[PATCH 2/5] regulator: Add driver for Maxim 77802 PMIC regulators

[Javier Martinez Canillas]

The MAX77802 PMIC has 10 high-efficiency Buck and 32 Low-dropout
(LDO) regulators. This patch adds support for all these regulators
found on the MAX77802 PMIC and is based on a driver added by Simon
Glass to the Chrome OS kernel 3.8 tree.

Signed-off-by: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx>
---
 drivers/regulator/Kconfig    |   9 +
 drivers/regulator/Makefile   |   1 +
 drivers/regulator/max77802.c | 678 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 688 insertions(+)
 create mode 100644 drivers/regulator/max77802.c

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 789eb46..17873d3 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -377,6 +377,15 @@ config REGULATOR_MAX77693
 	  and one current regulator 'CHARGER'. This is suitable for
 	  Exynos-4x12 chips.
 
+config REGULATOR_MAX77802
+	tristate "Maxim 77802 regulator"
+	depends on MFD_MAX77802
+	help
+	  This driver controls a Maxim 77802 regulator
+	  via I2C bus. The provided regulator is suitable for
+	  Exynos-5 chips to control various voltages. It includes
+	  support for control of voltage and ramp speed.
+
 config REGULATOR_MC13XXX_CORE
 	tristate
 
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index d461110..2aea4b6 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_REGULATOR_MAX8997) += max8997.o
 obj-$(CONFIG_REGULATOR_MAX8998) += max8998.o
 obj-$(CONFIG_REGULATOR_MAX77686) += max77686.o
 obj-$(CONFIG_REGULATOR_MAX77693) += max77693.o
+obj-$(CONFIG_REGULATOR_MAX77802) += max77802.o
 obj-$(CONFIG_REGULATOR_MC13783) += mc13783-regulator.o
 obj-$(CONFIG_REGULATOR_MC13892) += mc13892-regulator.o
 obj-$(CONFIG_REGULATOR_MC13XXX_CORE) +=  mc13xxx-regulator-core.o
diff --git a/drivers/regulator/max77802.c b/drivers/regulator/max77802.c
new file mode 100644
index 0000000..93e8f69
--- /dev/null
+++ b/drivers/regulator/max77802.c
@@ -0,0 +1,678 @@
+/*
+ * max77802.c - Regulator driver for the Maxim 77802
+ *
+ * Copyright (C) 2013-2014 Google, Inc
+ * Simon Glass <sjg@xxxxxxxxxxxx>
+ *
+ * Copyright (C) 2012 Samsung Electronics
+ * Chiwoong Byun <woong.byun@xxxxxxxxxxx>
+ * Jonghwa Lee <jonghwa3.lee@xxxxxxxxxxx>
+ *
+ * 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.
+ *
+ * This driver is based on max8997.c
+ */
+
+#include <linux/kernel.h>
+#include <linux/bug.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/regulator/of_regulator.h>
+#include <linux/mfd/max77802.h>
+#include <linux/mfd/max77802-private.h>
+
+/* Default ramp delay in case it is not manually set */
+#define MAX77802_RAMP_DELAY		100000		/* uV/us */
+
+#define MAX77802_OPMODE_SHIFT_LDO	6
+#define MAX77802_OPMODE_BUCK234_SHIFT	4
+#define MAX77802_OPMODE_MASK		0x3
+
+#define MAX77802_VSEL_MASK		0x3F
+#define MAX77802_DVS_VSEL_MASK		0xFF
+
+#define MAX77802_RAMP_RATE_MASK_2BIT	0xC0
+#define MAX77802_RAMP_RATE_SHIFT_2BIT	6
+#define MAX77802_RAMP_RATE_MASK_4BIT	0xF0
+#define MAX77802_RAMP_RATE_SHIFT_4BIT	4
+
+/* LDO16, LDO22 and LDO31 are not available on MAX77802 */
+#define MAX77802_MAX_REGULATORS		(MAX77802_REG_MAX - 3)
+
+/* MAX77802 has two register formats: 2-bit and 4-bit */
+static const unsigned int ramp_table_77802_2bit[] = {
+	12500,
+	25000,
+	50000,
+	100000,
+};
+
+static unsigned int ramp_table_77802_4bit[] = {
+	1000,	2000,	3030,	4000,
+	5000,	5880,	7140,	8330,
+	9090,	10000,	11110,	12500,
+	16670,	25000,	50000,	100000,
+};
+
+struct max77802_regulator_prv {
+	int num_regulators;
+	struct regulator_dev *rdev[MAX77802_MAX_REGULATORS];
+	unsigned int opmode[MAX77802_MAX_REGULATORS];
+};
+
+static int max77802_get_opmode_shift(int id)
+{
+	if (id >= MAX77802_LDO1 && id <= MAX77802_LDO35)
+		return MAX77802_OPMODE_SHIFT_LDO;
+	else if (id == MAX77802_BUCK1 || (id >= MAX77802_BUCK5 &&
+					  id <= MAX77802_BUCK10))
+		return 0;
+	else if (id >= MAX77802_BUCK2 && id <= MAX77802_BUCK4)
+		return MAX77802_OPMODE_BUCK234_SHIFT;
+	else
+		return -EINVAL;
+}
+
+/*
+ * Some BUCKS supports Normal[ON/OFF] mode during suspend
+ *
+ * BUCK 1, 6, 2-4, 5, 7-10 (all)
+ *
+ * The other mode (0x02) will make pwrreq switch between normal
+ * and low power.
