selftests/bpf: Reject graph kptr use after RCU unlockgrafted

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 1048 insertions, 0 deletions

diff --git a/drivers/hwmon/ina238.c b/drivers/hwmon/ina238.c
new file mode 100644
index 000000000..3632bbca6
--- /dev/null
+++ b/drivers/hwmon/ina238.c
@@ -0,0 +1,1048 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Texas Instruments INA238 power monitor chip
+ * Datasheet: https://www.ti.com/product/ina238
+ *
+ * Copyright (C) 2021 Nathan Rossi <nathan.rossi@digi.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/util_macros.h>
+
+/* INA238 register definitions */
+#define INA238_CONFIG			0x0
+#define INA238_ADC_CONFIG		0x1
+#define INA238_SHUNT_CALIBRATION	0x2
+#define SQ52206_SHUNT_TEMPCO		0x3
+#define INA238_SHUNT_VOLTAGE		0x4
+#define INA238_BUS_VOLTAGE		0x5
+#define INA238_DIE_TEMP			0x6
+#define INA238_CURRENT			0x7
+#define INA238_POWER			0x8
+#define SQ52206_ENERGY			0x9
+#define SQ52206_CHARGE			0xa
+#define INA238_DIAG_ALERT		0xb
+#define INA238_SHUNT_OVER_VOLTAGE	0xc
+#define INA238_SHUNT_UNDER_VOLTAGE	0xd
+#define INA238_BUS_OVER_VOLTAGE		0xe
+#define INA238_BUS_UNDER_VOLTAGE	0xf
+#define INA238_TEMP_LIMIT		0x10
+#define INA238_POWER_LIMIT		0x11
+#define SQ52206_POWER_PEAK		0x20
+#define INA238_DEVICE_ID		0x3f /* not available on INA237 */
+
+#define INA238_CONFIG_ADCRANGE		BIT(4)
+#define SQ52206_CONFIG_ADCRANGE_HIGH	BIT(4)
+#define SQ52206_CONFIG_ADCRANGE_LOW	BIT(3)
+
+#define INA238_DIAG_ALERT_TMPOL		BIT(7)
+#define INA238_DIAG_ALERT_SHNTOL	BIT(6)
+#define INA238_DIAG_ALERT_SHNTUL	BIT(5)
+#define INA238_DIAG_ALERT_BUSOL		BIT(4)
+#define INA238_DIAG_ALERT_BUSUL		BIT(3)
+#define INA238_DIAG_ALERT_POL		BIT(2)
+
+/* INA238_ADC_CONFIG register field masks and shifts */
+#define INA238_ADC_CONFIG_MODE_MASK	GENMASK(15, 12)
+#define INA238_ADC_CONFIG_VBUSCT_SHIFT	9
+#define INA238_ADC_CONFIG_VBUSCT_MASK	GENMASK(11, 9)
+#define INA238_ADC_CONFIG_VSHCT_SHIFT	6
+#define INA238_ADC_CONFIG_VSHCT_MASK	GENMASK(8, 6)
+#define INA238_ADC_CONFIG_VTCT_SHIFT	3
+#define INA238_ADC_CONFIG_VTCT_MASK	GENMASK(5, 3)
+#define INA238_ADC_CONFIG_AVG_SHIFT	0
+#define INA238_ADC_CONFIG_AVG_MASK	GENMASK(2, 0)
+
+#define INA238_REGISTERS		0x20
+
+#define INA238_RSHUNT_DEFAULT		2500	/* uOhm */
+
+/* Default configuration of device on reset. */
+#define INA238_CONFIG_DEFAULT		0
+#define SQ52206_CONFIG_DEFAULT		0x0005
+/* 16 sample averaging, 1052us conversion time, continuous mode */
+#define INA238_ADC_CONFIG_DEFAULT	0xfb6a
+/* Configure alerts to be based on averaged value (SLOWALERT) */
+#define INA238_DIAG_ALERT_DEFAULT	0x2000
+#define INA238_DIAG_ALERT_APOL		BIT(12)
+/*
+ * This driver uses a fixed calibration value in order to scale current/power
+ * based on a fixed shunt resistor value. This allows for conversion within the
+ * device to avoid integer limits whilst current/power accuracy is scaled
+ * relative to the shunt resistor value within the driver. This is similar to
+ * how the ina2xx driver handles current/power scaling.
