drivers/regulator/sgm3804-regulator.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 //
 // SGMicro SGM3804 regulator Driver
 //
 // Copyright (C) 2025 Kancy Joe <kancy2333@outlook.com>
 // Copyright (C) 2026 Linaro Limited
 // Author: Neil Armstrong <neil.armstrong@linaro.org>

 #include <linux/err.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/regmap.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/of_regulator.h>
 #include <linux/gpio/consumer.h>

 #define SGM3804_POS_RAIL_VOLTAGE_REG	0x0
 #define SGM3804_NEG_RAIL_VOLTAGE_REG	0x1
 #define SGM3804_RAIL_DISCHARGE_REG	0x3

 #define RAIL_VOLTAGE_MASK	GENMASK(5, 0)

 #define POS_RAIL_DISCHARGE_EN	BIT(1)
 #define NEG_RAIL_DISCHARGE_EN	BIT(0)

 #define RAIL_VOLTAGE_INVALID		RAIL_VOLTAGE_MASK
 #define RAIL_DISCHARGE_REG_DEFAULT	(POS_RAIL_DISCHARGE_EN | NEG_RAIL_DISCHARGE_EN)

 #define SGM3804_VOLTAGES_MAX_SELECTOR	0x2f

 enum {
 	SGM3804_POS_RAIL = 0,
 	SGM3804_NEG_RAIL,
 	SGM3804_RAIL_COUNT,
 };

 /*
  * The registers are only writable when the gpio is enabled, so
  * we need to use the cache for read operations and set the regmap
  * as cache_only when both GPIOs are down.
  */
 struct sgm3804_data {
 	struct regmap *regmap;
 	/* Protects the regcache state update */
 	struct mutex lock;
 	struct gpio_desc *gpios[SGM3804_RAIL_COUNT];
 };

 static const struct linear_range sgm3804_voltages[] = {
 	REGULATOR_LINEAR_RANGE(2400000, 0x20, 0x2f, 100000),
 	REGULATOR_LINEAR_RANGE(4000000, 0x00, 0x17, 100000),
 };

 /*
  * The cache is populated with those hardware default values
  * so the regmap_update_bits operation will use the cached
  * value to build a new register value and write it when GPIOs
  * are enabled.
  */
 static const struct reg_default sgm3804_reg_defaults[] = {
 	{ SGM3804_POS_RAIL_VOLTAGE_REG, RAIL_VOLTAGE_INVALID },
 	{ SGM3804_NEG_RAIL_VOLTAGE_REG, RAIL_VOLTAGE_INVALID },
 	{ SGM3804_RAIL_DISCHARGE_REG, RAIL_DISCHARGE_REG_DEFAULT },
 };

 /* Registers are only writable */
 static bool sgm3804_writeable_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
 	case SGM3804_POS_RAIL_VOLTAGE_REG:
 	case SGM3804_NEG_RAIL_VOLTAGE_REG:
 	case SGM3804_RAIL_DISCHARGE_REG:
 		return true;
 	default:
 		return false;
 	}
 }

 /*
  * Since all registers are only writeable, regmap will only read from the cache data.
  */
 static bool sgm3804_readable_reg(struct device *dev, unsigned int reg)
 {
 	return false;
 }

 static const struct regmap_config sgm3804_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 	.max_register = 0x03,
 	.writeable_reg = sgm3804_writeable_reg,
 	.readable_reg = sgm3804_readable_reg,
 	.cache_type = REGCACHE_MAPLE,
 	.reg_defaults = sgm3804_reg_defaults,
 	.num_reg_defaults = ARRAY_SIZE(sgm3804_reg_defaults),
 };

 static int sgm3804_sync_regcache_state(struct sgm3804_data *ctx)
 {
 	guard(mutex)(&ctx->lock);

