[PATCH v7 2/2] regulator: rtq2208: Add Richtek RTQ2208 SubPMIC driver

[Alina Yu]

Add support for the RTQ2208 SubPMIC
This ic integrates with configurable, synchrnous buck converters and two ldos.

Signed-off-by: Alina Yu <alina_yu@xxxxxxxxxxx>
---
v7
- Include missing <linux/mod_devicetable.h>
- Remove fixed_uV in self-defined structure and rtq2208_ldo_get_voltage
- Modify sizeof() parameter in rdesc = devm_kzalloc(..., sizeof().....)
- Add const to type casting in regulator_ops to avoid unexpected manipulation
- Remove rtq2208_of_parse_cb and use of_regulator_match to get constraints.min_uV
- Return devm_request_threaded_irq directly
- Remove __maybe_unused and redundant comma in rtq2208_device_tables
- Remove v2 in MODULE_LICENSE
v6
- Remove Reported-by tag
v5
- Modify 'rdesc->fixed_uV' get, becasue "richtek,fixed-uV" is removed from yaml
- Modify 'mtp_sel' get because read property is changed from "richtek,mtp-sel" to
  "richtek,mtp-sel-high" in yaml
- Add missing regulators_node points to regulator node in yaml
- Include <linux/bitfield.h> for 'FIELD_PREP' reported by kernel test robot
---
 drivers/regulator/Kconfig             |  11 +
 drivers/regulator/Makefile            |   1 +
 drivers/regulator/rtq2208-regulator.c | 583 ++++++++++++++++++++++++++++++++++
 3 files changed, 595 insertions(+)
 create mode 100644 drivers/regulator/rtq2208-regulator.c

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index e5f3613..a6b2c84 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -1213,6 +1213,17 @@ config REGULATOR_RTQ6752
 	  synchronous boost converters for PAVDD, and one synchronous NAVDD
 	  buck-boost. This device is suitable for automotive TFT-LCD panel.
 
+config REGULATOR_RTQ2208
+	tristate "Richtek RTQ2208 SubPMIC Regulator"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  This driver adds support for RTQ2208 SubPMIC regulators.
+	  The RTQ2208 is a multi-phase, programmable power management IC that
+	  integrate with dual multi-configurable, synchronous buck converters
+	  and two ldos. It features wide output voltage range from 0.4V to 2.05V
+	  and the capability to configure the corresponding power stages.
+
 config REGULATOR_S2MPA01
 	tristate "Samsung S2MPA01 voltage regulator"
 	depends on MFD_SEC_CORE || COMPILE_TEST
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 58dfe01..04cbad17 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -143,6 +143,7 @@ obj-$(CONFIG_REGULATOR_RT6245)	+= rt6245-regulator.o
 obj-$(CONFIG_REGULATOR_RTMV20)	+= rtmv20-regulator.o
 obj-$(CONFIG_REGULATOR_RTQ2134) += rtq2134-regulator.o
 obj-$(CONFIG_REGULATOR_RTQ6752)	+= rtq6752-regulator.o
+obj-$(CONFIG_REGULATOR_RTQ2208) += rtq2208-regulator.o
 obj-$(CONFIG_REGULATOR_S2MPA01) += s2mpa01.o
 obj-$(CONFIG_REGULATOR_S2MPS11) += s2mps11.o
 obj-$(CONFIG_REGULATOR_S5M8767) += s5m8767.o
diff --git a/drivers/regulator/rtq2208-regulator.c b/drivers/regulator/rtq2208-regulator.c
new file mode 100644
index 0000000..2463aea
--- /dev/null
+++ b/drivers/regulator/rtq2208-regulator.c
@@ -0,0 +1,583 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <linux/bitops.h>
+#include <linux/bitfield.h>
+#include <linux/util_macros.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/mod_devicetable.h>
+
+/* Register */
+#define RTQ2208_REG_GLOBAL_INT1			0x12
+#define RTQ2208_REG_FLT_RECORDBUCK_CB		0x18
+#define RTQ2208_REG_GLOBAL_INT1_MASK		0x1D
+#define RTQ2208_REG_FLT_MASKBUCK_CB		0x1F