+ */
+static int max77802_buck_set_suspend_disable(struct regulator_dev *rdev)
+{
+	unsigned int val = MAX77802_OPMODE_STANDBY;
+	struct max77802_regulator_prv *max77802 = rdev_get_drvdata(rdev);
+	int id = rdev_get_id(rdev);
+	int shift = max77802_get_opmode_shift(id);
+
+	max77802->opmode[id] = val;
+	return regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
+				  rdev->desc->enable_mask, val << shift);
+}
+
+/*
+ * Some LDOs supports LPM-ON/OFF/Normal-ON mode during suspend state
+ *
+ * LDOs 3-7, 9-14, 18-26, 28, 29, 32-34, 1, 2, 8, 15, 17, 27, 30, 35 (all)
+ *
+ * LDOs 1, 20, 21, and 3, mode 1 is not supported
+ */
+static int max77802_ldo_set_suspend_mode(struct regulator_dev *rdev,
+					 unsigned int mode)
+{
+	struct max77802_regulator_prv *max77802 = rdev_get_drvdata(rdev);
+	int id = rdev_get_id(rdev);
+	unsigned int val;
+	int shift = max77802_get_opmode_shift(id);
+
+	switch (mode) {
+	case REGULATOR_MODE_IDLE:			/* ON in LP Mode */
+		val = MAX77802_OPMODE_LP;
+		break;
+	case REGULATOR_MODE_NORMAL:			/* ON in Normal Mode */
+		val = MAX77802_OPMODE_NORMAL;
+		break;
+	case REGULATOR_MODE_STANDBY:			/* switch off */
+		if (id != MAX77802_LDO1 && id != MAX77802_LDO20 &&
+			id != MAX77802_LDO21 && id != MAX77802_LDO3) {
+			val = MAX77802_OPMODE_STANDBY;
+			break;
+		}
+		/* no break */
+	default:
+		pr_warn("%s: regulator_suspend_mode : 0x%x not supported\n",
+			rdev->desc->name, mode);
+		return -EINVAL;
+	}
+
+	max77802->opmode[rdev_get_id(rdev)] = val;
+	return regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
+				  rdev->desc->enable_mask, val << shift);
+}
+
+static int max77802_enable(struct regulator_dev *rdev)
+{
+	struct max77802_regulator_prv *max77802 = rdev_get_drvdata(rdev);
+	int id = rdev_get_id(rdev);
+	int shift = max77802_get_opmode_shift(id);
+
+	return regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
+				  rdev->desc->enable_mask,
+				  max77802->opmode[id] << shift);
+}
+
+static int max77802_find_ramp_value(struct regulator_dev *rdev,
+				    const unsigned int limits[], int size,
+				    unsigned int ramp_delay)
+{
+	int i;
+
+	for (i = 0; i < size; i++) {
+		if (ramp_delay <= limits[i])
+			return i;
+	}
+
+	/* Use maximum value for no ramp control */
+	pr_warn("%s: ramp_delay: %d not supported, setting 100000\n",
+		rdev->desc->name, ramp_delay);
+	return size - 1;
+}
+
+/* Used for BUCKs 2-4 */
+static int max77802_set_ramp_delay_2bit(struct regulator_dev *rdev,
+					int ramp_delay)
+{
+	int id = rdev_get_id(rdev);
+	unsigned int ramp_value;
+
+	if (id > MAX77802_BUCK4) {
+		pr_warn("%s: regulator_suspend_mode: ramp delay not supported\n",
+			rdev->desc->name);
+		return -EINVAL;
+	}
+	ramp_value = max77802_find_ramp_value(rdev, ramp_table_77802_2bit,
+				ARRAY_SIZE(ramp_table_77802_2bit), ramp_delay);
+
+	return regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
+				  MAX77802_RAMP_RATE_MASK_2BIT,
+				  ramp_value << MAX77802_RAMP_RATE_SHIFT_2BIT);
