kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted

Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit
`objtool` errors such as:

    vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a:
    can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd

The reason is that in such builds, the Clang invocation that compiles
the combined Rust plus helpers bitcode emits LLVM bitcode (again) --
the final code generation happens in the linker's LTO step, which the
`-mllvm` trap options passed to Clang do not reach.

This, in turn, means that unreachable traps are missing, and the
impossible paths do not merely fallthrough to the next symbol, but past
the end of their own section, since LTO builds place each function in
its own section.

Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always
emits machine code directly, with the traps in place.

Assisted-by: LLM
Cc: Gary Guo <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 784 insertions, 0 deletions

diff --git a/drivers/regulator/max8998.c b/drivers/regulator/max8998.c
new file mode 100644
index 000000000..cc85fbe8b
--- /dev/null
+++ b/drivers/regulator/max8998.c
@@ -0,0 +1,784 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// max8998.c - Voltage regulator driver for the Maxim 8998
+//
+//  Copyright (C) 2009-2010 Samsung Electronics
+//  Kyungmin Park <kyungmin.park@samsung.com>
+//  Marek Szyprowski <m.szyprowski@samsung.com>
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/bits.h>
+#include <linux/gpio/consumer.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/mfd/max8998.h>
+#include <linux/mfd/max8998-private.h>
+
+struct max8998_data {
+	struct device		*dev;
+	struct max8998_dev	*iodev;
+	int			num_regulators;
+	u8                      buck1_vol[4]; /* voltages for selection */
+	u8                      buck2_vol[2];
+	unsigned int		buck1_idx; /* index to last changed voltage */
+					   /* value in a set */
+	unsigned int		buck2_idx;
+	struct gpio_desc	*buck1_gpio1;
+	struct gpio_desc	*buck1_gpio2;
+	struct gpio_desc	*buck2_gpio;
+};
+
+static const unsigned int charger_current_table[] = {
+	90000, 380000, 475000, 550000, 570000, 600000, 700000, 800000,
+};
+
+static int max8998_get_enable_register(struct regulator_dev *rdev,
+					int *reg, int *shift)
+{
+	int ldo = rdev_get_id(rdev);
+
+	switch (ldo) {
+	case MAX8998_LDO2 ... MAX8998_LDO5:
+		*reg = MAX8998_REG_ONOFF1;
+		*shift = 3 - (ldo - MAX8998_LDO2);
+		break;
+	case MAX8998_LDO6 ... MAX8998_LDO13:
+		*reg = MAX8998_REG_ONOFF2;
+		*shift = 7 - (ldo - MAX8998_LDO6);
+		break;
+	case MAX8998_LDO14 ... MAX8998_LDO17:
+		*reg = MAX8998_REG_ONOFF3;
+		*shift = 7 - (ldo - MAX8998_LDO14);
+		break;
+	case MAX8998_BUCK1 ... MAX8998_BUCK4:
+		*reg = MAX8998_REG_ONOFF1;
+		*shift = 7 - (ldo - MAX8998_BUCK1);
+		break;
+	case MAX8998_EN32KHZ_AP ... MAX8998_ENVICHG:
+		*reg = MAX8998_REG_ONOFF4;
+		*shift = 7 - (ldo - MAX8998_EN32KHZ_AP);
+		break;
