v4.19.13 snapshot.
diff --git a/drivers/regulator/fan53555.c b/drivers/regulator/fan53555.c
new file mode 100644
index 0000000..a3bc803
--- /dev/null
+++ b/drivers/regulator/fan53555.c
@@ -0,0 +1,496 @@
+/*
+ * FAN53555 Fairchild Digitally Programmable TinyBuck Regulator Driver.
+ *
+ * Supported Part Numbers:
+ * FAN53555UC00X/01X/03X/04X/05X
+ *
+ * Copyright (c) 2012 Marvell Technology Ltd.
+ * Yunfan Zhang <yfzhang@marvell.com>
+ *
+ * This package is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#include <linux/module.h>
+#include <linux/param.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/of_device.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+#include <linux/regulator/fan53555.h>
+
+/* Voltage setting */
+#define FAN53555_VSEL0		0x00
+#define FAN53555_VSEL1		0x01
+/* Control register */
+#define FAN53555_CONTROL	0x02
+/* IC Type */
+#define FAN53555_ID1		0x03
+/* IC mask version */
+#define FAN53555_ID2		0x04
+/* Monitor register */
+#define FAN53555_MONITOR	0x05
+
+/* VSEL bit definitions */
+#define VSEL_BUCK_EN	(1 << 7)
+#define VSEL_MODE		(1 << 6)
+#define VSEL_NSEL_MASK	0x3F
+/* Chip ID and Verison */
+#define DIE_ID		0x0F	/* ID1 */
+#define DIE_REV		0x0F	/* ID2 */
+/* Control bit definitions */
+#define CTL_OUTPUT_DISCHG	(1 << 7)
+#define CTL_SLEW_MASK		(0x7 << 4)
+#define CTL_SLEW_SHIFT		4
+#define CTL_RESET			(1 << 2)
+
+#define FAN53555_NVOLTAGES	64	/* Numbers of voltages */
+
+enum fan53555_vendor {
+	FAN53555_VENDOR_FAIRCHILD = 0,
+	FAN53555_VENDOR_SILERGY,
+};
+
+/* IC Type */
+enum {
+	FAN53555_CHIP_ID_00 = 0,
+	FAN53555_CHIP_ID_01,
+	FAN53555_CHIP_ID_02,
+	FAN53555_CHIP_ID_03,
+	FAN53555_CHIP_ID_04,
+	FAN53555_CHIP_ID_05,
+	FAN53555_CHIP_ID_08 = 8,
+};
+
+/* IC mask revision */
+enum {
+	FAN53555_CHIP_REV_00 = 0x3,
+	FAN53555_CHIP_REV_13 = 0xf,
+};
+
+enum {
+	SILERGY_SYR82X = 8,
+};
+
+struct fan53555_device_info {
+	enum fan53555_vendor vendor;
+	struct regmap *regmap;
+	struct device *dev;
+	struct regulator_desc desc;
+	struct regulator_dev *rdev;
+	struct regulator_init_data *regulator;
+	/* IC Type and Rev */
+	int chip_id;
+	int chip_rev;
+	/* Voltage setting register */
+	unsigned int vol_reg;
+	unsigned int sleep_reg;
+	/* Voltage range and step(linear) */
+	unsigned int vsel_min;
+	unsigned int vsel_step;
+	/* Voltage slew rate limiting */
+	unsigned int slew_rate;
+	/* Sleep voltage cache */
+	unsigned int sleep_vol_cache;
+};
+
+static int fan53555_set_suspend_voltage(struct regulator_dev *rdev, int uV)
+{
+	struct fan53555_device_info *di = rdev_get_drvdata(rdev);
+	int ret;
+
+	if (di->sleep_vol_cache == uV)
+		return 0;
+	ret = regulator_map_voltage_linear(rdev, uV, uV);
+	if (ret < 0)
+		return ret;
+	ret = regmap_update_bits(di->regmap, di->sleep_reg,
+					VSEL_NSEL_MASK, ret);
+	if (ret < 0)
+		return ret;
+	/* Cache the sleep voltage setting.