+#define RTQ2208_REG_BUCK_C_CFG0			0x32
+#define RTQ2208_REG_BUCK_B_CFG0			0x42
+#define RTQ2208_REG_BUCK_A_CFG0			0x52
+#define RTQ2208_REG_BUCK_D_CFG0			0x62
+#define RTQ2208_REG_BUCK_G_CFG0			0x72
+#define RTQ2208_REG_BUCK_F_CFG0			0x82
+#define RTQ2208_REG_BUCK_E_CFG0			0x92
+#define RTQ2208_REG_BUCK_H_CFG0			0xA2
+#define RTQ2208_REG_LDO1_CFG			0xB1
+#define RTQ2208_REG_LDO2_CFG			0xC1
+
+/* Mask */
+#define RTQ2208_BUCK_NR_MTP_SEL_MASK		GENMASK(7, 0)
+#define RTQ2208_BUCK_EN_NR_MTP_SEL0_MASK	BIT(0)
+#define RTQ2208_BUCK_EN_NR_MTP_SEL1_MASK	BIT(1)
+#define RTQ2208_BUCK_RSPUP_MASK			GENMASK(6, 4)
+#define RTQ2208_BUCK_RSPDN_MASK			GENMASK(2, 0)
+#define RTQ2208_BUCK_NRMODE_MASK		BIT(5)
+#define RTQ2208_BUCK_STRMODE_MASK		BIT(5)
+#define RTQ2208_BUCK_EN_STR_MASK		BIT(0)
+#define RTQ2208_LDO_EN_STR_MASK			BIT(7)
+#define RTQ2208_EN_DIS_MASK			BIT(0)
+#define RTQ2208_BUCK_RAMP_SEL_MASK		GENMASK(2, 0)
+#define RTQ2208_HD_INT_MASK			BIT(0)
+
+/* Size */
+#define RTQ2208_VOUT_MAXNUM			256
+#define RTQ2208_BUCK_NUM_IRQ_REGS		5
+#define RTQ2208_STS_NUM_IRQ_REGS		2
+
+/* Value */
+#define RTQ2208_RAMP_VALUE_MIN_uV		500
+#define RTQ2208_RAMP_VALUE_MAX_uV		64000
+
+#define RTQ2208_BUCK_MASK(uv_irq, ov_irq)	(1 << ((uv_irq) % 8) | 1 << ((ov_irq) % 8))
+
+enum {
+	RTQ2208_BUCK_B = 0,
+	RTQ2208_BUCK_C,
+	RTQ2208_BUCK_D,
+	RTQ2208_BUCK_A,
+	RTQ2208_BUCK_F,
+	RTQ2208_BUCK_G,
+	RTQ2208_BUCK_H,
+	RTQ2208_BUCK_E,
+	RTQ2208_LDO2,
+	RTQ2208_LDO1,
+	RTQ2208_LDO_MAX,
+};
+
+enum {
+	RTQ2208_AUTO_MODE = 0,
+	RTQ2208_FCCM,
+};
+
+struct rtq2208_regulator_desc {
+	struct regulator_desc desc;
+	unsigned int mtp_sel_reg;
+	unsigned int mtp_sel_mask;
+	unsigned int mode_reg;
+	unsigned int mode_mask;
+	unsigned int suspend_config_reg;
+	unsigned int suspend_enable_mask;
+	unsigned int suspend_mode_mask;
+};
+
+struct rtq2208_rdev_map {
+	struct regulator_dev *rdev[RTQ2208_LDO_MAX];
+	struct regmap *regmap;
+	struct device *dev;
+};
+
+/* set Normal Auto/FCCM mode */
+static int rtq2208_set_mode(struct regulator_dev *rdev, unsigned int mode)
+{
+	const struct rtq2208_regulator_desc *rdesc =
+		(const struct rtq2208_regulator_desc *)rdev->desc;
+	unsigned int val, shift;
+
+	switch (mode) {
+	case REGULATOR_MODE_NORMAL:
+		val = RTQ2208_AUTO_MODE;
+		break;
+	case REGULATOR_MODE_FAST:
+		val = RTQ2208_FCCM;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	shift = ffs(rdesc->mode_mask) - 1;
+	return regmap_update_bits(rdev->regmap, rdesc->mode_reg,
+				  rdesc->mode_mask, val << shift);
+}
+
+static unsigned int rtq2208_get_mode(struct regulator_dev *rdev)
+{
+	const struct rtq2208_regulator_desc *rdesc =
+		(const struct rtq2208_regulator_desc *)rdev->desc;
+	unsigned int mode_val;
+	int ret;
+
+	ret = regmap_read(rdev->regmap, rdesc->mode_reg, &mode_val);
+	if (ret)
+		return REGULATOR_MODE_INVALID;
+
+	return (mode_val & rdesc->mode_mask) ? REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
+}
+
+static int rtq2208_set_ramp_delay(struct regulator_dev *rdev, int ramp_delay)
+{
+	const struct regulator_desc *desc = rdev->desc;
+	unsigned int sel = 0, val;
+
+	ramp_delay = max(ramp_delay, RTQ2208_RAMP_VALUE_MIN_uV);
+	ramp_delay = min(ramp_delay, RTQ2208_RAMP_VALUE_MAX_uV);
+
+	ramp_delay /= RTQ2208_RAMP_VALUE_MIN_uV;
+
+	/*
+	 * fls(ramp_delay) - 1: doing LSB shift, let it starts from 0
+	 *
+	 * RTQ2208_BUCK_RAMP_SEL_MASK - sel: doing descending order shifting.