+	case MAX8998_ESAFEOUT1 ... MAX8998_ESAFEOUT2:
+		*reg = MAX8998_REG_CHGR2;
+		*shift = 7 - (ldo - MAX8998_ESAFEOUT1);
+		break;
+	case MAX8998_CHARGER:
+		*reg = MAX8998_REG_CHGR2;
+		*shift = 0;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int max8998_ldo_is_enabled(struct regulator_dev *rdev)
+{
+	struct max8998_data *max8998 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8998->iodev->i2c;
+	int ret, reg, shift = 8;
+	u8 val;
+
+	ret = max8998_get_enable_register(rdev, &reg, &shift);
+	if (ret)
+		return ret;
+
+	ret = max8998_read_reg(i2c, reg, &val);
+	if (ret)
+		return ret;
+
+	return val & (1 << shift);
+}
+
+static int max8998_ldo_is_enabled_inverted(struct regulator_dev *rdev)
+{
+	return (!max8998_ldo_is_enabled(rdev));
+}
+
+static int max8998_ldo_enable(struct regulator_dev *rdev)
+{
+	struct max8998_data *max8998 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8998->iodev->i2c;
+	int reg, shift = 8, ret;
+
+	ret = max8998_get_enable_register(rdev, &reg, &shift);
+	if (ret)
+		return ret;
+
+	return max8998_update_reg(i2c, reg, 1<<shift, 1<<shift);
+}
+
+static int max8998_ldo_disable(struct regulator_dev *rdev)
+{
+	struct max8998_data *max8998 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8998->iodev->i2c;
+	int reg, shift = 8, ret;
+
+	ret = max8998_get_enable_register(rdev, &reg, &shift);
+	if (ret)
+		return ret;
+
+	return max8998_update_reg(i2c, reg, 0, 1<<shift);
+}
+
+static int max8998_get_voltage_register(struct regulator_dev *rdev,
+				int *_reg, int *_shift, int *_mask)
+{
+	int ldo = rdev_get_id(rdev);
+	struct max8998_data *max8998 = rdev_get_drvdata(rdev);
+	int reg, shift = 0, mask = 0xff;
+
+	switch (ldo) {
+	case MAX8998_LDO2 ... MAX8998_LDO3:
+		reg = MAX8998_REG_LDO2_LDO3;
+		mask = 0xf;
+		if (ldo == MAX8998_LDO2)
+			shift = 4;
+		else
+			shift = 0;
+		break;
+	case MAX8998_LDO4 ... MAX8998_LDO7:
+		reg = MAX8998_REG_LDO4 + (ldo - MAX8998_LDO4);
+		break;
+	case MAX8998_LDO8 ... MAX8998_LDO9:
+		reg = MAX8998_REG_LDO8_LDO9;
+		mask = 0xf;
+		if (ldo == MAX8998_LDO8)
+			shift = 4;
+		else
+			shift = 0;
+		break;
+	case MAX8998_LDO10 ... MAX8998_LDO11:
+		reg = MAX8998_REG_LDO10_LDO11;
+		if (ldo == MAX8998_LDO10) {
+			shift = 5;
+			mask = 0x7;
+		} else {
+			shift = 0;
+			mask = 0x1f;
+		}
+		break;
+	case MAX8998_LDO12 ... MAX8998_LDO17:
+		reg = MAX8998_REG_LDO12 + (ldo - MAX8998_LDO12);
+		break;
+	case MAX8998_BUCK1:
+		reg = MAX8998_REG_BUCK1_VOLTAGE1 + max8998->buck1_idx;
+		break;
+	case MAX8998_BUCK2:
+		reg = MAX8998_REG_BUCK2_VOLTAGE1 + max8998->buck2_idx;
+		break;
+	case MAX8998_BUCK3:
+		reg = MAX8998_REG_BUCK3;
+		break;
+	case MAX8998_BUCK4:
+		reg = MAX8998_REG_BUCK4;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	*_reg = reg;
+	*_shift = shift;
+	*_mask = mask;
+
+	return 0;
+}
+
+static int max8998_get_voltage_sel(struct regulator_dev *rdev)
+{
+	struct max8998_data *max8998 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8998->iodev->i2c;