+ *
+ * To achieve the best possible dynamic range, the value of the shunt voltage
+ * register should match the value of the current register. With that, the shunt
+ * voltage of 0x7fff = 32,767 uV = 163,785 uV matches the maximum current,
+ * and no accuracy is lost. Experiments with a real chip show that this is
+ * achieved by setting the SHUNT_CAL register to a value of 0x1000 = 4,096.
+ * Per datasheet,
+ *  SHUNT_CAL = 819.2 x 10^6 x CURRENT_LSB x Rshunt
+ *            = 819,200,000 x CURRENT_LSB x Rshunt
+ * With SHUNT_CAL set to 4,096, we get
+ *  CURRENT_LSB = 4,096 / (819,200,000 x Rshunt)
+ * Assuming an Rshunt value of 5 mOhm, we get
+ *  CURRENT_LSB = 4,096 / (819,200,000 x 0.005) = 1mA
+ * and thus a dynamic range of 1mA ... 32,767mA, which is sufficient for most
+ * applications. The actual dynamic range is of course determined by the actual
+ * shunt resistor value.
+ *
+ * Power and energy values are scaled accordingly.
+ */
+#define INA238_CALIBRATION_VALUE	4096
+#define INA238_FIXED_SHUNT		5000
+
+#define INA238_SHUNT_VOLTAGE_LSB	5000	/* 5 uV/lsb, in nV */
+#define INA238_BUS_VOLTAGE_LSB		3125000	/* 3.125 mV/lsb, in nV */
+#define SQ52206_BUS_VOLTAGE_LSB		3750000	/* 3.75 mV/lsb, in nV */
+
+#define NUNIT_PER_MUNIT		1000000	/* n[AV] -> m[AV] */
+
+static const struct regmap_config ina238_regmap_config = {
+	.max_register = INA238_REGISTERS,
+	.reg_bits = 8,
+	.val_bits = 16,
+};
+
+/* Lookup table for conversion times in usec for INA238 family */
+static const u16 ina238_conv_time[] = {
+	50, 84, 150, 280, 540, 1052, 2074, 4120,
+};
+
+/* Lookup table for conversion times in usec for SQ52206 */
+static const u16 sq52206_conv_time[] = {
+	66, 118, 310, 566, 1070, 2090, 4140, 8230,
+};
+
+/* Lookup table for number of samples used in averaging mode */
+static const int ina238_avg_samples[] = {
+	1, 4, 16, 64, 128, 256, 512, 1024,
+};
+
+enum ina238_ids { ina228, ina237, ina238, ina700, ina780, sq52206 };
+
+struct ina238_config {
+	bool has_20bit_voltage_current; /* vshunt, vbus and current are 20-bit fields */
+	bool has_power_highest;		/* chip detection power peak */
+	bool has_energy;		/* chip detection energy */
+	u8 temp_resolution;		/* temperature register resolution in bit */
+	u16 config_default;		/* Power-on default state */
+	u32 power_calculate_factor;	/* fixed parameter for power calculation, from datasheet */
+	u32 bus_voltage_lsb;		/* bus voltage LSB, in nV */
+	int current_lsb;		/* current LSB, in uA */
+	const u16 *conv_time;		/* conversion time lookup table */
+};
+
+struct ina238_data {
+	const struct ina238_config *config;
+	struct i2c_client *client;
+	struct regmap *regmap;
+	u32 rshunt;
+	int gain;
+	u32 voltage_lsb[2];		/* shunt, bus voltage LSB, in nV */
+	int current_lsb;		/* current LSB, in uA */
+	int power_lsb;			/* power LSB, in uW */
+	int energy_lsb;			/* energy LSB, in uJ */
+	u16 adc_config;			/* cached ADC_CONFIG register value */
+};
+
+static const struct ina238_config ina238_config[] = {
+	[ina228] = {
+		.has_20bit_voltage_current = true,
+		.has_energy = true,