+}
+
+/* For BUCK1, 6 */
+static int max77802_set_ramp_delay_4bit(struct regulator_dev *rdev,
+					    int ramp_delay)
+{
+	unsigned int ramp_value;
+
+	ramp_value = max77802_find_ramp_value(rdev, ramp_table_77802_4bit,
+				ARRAY_SIZE(ramp_table_77802_4bit), ramp_delay);
+
+	return regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
+				  MAX77802_RAMP_RATE_MASK_4BIT,
+				  ramp_value << MAX77802_RAMP_RATE_SHIFT_4BIT);
+}
+
+/*
+ * LDOs 3-7, 9-14, 18-26, 28, 29, 32-34, 1, 2, 8, 15, 17, 27, 30, 35 (all)
+ */
+static struct regulator_ops max77802_ldo_ops = {
+	.list_voltage		= regulator_list_voltage_linear,
+	.map_voltage		= regulator_map_voltage_linear,
+	.is_enabled		= regulator_is_enabled_regmap,
+	.enable			= max77802_enable,
+	.disable		= regulator_disable_regmap,
+	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
+	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
+	.set_voltage_time_sel	= regulator_set_voltage_time_sel,
+	.set_suspend_mode	= max77802_ldo_set_suspend_mode,
+};
+
+/* BUCKS 1, 6 */
+static struct regulator_ops max77802_buck_16_dvs_ops = {
+	.list_voltage		= regulator_list_voltage_linear,
+	.map_voltage		= regulator_map_voltage_linear,
+	.is_enabled		= regulator_is_enabled_regmap,
+	.enable			= max77802_enable,
+	.disable		= regulator_disable_regmap,
+	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
+	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
+	.set_voltage_time_sel	= regulator_set_voltage_time_sel,
+	.set_ramp_delay		= max77802_set_ramp_delay_4bit,
+	.set_suspend_disable	= max77802_buck_set_suspend_disable,
+};
+
+/* BUCKs 2-4, 5, 7-10 */
+static struct regulator_ops max77802_buck_dvs_ops = {
+	.list_voltage		= regulator_list_voltage_linear,
+	.map_voltage		= regulator_map_voltage_linear,
+	.is_enabled		= regulator_is_enabled_regmap,
+	.enable			= max77802_enable,
+	.disable		= regulator_disable_regmap,
+	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
+	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
+	.set_voltage_time_sel	= regulator_set_voltage_time_sel,
+	.set_ramp_delay		= max77802_set_ramp_delay_2bit,
+	.set_suspend_disable	= max77802_buck_set_suspend_disable,
+};
+
+/* LDOs 3-7, 9-14, 18-26, 28, 29, 32-34 */
+#define regulator_77802_desc_p_ldo(num)	{				\
+	.name		= "LDO"#num,					\
+	.id		= MAX77802_LDO##num,				\
+	.ops		= &max77802_ldo_ops,				\
+	.type		= REGULATOR_VOLTAGE,				\
+	.owner		= THIS_MODULE,					\
+	.min_uV		= 800000,					\
+	.uV_step	= 50000,					\
+	.ramp_delay	= MAX77802_RAMP_DELAY,				\
+	.n_voltages	= 1 << 6,					\
+	.vsel_reg	= MAX77802_REG_LDO1CTRL1 + num - 1,		\
+	.vsel_mask	= MAX77802_VSEL_MASK,				\
+	.enable_reg	= MAX77802_REG_LDO1CTRL1 + num - 1,		\
+	.enable_mask	= MAX77802_OPMODE_MASK << MAX77802_OPMODE_SHIFT_LDO, \
+}
+
+/* LDOs 1, 2, 8, 15, 17, 27, 30, 35 */
+#define regulator_77802_desc_n_ldo(num)	{				\
+	.name		= "LDO"#num,					\
+	.id		= MAX77802_LDO##num,				\