+	 * Because the relation of seleltion and value is like that
+	 *
+	 * seletion: value
+	 * 000: 64mv
+	 * 001: 32mv
+	 * ...
+	 * 111: 0.5mv
+	 *
+	 * For example, if I would like to select 64mv, the fls(ramp_delay) - 1 will be 0b111,
+	 * and I need to use 0b111 - sel to do the shifting
+	 */
+
+	sel = fls(ramp_delay) - 1;
+	sel = RTQ2208_BUCK_RAMP_SEL_MASK - sel;
+
+	val = FIELD_PREP(RTQ2208_BUCK_RSPUP_MASK, sel) | FIELD_PREP(RTQ2208_BUCK_RSPDN_MASK, sel);
+
+	return regmap_update_bits(rdev->regmap, desc->ramp_reg,
+				  RTQ2208_BUCK_RSPUP_MASK | RTQ2208_BUCK_RSPDN_MASK, val);
+}
+
+static int rtq2208_set_suspend_enable(struct regulator_dev *rdev)
+{
+	const struct rtq2208_regulator_desc *rdesc =
+		(const struct rtq2208_regulator_desc *)rdev->desc;
+
+	return regmap_set_bits(rdev->regmap, rdesc->suspend_config_reg, rdesc->suspend_enable_mask);
+}
+
+static int rtq2208_set_suspend_disable(struct regulator_dev *rdev)
+{
+	const struct rtq2208_regulator_desc *rdesc =
+		(const struct rtq2208_regulator_desc *)rdev->desc;
+
+	return regmap_update_bits(rdev->regmap, rdesc->suspend_config_reg, rdesc->suspend_enable_mask, 0);
+}
+
+static int rtq2208_set_suspend_mode(struct regulator_dev *rdev, unsigned int mode)
+{
+	const struct rtq2208_regulator_desc *rdesc =
+		(const struct rtq2208_regulator_desc *)rdev->desc;
+	unsigned int val, shift;
+
+	switch (mode) {
+	case REGULATOR_MODE_NORMAL:
+		val = RTQ2208_AUTO_MODE;
+		break;
+	case REGULATOR_MODE_FAST:
+		val = RTQ2208_FCCM;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	shift = ffs(rdesc->suspend_mode_mask) - 1;
+
+	return regmap_update_bits(rdev->regmap, rdesc->suspend_config_reg,
+			rdesc->suspend_mode_mask, val << shift);
+}
+
+static const struct regulator_ops rtq2208_regulator_buck_ops = {
+	.enable = regulator_enable_regmap,
+	.disable = regulator_disable_regmap,
+	.is_enabled = regulator_is_enabled_regmap,
+	.list_voltage = regulator_list_voltage_linear_range,
+	.set_voltage_sel = regulator_set_voltage_sel_regmap,
+	.get_voltage_sel = regulator_get_voltage_sel_regmap,
+	.set_mode = rtq2208_set_mode,
+	.get_mode = rtq2208_get_mode,
+	.set_ramp_delay = rtq2208_set_ramp_delay,
+	.set_active_discharge = regulator_set_active_discharge_regmap,
+	.set_suspend_enable = rtq2208_set_suspend_enable,
+	.set_suspend_disable = rtq2208_set_suspend_disable,
+	.set_suspend_mode = rtq2208_set_suspend_mode,
+};
+
+static const struct regulator_ops rtq2208_regulator_ldo_ops = {
+	.enable = regulator_enable_regmap,
+	.disable = regulator_disable_regmap,
+	.is_enabled = regulator_is_enabled_regmap,
+	.set_active_discharge = regulator_set_active_discharge_regmap,
+	.set_suspend_enable = rtq2208_set_suspend_enable,
+	.set_suspend_disable = rtq2208_set_suspend_disable,