+		.has_power_highest = false,
+		.power_calculate_factor = 20,
+		.config_default = INA238_CONFIG_DEFAULT,
+		.bus_voltage_lsb = INA238_BUS_VOLTAGE_LSB,
+		.temp_resolution = 16,
+		.conv_time = ina238_conv_time,
+	},
+	[ina237] = {
+		.has_20bit_voltage_current = false,
+		.has_energy = false,
+		.has_power_highest = false,
+		.power_calculate_factor = 20,
+		.config_default = INA238_CONFIG_DEFAULT,
+		.bus_voltage_lsb = INA238_BUS_VOLTAGE_LSB,
+		.temp_resolution = 12,
+		.conv_time = ina238_conv_time,
+	},
+	[ina238] = {
+		.has_20bit_voltage_current = false,
+		.has_energy = false,
+		.has_power_highest = false,
+		.power_calculate_factor = 20,
+		.config_default = INA238_CONFIG_DEFAULT,
+		.bus_voltage_lsb = INA238_BUS_VOLTAGE_LSB,
+		.temp_resolution = 12,
+		.conv_time = ina238_conv_time,
+	},
+	[ina700] = {
+		.has_20bit_voltage_current = false,
+		.has_energy = true,
+		.has_power_highest = false,
+		.power_calculate_factor = 20,
+		.config_default = INA238_CONFIG_DEFAULT,
+		.bus_voltage_lsb = INA238_BUS_VOLTAGE_LSB,
+		.temp_resolution = 12,
+		.current_lsb = 480,
+		.conv_time = ina238_conv_time,
+	},
+	[ina780] = {
+		.has_20bit_voltage_current = false,
+		.has_energy = true,
+		.has_power_highest = false,
+		.power_calculate_factor = 20,
+		.config_default = INA238_CONFIG_DEFAULT,
+		.bus_voltage_lsb = INA238_BUS_VOLTAGE_LSB,
+		.temp_resolution = 12,
+		.current_lsb = 2400,
+		.conv_time = ina238_conv_time,
+	},
+	[sq52206] = {
+		.has_20bit_voltage_current = false,
+		.has_energy = true,
+		.has_power_highest = true,
+		.power_calculate_factor = 24,
+		.config_default = SQ52206_CONFIG_DEFAULT,
+		.bus_voltage_lsb = SQ52206_BUS_VOLTAGE_LSB,
+		.temp_resolution = 16,
+		.conv_time = sq52206_conv_time,
+	},
+};
+
+static int ina238_read_reg24(const struct i2c_client *client, u8 reg, u32 *val)
+{
+	u8 data[3];
+	int err;
+
+	/* 24-bit register read */
+	err = i2c_smbus_read_i2c_block_data(client, reg, 3, data);
+	if (err < 0)
+		return err;
+	if (err != 3)
+		return -EIO;
+	*val = (data[0] << 16) | (data[1] << 8) | data[2];
+
+	return 0;
+}
+
+static int ina238_read_reg40(const struct i2c_client *client, u8 reg, u64 *val)
+{
+	u8 data[5];
+	u32 low;
+	int err;
+
+	/* 40-bit register read */
+	err = i2c_smbus_read_i2c_block_data(client, reg, 5, data);
+	if (err < 0)
+		return err;
+	if (err != 5)
+		return -EIO;
+	low = (data[1] << 24) | (data[2] << 16) | (data[3] << 8) | data[4];
+	*val = ((long long)data[0] << 32) | low;
+
+	return 0;
+}
+
+static int ina238_read_field_s20(const struct i2c_client *client, u8 reg, s32 *val)
+{
+	u32 regval;
+	int err;
+
+	err = ina238_read_reg24(client, reg, &regval);
+	if (err)
+		return err;
+
+	/* bits 3-0 Reserved, always zero */
+	regval >>= 4;
+
+	*val = sign_extend32(regval, 19);
+
+	return 0;
+}
+
+static int ina228_read_voltage(struct ina238_data *data, int channel, long *val)
+{
+	int reg = channel ? INA238_BUS_VOLTAGE : INA238_CURRENT;
+	u32 lsb = data->voltage_lsb[channel];
+	u32 factor = NUNIT_PER_MUNIT;
+	int err, regval;
+
+	if (data->config->has_20bit_voltage_current) {