+	.ops		= &max77802_ldo_ops,				\
+	.type		= REGULATOR_VOLTAGE,				\
+	.owner		= THIS_MODULE,					\
+	.min_uV		= 800000,					\
+	.uV_step	= 25000,					\
+	.ramp_delay	= MAX77802_RAMP_DELAY,				\
+	.n_voltages	= 1 << 6,					\
+	.vsel_reg	= MAX77802_REG_LDO1CTRL1 + num - 1,		\
+	.vsel_mask	= MAX77802_VSEL_MASK,				\
+	.enable_reg	= MAX77802_REG_LDO1CTRL1 + num - 1,		\
+	.enable_mask	= MAX77802_OPMODE_MASK << MAX77802_OPMODE_SHIFT_LDO, \
+}
+
+/* BUCKs 1, 6 */
+#define regulator_77802_desc_16_buck(num)	{			\
+	.name		= "BUCK"#num,					\
+	.id		= MAX77802_BUCK##num,				\
+	.ops		= &max77802_buck_16_dvs_ops,			\
+	.type		= REGULATOR_VOLTAGE,				\
+	.owner		= THIS_MODULE,					\
+	.min_uV		= 612500,					\
+	.uV_step	= 6250,						\
+	.ramp_delay	= MAX77802_RAMP_DELAY,				\
+	.n_voltages	= 1 << 8,					\
+	.vsel_reg	= MAX77802_REG_BUCK ## num ## DVS1,		\
+	.vsel_mask	= MAX77802_DVS_VSEL_MASK,			\
+	.enable_reg	= MAX77802_REG_BUCK ## num ## CTRL,		\
+	.enable_mask	= MAX77802_OPMODE_MASK,				\
+}
+
+/* BUCKS 2-4 */
+#define regulator_77802_desc_234_buck(num)	{			\
+	.name		= "BUCK"#num,					\
+	.id		= MAX77802_BUCK##num,				\
+	.ops		= &max77802_buck_dvs_ops,			\
+	.type		= REGULATOR_VOLTAGE,				\
+	.owner		= THIS_MODULE,					\
+	.min_uV		= 600000,					\
+	.uV_step	= 6250,						\
+	.ramp_delay	= MAX77802_RAMP_DELAY,				\
+	.n_voltages	= 0x91,						\
+	.vsel_reg	= MAX77802_REG_BUCK ## num ## DVS1,		\
+	.vsel_mask	= MAX77802_DVS_VSEL_MASK,			\
+	.enable_reg	= MAX77802_REG_BUCK ## num ## CTRL1,		\
+	.enable_mask	= MAX77802_OPMODE_MASK <<			\
+				MAX77802_OPMODE_BUCK234_SHIFT,		\
+}
+
+/* BUCK 5 */
+#define regulator_77802_desc_buck5(num)		{			\
+	.name		= "BUCK"#num,					\
+	.id		= MAX77802_BUCK##num,				\
+	.ops		= &max77802_buck_dvs_ops,			\
+	.type		= REGULATOR_VOLTAGE,				\
+	.owner		= THIS_MODULE,					\
+	.min_uV		= 750000,					\
+	.uV_step	= 50000,					\
+	.ramp_delay	= MAX77802_RAMP_DELAY,				\
+	.n_voltages	= 1 << 6,					\
+	.vsel_reg	= MAX77802_REG_BUCK5OUT,			\
+	.vsel_mask	= MAX77802_VSEL_MASK,				\
+	.enable_reg	= MAX77802_REG_BUCK5CTRL,			\
+	.enable_mask	= MAX77802_OPMODE_MASK,				\
+}
+
+/* BUCKs 7-10 */
+#define regulator_77802_desc_buck7_10(num)	{			\
+	.name		= "BUCK"#num,					\
+	.id		= MAX77802_BUCK##num,				\
+	.ops		= &max77802_buck_dvs_ops,			\
+	.type		= REGULATOR_VOLTAGE,				\
+	.owner		= THIS_MODULE,					\
+	.min_uV		= 750000,					\
+	.uV_step	= 50000,					\
+	.ramp_delay	= MAX77802_RAMP_DELAY,				\
+	.n_voltages	= 1 << 6,					\
+	.vsel_reg	= MAX77802_REG_BUCK7OUT + (num - 7) * 3,	\
+	.vsel_mask	= MAX77802_VSEL_MASK,				\
+	.enable_reg	= MAX77802_REG_BUCK7CTRL + (num - 7) * 3,	\
+	.enable_mask	= MAX77802_OPMODE_MASK,				\
+}
+
+static struct regulator_desc regulators[] = {
+	regulator_77802_desc_n_ldo(1),
+	regulator_77802_desc_n_ldo(2),
+	regulator_77802_desc_p_ldo(3),
+	regulator_77802_desc_p_ldo(4),
+	regulator_77802_desc_p_ldo(5),
+	regulator_77802_desc_p_ldo(6),
+	regulator_77802_desc_p_ldo(7),
