regulator: add support for SY8827N regulator

The SY8827N from Silergy Corp is a single output DC/DC converter. The
voltage can be controlled via I2C.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Link: https://lore.kernel.org/r/20200702171438.20edc523@xhacker.debian
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/Kconfig

@@ -1009,6 +1009,13 @@ config REGULATOR_SY8824X
 	help
 	  This driver supports SY8824C single output regulator.
 
+config REGULATOR_SY8827N
+	tristate "Silergy SY8827N regulator"
+	depends on I2C && (OF || COMPILE_TEST)
+	select REGMAP_I2C
+	help
+	  This driver supports SY8827N single output regulator.
+
 config REGULATOR_TPS51632
 	tristate "TI TPS51632 Power Regulator"
 	depends on I2C

drivers/regulator/Makefile

@@ -122,6 +122,7 @@ obj-$(CONFIG_REGULATOR_STPMIC1) += stpmic1_regulator.o
 obj-$(CONFIG_REGULATOR_STW481X_VMMC) += stw481x-vmmc.o
 obj-$(CONFIG_REGULATOR_SY8106A) += sy8106a-regulator.o
 obj-$(CONFIG_REGULATOR_SY8824X) += sy8824x.o
+obj-$(CONFIG_REGULATOR_SY8827N) += sy8827n.o
 obj-$(CONFIG_REGULATOR_TI_ABB) += ti-abb-regulator.o
 obj-$(CONFIG_REGULATOR_TPS6105X) += tps6105x-regulator.o
 obj-$(CONFIG_REGULATOR_TPS62360) += tps62360-regulator.o