+	int reg, shift = 0, mask, ret;
+	u8 val;
+
+	ret = max8998_get_voltage_register(rdev, &reg, &shift, &mask);
+	if (ret)
+		return ret;
+
+	ret = max8998_read_reg(i2c, reg, &val);
+	if (ret)
+		return ret;
+
+	val >>= shift;
+	val &= mask;
+
+	return val;
+}
+
+static int max8998_set_voltage_ldo_sel(struct regulator_dev *rdev,
+				       unsigned selector)
+{
+	struct max8998_data *max8998 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8998->iodev->i2c;
+	int reg, shift = 0, mask, ret;
+
+	ret = max8998_get_voltage_register(rdev, &reg, &shift, &mask);
+	if (ret)
+		return ret;
+
+	ret = max8998_update_reg(i2c, reg, selector<<shift, mask<<shift);
+
+	return ret;
+}
+
+static inline void buck1_gpio_set(struct gpio_desc *gpio1, struct gpio_desc *gpio2, int v)
+{
+	gpiod_set_value(gpio1, v & 0x1);
+	gpiod_set_value(gpio2, (v >> 1) & 0x1);
+}
+
+static inline void buck2_gpio_set(struct gpio_desc *gpio, int v)
+{
+	gpiod_set_value(gpio, v & 0x1);
+}
+
+static int max8998_set_voltage_buck_sel(struct regulator_dev *rdev,
+					unsigned selector)
+{
+	struct max8998_data *max8998 = rdev_get_drvdata(rdev);
+	struct max8998_platform_data *pdata = max8998->iodev->pdata;
+	struct i2c_client *i2c = max8998->iodev->i2c;
+	int buck = rdev_get_id(rdev);
+	int reg, shift = 0, mask, ret, j;
+	static u8 buck1_last_val;
+
+	ret = max8998_get_voltage_register(rdev, &reg, &shift, &mask);
+	if (ret)
+		return ret;
+
+	switch (buck) {
+	case MAX8998_BUCK1:
+		dev_dbg(max8998->dev,
+			"BUCK1, selector:%d, buck1_vol1:%d, buck1_vol2:%d\n"
+			"buck1_vol3:%d, buck1_vol4:%d\n",
+			selector, max8998->buck1_vol[0], max8998->buck1_vol[1],
+			max8998->buck1_vol[2], max8998->buck1_vol[3]);
+
+		if (max8998->buck1_gpio1 && max8998->buck1_gpio2) {
+
+			/* check if requested voltage */
+			/* value is already defined */
+			for (j = 0; j < ARRAY_SIZE(max8998->buck1_vol); j++) {
+				if (max8998->buck1_vol[j] == selector) {
+					max8998->buck1_idx = j;
+					buck1_gpio_set(max8998->buck1_gpio1,
+						       max8998->buck1_gpio2, j);
+					goto buck1_exit;
+				}
+			}
+
+			if (pdata->buck_voltage_lock)
+				return -EINVAL;
+
+			/* no predefine regulator found */
+			max8998->buck1_idx = (buck1_last_val % 2) + 2;
+			dev_dbg(max8998->dev, "max8998->buck1_idx:%d\n",
+				max8998->buck1_idx);
+			max8998->buck1_vol[max8998->buck1_idx] = selector;
+			ret = max8998_get_voltage_register(rdev, &reg,
+							   &shift,
+							   &mask);
+			ret = max8998_write_reg(i2c, reg, selector);
+			buck1_gpio_set(max8998->buck1_gpio1,
+				       max8998->buck1_gpio2, max8998->buck1_idx);
+			buck1_last_val++;
+buck1_exit:
+			dev_dbg(max8998->dev, "%s: SET1:%d, SET2:%d\n",
+				i2c->name, gpiod_get_value(max8998->buck1_gpio1),
+				gpiod_get_value(max8998->buck1_gpio2));
+			break;
+		} else {
+			ret = max8998_write_reg(i2c, reg, selector);
+		}
+		break;
+
+	case MAX8998_BUCK2:
+		dev_dbg(max8998->dev,