 	/* If both GPIOs are down, IC is powered down and I2C writes will fail */
 	if (!gpiod_get_value_cansleep(ctx->gpios[SGM3804_POS_RAIL]) &&
 	    !gpiod_get_value_cansleep(ctx->gpios[SGM3804_NEG_RAIL])) {
 		regcache_cache_only(ctx->regmap, true);
 		regcache_mark_dirty(ctx->regmap);
 	} else {
 		int ret;

 		/* At least a GPIO is up, we can write registers */
 		regcache_cache_only(ctx->regmap, false);
 		ret = regcache_sync(ctx->regmap);
 		if (ret) {
 			regcache_cache_only(ctx->regmap, true);
 			return ret;
 		}
 	}

 	return 0;
 }

 static int sgm3804_get_voltage_sel(struct regulator_dev *rdev)
 {
 	int ret;

 	ret = regulator_get_voltage_sel_regmap(rdev);
 	if (ret < 0)
 		return ret;

 	/* Force setting a voltage on probe */
 	if (ret == RAIL_VOLTAGE_INVALID)
 		return -ENOTRECOVERABLE;

 	return ret;
 }

 static int sgm3804_enable(struct regulator_dev *rdev)
 {
 	struct sgm3804_data *ctx = rdev->reg_data;
 	int ret;

 	ret = gpiod_set_value_cansleep(ctx->gpios[rdev_get_id(rdev)], 1);
 	if (ret)
 		return ret;

 	ret = sgm3804_sync_regcache_state(ctx);
 	if (ret)
 		goto err;

 	return 0;

 err:
 	gpiod_set_value_cansleep(ctx->gpios[rdev_get_id(rdev)], 0);
 	return ret;
 }

 static int sgm3804_disable(struct regulator_dev *rdev)
 {
 	struct sgm3804_data *ctx = rdev->reg_data;
 	int ret;

 	ret = gpiod_set_value_cansleep(ctx->gpios[rdev_get_id(rdev)], 0);
 	if (ret)
 		return ret;

 	return sgm3804_sync_regcache_state(ctx);
 }

 static int sgm3804_is_enabled(struct regulator_dev *rdev)
 {
 	struct sgm3804_data *ctx = rdev->reg_data;

 	return gpiod_get_value_cansleep(ctx->gpios[rdev_get_id(rdev)]);
 }

 static const struct regulator_ops sgm3804_ops = {
 	.list_voltage = regulator_list_voltage_linear_range,
 	.map_voltage = regulator_map_voltage_linear_range,
 	.set_voltage_sel = regulator_set_voltage_sel_regmap,
 	.get_voltage_sel = sgm3804_get_voltage_sel,
 	.set_active_discharge = regulator_set_active_discharge_regmap,
 	.enable = sgm3804_enable,
 	.disable = sgm3804_disable,
 	.is_enabled = sgm3804_is_enabled,
 };

 static const struct regulator_desc sgm3804_regulator_desc[] = {
 	/* Positive Output */
 	{
 		.name = "pos",
 		.of_match = "pos",
 		.supply_name = "vin",
 		.id = SGM3804_POS_RAIL,
 		.ops = &sgm3804_ops,
 		.type = REGULATOR_VOLTAGE,
 		.linear_ranges = sgm3804_voltages,
 		.n_linear_ranges = ARRAY_SIZE(sgm3804_voltages),
 		.n_voltages = SGM3804_VOLTAGES_MAX_SELECTOR + 1,
 		.vsel_reg = SGM3804_POS_RAIL_VOLTAGE_REG,
 		.vsel_mask = RAIL_VOLTAGE_MASK,
 		.active_discharge_on = POS_RAIL_DISCHARGE_EN,
 		.active_discharge_mask = POS_RAIL_DISCHARGE_EN,
 		.active_discharge_reg = SGM3804_RAIL_DISCHARGE_REG,
 		.enable_time = 40000,
 		.owner = THIS_MODULE,
 	},
 	/* Negative Output */
 	{
 		.name = "neg",
 		.of_match = "neg",
 		.supply_name = "vin",
 		.id = SGM3804_NEG_RAIL,
 		.ops = &sgm3804_ops,
 		.type = REGULATOR_VOLTAGE,
 		.linear_ranges = sgm3804_voltages,
 		.n_linear_ranges = ARRAY_SIZE(sgm3804_voltages),
 		.n_voltages = SGM3804_VOLTAGES_MAX_SELECTOR + 1,
 		.vsel_reg = SGM3804_NEG_RAIL_VOLTAGE_REG,
 		.vsel_mask = RAIL_VOLTAGE_MASK,
 		.active_discharge_on = NEG_RAIL_DISCHARGE_EN,
 		.active_discharge_mask = NEG_RAIL_DISCHARGE_EN,
 		.active_discharge_reg = SGM3804_RAIL_DISCHARGE_REG,
 		.enable_time = 40000,
 		.owner = THIS_MODULE,
 	},
 };

