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regulator: max77838: add max77838 regulator driver
The max77838 PMIC contains a BUCK regulator and 4 LDOs. It's primarily used in the Samsung Galaxy S7 lineup and is accessed over I2C. Signed-off-by: Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com> Link: https://patch.msgid.link/20250914130230.2622030-3-ivo.ivanov.ivanov1@gmail.com Signed-off-by: Mark Brown <broonie@kernel.org>
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‎MAINTAINERS‎

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@@ -15074,6 +15074,7 @@ M: Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>
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L: linux-kernel@vger.kernel.org
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S: Maintained
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F: Documentation/devicetree/bindings/regulator/maxim,max77838.yaml
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F: drivers/regulator/max77838-regulator.c
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MAXIM MAX77976 BATTERY CHARGER
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M: Luca Ceresoli <luca@lucaceresoli.net>

‎drivers/regulator/Kconfig‎

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@@ -777,6 +777,14 @@ config REGULATOR_MAX77826
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It includes support for control of output voltage. This
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regulator is found on the Samsung Galaxy S5 (klte) smartphone.
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config REGULATOR_MAX77838
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tristate "Maxim 77838 regulator"
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depends on REGMAP_I2C
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help
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This driver controls a Maxim 77838 regulator via I2C bus.
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The regulator include 4 LDOs and a BUCK regulator. It's
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present on the Samsung Galaxy S7 lineup of smartphones.
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config REGULATOR_MC13XXX_CORE
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tristate
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‎drivers/regulator/Makefile‎

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@@ -92,6 +92,7 @@ obj-$(CONFIG_REGULATOR_MAX77686) += max77686-regulator.o
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obj-$(CONFIG_REGULATOR_MAX77693) += max77693-regulator.o
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obj-$(CONFIG_REGULATOR_MAX77802) += max77802-regulator.o
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obj-$(CONFIG_REGULATOR_MAX77826) += max77826-regulator.o
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obj-$(CONFIG_REGULATOR_MAX77838) += max77838-regulator.o
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obj-$(CONFIG_REGULATOR_MAX77857) += max77857-regulator.o
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obj-$(CONFIG_REGULATOR_MC13783) += mc13783-regulator.o
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obj-$(CONFIG_REGULATOR_MC13892) += mc13892-regulator.o