+	regulator_77802_desc_n_ldo(8),
+	regulator_77802_desc_p_ldo(9),
+	regulator_77802_desc_p_ldo(10),
+	regulator_77802_desc_p_ldo(11),
+	regulator_77802_desc_p_ldo(12),
+	regulator_77802_desc_p_ldo(13),
+	regulator_77802_desc_p_ldo(14),
+	regulator_77802_desc_n_ldo(15),
+	regulator_77802_desc_n_ldo(17),
+	regulator_77802_desc_p_ldo(18),
+	regulator_77802_desc_p_ldo(19),
+	regulator_77802_desc_p_ldo(20),
+	regulator_77802_desc_p_ldo(21),
+	regulator_77802_desc_p_ldo(23),
+	regulator_77802_desc_p_ldo(24),
+	regulator_77802_desc_p_ldo(25),
+	regulator_77802_desc_p_ldo(26),
+	regulator_77802_desc_n_ldo(27),
+	regulator_77802_desc_p_ldo(28),
+	regulator_77802_desc_p_ldo(29),
+	regulator_77802_desc_n_ldo(30),
+	regulator_77802_desc_p_ldo(32),
+	regulator_77802_desc_p_ldo(33),
+	regulator_77802_desc_p_ldo(34),
+	regulator_77802_desc_n_ldo(35),
+	regulator_77802_desc_16_buck(1),
+	regulator_77802_desc_234_buck(2),
+	regulator_77802_desc_234_buck(3),
+	regulator_77802_desc_234_buck(4),
+	regulator_77802_desc_buck5(5),
+	regulator_77802_desc_16_buck(6),
+	regulator_77802_desc_buck7_10(7),
+	regulator_77802_desc_buck7_10(8),
+	regulator_77802_desc_buck7_10(9),
+	regulator_77802_desc_buck7_10(10),
+};
+
+#ifdef CONFIG_OF
+static int max77802_pmic_dt_parse_pdata(struct platform_device *pdev,
+					struct max77802_platform_data *pdata)
+{
+	struct max77802_dev *iodev = dev_get_drvdata(pdev->dev.parent);
+	struct device_node *pmic_np, *regulators_np;
+	struct max77802_regulator_data *rdata;
+	struct of_regulator_match rmatch;
+	unsigned int i;
+
+	pmic_np = iodev->dev->of_node;
+	regulators_np = of_get_child_by_name(pmic_np, "voltage-regulators");
+	if (!regulators_np) {
+		dev_err(&pdev->dev, "could not find regulators sub-node\n");
+		return -EINVAL;
+	}
+
+	pdata->num_regulators = ARRAY_SIZE(regulators);
+	rdata = devm_kzalloc(&pdev->dev, sizeof(*rdata) *
+			     pdata->num_regulators, GFP_KERNEL);
+	if (!rdata) {
+		of_node_put(regulators_np);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < pdata->num_regulators; i++) {
+		rmatch.name = regulators[i].name;
+		rmatch.init_data = NULL;
+		rmatch.of_node = NULL;
+		if (of_regulator_match(&pdev->dev, regulators_np, &rmatch,
+				       1) != 1) {
+			dev_warn(&pdev->dev,
+				 "No matching regulator for '%s'\n", rmatch.name);
+			continue;
+		}
+		rdata[i].initdata = rmatch.init_data;
+		rdata[i].of_node = rmatch.of_node;
+		rdata[i].id = regulators[i].id;
+	}
+
+	pdata->regulators = rdata;
+	of_node_put(regulators_np);
+
+	return 0;
+}
+#else
+static int max77802_pmic_dt_parse_pdata(struct platform_device *pdev,
+					struct max77802_platform_data *pdata)
+{
+	return 0;
+}
+#endif /* CONFIG_OF */
+
+/**
+ * max77802_setup_gpios - init DVS-related GPIOs
+ *
+ * This function claims / initalizations GPIOs related to DVS if they are
+ * defined. This may have the effect of switching voltages if the
+ * pdata->buck_default_idx does not match the boot time state of pins.