+};
+
+static unsigned int rtq2208_of_map_mode(unsigned int mode)
+{
+	switch (mode) {
+	case RTQ2208_AUTO_MODE:
+		return REGULATOR_MODE_NORMAL;
+	case RTQ2208_FCCM:
+		return REGULATOR_MODE_FAST;
+	default:
+		return REGULATOR_MODE_INVALID;
+	}
+}
+
+static int rtq2208_init_irq_mask(struct rtq2208_rdev_map *rdev_map, unsigned int *buck_masks)
+{
+	unsigned char buck_clr_masks[5] = {0x33, 0x33, 0x33, 0x33, 0x33},
+		      sts_clr_masks[2] = {0xE7, 0xF7}, sts_masks[2] = {0xE6, 0xF6};
+	int ret;
+
+	/* write clear all buck irq once */
+	ret = regmap_bulk_write(rdev_map->regmap, RTQ2208_REG_FLT_RECORDBUCK_CB, buck_clr_masks, 5);
+	if (ret)
+		return dev_err_probe(rdev_map->dev, ret, "Failed to clr buck irqs\n");
+
+	/* write clear general irq once */
+	ret = regmap_bulk_write(rdev_map->regmap, RTQ2208_REG_GLOBAL_INT1, sts_clr_masks, 2);
+	if (ret)
+		return dev_err_probe(rdev_map->dev, ret, "Failed to clr general irqs\n");
+
+	/* unmask buck ov/uv irq */
+	ret = regmap_bulk_write(rdev_map->regmap, RTQ2208_REG_FLT_MASKBUCK_CB, buck_masks, 5);
+	if (ret)
+		return dev_err_probe(rdev_map->dev, ret, "Failed to unmask buck irqs\n");
+
+	/* unmask needed general irq */
+	return regmap_bulk_write(rdev_map->regmap, RTQ2208_REG_GLOBAL_INT1_MASK, sts_masks, 2);
+}
+
+static irqreturn_t rtq2208_irq_handler(int irqno, void *devid)
+{
+	unsigned char buck_flags[RTQ2208_BUCK_NUM_IRQ_REGS], sts_flags[RTQ2208_STS_NUM_IRQ_REGS];
+	int ret = 0, i, uv_bit, ov_bit;
+	struct rtq2208_rdev_map *rdev_map = devid;
+	struct regulator_dev *rdev;
+
+	if (!rdev_map)
+		return IRQ_NONE;
+
+	/* read irq event */
+	ret = regmap_bulk_read(rdev_map->regmap, RTQ2208_REG_FLT_RECORDBUCK_CB,
+				buck_flags, ARRAY_SIZE(buck_flags));
+	if (ret)
+		return IRQ_NONE;
+
+	ret = regmap_bulk_read(rdev_map->regmap, RTQ2208_REG_GLOBAL_INT1,
+				sts_flags, ARRAY_SIZE(sts_flags));
+	if (ret)
+		return IRQ_NONE;
+
+	/* clear irq event */
+	ret = regmap_bulk_write(rdev_map->regmap, RTQ2208_REG_FLT_RECORDBUCK_CB,
+				buck_flags, ARRAY_SIZE(buck_flags));
+	if (ret)
+		return IRQ_NONE;
+
+	ret = regmap_bulk_write(rdev_map->regmap, RTQ2208_REG_GLOBAL_INT1,
+				sts_flags, ARRAY_SIZE(sts_flags));
+	if (ret)
+		return IRQ_NONE;
+
+	for (i = 0; i < RTQ2208_LDO_MAX; i++) {
+		if (!rdev_map->rdev[i])
+			continue;
+
+		rdev = rdev_map->rdev[i];
+		/* uv irq */
+		uv_bit = (i & 1) ? 4 : 0;
+		if (buck_flags[i >> 1] & (1 << uv_bit))
+			regulator_notifier_call_chain(rdev,
+					REGULATOR_EVENT_UNDER_VOLTAGE, NULL);
+		/* ov irq */
+		ov_bit = uv_bit + 1;
+		if (buck_flags[i >> 1] & (1 << ov_bit))
+			regulator_notifier_call_chain(rdev,
+					REGULATOR_EVENT_REGULATION_OUT, NULL);
+
+		/* hd irq */
+		if (sts_flags[1] & RTQ2208_HD_INT_MASK)