drivers/regulator/sy8827n.c

@@ -0,0 +1,185 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// SY8827N regulator driver
+//
+// Copyright (C) 2020 Synaptics Incorporated
+//
+// Author: Jisheng Zhang <jszhang@kernel.org>
+
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/of_regulator.h>
+
+#define SY8827N_VSEL0		0
+#define   SY8827N_BUCK_EN	(1 << 7)
+#define   SY8827N_MODE		(1 << 6)
+#define SY8827N_VSEL1		1
+#define SY8827N_CTRL		2
+
+#define SY8827N_NVOLTAGES	64
+#define SY8827N_VSELMIN		600000
+#define SY8827N_VSELSTEP	12500
+
+struct sy8827n_device_info {
+	struct device *dev;
+	struct regulator_desc desc;
+	struct regulator_init_data *regulator;
+	struct gpio_desc *en_gpio;
+	unsigned int vsel_reg;
+};
+
+static int sy8827n_set_mode(struct regulator_dev *rdev, unsigned int mode)
+{
+	struct sy8827n_device_info *di = rdev_get_drvdata(rdev);
+
+	switch (mode) {
+	case REGULATOR_MODE_FAST:
+		regmap_update_bits(rdev->regmap, di->vsel_reg,
+				   SY8827N_MODE, SY8827N_MODE);
+		break;
+	case REGULATOR_MODE_NORMAL:
+		regmap_update_bits(rdev->regmap, di->vsel_reg,
+				   SY8827N_MODE, 0);
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static unsigned int sy8827n_get_mode(struct regulator_dev *rdev)
+{
+	struct sy8827n_device_info *di = rdev_get_drvdata(rdev);
+	u32 val;
+	int ret = 0;
+
+	ret = regmap_read(rdev->regmap, di->vsel_reg, &val);
+	if (ret < 0)
+		return ret;
+	if (val & SY8827N_MODE)
+		return REGULATOR_MODE_FAST;
+	else
+		return REGULATOR_MODE_NORMAL;
+}
+
+static const struct regulator_ops sy8827n_regulator_ops = {
+	.set_voltage_sel = regulator_set_voltage_sel_regmap,
+	.get_voltage_sel = regulator_get_voltage_sel_regmap,
+	.set_voltage_time_sel = regulator_set_voltage_time_sel,
+	.map_voltage = regulator_map_voltage_linear,
+	.list_voltage = regulator_list_voltage_linear,
+	.enable = regulator_enable_regmap,
+	.disable = regulator_disable_regmap,
+	.is_enabled = regulator_is_enabled_regmap,
+	.set_mode = sy8827n_set_mode,
+	.get_mode = sy8827n_get_mode,
+};
+
+static int sy8827n_regulator_register(struct sy8827n_device_info *di,
+			struct regulator_config *config)
+{
+	struct regulator_desc *rdesc = &di->desc;
+	struct regulator_dev *rdev;
+
+	rdesc->name = "sy8827n-reg";
+	rdesc->supply_name = "vin";
+	rdesc->ops = &sy8827n_regulator_ops;
+	rdesc->type = REGULATOR_VOLTAGE;
+	rdesc->n_voltages = SY8827N_NVOLTAGES;
+	rdesc->enable_reg = di->vsel_reg;
+	rdesc->enable_mask = SY8827N_BUCK_EN;
+	rdesc->min_uV = SY8827N_VSELMIN;
+	rdesc->uV_step = SY8827N_VSELSTEP;
+	rdesc->vsel_reg = di->vsel_reg;
+	rdesc->vsel_mask = rdesc->n_voltages - 1;
+	rdesc->owner = THIS_MODULE;
+
+	rdev = devm_regulator_register(di->dev, &di->desc, config);
+	return PTR_ERR_OR_ZERO(rdev);
+}
+
+static const struct regmap_config sy8827n_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static int sy8827n_i2c_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct device_node *np = dev->of_node;
+	struct sy8827n_device_info *di;
+	struct regulator_config config = { };
+	struct regmap *regmap;
+	int ret;
+
+	di = devm_kzalloc(dev, sizeof(struct sy8827n_device_info), GFP_KERNEL);
+	if (!di)
+		return -ENOMEM;
+
+	di->regulator = of_get_regulator_init_data(dev, np, &di->desc);
+	if (!di->regulator) {
+		dev_err(dev, "Platform data not found!\n");
+		return -EINVAL;
+	}
+
+	di->en_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_HIGH);
+	if (IS_ERR(di->en_gpio))
+		return PTR_ERR(di->en_gpio);
+
+	if (of_property_read_bool(np, "silergy,vsel-state-high"))
+		di->vsel_reg = SY8827N_VSEL1;
+	else
+		di->vsel_reg = SY8827N_VSEL0;
+
+	di->dev = dev;
+
+	regmap = devm_regmap_init_i2c(client, &sy8827n_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(dev, "Failed to allocate regmap!\n");
+		return PTR_ERR(regmap);
+	}
+	i2c_set_clientdata(client, di);
+
+	config.dev = di->dev;
+	config.init_data = di->regulator;
+	config.regmap = regmap;
+	config.driver_data = di;
+	config.of_node = np;
+
+	ret = sy8827n_regulator_register(di, &config);
+	if (ret < 0)
+		dev_err(dev, "Failed to register regulator!\n");
+	return ret;
+}
+
+static const struct of_device_id sy8827n_dt_ids[] = {
+	{
+		.compatible = "silergy,sy8827n",
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, sy8827n_dt_ids);
+
+static const struct i2c_device_id sy8827n_id[] = {
+	{ "sy8827n", },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, sy8827n_id);
+
+static struct i2c_driver sy8827n_regulator_driver = {
+	.driver = {
+		.name = "sy8827n-regulator",
+		.of_match_table = of_match_ptr(sy8827n_dt_ids),
+	},
+	.probe_new = sy8827n_i2c_probe,
+	.id_table = sy8827n_id,
+};
+module_i2c_driver(sy8827n_regulator_driver);
+
+MODULE_AUTHOR("Jisheng Zhang <jszhang@kernel.org>");
+MODULE_DESCRIPTION("SY8827N regulator driver");
+MODULE_LICENSE("GPL v2");