+	 * Might not be the real voltage which is rounded */
+	di->sleep_vol_cache = uV;
+
+	return 0;
+}
+
+static int fan53555_set_suspend_enable(struct regulator_dev *rdev)
+{
+	struct fan53555_device_info *di = rdev_get_drvdata(rdev);
+
+	return regmap_update_bits(di->regmap, di->sleep_reg,
+				  VSEL_BUCK_EN, VSEL_BUCK_EN);
+}
+
+static int fan53555_set_suspend_disable(struct regulator_dev *rdev)
+{
+	struct fan53555_device_info *di = rdev_get_drvdata(rdev);
+
+	return regmap_update_bits(di->regmap, di->sleep_reg,
+				  VSEL_BUCK_EN, 0);
+}
+
+static int fan53555_set_mode(struct regulator_dev *rdev, unsigned int mode)
+{
+	struct fan53555_device_info *di = rdev_get_drvdata(rdev);
+
+	switch (mode) {
+	case REGULATOR_MODE_FAST:
+		regmap_update_bits(di->regmap, di->vol_reg,
+				VSEL_MODE, VSEL_MODE);
+		break;
+	case REGULATOR_MODE_NORMAL:
+		regmap_update_bits(di->regmap, di->vol_reg, VSEL_MODE, 0);
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static unsigned int fan53555_get_mode(struct regulator_dev *rdev)
+{
+	struct fan53555_device_info *di = rdev_get_drvdata(rdev);
+	unsigned int val;
+	int ret = 0;
+
+	ret = regmap_read(di->regmap, di->vol_reg, &val);
+	if (ret < 0)
+		return ret;
+	if (val & VSEL_MODE)
+		return REGULATOR_MODE_FAST;
+	else
+		return REGULATOR_MODE_NORMAL;
+}
+
+static const int slew_rates[] = {
+	64000,
+	32000,
+	16000,
+	 8000,
+	 4000,
+	 2000,
+	 1000,
+	  500,
+};
+
+static int fan53555_set_ramp(struct regulator_dev *rdev, int ramp)
+{
+	struct fan53555_device_info *di = rdev_get_drvdata(rdev);
+	int regval = -1, i;
+
+	for (i = 0; i < ARRAY_SIZE(slew_rates); i++) {
+		if (ramp <= slew_rates[i])
+			regval = i;
+		else
+			break;
+	}
+
+	if (regval < 0) {
+		dev_err(di->dev, "unsupported ramp value %d\n", ramp);
+		return -EINVAL;
+	}
+
+	return regmap_update_bits(di->regmap, FAN53555_CONTROL,
+				  CTL_SLEW_MASK, regval << CTL_SLEW_SHIFT);
+}
+
+static const struct regulator_ops fan53555_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,
+	.set_suspend_voltage = fan53555_set_suspend_voltage,
+	.enable = regulator_enable_regmap,
+	.disable = regulator_disable_regmap,
+	.is_enabled = regulator_is_enabled_regmap,
+	.set_mode = fan53555_set_mode,
+	.get_mode = fan53555_get_mode,
+	.set_ramp_delay = fan53555_set_ramp,
+	.set_suspend_enable = fan53555_set_suspend_enable,
+	.set_suspend_disable = fan53555_set_suspend_disable,
+};
+
+static int fan53555_voltages_setup_fairchild(struct fan53555_device_info *di)
+{
+	/* Init voltage range and step */
+	switch (di->chip_id) {
+	case FAN53555_CHIP_ID_00:
+		switch (di->chip_rev) {
+		case FAN53555_CHIP_REV_00:
+			di->vsel_min = 600000;
+			di->vsel_step = 10000;
+			break;
+		case FAN53555_CHIP_REV_13:
+			di->vsel_min = 800000;
+			di->vsel_step = 10000;
+			break;
+		default:
+			dev_err(di->dev,
+				"Chip ID %d with rev %d not supported!\n",
+				di->chip_id, di->chip_rev);
+			return -EINVAL;
+		}
+		break;
+	case FAN53555_CHIP_ID_01:
+	case FAN53555_CHIP_ID_03:
+	case FAN53555_CHIP_ID_05:
+	case FAN53555_CHIP_ID_08:
+		di->vsel_min = 600000;
+		di->vsel_step = 10000;
+		break;
+	case FAN53555_CHIP_ID_04:
+		di->vsel_min = 603000;
+		di->vsel_step = 12826;
+		break;
+	default:
+		dev_err(di->dev,
+			"Chip ID %d not supported!\n", di->chip_id);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int fan53555_voltages_setup_silergy(struct fan53555_device_info *di)
+{
+	/* Init voltage range and step */
+	switch (di->chip_id) {
+	case SILERGY_SYR82X:
+		di->vsel_min = 712500;
+		di->vsel_step = 12500;
+		break;
+	default:
+		dev_err(di->dev,
+			"Chip ID %d not supported!\n", di->chip_id);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* For 00,01,03,05 options:
+ * VOUT = 0.60V + NSELx * 10mV, from 0.60 to 1.23V.