+ */
+static int max77802_setup_gpios(struct device *dev,
+				struct max77802_platform_data *pdata)
+{
+	int buck_default_idx = pdata->buck_default_idx;
+	int ret;
+	int i;
+
+	/* Set all SELB high to avoid glitching while DVS is changing */
+	for (i = 0; i < ARRAY_SIZE(pdata->buck_gpio_selb); i++) {
+		int gpio = pdata->buck_gpio_selb[i];
+
+		/* OK if some GPIOs aren't defined */
+		if (!gpio_is_valid(gpio))
+			continue;
+
+		/* If a GPIO is valid, we'd better be able to claim it */
+		ret = devm_gpio_request_one(dev, gpio, GPIOF_OUT_INIT_HIGH,
+					    "max77802 selb");
+		if (ret) {
+			dev_err(dev, "can't claim gpio[%d]: %d\n", i, ret);
+			return ret;
+		}
+	}
+
+	/* Set our initial setting */
+	for (i = 0; i < ARRAY_SIZE(pdata->buck_gpio_dvs); i++) {
+		int gpio = pdata->buck_gpio_dvs[i];
+
+		/* OK if some GPIOs aren't defined */
+		if (!gpio_is_valid(gpio))
+			continue;
+
+		/* If a GPIO is valid, we'd better be able to claim it */
+		ret = devm_gpio_request(dev, gpio, "max77802 dvs");
+		if (ret) {
+			dev_err(dev, "can't claim gpio[%d]: %d\n", i, ret);
+			return ret;
+		}
+		gpio_direction_output(gpio, (buck_default_idx >> i) & 1);
+	}
+
+	/* Now set SELB low to take effect */
+	for (i = 0; i < ARRAY_SIZE(pdata->buck_gpio_selb); i++) {
+		int gpio = pdata->buck_gpio_selb[i];
+
+		if (gpio_is_valid(gpio))
+			gpio_set_value(gpio, 0);
+	}
+
+	return 0;
+}
+
+/**
+ * max77802_read_gpios - read the current state of the dvs GPIOs
+ *
+ * We call this function at bootup to detect what slot the firmware was
+ * using for the DVS GPIOs.  That way we can properly preserve the firmware's
+ * voltage settings
+ */
+static int max77802_read_gpios(struct max77802_platform_data *pdata)
+{
+	int buck_default_idx = pdata->buck_default_idx;
+	int result = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(pdata->buck_gpio_dvs); i++) {
+		int gpio = pdata->buck_gpio_dvs[i];
+
+		/* OK if some GPIOs aren't defined; we'll use default */
+		if (!gpio_is_valid(gpio)) {
+			result |= buck_default_idx & (1 << i);
+			continue;
+		}
+
+		if (gpio_get_value_cansleep(gpio))
+			result |= 1 << i;
+	}
+
+	return result;
+}
+
+static inline bool max77802_is_dvs_buck(int id)
+{
+	/* on 77802 bucks 1-4, 6 are */
+	return ((id >= MAX77802_BUCK1 && id <= MAX77802_BUCK4) ||
+		(id == MAX77802_BUCK6));
+}
+
+static void max77802_copy_reg(struct device *dev, struct regmap *regmap,
+			      int from_reg, int to_reg)
+{
+	int val;
+	int ret;
+
+	if (from_reg == to_reg)
+		return;
+
+	ret = regmap_read(regmap, from_reg, &val);
+	if (!ret)
+		ret = regmap_write(regmap, to_reg, val);
+
+	if (ret)
+		dev_warn(dev, "Copy err %d => %d (%d)\n",
+			 from_reg, to_reg, ret);
+}
+
+static int max77802_pmic_probe(struct platform_device *pdev)
+{
+	struct max77802_dev *iodev = dev_get_drvdata(pdev->dev.parent);