 static int sgm3804_probe(struct i2c_client *i2c)
 {
 	struct device *dev = &i2c->dev;
 	struct sgm3804_data *ctx;
 	int ret, i;

 	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
 		return -ENOMEM;

 	mutex_init(&ctx->lock);

 	ctx->regmap = devm_regmap_init_i2c(i2c, &sgm3804_regmap_config);
 	if (IS_ERR(ctx->regmap))
 		return dev_err_probe(dev, PTR_ERR(ctx->regmap),
 				     "failed to init regmap\n");

 	/* Get enable GPIOs */
 	for (i = 0; i < ARRAY_SIZE(sgm3804_regulator_desc); i++) {
 		const struct regulator_desc *reg = &sgm3804_regulator_desc[i];
 		struct fwnode_handle *child;

 		child = device_get_named_child_node(dev, reg->of_match);
 		if (!child) {
 			dev_err(dev, "missing child '%s'\n", reg->of_match);
 			return -EINVAL;
 		}

 		ctx->gpios[i] = devm_fwnode_gpiod_get(dev, child, "enable",
 						      GPIOD_ASIS, reg->name);
 		fwnode_handle_put(child);
 		if (IS_ERR(ctx->gpios[i]))
 			return dev_err_probe(dev, PTR_ERR(ctx->gpios[i]),
 					     "failed to get '%s' enable GPIO\n",
 					     reg->name);
 	}

 	ret = sgm3804_sync_regcache_state(ctx);
 	if (ret)
 		return ret;

 	for (i = 0; i < ARRAY_SIZE(sgm3804_regulator_desc); i++) {
 		struct regulator_config config = { };
 		struct regulator_dev *rdev;

 		config.dev = dev;
 		config.regmap = ctx->regmap;
 		config.of_node = dev_of_node(dev);
 		config.driver_data = ctx;
 		rdev = devm_regulator_register(dev, &sgm3804_regulator_desc[i],
 					       &config);
 		if (IS_ERR(rdev))
 			return dev_err_probe(dev, PTR_ERR(rdev),
 					     "failed to register regulator %d\n", i);
 	}

 	return 0;
 }

 static const struct i2c_device_id sgm3804_id[] = {
 	{ .name = "sgm3804" },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, sgm3804_id);

 static const struct of_device_id sgm3804_of_match[] = {
 	{ .compatible = "sgmicro,sgm3804" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, sgm3804_of_match);

 static struct i2c_driver sgm3804_regulator_driver = {
 	.driver = {
 		.name = "sgm3804",
 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
 		.of_match_table = sgm3804_of_match,
 	},
 	.probe = sgm3804_probe,
 	.id_table = sgm3804_id,
 };

 module_i2c_driver(sgm3804_regulator_driver);

