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@xxxxxxxxx>
---
MAINTAINERS | 1 +
drivers/regulator/Kconfig | 8 +
drivers/regulator/Makefile | 1 +
drivers/regulator/max77838-regulator.c | 221 +++++++++++++++++++++++++
4 files changed, 231 insertions(+)
create mode 100644 drivers/regulator/max77838-regulator.c
diff --git a/MAINTAINERS b/MAINTAINERS
index a4916a178..276374ba7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15066,6 +15066,7 @@ M: Ivaylo Ivanov <ivo.ivanov.ivanov1@xxxxxxxxx>
L: linux-kernel@xxxxxxxxxxxxxxx
S: Maintained
F: Documentation/devicetree/bindings/regulator/maxim,max77838.yaml
+F: drivers/regulator/max77838-regulator.c
MAXIM MAX77976 BATTERY CHARGER
M: Luca Ceresoli <luca@xxxxxxxxxxxxxxxx>
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 41b56b647..18601bdc0 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -777,6 +777,14 @@ config REGULATOR_MAX77826
It includes support for control of output voltage. This
regulator is found on the Samsung Galaxy S5 (klte) smartphone.
+config REGULATOR_MAX77838
+ tristate "Maxim 77838 regulator"
+ depends on REGMAP_I2C
+ help
+ This driver controls a Maxim 77838 regulator via I2C bus.
+ The regulator include 4 LDOs and a BUCK regulator. It's
+ present on the Samsung Galaxy S7 lineup of smartphones.
+
config REGULATOR_MC13XXX_CORE
tristate
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index be98b29d6..0622e9de6 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -92,6 +92,7 @@ obj-$(CONFIG_REGULATOR_MAX77686) += max77686-regulator.o
obj-$(CONFIG_REGULATOR_MAX77693) += max77693-regulator.o
obj-$(CONFIG_REGULATOR_MAX77802) += max77802-regulator.o
obj-$(CONFIG_REGULATOR_MAX77826) += max77826-regulator.o
+obj-$(CONFIG_REGULATOR_MAX77838) += max77838-regulator.o
obj-$(CONFIG_REGULATOR_MAX77857) += max77857-regulator.o
obj-$(CONFIG_REGULATOR_MC13783) += mc13783-regulator.o
obj-$(CONFIG_REGULATOR_MC13892) += mc13892-regulator.o
diff --git a/drivers/regulator/max77838-regulator.c b/drivers/regulator/max77838-regulator.c
new file mode 100644
index 000000000..9faddbfd2
--- /dev/null
+++ b/drivers/regulator/max77838-regulator.c
@@ -0,0 +1,221 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+//
+// regulator driver for Maxim MAX77838
+//
+// based on max77826-regulator.c
+//
+// Copyright (c) 2025, Ivaylo Ivanov <ivo.ivanov.ivanov1@xxxxxxxxx>
+
+#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/of_regulator.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+
+enum max77838_registers {
+ MAX77838_REG_DEVICE_ID = 0x00,
+ MAX77838_REG_TOPSYS_STAT,
+ MAX77838_REG_STAT,
+ MAX77838_REG_EN,
+ MAX77838_REG_GPIO_PD_CTRL,
+ MAX77838_REG_UVLO_CFG1,
+ /* 0x06 - 0x0B: reserved */
+ MAX77838_REG_I2C_CFG = 0x0C,
+ /* 0x0D - 0x0F: reserved */
+ MAX77838_REG_LDO1_CFG = 0x10,
+ MAX77838_REG_LDO2_CFG,
+ MAX77838_REG_LDO3_CFG,
+ MAX77838_REG_LDO4_CFG,
+ /* 0x14 - 0x1F: reserved */
+ MAX77838_REG_BUCK_CFG1 = 0x20,
+ MAX77838_REG_BUCK_VOUT,
+};
+
+enum max77838_regulators {
+ MAX77838_LDO1 = 0,
+ MAX77838_LDO2,
+ MAX77838_LDO3,
+ MAX77838_LDO4,
+ MAX77838_BUCK,
+ MAX77838_MAX_REGULATORS,
+};
+
+#define MAX77838_MASK_LDO 0x7f
+#define MAX77838_MASK_BUCK 0xff
+
+#define MAX77838_LDO1_EN BIT(0)
+#define MAX77838_LDO2_EN BIT(1)
+#define MAX77838_LDO3_EN BIT(2)
+#define MAX77838_LDO4_EN BIT(3)
+#define MAX77838_BUCK_EN BIT(4)
+
+#define MAX77838_BUCK_AD BIT(3)
+#define MAX77838_LDO_AD BIT(7)
+
+#define MAX77838_LDO_VOLT_MIN 600000
+#define MAX77838_LDO_VOLT_MAX 3775000
+#define MAX77838_LDO_VOLT_STEP 25000
+
+#define MAX77838_BUCK_VOLT_MIN 500000
+#define MAX77838_BUCK_VOLT_MAX 2093750
+#define MAX77838_BUCK_VOLT_STEP 6250
+
+#define MAX77838_VOLT_RANGE(_type) \
+ ((MAX77838_ ## _type ## _VOLT_MAX - \
+ MAX77838_ ## _type ## _VOLT_MIN) / \
+ MAX77838_ ## _type ## _VOLT_STEP + 1)
+
+#define MAX77838_LDO(_id) \
+ [MAX77838_LDO ## _id] = { \
+ .id = MAX77838_LDO ## _id, \
+ .name = "ldo"#_id, \
+ .of_match = of_match_ptr("ldo"#_id), \
+ .regulators_node = "regulators", \
+ .ops = &max77838_regulator_ops, \
