	if (pdata->buck1_gpiodvs || pdata->buck2_gpiodvs ||
+			pdata->buck5_gpiodvs) {
+		bool gpio1set = false, gpio2set = false;
+
+		if (!gpio_is_valid(pdata->buck125_gpios[0]) ||
+				!gpio_is_valid(pdata->buck125_gpios[1]) ||
+				!gpio_is_valid(pdata->buck125_gpios[2])) {
+			dev_err(&pdev->dev, "GPIO NOT VALID\n");
+			ret = -EINVAL;
+			goto err_alloc;
+		}
+
+		ret = gpio_request(pdata->buck125_gpios[0],
+				"MAX8997 SET1");
+		if (ret == -EBUSY)
+			dev_warn(&pdev->dev, "Duplicated gpio request"
+					" on SET1\n");
+		else if (ret)
+			goto err_alloc;
+		else
+			gpio1set = true;
+
+		ret = gpio_request(pdata->buck125_gpios[1],
+				"MAX8997 SET2");
+		if (ret == -EBUSY)
+			dev_warn(&pdev->dev, "Duplicated gpio request"
+					" on SET2\n");
+		else if (ret) {
+			if (gpio1set)
+				gpio_free(pdata->buck125_gpios[0]);
+			goto err_alloc;
+		} else
+			gpio2set = true;
+
+		ret = gpio_request(pdata->buck125_gpios[2],
+				"MAX8997 SET3");
+		if (ret == -EBUSY)
+			dev_warn(&pdev->dev, "Duplicated gpio request"
+					" on SET3\n");
+		else if (ret) {
+			if (gpio1set)
+				gpio_free(pdata->buck125_gpios[0]);
+			if (gpio2set)
+				gpio_free(pdata->buck125_gpios[1]);
+			goto err_alloc;
+		}
+
+		gpio_direction_output(pdata->buck125_gpios[0],
+				(max8997->buck125_gpioindex >> 2)
+				& 0x1); /* SET1 */
+		gpio_direction_output(pdata->buck125_gpios[1],
+				(max8997->buck125_gpioindex >> 1)
+				& 0x1); /* SET2 */
+		gpio_direction_output(pdata->buck125_gpios[2],
+				(max8997->buck125_gpioindex >> 0)
+				& 0x1); /* SET3 */
+		ret = 0;
+	}
+
+	/* DVS-GPIO disabled */
+	max8997_update_reg(i2c, MAX8997_REG_BUCK1CTRL, (pdata->buck1_gpiodvs) ?
+			(1 << 1) : (0 << 1), 1 << 1);
+	max8997_update_reg(i2c, MAX8997_REG_BUCK2CTRL, (pdata->buck2_gpiodvs) ?
+			(1 << 1) : (0 << 1), 1 << 1);
+	max8997_update_reg(i2c, MAX8997_REG_BUCK5CTRL, (pdata->buck5_gpiodvs) ?
+			(1 << 1) : (0 << 1), 1 << 1);
+
+	/* Initialize all the DVS related BUCK registers */
+	for (i = 0; i < 8; i++) {
+		max8997_update_reg(i2c, MAX8997_REG_BUCK1DVS(i + 1),
+				max8997->buck1_vol[i],
+				0x3f);
+		max8997_update_reg(i2c, MAX8997_REG_BUCK2DVS(i + 1),
+				max8997->buck2_vol[i],
+				0x3f);
+		max8997_update_reg(i2c, MAX8997_REG_BUCK5DVS(i + 1),
+				max8997->buck5_vol[i],
+				0x3f);
+	}
+
+	for (i = 0; i < pdata->num_regulators; i++) {
+		const struct voltage_map_desc *desc;
+		int id = pdata->regulators[i].id;
+
+		desc = reg_voltage_map[id];
+		if (desc)
+			regulators[id].n_voltages =
+				(desc->max - desc->min) / desc->step + 1;
+		else if (id == MAX8997_ESAFEOUT1 || id == MAX8997_ESAFEOUT2)
+			regulators[id].n_voltages = 4;
+		else if (id == MAX8997_CHARGER_CV)
+			regulators[id].n_voltages = 16;
+
+		rdev[i] = regulator_register(&regulators[id], max8997->dev,
+				pdata->regulators[i].initdata, max8997);
+		if (IS_ERR(rdev[i])) {
+			ret = PTR_ERR(rdev[i]);
+			dev_err(max8997->dev, "regulator init failed for %d\n",
+					id);
+			rdev[i] = NULL;
+			goto err;
+		}
+	}
+
+	/* Misc Settings */
+	max8997->ramp_delay = 10; /* set 10mV/us, which is the default */
+	max8997_write_reg(i2c, MAX8997_REG_BUCKRAMP, (0xf << 4) | 0x9);
+
+	return 0;
+err:
+	for (i = 0; i < max8997->num_regulators; i++)
+		if (rdev[i])
+			regulator_unregister(rdev[i]);
+err_alloc:
+	kfree(max8997->rdev);
+	kfree(max8997);
+
+	return ret;
+}
+
+static int __devexit max8997_pmic_remove(struct platform_device *pdev)
+{
+	struct max8997_data *max8997 = platform_get_drvdata(pdev);
+	struct regulator_dev **rdev = max8997->rdev;
+	int i;
+
+	for (i = 0; i < max8997->num_regulators; i++)
+		if (rdev[i])
+			regulator_unregister(rdev[i]);
+
+	kfree(max8997->rdev);
+	kfree(max8997);
+
+	return 0;
+}
+
+static const struct platform_device_id max8997_pmic_id[] = {
+	{ "max8997-pmic", 0},
+	{ },
+};
+
+static struct platform_driver max8997_pmic_driver = {
+	.driver = {
+		.name = "max8997-pmic",
+		.owner = THIS_MODULE,
+	},
+	.probe = max8997_pmic_probe,
+	.remove = __devexit_p(max8997_pmic_remove),
+	.id_table = max8997_pmic_id,
+};
+
+static int __init max8997_pmic_init(void)
+{
+	return platform_driver_register(&max8997_pmic_driver);
+}
+subsys_initcall(max8997_pmic_init);
+
+static void __exit max8997_pmic_cleanup(void)
+{
+	platform_driver_unregister(&max8997_pmic_driver);
+}
+module_exit(max8997_pmic_cleanup);
+
+MODULE_DESCRIPTION("MAXIM 8997/8966 Regulator Driver");
+MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
+MODULE_LICENSE("GPL");