+			"BUCK2, selector:%d buck2_vol1:%d, buck2_vol2:%d\n",
+			selector, max8998->buck2_vol[0], max8998->buck2_vol[1]);
+		if (max8998->buck2_gpio) {
+			/* check if requested voltage */
+			/* value is already defined */
+			for (j = 0; j < ARRAY_SIZE(max8998->buck2_vol); j++) {
+				if (max8998->buck2_vol[j] == selector) {
+					max8998->buck2_idx = j;
+					buck2_gpio_set(max8998->buck2_gpio, j);
+					goto buck2_exit;
+				}
+			}
+
+			if (pdata->buck_voltage_lock)
+				return -EINVAL;
+
+			max8998_get_voltage_register(rdev,
+					&reg, &shift, &mask);
+			ret = max8998_write_reg(i2c, reg, selector);
+			max8998->buck2_vol[max8998->buck2_idx] = selector;
+			buck2_gpio_set(max8998->buck2_gpio, max8998->buck2_idx);
+buck2_exit:
+			dev_dbg(max8998->dev, "%s: SET3:%d\n", i2c->name,
+				gpiod_get_value(max8998->buck2_gpio));
+		} else {
+			ret = max8998_write_reg(i2c, reg, selector);
+		}
+		break;
+
+	case MAX8998_BUCK3:
+	case MAX8998_BUCK4:
+		ret = max8998_update_reg(i2c, reg, selector<<shift,
+					 mask<<shift);
+		break;
+	}
+
+	return ret;
+}
+
+static int max8998_set_voltage_buck_time_sel(struct regulator_dev *rdev,
+					     unsigned int old_selector,
+					     unsigned int new_selector)
+{
+	struct max8998_data *max8998 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8998->iodev->i2c;
+	int buck = rdev_get_id(rdev);
+	u8 val = 0;
+	int difference, ret;
+
+	if (buck < MAX8998_BUCK1 || buck > MAX8998_BUCK4)
+		return -EINVAL;
+
+	/* Voltage stabilization */
+	ret = max8998_read_reg(i2c, MAX8998_REG_ONOFF4, &val);
+	if (ret)
+		return ret;
+
+	/* lp3974 hasn't got ENRAMP bit - ramp is assumed as true */
+	/* MAX8998 has ENRAMP bit implemented, so test it*/
+	if (max8998->iodev->type == TYPE_MAX8998 && !(val & MAX8998_ENRAMP))
+		return 0;
+
+	difference = (new_selector - old_selector) * rdev->desc->uV_step / 1000;
+	if (difference > 0)
+		return DIV_ROUND_UP(difference, (val & 0x0f) + 1);
+
+	return 0;
+}
+
+static int max8998_set_current_limit(struct regulator_dev *rdev,
+				     int min_uA, int max_uA)
+{
+	struct max8998_data *max8998 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8998->iodev->i2c;
+	unsigned int n_currents = rdev->desc->n_current_limits;
+	int i, sel = -1;
+
+	if (n_currents == 0)
+		return -EINVAL;
+
+	if (rdev->desc->curr_table) {
+		const unsigned int *curr_table = rdev->desc->curr_table;
+		bool ascend = curr_table[n_currents - 1] > curr_table[0];
+
+		/* search for closest to maximum */
+		if (ascend) {
+			for (i = n_currents - 1; i >= 0; i--) {
+				if (min_uA <= curr_table[i] &&
+				    curr_table[i] <= max_uA) {
+					sel = i;
+					break;
+				}
+			}
+		} else {
+			for (i = 0; i < n_currents; i++) {
+				if (min_uA <= curr_table[i] &&
+				    curr_table[i] <= max_uA) {
+					sel = i;
+					break;
+				}
+			}
+		}
+	}
+
+	if (sel < 0)
+		return -EINVAL;
+
+	sel <<= ffs(rdev->desc->csel_mask) - 1;
+
+	return max8998_update_reg(i2c, rdev->desc->csel_reg,