+ .min_uV = MAX77838_LDO_VOLT_MIN, \
+ .uV_step = MAX77838_LDO_VOLT_STEP, \
+ .n_voltages = MAX77838_VOLT_RANGE(LDO), \
+ .enable_reg = MAX77838_REG_EN, \
+ .enable_mask = MAX77838_LDO ## _id ## _EN, \
+ .vsel_reg = MAX77838_REG_LDO ## _id ## _CFG, \
+ .vsel_mask = MAX77838_MASK_LDO, \
+ .active_discharge_off = 0, \
+ .active_discharge_on = MAX77838_LDO_AD, \
+ .active_discharge_mask = MAX77838_LDO_AD, \
+ .active_discharge_reg = MAX77838_REG_LDO ## _id ## _CFG, \
+ .owner = THIS_MODULE, \
+ }
+
+#define MAX77838_BUCK_DESC \
+ [MAX77838_BUCK] = { \
+ .id = MAX77838_BUCK, \
+ .name = "buck", \
+ .of_match = of_match_ptr("buck"), \
+ .regulators_node = "regulators", \
+ .ops = &max77838_regulator_ops, \
+ .min_uV = MAX77838_BUCK_VOLT_MIN, \
+ .uV_step = MAX77838_BUCK_VOLT_STEP, \
+ .n_voltages = MAX77838_VOLT_RANGE(BUCK), \
+ .enable_reg = MAX77838_REG_EN, \
+ .enable_mask = MAX77838_BUCK_EN, \
+ .vsel_reg = MAX77838_REG_BUCK_VOUT, \
+ .vsel_mask = MAX77838_MASK_BUCK, \
+ .active_discharge_off = 0, \
+ .active_discharge_on = MAX77838_BUCK_AD, \
+ .active_discharge_mask = MAX77838_BUCK_AD, \
+ .active_discharge_reg = MAX77838_REG_BUCK_CFG1, \
+ .owner = THIS_MODULE, \
+ }
+
+struct max77838_regulator_info {
+ struct regmap *regmap;
+};
+
+static const struct regmap_config max77838_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = MAX77838_REG_BUCK_VOUT,
+};
+
+static const struct regulator_ops max77838_regulator_ops = {
+ .enable = regulator_enable_regmap,
+ .disable = regulator_disable_regmap,
+ .is_enabled = regulator_is_enabled_regmap,
+ .list_voltage = regulator_list_voltage_linear,
+ .map_voltage = regulator_map_voltage_linear,
+ .get_voltage_sel = regulator_get_voltage_sel_regmap,
+ .set_voltage_sel = regulator_set_voltage_sel_regmap,
+ .set_active_discharge = regulator_set_active_discharge_regmap,
+};
+
+static const struct regulator_desc max77838_regulators_desc[] = {
+ MAX77838_LDO(1),
+ MAX77838_LDO(2),
+ MAX77838_LDO(3),
+ MAX77838_LDO(4),
+ MAX77838_BUCK_DESC,
+};
+
+static int max77838_read_device_id(struct regmap *regmap, struct device *dev)
+{
+ unsigned int device_id;
+ int ret;
+
+ ret = regmap_read(regmap, MAX77838_REG_DEVICE_ID, &device_id);
+ if (!ret)
+ dev_dbg(dev, "DEVICE_ID: 0x%x\n", device_id);
+
+ return ret;
+}
+
+static int max77838_i2c_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ struct max77838_regulator_info *info;
+ struct regulator_config config = {};
+ struct regulator_dev *rdev;
+ struct regmap *regmap;
+ int i;
+
+ info = devm_kzalloc(dev, sizeof(struct max77838_regulator_info),
+ GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+
+ regmap = devm_regmap_init_i2c(client, &max77838_regmap_config);
+ if (IS_ERR(regmap)) {
+ dev_err(dev, "Failed to allocate regmap!\n");
+ return PTR_ERR(regmap);
+ }
+
+ info->regmap = regmap;
+ i2c_set_clientdata(client, info);
+
+ config.dev = dev;
+ config.regmap = regmap;
+ config.driver_data = info;
+
+ for (i = 0; i < MAX77838_MAX_REGULATORS; i++) {
+ rdev = devm_regulator_register(dev,
+ &max77838_regulators_desc[i],
+ &config);
+ if (IS_ERR(rdev)) {
+ dev_err(dev, "Failed to register regulator!\n");
+ return PTR_ERR(rdev);
+ }
+ }
+
+ return max77838_read_device_id(regmap, dev);
+}
+
+static const struct of_device_id __maybe_unused max77838_of_match[] = {
+ { .compatible = "maxim,max77838" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, max77838_of_match);
+
+static const struct i2c_device_id max77838_id[] = {
+ { "max77838-regulator" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, max77838_id);
+
+static struct i2c_driver max77838_regulator_driver = {
+ .driver = {
+ .name = "max77838",
+ .probe_type = PROBE_PREFER_ASYNCHRONOUS,
+ .of_match_table = of_match_ptr(max77838_of_match),
+ },
+ .probe = max77838_i2c_probe,
+ .id_table = max77838_id,
+};
+module_i2c_driver(max77838_regulator_driver);
+
+MODULE_AUTHOR("Ivaylo Ivanov <ivo.ivanov.ivanov1@xxxxxxxxx>");
+MODULE_DESCRIPTION("MAX77838 PMIC regulator driver");
+MODULE_LICENSE("GPL");
--
2.43.0