+			regulator_notifier_call_chain(rdev,
+					REGULATOR_EVENT_OVER_TEMP, NULL);
+	}
+
+	return IRQ_HANDLED;
+}
+
+#define RTQ2208_REGULATOR_INFO(_name, _base) \
+{ \
+	.name = #_name, \
+	.base = _base, \
+}
+#define BUCK_RG_BASE(_id)	RTQ2208_REG_BUCK_##_id##_CFG0
+#define BUCK_RG_SHIFT(_base, _shift)	(_base + _shift)
+#define LDO_RG_BASE(_id)	RTQ2208_REG_LDO##_id##_CFG
+#define LDO_RG_SHIFT(_base, _shift)	(_base + _shift)
+#define	VSEL_SHIFT(_sel)	(_sel ? 3 : 1)
+#define MTP_SEL_MASK(_sel)	RTQ2208_BUCK_EN_NR_MTP_SEL##_sel##_MASK
+
+static const struct linear_range rtq2208_vout_range[] = {
+	REGULATOR_LINEAR_RANGE(400000, 0, 180, 5000),
+	REGULATOR_LINEAR_RANGE(1310000, 181, 255, 10000),
+};
+
+static int rtq2208_of_get_fixed_voltage(struct device *dev,
+					struct of_regulator_match *rtq2208_ldo_match, int n_fixed)
+{
+	struct device_node *np;
+	struct of_regulator_match *match;
+	struct rtq2208_regulator_desc *rdesc;
+	struct regulator_init_data *init_data;
+	int ret, i;
+
+	if (!dev->of_node)
+		return -ENODEV;
+
+	np = of_get_child_by_name(dev->of_node, "regulators");
+	if (!np)
+		np = dev->of_node;
+
+	ret = of_regulator_match(dev, np, rtq2208_ldo_match, n_fixed);
+
+	of_node_put(np);
+
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < n_fixed; i++) {
+		match = rtq2208_ldo_match + i;
+		init_data = match->init_data;
+		rdesc = (struct rtq2208_regulator_desc *)match->driver_data;
+
+		if (!init_data || !rdesc)
+			continue;
+
+		if (init_data->constraints.min_uV == init_data->constraints.max_uV)
+			rdesc->desc.fixed_uV = init_data->constraints.min_uV;
+	}
+
+	return 0;
+}
+
+static void rtq2208_init_regulator_desc(struct rtq2208_regulator_desc *rdesc, int mtp_sel,
+					int idx, struct of_regulator_match *rtq2208_ldo_match, int *ldo_idx)
+{
+	struct regulator_desc *desc;
+	static const struct {
+		char *name;
+		int base;
+	} regulator_info[] = {
+		RTQ2208_REGULATOR_INFO(buck-b, BUCK_RG_BASE(B)),
+		RTQ2208_REGULATOR_INFO(buck-c, BUCK_RG_BASE(C)),
+		RTQ2208_REGULATOR_INFO(buck-d, BUCK_RG_BASE(D)),
+		RTQ2208_REGULATOR_INFO(buck-a, BUCK_RG_BASE(A)),
+		RTQ2208_REGULATOR_INFO(buck-f, BUCK_RG_BASE(F)),
+		RTQ2208_REGULATOR_INFO(buck-g, BUCK_RG_BASE(G)),
+		RTQ2208_REGULATOR_INFO(buck-h, BUCK_RG_BASE(H)),
+		RTQ2208_REGULATOR_INFO(buck-e, BUCK_RG_BASE(E)),
+		RTQ2208_REGULATOR_INFO(ldo2, LDO_RG_BASE(2)),
+		RTQ2208_REGULATOR_INFO(ldo1, LDO_RG_BASE(1)),
+	}, *curr_info;
+
+	curr_info = regulator_info + idx;
+	desc = &rdesc->desc;
+	desc->name = curr_info->name;
+	desc->of_match = of_match_ptr(curr_info->name);
+	desc->regulators_node = of_match_ptr("regulators");
+	desc->id = idx;
+	desc->owner = THIS_MODULE;
+	desc->type = REGULATOR_VOLTAGE;
+	desc->enable_mask = mtp_sel ? MTP_SEL_MASK(1) : MTP_SEL_MASK(0);