+				  sel, rdev->desc->csel_mask);
+}
+
+static int max8998_get_current_limit(struct regulator_dev *rdev)
+{
+	struct max8998_data *max8998 = rdev_get_drvdata(rdev);
+	struct i2c_client *i2c = max8998->iodev->i2c;
+	u8 val;
+	int ret;
+
+	ret = max8998_read_reg(i2c, rdev->desc->csel_reg, &val);
+	if (ret != 0)
+		return ret;
+
+	val &= rdev->desc->csel_mask;
+	val >>= ffs(rdev->desc->csel_mask) - 1;
+
+	if (rdev->desc->curr_table) {
+		if (val >= rdev->desc->n_current_limits)
+			return -EINVAL;
+
+		return rdev->desc->curr_table[val];
+	}
+
+	return -EINVAL;
+}
+
+static const struct regulator_ops max8998_ldo_ops = {
+	.list_voltage		= regulator_list_voltage_linear,
+	.map_voltage		= regulator_map_voltage_linear,
+	.is_enabled		= max8998_ldo_is_enabled,
+	.enable			= max8998_ldo_enable,
+	.disable		= max8998_ldo_disable,
+	.get_voltage_sel	= max8998_get_voltage_sel,
+	.set_voltage_sel	= max8998_set_voltage_ldo_sel,
+};
+
+static const struct regulator_ops max8998_buck_ops = {
+	.list_voltage		= regulator_list_voltage_linear,
+	.map_voltage		= regulator_map_voltage_linear,
+	.is_enabled		= max8998_ldo_is_enabled,
+	.enable			= max8998_ldo_enable,
+	.disable		= max8998_ldo_disable,
+	.get_voltage_sel	= max8998_get_voltage_sel,
+	.set_voltage_sel	= max8998_set_voltage_buck_sel,
+	.set_voltage_time_sel	= max8998_set_voltage_buck_time_sel,
+};
+
+static const struct regulator_ops max8998_charger_ops = {
+	.set_current_limit	= max8998_set_current_limit,
+	.get_current_limit	= max8998_get_current_limit,
+	.is_enabled		= max8998_ldo_is_enabled_inverted,
+	/* Swapped as register is inverted */
+	.enable			= max8998_ldo_disable,
+	.disable		= max8998_ldo_enable,
+};
+
+static const struct regulator_ops max8998_others_ops = {
+	.is_enabled		= max8998_ldo_is_enabled,
+	.enable			= max8998_ldo_enable,
+	.disable		= max8998_ldo_disable,
+};
+
+#define MAX8998_LINEAR_REG(_name, _ops, _min, _step, _max) \
+	{ \
+		.name = #_name, \
+		.id = MAX8998_##_name, \
+		.ops = _ops, \
+		.min_uV = (_min), \
+		.uV_step = (_step), \
+		.n_voltages = ((_max) - (_min)) / (_step) + 1, \
+		.type = REGULATOR_VOLTAGE, \
+		.owner = THIS_MODULE, \
+	}
+
+#define MAX8998_CURRENT_REG(_name, _ops, _table, _reg, _mask) \
+	{ \
+		.name = #_name, \
+		.id = MAX8998_##_name, \
+		.ops = _ops, \
+		.curr_table = _table, \
+		.n_current_limits = ARRAY_SIZE(_table), \
+		.csel_reg = _reg, \
+		.csel_mask = _mask, \
+		.type = REGULATOR_CURRENT, \
+		.owner = THIS_MODULE, \
+	}
+
+#define MAX8998_OTHERS_REG(_name, _id) \
+	{ \
+		.name = #_name, \
+		.id = _id, \
+		.ops = &max8998_others_ops, \
+		.type = REGULATOR_VOLTAGE, \
+		.owner = THIS_MODULE, \
+	}
+
+static const struct regulator_desc regulators[] = {
+	MAX8998_LINEAR_REG(LDO2, &max8998_ldo_ops, 800000, 50000, 1300000),
+	MAX8998_LINEAR_REG(LDO3, &max8998_ldo_ops, 800000, 50000, 1300000),
+	MAX8998_LINEAR_REG(LDO4, &max8998_ldo_ops, 1600000, 100000, 3600000),
+	MAX8998_LINEAR_REG(LDO5, &max8998_ldo_ops, 1600000, 100000, 3600000),