 MODULE_DESCRIPTION("SGMicro SGM3804 regulator Driver");
 MODULE_AUTHOR("Kancy Joe <kancy2333@outlook.com>");
 MODULE_AUTHOR("Neil Armstrong <neil.armstrong@linaro.org>");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-only
	//
	// SGMicro SGM3804 regulator Driver
	//
	// Copyright (C) 2025 Kancy Joe <kancy2333@outlook.com>
	// Copyright (C) 2026 Linaro Limited
	// Author: Neil Armstrong <neil.armstrong@linaro.org>

	#include <linux/err.h>
	#include <linux/i2c.h>
	#include <linux/module.h>
	#include <linux/regmap.h>
	#include <linux/regulator/driver.h>
	#include <linux/regulator/of_regulator.h>
	#include <linux/gpio/consumer.h>

	#define SGM3804_POS_RAIL_VOLTAGE_REG 0x0
	#define SGM3804_NEG_RAIL_VOLTAGE_REG 0x1
	#define SGM3804_RAIL_DISCHARGE_REG 0x3

	#define RAIL_VOLTAGE_MASK GENMASK(5, 0)

	#define POS_RAIL_DISCHARGE_EN BIT(1)
	#define NEG_RAIL_DISCHARGE_EN BIT(0)

	#define RAIL_VOLTAGE_INVALID RAIL_VOLTAGE_MASK
	#define RAIL_DISCHARGE_REG_DEFAULT (POS_RAIL_DISCHARGE_EN \| NEG_RAIL_DISCHARGE_EN)

	#define SGM3804_VOLTAGES_MAX_SELECTOR 0x2f

	enum {
	SGM3804_POS_RAIL = 0,
	SGM3804_NEG_RAIL,
	SGM3804_RAIL_COUNT,
	};

	/*
	* The registers are only writable when the gpio is enabled, so
	* we need to use the cache for read operations and set the regmap
	* as cache_only when both GPIOs are down.
	*/
	struct sgm3804_data {
	struct regmap *regmap;
	/* Protects the regcache state update */
	struct mutex lock;
	struct gpio_desc *gpios[SGM3804_RAIL_COUNT];
	};

	static const struct linear_range sgm3804_voltages[] = {
	REGULATOR_LINEAR_RANGE(2400000, 0x20, 0x2f, 100000),
	REGULATOR_LINEAR_RANGE(4000000, 0x00, 0x17, 100000),
	};

	/*
	* The cache is populated with those hardware default values
	* so the regmap_update_bits operation will use the cached
	* value to build a new register value and write it when GPIOs
	* are enabled.
	*/
	static const struct reg_default sgm3804_reg_defaults[] = {
	{ SGM3804_POS_RAIL_VOLTAGE_REG, RAIL_VOLTAGE_INVALID },
	{ SGM3804_NEG_RAIL_VOLTAGE_REG, RAIL_VOLTAGE_INVALID },
	{ SGM3804_RAIL_DISCHARGE_REG, RAIL_DISCHARGE_REG_DEFAULT },
	};

	/* Registers are only writable */
	static bool sgm3804_writeable_reg(struct device *dev, unsigned int reg)
	{
	switch (reg) {
	case SGM3804_POS_RAIL_VOLTAGE_REG:
	case SGM3804_NEG_RAIL_VOLTAGE_REG:
	case SGM3804_RAIL_DISCHARGE_REG:
	return true;
	default:
	return false;
	}
	}

	/*
	* Since all registers are only writeable, regmap will only read from the cache data.
	*/
	static bool sgm3804_readable_reg(struct device *dev, unsigned int reg)
	{
	return false;
	}

	static const struct regmap_config sgm3804_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = 0x03,
	.writeable_reg = sgm3804_writeable_reg,
	.readable_reg = sgm3804_readable_reg,
	.cache_type = REGCACHE_MAPLE,
	.reg_defaults = sgm3804_reg_defaults,
	.num_reg_defaults = ARRAY_SIZE(sgm3804_reg_defaults),
	};

	static int sgm3804_sync_regcache_state(struct sgm3804_data *ctx)
	{
	guard(mutex)(&ctx->lock);