+ * For 04 option:
+ * VOUT = 0.603V + NSELx * 12.826mV, from 0.603 to 1.411V.
+ * */
+static int fan53555_device_setup(struct fan53555_device_info *di,
+				struct fan53555_platform_data *pdata)
+{
+	int ret = 0;
+
+	/* Setup voltage control register */
+	switch (pdata->sleep_vsel_id) {
+	case FAN53555_VSEL_ID_0:
+		di->sleep_reg = FAN53555_VSEL0;
+		di->vol_reg = FAN53555_VSEL1;
+		break;
+	case FAN53555_VSEL_ID_1:
+		di->sleep_reg = FAN53555_VSEL1;
+		di->vol_reg = FAN53555_VSEL0;
+		break;
+	default:
+		dev_err(di->dev, "Invalid VSEL ID!\n");
+		return -EINVAL;
+	}
+
+	switch (di->vendor) {
+	case FAN53555_VENDOR_FAIRCHILD:
+		ret = fan53555_voltages_setup_fairchild(di);
+		break;
+	case FAN53555_VENDOR_SILERGY:
+		ret = fan53555_voltages_setup_silergy(di);
+		break;
+	default:
+		dev_err(di->dev, "vendor %d not supported!\n", di->vendor);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int fan53555_regulator_register(struct fan53555_device_info *di,
+			struct regulator_config *config)
+{
+	struct regulator_desc *rdesc = &di->desc;
+
+	rdesc->name = "fan53555-reg";
+	rdesc->supply_name = "vin";
+	rdesc->ops = &fan53555_regulator_ops;
+	rdesc->type = REGULATOR_VOLTAGE;
+	rdesc->n_voltages = FAN53555_NVOLTAGES;
+	rdesc->enable_reg = di->vol_reg;
+	rdesc->enable_mask = VSEL_BUCK_EN;
+	rdesc->min_uV = di->vsel_min;
+	rdesc->uV_step = di->vsel_step;
+	rdesc->vsel_reg = di->vol_reg;
+	rdesc->vsel_mask = VSEL_NSEL_MASK;
+	rdesc->owner = THIS_MODULE;
+
+	di->rdev = devm_regulator_register(di->dev, &di->desc, config);
+	return PTR_ERR_OR_ZERO(di->rdev);
+}
+
+static const struct regmap_config fan53555_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static struct fan53555_platform_data *fan53555_parse_dt(struct device *dev,
+					      struct device_node *np,
+					      const struct regulator_desc *desc)
+{
+	struct fan53555_platform_data *pdata;
+	int ret;
+	u32 tmp;
+
+	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return NULL;
+
+	pdata->regulator = of_get_regulator_init_data(dev, np, desc);
+
+	ret = of_property_read_u32(np, "fcs,suspend-voltage-selector",
+				   &tmp);
+	if (!ret)
+		pdata->sleep_vsel_id = tmp;
+
+	return pdata;
+}
+
+static const struct of_device_id fan53555_dt_ids[] = {
+	{
+		.compatible = "fcs,fan53555",
+		.data = (void *)FAN53555_VENDOR_FAIRCHILD
+	}, {
+		.compatible = "silergy,syr827",
+		.data = (void *)FAN53555_VENDOR_SILERGY,
+	}, {
+		.compatible = "silergy,syr828",
+		.data = (void *)FAN53555_VENDOR_SILERGY,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, fan53555_dt_ids);
+
+static int fan53555_regulator_probe(struct i2c_client *client,
+				const struct i2c_device_id *id)
+{
+	struct device_node *np = client->dev.of_node;
+	struct fan53555_device_info *di;
+	struct fan53555_platform_data *pdata;
+	struct regulator_config config = { };