+	MAX8998_LINEAR_REG(LDO6, &max8998_ldo_ops, 1600000, 100000, 3600000),
+	MAX8998_LINEAR_REG(LDO7, &max8998_ldo_ops, 1600000, 100000, 3600000),
+	MAX8998_LINEAR_REG(LDO8, &max8998_ldo_ops, 3000000, 100000, 3600000),
+	MAX8998_LINEAR_REG(LDO9, &max8998_ldo_ops, 2800000, 100000, 3100000),
+	MAX8998_LINEAR_REG(LDO10, &max8998_ldo_ops, 950000, 50000, 1300000),
+	MAX8998_LINEAR_REG(LDO11, &max8998_ldo_ops, 1600000, 100000, 3600000),
+	MAX8998_LINEAR_REG(LDO12, &max8998_ldo_ops, 800000, 100000, 3300000),
+	MAX8998_LINEAR_REG(LDO13, &max8998_ldo_ops, 800000, 100000, 3300000),
+	MAX8998_LINEAR_REG(LDO14, &max8998_ldo_ops, 1200000, 100000, 3300000),
+	MAX8998_LINEAR_REG(LDO15, &max8998_ldo_ops, 1200000, 100000, 3300000),
+	MAX8998_LINEAR_REG(LDO16, &max8998_ldo_ops, 1600000, 100000, 3600000),
+	MAX8998_LINEAR_REG(LDO17, &max8998_ldo_ops, 1600000, 100000, 3600000),
+	MAX8998_LINEAR_REG(BUCK1, &max8998_buck_ops, 750000, 25000, 1525000),
+	MAX8998_LINEAR_REG(BUCK2, &max8998_buck_ops, 750000, 25000, 1525000),
+	MAX8998_LINEAR_REG(BUCK3, &max8998_buck_ops, 1600000, 100000, 3600000),
+	MAX8998_LINEAR_REG(BUCK4, &max8998_buck_ops, 800000, 100000, 2300000),
+	MAX8998_OTHERS_REG(EN32KHz-AP, MAX8998_EN32KHZ_AP),
+	MAX8998_OTHERS_REG(EN32KHz-CP, MAX8998_EN32KHZ_CP),
+	MAX8998_OTHERS_REG(ENVICHG, MAX8998_ENVICHG),
+	MAX8998_OTHERS_REG(ESAFEOUT1, MAX8998_ESAFEOUT1),
+	MAX8998_OTHERS_REG(ESAFEOUT2, MAX8998_ESAFEOUT2),
+	MAX8998_CURRENT_REG(CHARGER, &max8998_charger_ops,
+			    charger_current_table, MAX8998_REG_CHGR1, 0x7),
+};
+
+static int max8998_pmic_dt_parse_pdata(struct max8998_dev *iodev,
+					struct max8998_platform_data *pdata)
+{
+	struct device_node *pmic_np = iodev->dev->of_node;
+	struct device_node *regulators_np, *reg_np;
+	struct max8998_regulator_data *rdata;
+	unsigned int i;
+	int ret;
+
+	regulators_np = of_get_child_by_name(pmic_np, "regulators");
+	if (!regulators_np) {
+		dev_err(iodev->dev, "could not find regulators sub-node\n");
+		return -EINVAL;
+	}
+
+	/* count the number of regulators to be supported in pmic */
+	pdata->num_regulators = of_get_child_count(regulators_np);
+
+	rdata = devm_kcalloc(iodev->dev,
+			     pdata->num_regulators, sizeof(*rdata),
+			     GFP_KERNEL);
+	if (!rdata) {
+		of_node_put(regulators_np);
+		return -ENOMEM;
+	}
+
+	pdata->regulators = rdata;
+	for (i = 0; i < ARRAY_SIZE(regulators); ++i) {
+		reg_np = of_get_child_by_name(regulators_np,
+							regulators[i].name);
+		if (!reg_np)
+			continue;
+
+		rdata->id = regulators[i].id;
+		rdata->initdata = of_get_regulator_init_data(iodev->dev,
+							     reg_np,
+							     &regulators[i]);
+		rdata->reg_node = reg_np;
+		++rdata;
+	}
+	pdata->num_regulators = rdata - pdata->regulators;
+
+	of_node_put(reg_np);
+	of_node_put(regulators_np);
+
+	pdata->buck_voltage_lock = of_property_read_bool(pmic_np, "max8998,pmic-buck-voltage-lock");
+
+	ret = of_property_read_u32(pmic_np,