	/* If both GPIOs are down, IC is powered down and I2C writes will fail */
	if (!gpiod_get_value_cansleep(ctx->gpios[SGM3804_POS_RAIL]) &&
	!gpiod_get_value_cansleep(ctx->gpios[SGM3804_NEG_RAIL])) {
	regcache_cache_only(ctx->regmap, true);
	regcache_mark_dirty(ctx->regmap);
	} else {
	int ret;

	/* At least a GPIO is up, we can write registers */
	regcache_cache_only(ctx->regmap, false);
	ret = regcache_sync(ctx->regmap);
	if (ret) {
	regcache_cache_only(ctx->regmap, true);
	return ret;
	}
	}

	return 0;
	}

	static int sgm3804_get_voltage_sel(struct regulator_dev *rdev)
	{
	int ret;

	ret = regulator_get_voltage_sel_regmap(rdev);
	if (ret < 0)
	return ret;

	/* Force setting a voltage on probe */
	if (ret == RAIL_VOLTAGE_INVALID)
	return -ENOTRECOVERABLE;

	return ret;
	}

	static int sgm3804_enable(struct regulator_dev *rdev)
	{
	struct sgm3804_data *ctx = rdev->reg_data;
	int ret;

	ret = gpiod_set_value_cansleep(ctx->gpios[rdev_get_id(rdev)], 1);
	if (ret)
	return ret;

	ret = sgm3804_sync_regcache_state(ctx);
	if (ret)
	goto err;

	return 0;

	err:
	gpiod_set_value_cansleep(ctx->gpios[rdev_get_id(rdev)], 0);
	return ret;
	}

	static int sgm3804_disable(struct regulator_dev *rdev)
	{
	struct sgm3804_data *ctx = rdev->reg_data;
	int ret;

	ret = gpiod_set_value_cansleep(ctx->gpios[rdev_get_id(rdev)], 0);
	if (ret)
	return ret;

	return sgm3804_sync_regcache_state(ctx);
	}

	static int sgm3804_is_enabled(struct regulator_dev *rdev)
	{
	struct sgm3804_data *ctx = rdev->reg_data;

	return gpiod_get_value_cansleep(ctx->gpios[rdev_get_id(rdev)]);
	}

	static const struct regulator_ops sgm3804_ops = {
	.list_voltage = regulator_list_voltage_linear_range,
	.map_voltage = regulator_map_voltage_linear_range,
	.set_voltage_sel = regulator_set_voltage_sel_regmap,
	.get_voltage_sel = sgm3804_get_voltage_sel,
	.set_active_discharge = regulator_set_active_discharge_regmap,
	.enable = sgm3804_enable,
	.disable = sgm3804_disable,
	.is_enabled = sgm3804_is_enabled,
	};

	static const struct regulator_desc sgm3804_regulator_desc[] = {
	/* Positive Output */
	{
	.name = "pos",
	.of_match = "pos",
	.supply_name = "vin",
	.id = SGM3804_POS_RAIL,
	.ops = &sgm3804_ops,
	.type = REGULATOR_VOLTAGE,
	.linear_ranges = sgm3804_voltages,
	.n_linear_ranges = ARRAY_SIZE(sgm3804_voltages),
	.n_voltages = SGM3804_VOLTAGES_MAX_SELECTOR + 1,
	.vsel_reg = SGM3804_POS_RAIL_VOLTAGE_REG,
	.vsel_mask = RAIL_VOLTAGE_MASK,
	.active_discharge_on = POS_RAIL_DISCHARGE_EN,
	.active_discharge_mask = POS_RAIL_DISCHARGE_EN,
	.active_discharge_reg = SGM3804_RAIL_DISCHARGE_REG,
	.enable_time = 40000,
	.owner = THIS_MODULE,
	},
	/* Negative Output */
	{
	.name = "neg",
	.of_match = "neg",
	.supply_name = "vin",
	.id = SGM3804_NEG_RAIL,
	.ops = &sgm3804_ops,
	.type = REGULATOR_VOLTAGE,
	.linear_ranges = sgm3804_voltages,
	.n_linear_ranges = ARRAY_SIZE(sgm3804_voltages),
	.n_voltages = SGM3804_VOLTAGES_MAX_SELECTOR + 1,
	.vsel_reg = SGM3804_NEG_RAIL_VOLTAGE_REG,
	.vsel_mask = RAIL_VOLTAGE_MASK,
	.active_discharge_on = NEG_RAIL_DISCHARGE_EN,
	.active_discharge_mask = NEG_RAIL_DISCHARGE_EN,
	.active_discharge_reg = SGM3804_RAIL_DISCHARGE_REG,
	.enable_time = 40000,
	.owner = THIS_MODULE,
	},
	};