+	desc->active_discharge_on = RTQ2208_EN_DIS_MASK;
+	desc->active_discharge_off = 0;
+	desc->active_discharge_mask = RTQ2208_EN_DIS_MASK;
+
+	rdesc->mode_mask = RTQ2208_BUCK_NRMODE_MASK;
+
+	if (idx >= RTQ2208_BUCK_B && idx <= RTQ2208_BUCK_E) {
+		/* init buck desc */
+		desc->enable_reg = BUCK_RG_SHIFT(curr_info->base, 2);
+		desc->ops = &rtq2208_regulator_buck_ops;
+		desc->vsel_reg = curr_info->base + VSEL_SHIFT(mtp_sel);
+		desc->vsel_mask = RTQ2208_BUCK_NR_MTP_SEL_MASK;
+		desc->n_voltages = RTQ2208_VOUT_MAXNUM;
+		desc->linear_ranges = rtq2208_vout_range;
+		desc->n_linear_ranges = ARRAY_SIZE(rtq2208_vout_range);
+		desc->ramp_reg = BUCK_RG_SHIFT(curr_info->base, 5);
+		desc->active_discharge_reg = curr_info->base;
+		desc->of_map_mode = rtq2208_of_map_mode;
+
+		rdesc->mode_reg = BUCK_RG_SHIFT(curr_info->base, 2);
+		rdesc->suspend_config_reg = BUCK_RG_SHIFT(curr_info->base, 4);
+		rdesc->suspend_enable_mask = RTQ2208_BUCK_EN_STR_MASK;
+		rdesc->suspend_mode_mask = RTQ2208_BUCK_STRMODE_MASK;
+	} else {
+		/* init ldo desc */
+		desc->enable_reg = curr_info->base;
+		desc->ops = &rtq2208_regulator_ldo_ops;
+		desc->n_voltages = 1;
+		desc->active_discharge_reg = LDO_RG_SHIFT(curr_info->base, 2);
+
+		rtq2208_ldo_match[*ldo_idx].name = desc->name;
+		rtq2208_ldo_match[*ldo_idx].driver_data = rdesc;
+		rtq2208_ldo_match[(*ldo_idx)++].desc = desc;
+
+		rdesc->suspend_config_reg = curr_info->base;
+		rdesc->suspend_enable_mask = RTQ2208_LDO_EN_STR_MASK;
+	}
+}
+
+static int rtq2208_parse_regulator_dt_data(int n_regulator, const unsigned int *regulator_idx_table,
+		struct rtq2208_regulator_desc *rdesc[RTQ2208_LDO_MAX], struct device *dev)
+{
+	struct of_regulator_match rtq2208_ldo_match[2];
+	int mtp_sel, ret, i, idx, ldo_idx = 0;
+
+	/* get mtp_sel0 or mtp_sel1 */
+	mtp_sel = device_property_read_bool(dev, "richtek,mtp-sel-high");
+
+	for (i = 0; i < n_regulator; i++) {
+		idx = regulator_idx_table[i];
+
+		rdesc[i] = devm_kcalloc(dev, 1, sizeof(*rdesc[0]), GFP_KERNEL);
+		if (!rdesc[i])
+			return -ENOMEM;
+
+		rtq2208_init_regulator_desc(rdesc[i], mtp_sel, idx, rtq2208_ldo_match, &ldo_idx);
+	}
+
+	/* init ldo fixed_uV */
+	ret = rtq2208_of_get_fixed_voltage(dev, rtq2208_ldo_match, ldo_idx);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get ldo fixed_uV\n");
+
+	return 0;
+
+}
+
+/** different slave address corresponds different used bucks
+ * slave address 0x10: BUCK[BCA FGE]
+ * slave address 0x20: BUCK[BC FGHE]
+ * slave address 0x40: BUCK[C G]
+ */
+static int rtq2208_regulator_check(int slave_addr, int *num,
+				int *regulator_idx_table, unsigned int *buck_masks)
+{
+	static bool rtq2208_used_table[3][RTQ2208_LDO_MAX] = {
+		/* BUCK[BCA FGE], LDO[12] */
+		{1, 1, 0, 1, 1, 1, 0, 1, 1, 1},