+					"max8998,pmic-buck1-default-dvs-idx",
+					&pdata->buck1_default_idx);
+	if (!ret && pdata->buck1_default_idx >= 4) {
+		pdata->buck1_default_idx = 0;
+		dev_warn(iodev->dev, "invalid value for default dvs index, using 0 instead\n");
+	}
+
+	ret = of_property_read_u32(pmic_np,
+					"max8998,pmic-buck2-default-dvs-idx",
+					&pdata->buck2_default_idx);
+	if (!ret && pdata->buck2_default_idx >= 2) {
+		pdata->buck2_default_idx = 0;
+		dev_warn(iodev->dev, "invalid value for default dvs index, using 0 instead\n");
+	}
+
+	ret = of_property_read_u32_array(pmic_np,
+					"max8998,pmic-buck1-dvs-voltage",
+					pdata->buck1_voltage,
+					ARRAY_SIZE(pdata->buck1_voltage));
+	if (ret) {
+		dev_err(iodev->dev, "buck1 voltages not specified\n");
+		return -EINVAL;
+	}
+
+	ret = of_property_read_u32_array(pmic_np,
+					"max8998,pmic-buck2-dvs-voltage",
+					pdata->buck2_voltage,
+					ARRAY_SIZE(pdata->buck2_voltage));
+	if (ret) {
+		dev_err(iodev->dev, "buck2 voltages not specified\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int max8998_pmic_probe(struct platform_device *pdev)
+{
+	struct max8998_dev *iodev = dev_get_drvdata(pdev->dev.parent);
+	struct max8998_platform_data *pdata = iodev->pdata;
+	struct regulator_config config = { };
+	struct regulator_dev *rdev;
+	struct max8998_data *max8998;
+	struct i2c_client *i2c;
+	enum gpiod_flags flags;
+	int i, ret;
+	unsigned int v;
+
+	if (!pdata) {
+		dev_err(pdev->dev.parent, "No platform init data supplied\n");
+		return -ENODEV;
+	}
+
+	if (IS_ENABLED(CONFIG_OF) && iodev->dev->of_node) {
+		ret = max8998_pmic_dt_parse_pdata(iodev, pdata);
+		if (ret)
+			return ret;
+	}
+
+	max8998 = devm_kzalloc(&pdev->dev, sizeof(struct max8998_data),
+			       GFP_KERNEL);
+	if (!max8998)
+		return -ENOMEM;
+
+	max8998->dev = &pdev->dev;
+	max8998->iodev = iodev;
+	max8998->num_regulators = pdata->num_regulators;
+	platform_set_drvdata(pdev, max8998);
+	i2c = max8998->iodev->i2c;
+
+	max8998->buck1_idx = pdata->buck1_default_idx;
+	max8998->buck2_idx = pdata->buck2_default_idx;
+
+	/* Check if MAX8998 voltage selection GPIOs are defined */
+	flags = (max8998->buck1_idx & BIT(0)) ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
+	max8998->buck1_gpio1 = devm_gpiod_get_index_optional(iodev->dev,
+							     "max8998,pmic-buck1-dvs",
+							     0,
+							     flags);
+	if (IS_ERR(max8998->buck1_gpio1))
+		return dev_err_probe(&pdev->dev, PTR_ERR(max8998->buck1_gpio1),
+				     "could not get BUCK1 GPIO1\n");
+	gpiod_set_consumer_name(max8998->buck1_gpio1, "MAX8998 BUCK1_SET1");
+
+	flags = (max8998->buck1_idx & BIT(1)) ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
+	max8998->buck1_gpio2 = devm_gpiod_get_index_optional(iodev->dev,
+							     "max8998,pmic-buck1-dvs",
+							     1,
+							     flags);
+	if (IS_ERR(max8998->buck1_gpio2))
+		return dev_err_probe(&pdev->dev, PTR_ERR(max8998->buck1_gpio2),
+				     "could not get BUCK1 GPIO2\n");