+	struct max77802_platform_data *pdata = dev_get_platdata(iodev->dev);
+	struct max77802_regulator_prv *max77802;
+	int i, ret = 0;
+	struct regulator_config config = { };
+	unsigned int reg;
+	int buck_default_idx;
+	int buck_old_idx;
+
+	dev_dbg(&pdev->dev, "%s\n", __func__);
+
+	/* This is allocated by the MFD driver */
+	if (!pdata) {
+		dev_err(&pdev->dev, "no platform data found for regulator\n");
+		return -ENODEV;
+	}
+
+	max77802 = devm_kzalloc(&pdev->dev,
+				sizeof(struct max77802_regulator_prv),
+				GFP_KERNEL);
+	if (!max77802)
+		return -ENOMEM;
+
+	if (iodev->dev->of_node) {
+		ret = max77802_pmic_dt_parse_pdata(pdev, pdata);
+		if (ret)
+			return ret;
+	}
+
+	if (pdata->num_regulators != MAX77802_MAX_REGULATORS) {
+		dev_err(&pdev->dev,
+			"Invalid initial data for regulator's initialiation: " \
+			"expected %d, pdata/dt provided %d\n",
+			MAX77802_MAX_REGULATORS,
+			pdata->num_regulators);
+		return -EINVAL;
+	}
+
+	config.dev = &pdev->dev;
+	config.regmap = iodev->regmap;
+	config.driver_data = max77802;
+	platform_set_drvdata(pdev, max77802);
+
+	buck_default_idx = pdata->buck_default_idx;
+	buck_old_idx = max77802_read_gpios(pdata);
+
+	for (i = 0; i < MAX77802_MAX_REGULATORS; i++) {
+		struct regulator_dev *rdev;
+		int id = pdata->regulators[i].id;
+
+		config.init_data = pdata->regulators[i].initdata;
+		config.of_node = pdata->regulators[i].of_node;
+
+		max77802->opmode[id] = MAX77802_OPMODE_NORMAL;
+
+		if (max77802_is_dvs_buck(id)) {
+			/* Try to copy over data so we keep firmware settings */
+			reg = regulators[i].vsel_reg;
+			max77802_copy_reg(&pdev->dev, iodev->regmap,
+					  reg + buck_old_idx,
+					  reg + buck_default_idx);
+			regulators[i].vsel_reg += buck_default_idx;
+		}
+
+		rdev = devm_regulator_register(&pdev->dev,
+						&regulators[i], &config);
+		if (IS_ERR(rdev)) {
+			dev_err(&pdev->dev,
+				"regulator init failed for %d\n", i);
+			return PTR_ERR(rdev);
+		}
+	}
+
+	ret = max77802_setup_gpios(&pdev->dev, pdata);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct platform_device_id max77802_pmic_id[] = {
+	{"max77802-pmic", 0},
+	{ },
+};
+MODULE_DEVICE_TABLE(platform, max77802_pmic_id);
+
+static struct platform_driver max77802_pmic_driver = {
+	.driver = {
+		.name = "max77802-pmic",
+		.owner = THIS_MODULE,
+	},
+	.probe = max77802_pmic_probe,
+	.id_table = max77802_pmic_id,
+};
+
+static int __init max77802_pmic_init(void)
+{
+	return platform_driver_register(&max77802_pmic_driver);
+}
+subsys_initcall(max77802_pmic_init);
+
+static void __exit max77802_pmic_cleanup(void)
+{
+	platform_driver_unregister(&max77802_pmic_driver);
+}
+module_exit(max77802_pmic_cleanup);
+
+MODULE_DESCRIPTION("MAXIM 77802 Regulator Driver");
+MODULE_AUTHOR("Simon Glass <sjg@xxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
-- 
2.0.0.rc2

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