+		/* BUCK[BC FGHE], LDO[12]*/
+		{1, 1, 0, 0, 1, 1, 1, 1, 1, 1},
+		/* BUCK[C G], LDO[12] */
+		{0, 1, 0, 0, 0, 1, 0, 0, 1, 1},
+	};
+	int i, idx = ffs(slave_addr >> 4) - 1;
+	u8 mask;
+
+	for (i = 0; i < RTQ2208_LDO_MAX; i++) {
+		if (!rtq2208_used_table[idx][i])
+			continue;
+
+		regulator_idx_table[(*num)++] = i;
+
+		mask = RTQ2208_BUCK_MASK(4 * i, 4 * i + 1);
+		buck_masks[i >> 1] &= ~mask;
+	}
+
+	return 0;
+}
+
+static const struct regmap_config rtq2208_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0xEF,
+};
+
+static int rtq2208_probe(struct i2c_client *i2c)
+{
+	struct device *dev = &i2c->dev;
+	struct regmap *regmap;
+	struct rtq2208_regulator_desc *rdesc[RTQ2208_LDO_MAX];
+	struct regulator_dev *rdev;
+	struct regulator_config cfg;
+	struct rtq2208_rdev_map *rdev_map;
+	int i, ret = 0, idx, n_regulator = 0;
+	unsigned int regulator_idx_table[RTQ2208_LDO_MAX],
+		     buck_masks[RTQ2208_BUCK_NUM_IRQ_REGS] = {0x33, 0x33, 0x33, 0x33, 0x33};
+
+	rdev_map = devm_kzalloc(dev, sizeof(struct rtq2208_rdev_map), GFP_KERNEL);
+	if (!rdev_map)
+		return -ENOMEM;
+
+	regmap = devm_regmap_init_i2c(i2c, &rtq2208_regmap_config);
+	if (IS_ERR(regmap))
+		return dev_err_probe(dev, PTR_ERR(regmap), "Failed to allocate regmap\n");
+
+	/* get needed regulator */
+	ret = rtq2208_regulator_check(i2c->addr, &n_regulator, regulator_idx_table, buck_masks);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to check used regulators\n");
+
+	rdev_map->regmap = regmap;
+	rdev_map->dev = dev;
+
+	cfg.dev = dev;
+
+	/* init regulator desc */
+	ret = rtq2208_parse_regulator_dt_data(n_regulator, regulator_idx_table, rdesc, dev);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < n_regulator; i++) {
+		idx = regulator_idx_table[i];
+
+		/* register regulator */
+		rdev = devm_regulator_register(dev, &rdesc[i]->desc, &cfg);
+		if (IS_ERR(rdev))
+			return PTR_ERR(rdev);
+
+		rdev_map->rdev[idx] = rdev;
+	}
+
+	/* init interrupt mask */
+	ret = rtq2208_init_irq_mask(rdev_map, buck_masks);
+	if (ret)
+		return ret;
+
+	/* register interrupt */
+	return devm_request_threaded_irq(dev, i2c->irq, NULL, rtq2208_irq_handler,
+					IRQF_ONESHOT, dev_name(dev), rdev_map);
+}
+
+static const struct of_device_id rtq2208_device_tables[] = {
+	{ .compatible = "richtek,rtq2208" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, rtq2208_device_tables);
+
+static struct i2c_driver rtq2208_driver = {
+	.driver = {
+		.name = "rtq2208",
+		.of_match_table = rtq2208_device_tables,
+	},
+	.probe_new = rtq2208_probe,
+};
+module_i2c_driver(rtq2208_driver);
+
+MODULE_AUTHOR("Alina Yu <alina_yu@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Richtek RTQ2208 Regulator Driver");
+MODULE_LICENSE("GPL");
-- 
2.7.4