+	unsigned int val;
+	int ret;
+
+	di = devm_kzalloc(&client->dev, sizeof(struct fan53555_device_info),
+					GFP_KERNEL);
+	if (!di)
+		return -ENOMEM;
+
+	pdata = dev_get_platdata(&client->dev);
+	if (!pdata)
+		pdata = fan53555_parse_dt(&client->dev, np, &di->desc);
+
+	if (!pdata || !pdata->regulator) {
+		dev_err(&client->dev, "Platform data not found!\n");
+		return -ENODEV;
+	}
+
+	di->regulator = pdata->regulator;
+	if (client->dev.of_node) {
+		di->vendor =
+			(unsigned long)of_device_get_match_data(&client->dev);
+	} else {
+		/* if no ramp constraint set, get the pdata ramp_delay */
+		if (!di->regulator->constraints.ramp_delay) {
+			int slew_idx = (pdata->slew_rate & 0x7)
+						? pdata->slew_rate : 0;
+
+			di->regulator->constraints.ramp_delay
+						= slew_rates[slew_idx];
+		}
+
+		di->vendor = id->driver_data;
+	}
+
+	di->regmap = devm_regmap_init_i2c(client, &fan53555_regmap_config);
+	if (IS_ERR(di->regmap)) {
+		dev_err(&client->dev, "Failed to allocate regmap!\n");
+		return PTR_ERR(di->regmap);
+	}
+	di->dev = &client->dev;
+	i2c_set_clientdata(client, di);
+	/* Get chip ID */
+	ret = regmap_read(di->regmap, FAN53555_ID1, &val);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to get chip ID!\n");
+		return ret;
+	}
+	di->chip_id = val & DIE_ID;
+	/* Get chip revision */
+	ret = regmap_read(di->regmap, FAN53555_ID2, &val);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to get chip Rev!\n");
+		return ret;
+	}
+	di->chip_rev = val & DIE_REV;
+	dev_info(&client->dev, "FAN53555 Option[%d] Rev[%d] Detected!\n",
+				di->chip_id, di->chip_rev);
+	/* Device init */
+	ret = fan53555_device_setup(di, pdata);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to setup device!\n");
+		return ret;
+	}
+	/* Register regulator */
+	config.dev = di->dev;
+	config.init_data = di->regulator;
+	config.regmap = di->regmap;
+	config.driver_data = di;
+	config.of_node = np;
+
+	ret = fan53555_regulator_register(di, &config);
+	if (ret < 0)
+		dev_err(&client->dev, "Failed to register regulator!\n");
+	return ret;
+
+}
+
+static const struct i2c_device_id fan53555_id[] = {
+	{
+		.name = "fan53555",
+		.driver_data = FAN53555_VENDOR_FAIRCHILD
+	}, {
+		.name = "syr827",
+		.driver_data = FAN53555_VENDOR_SILERGY
+	}, {
+		.name = "syr828",
+		.driver_data = FAN53555_VENDOR_SILERGY
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, fan53555_id);
+
+static struct i2c_driver fan53555_regulator_driver = {
+	.driver = {
+		.name = "fan53555-regulator",
+		.of_match_table = of_match_ptr(fan53555_dt_ids),
+	},
+	.probe = fan53555_regulator_probe,
+	.id_table = fan53555_id,
+};
+
+module_i2c_driver(fan53555_regulator_driver);
+
+MODULE_AUTHOR("Yunfan Zhang <yfzhang@marvell.com>");
+MODULE_DESCRIPTION("FAN53555 regulator driver");
+MODULE_LICENSE("GPL v2");