+	gpiod_set_consumer_name(max8998->buck1_gpio1, "MAX8998 BUCK1_SET2");
+
+	flags = (max8998->buck2_idx & BIT(0)) ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
+	max8998->buck2_gpio = devm_gpiod_get_index_optional(iodev->dev,
+							     "max8998,pmic-buck2-dvs",
+							     0,
+							     flags);
+	if (IS_ERR(max8998->buck2_gpio))
+		return dev_err_probe(&pdev->dev, PTR_ERR(max8998->buck2_gpio),
+				     "could not get BUCK2 GPIO\n");
+	gpiod_set_consumer_name(max8998->buck1_gpio1, "MAX8998 BUCK2_SET3");
+
+	if (max8998->buck1_gpio1 && max8998->buck1_gpio2) {
+		/* Set predefined values for BUCK1 registers */
+		for (v = 0; v < ARRAY_SIZE(pdata->buck1_voltage); ++v) {
+			int index = MAX8998_BUCK1 - MAX8998_LDO2;
+
+			i = 0;
+			while (regulators[index].min_uV +
+			       regulators[index].uV_step * i
+			       < pdata->buck1_voltage[v])
+				i++;
+
+			max8998->buck1_vol[v] = i;
+			ret = max8998_write_reg(i2c,
+					MAX8998_REG_BUCK1_VOLTAGE1 + v, i);
+			if (ret)
+				return ret;
+		}
+	}
+
+	if (max8998->buck2_gpio) {
+		/* Set predefined values for BUCK2 registers */
+		for (v = 0; v < ARRAY_SIZE(pdata->buck2_voltage); ++v) {
+			int index = MAX8998_BUCK2 - MAX8998_LDO2;
+
+			i = 0;
+			while (regulators[index].min_uV +
+			       regulators[index].uV_step * i
+			       < pdata->buck2_voltage[v])
+				i++;
+
+			max8998->buck2_vol[v] = i;
+			ret = max8998_write_reg(i2c,
+					MAX8998_REG_BUCK2_VOLTAGE1 + v, i);
+			if (ret)
+				return ret;
+		}
+	}
+
+	for (i = 0; i < pdata->num_regulators; i++) {
+		int index = pdata->regulators[i].id - MAX8998_LDO2;
+
+		config.dev = max8998->dev;
+		config.of_node = pdata->regulators[i].reg_node;
+		config.init_data = pdata->regulators[i].initdata;
+		config.driver_data = max8998;
+
+		rdev = devm_regulator_register(&pdev->dev, &regulators[index],
+					       &config);
+		if (IS_ERR(rdev)) {
+			ret = PTR_ERR(rdev);
+			dev_err(max8998->dev, "regulator %s init failed (%d)\n",
+						regulators[index].name, ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static const struct platform_device_id max8998_pmic_id[] = {
+	{ .name = "max8998-pmic", .driver_data = TYPE_MAX8998 },
+	{ .name = "lp3974-pmic", .driver_data = TYPE_LP3974 },
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, max8998_pmic_id);
+
+static struct platform_driver max8998_pmic_driver = {
+	.driver = {
+		.name = "max8998-pmic",
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+	.probe = max8998_pmic_probe,
+	.id_table = max8998_pmic_id,
+};
+
+static int __init max8998_pmic_init(void)
+{
+	return platform_driver_register(&max8998_pmic_driver);
+}
+subsys_initcall(max8998_pmic_init);
+
+static void __exit max8998_pmic_cleanup(void)
+{
+	platform_driver_unregister(&max8998_pmic_driver);
+}
+module_exit(max8998_pmic_cleanup);
+
+MODULE_DESCRIPTION("MAXIM 8998 voltage regulator driver");
+MODULE_AUTHOR("Kyungmin Park <kyungmin.park@samsung.com>");
+MODULE_LICENSE("GPL");