	static int sgm3804_probe(struct i2c_client *i2c)
	{
	struct device *dev = &i2c->dev;
	struct sgm3804_data *ctx;
	int ret, i;

	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
	if (!ctx)
	return -ENOMEM;

	mutex_init(&ctx->lock);

	ctx->regmap = devm_regmap_init_i2c(i2c, &sgm3804_regmap_config);
	if (IS_ERR(ctx->regmap))
	return dev_err_probe(dev, PTR_ERR(ctx->regmap),
	"failed to init regmap\n");

	/* Get enable GPIOs */
	for (i = 0; i < ARRAY_SIZE(sgm3804_regulator_desc); i++) {
	const struct regulator_desc *reg = &sgm3804_regulator_desc[i];
	struct fwnode_handle *child;

	child = device_get_named_child_node(dev, reg->of_match);
	if (!child) {
	dev_err(dev, "missing child '%s'\n", reg->of_match);
	return -EINVAL;
	}

	ctx->gpios[i] = devm_fwnode_gpiod_get(dev, child, "enable",
	GPIOD_ASIS, reg->name);
	fwnode_handle_put(child);
	if (IS_ERR(ctx->gpios[i]))
	return dev_err_probe(dev, PTR_ERR(ctx->gpios[i]),
	"failed to get '%s' enable GPIO\n",
	reg->name);
	}

	ret = sgm3804_sync_regcache_state(ctx);
	if (ret)
	return ret;

	for (i = 0; i < ARRAY_SIZE(sgm3804_regulator_desc); i++) {
	struct regulator_config config = { };
	struct regulator_dev *rdev;

	config.dev = dev;
	config.regmap = ctx->regmap;
	config.of_node = dev_of_node(dev);
	config.driver_data = ctx;
	rdev = devm_regulator_register(dev, &sgm3804_regulator_desc[i],
	&config);
	if (IS_ERR(rdev))
	return dev_err_probe(dev, PTR_ERR(rdev),
	"failed to register regulator %d\n", i);
	}

	return 0;
	}

	static const struct i2c_device_id sgm3804_id[] = {
	{ .name = "sgm3804" },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, sgm3804_id);

	static const struct of_device_id sgm3804_of_match[] = {
	{ .compatible = "sgmicro,sgm3804" },
	{ }
	};
	MODULE_DEVICE_TABLE(of, sgm3804_of_match);

	static struct i2c_driver sgm3804_regulator_driver = {
	.driver = {
	.name = "sgm3804",
	.probe_type = PROBE_PREFER_ASYNCHRONOUS,
	.of_match_table = sgm3804_of_match,
	},
	.probe = sgm3804_probe,
	.id_table = sgm3804_id,
	};

	module_i2c_driver(sgm3804_regulator_driver);

	MODULE_DESCRIPTION("SGMicro SGM3804 regulator Driver");
	MODULE_AUTHOR("Kancy Joe <kancy2333@outlook.com>");
	MODULE_AUTHOR("Neil Armstrong <neil.armstrong@linaro.org>");
	MODULE_LICENSE("GPL");