‎drivers/regulator/max77838-regulator.c‎

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// SPDX-License-Identifier: GPL-2.0-or-later
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//
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// regulator driver for Maxim MAX77838
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//
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// based on max77826-regulator.c
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//
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// Copyright (c) 2025, Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/regulator/driver.h>
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#include <linux/regulator/of_regulator.h>
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#include <linux/i2c.h>
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#include <linux/regmap.h>
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enum max77838_registers {
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MAX77838_REG_DEVICE_ID = 0x00,
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MAX77838_REG_TOPSYS_STAT,
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MAX77838_REG_STAT,
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MAX77838_REG_EN,
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MAX77838_REG_GPIO_PD_CTRL,
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MAX77838_REG_UVLO_CFG1,
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/* 0x06 - 0x0B: reserved */
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MAX77838_REG_I2C_CFG = 0x0C,
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/* 0x0D - 0x0F: reserved */
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MAX77838_REG_LDO1_CFG = 0x10,
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MAX77838_REG_LDO2_CFG,
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MAX77838_REG_LDO3_CFG,
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MAX77838_REG_LDO4_CFG,
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/* 0x14 - 0x1F: reserved */
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MAX77838_REG_BUCK_CFG1 = 0x20,
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MAX77838_REG_BUCK_VOUT,
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};
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enum max77838_regulators {
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MAX77838_LDO1 = 0,
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MAX77838_LDO2,
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MAX77838_LDO3,
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MAX77838_LDO4,
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MAX77838_BUCK,
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MAX77838_MAX_REGULATORS,
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};
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#define MAX77838_MASK_LDO 0x7f
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#define MAX77838_MASK_BUCK 0xff
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#define MAX77838_LDO1_EN BIT(0)
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#define MAX77838_LDO2_EN BIT(1)
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#define MAX77838_LDO3_EN BIT(2)
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#define MAX77838_LDO4_EN BIT(3)
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#define MAX77838_BUCK_EN BIT(4)
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#define MAX77838_BUCK_AD BIT(3)
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#define MAX77838_LDO_AD BIT(7)
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#define MAX77838_LDO_VOLT_MIN 600000
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#define MAX77838_LDO_VOLT_MAX 3775000
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#define MAX77838_LDO_VOLT_STEP 25000
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#define MAX77838_BUCK_VOLT_MIN 500000
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#define MAX77838_BUCK_VOLT_MAX 2093750
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#define MAX77838_BUCK_VOLT_STEP 6250
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#define MAX77838_VOLT_RANGE(_type) \
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((MAX77838_ ## _type ## _VOLT_MAX - \
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MAX77838_ ## _type ## _VOLT_MIN) / \
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MAX77838_ ## _type ## _VOLT_STEP + 1)
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#define MAX77838_LDO(_id) \
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[MAX77838_LDO ## _id] = { \
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.id = MAX77838_LDO ## _id, \
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.name = "ldo"#_id, \
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.of_match = of_match_ptr("ldo"#_id), \
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.regulators_node = "regulators", \
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.ops = &max77838_regulator_ops, \
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.min_uV = MAX77838_LDO_VOLT_MIN, \
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.uV_step = MAX77838_LDO_VOLT_STEP, \
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.n_voltages = MAX77838_VOLT_RANGE(LDO), \
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.enable_reg = MAX77838_REG_EN, \
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.enable_mask = MAX77838_LDO ## _id ## _EN, \
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.vsel_reg = MAX77838_REG_LDO ## _id ## _CFG, \
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.vsel_mask = MAX77838_MASK_LDO, \
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.active_discharge_off = 0, \
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.active_discharge_on = MAX77838_LDO_AD, \
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.active_discharge_mask = MAX77838_LDO_AD, \
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.active_discharge_reg = MAX77838_REG_LDO ## _id ## _CFG, \
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.owner = THIS_MODULE, \
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}
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#define MAX77838_BUCK_DESC \
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[MAX77838_BUCK] = { \
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.id = MAX77838_BUCK, \
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.name = "buck", \
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.of_match = of_match_ptr("buck"), \
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.regulators_node = "regulators", \
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.ops = &max77838_regulator_ops, \
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.min_uV = MAX77838_BUCK_VOLT_MIN, \
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.uV_step = MAX77838_BUCK_VOLT_STEP, \
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.n_voltages = MAX77838_VOLT_RANGE(BUCK), \
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.enable_reg = MAX77838_REG_EN, \
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.enable_mask = MAX77838_BUCK_EN, \
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.vsel_reg = MAX77838_REG_BUCK_VOUT, \
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.vsel_mask = MAX77838_MASK_BUCK, \
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.active_discharge_off = 0, \
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.active_discharge_on = MAX77838_BUCK_AD, \
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.active_discharge_mask = MAX77838_BUCK_AD, \
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.active_discharge_reg = MAX77838_REG_BUCK_CFG1, \
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.owner = THIS_MODULE, \
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}
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struct max77838_regulator_info {
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struct regmap *regmap;
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};
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static const struct regmap_config max77838_regmap_config = {
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.reg_bits = 8,
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.val_bits = 8,
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.max_register = MAX77838_REG_BUCK_VOUT,
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};
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static const struct regulator_ops max77838_regulator_ops = {
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.enable = regulator_enable_regmap,
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.disable = regulator_disable_regmap,
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.is_enabled = regulator_is_enabled_regmap,
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.list_voltage = regulator_list_voltage_linear,
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.map_voltage = regulator_map_voltage_linear,
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.get_voltage_sel = regulator_get_voltage_sel_regmap,
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.set_voltage_sel = regulator_set_voltage_sel_regmap,
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.set_active_discharge = regulator_set_active_discharge_regmap,
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};
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static const struct regulator_desc max77838_regulators_desc[] = {
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MAX77838_LDO(1),
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MAX77838_LDO(2),
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MAX77838_LDO(3),
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MAX77838_LDO(4),
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MAX77838_BUCK_DESC,
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};
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static int max77838_read_device_id(struct regmap *regmap, struct device *dev)
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{
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unsigned int device_id;
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int ret;
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ret = regmap_read(regmap, MAX77838_REG_DEVICE_ID, &device_id);
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if (!ret)
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dev_dbg(dev, "DEVICE_ID: 0x%x\n", device_id);
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return ret;
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}
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static int max77838_i2c_probe(struct i2c_client *client)
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{
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struct device *dev = &client->dev;
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struct max77838_regulator_info *info;
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struct regulator_config config = {};
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struct regulator_dev *rdev;
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struct regmap *regmap;
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int i;
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info = devm_kzalloc(dev, sizeof(struct max77838_regulator_info),
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GFP_KERNEL);
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if (!info)
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return -ENOMEM;
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regmap = devm_regmap_init_i2c(client, &max77838_regmap_config);
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if (IS_ERR(regmap)) {
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dev_err(dev, "Failed to allocate regmap!\n");
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return PTR_ERR(regmap);
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}
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info->regmap = regmap;
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i2c_set_clientdata(client, info);
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config.dev = dev;
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config.regmap = regmap;
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config.driver_data = info;
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for (i = 0; i < MAX77838_MAX_REGULATORS; i++) {
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rdev = devm_regulator_register(dev,
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&max77838_regulators_desc[i],
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&config);
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if (IS_ERR(rdev)) {
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dev_err(dev, "Failed to register regulator!\n");
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return PTR_ERR(rdev);
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}
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}
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return max77838_read_device_id(regmap, dev);
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}
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static const struct of_device_id __maybe_unused max77838_of_match[] = {
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{ .compatible = "maxim,max77838" },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, max77838_of_match);
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static const struct i2c_device_id max77838_id[] = {
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{ "max77838-regulator" },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(i2c, max77838_id);
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static struct i2c_driver max77838_regulator_driver = {
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.driver = {
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.name = "max77838",
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.probe_type = PROBE_PREFER_ASYNCHRONOUS,
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.of_match_table = of_match_ptr(max77838_of_match),
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},
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.probe = max77838_i2c_probe,
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.id_table = max77838_id,
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};
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module_i2c_driver(max77838_regulator_driver);
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MODULE_AUTHOR("Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>");
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MODULE_DESCRIPTION("MAX77838 PMIC regulator driver");
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MODULE_LICENSE("GPL");

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