+		err = ina238_read_field_s20(data->client, reg, &regval);
+		if (err)
+			return err;
+		/* Adjust accuracy: LSB in units of 500 pV */
+		lsb /= 8;
+		factor *= 2;
+	} else {
+		err = regmap_read(data->regmap, reg, &regval);
+		if (err)
+			return err;
+		regval = (s16)regval;
+	}
+
+	*val = DIV_S64_ROUND_CLOSEST((s64)regval * lsb, factor);
+	return 0;
+}
+
+/* Converting ADC_CONFIG register value to update_interval in usec */
+static inline u32 ina238_reg_to_interval_us(struct ina238_data *data)
+{
+	const u16 *ct = data->config->conv_time;
+	u32 vbusct = ct[(data->adc_config & INA238_ADC_CONFIG_VBUSCT_MASK) >>
+			INA238_ADC_CONFIG_VBUSCT_SHIFT];
+	u32 vshct  = ct[(data->adc_config & INA238_ADC_CONFIG_VSHCT_MASK) >>
+			INA238_ADC_CONFIG_VSHCT_SHIFT];
+	u32 vtct   = ct[(data->adc_config & INA238_ADC_CONFIG_VTCT_MASK) >>
+			INA238_ADC_CONFIG_VTCT_SHIFT];
+
+	return vbusct + vshct + vtct;
+}
+
+static inline u32 ina238_samples(struct ina238_data *data)
+{
+	return ina238_avg_samples[(data->adc_config & INA238_ADC_CONFIG_AVG_MASK) >>
+				  INA238_ADC_CONFIG_AVG_SHIFT];
+}
+
+/* Converting update_interval(_us) to a per-field conversion time in usec.
+ * interval_us is the total ADC cycle time including averaging in microseconds.
+ * All three conversion fields (VBUSCT, VSHCT, VTCT) are set equal, so the
+ * per-field time is interval_us / (samples * 3).
+ */
+static inline u32 ina238_interval_us_to_conv_time(u32 interval_us, u32 samples)
+{
+	return DIV_ROUND_CLOSEST_ULL(interval_us, samples * 3);
+}
+
+/* Write a per-field conversion time (in usec) to the ADC_CONFIG register */
+static int ina238_write_conv_time(struct ina238_data *data, u32 conv_time_us)
+{
+	u16 adc_config;
+	int idx, ret;
+
+	idx = find_closest(conv_time_us, data->config->conv_time,
+			   ARRAY_SIZE(ina238_conv_time));
+	adc_config = (data->adc_config &
+		      ~(INA238_ADC_CONFIG_VBUSCT_MASK |
+			INA238_ADC_CONFIG_VSHCT_MASK |
+			INA238_ADC_CONFIG_VTCT_MASK)) |
+		     ((u16)idx << INA238_ADC_CONFIG_VBUSCT_SHIFT) |
+		     ((u16)idx << INA238_ADC_CONFIG_VSHCT_SHIFT) |
+		     ((u16)idx << INA238_ADC_CONFIG_VTCT_SHIFT);
+	ret = regmap_write(data->regmap, INA238_ADC_CONFIG, adc_config);
+	if (ret)
+		return ret;
+	data->adc_config = adc_config;
+	return 0;
+}
+
+static int ina238_read_chip(struct device *dev, u32 attr, long *val)
+{
+	struct ina238_data *data = dev_get_drvdata(dev);
+
+	switch (attr) {
+	case hwmon_chip_samples:
+		*val = ina238_samples(data);
+		return 0;
+	case hwmon_chip_update_interval:
+		/* Return in msec */
+		*val = DIV_ROUND_CLOSEST(ina238_reg_to_interval_us(data) *
+					ina238_samples(data), 1000);
+		return 0;
+	case hwmon_chip_update_interval_us:
+		/* Return in usec */
+		*val = ina238_reg_to_interval_us(data) * ina238_samples(data);
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int ina238_write_chip(struct device *dev, u32 attr, long val)
+{
+	struct ina238_data *data = dev_get_drvdata(dev);
+	u16 adc_config;
+	int idx, ret;
+
+	switch (attr) {
+	case hwmon_chip_samples:
+		idx = find_closest(val, ina238_avg_samples,
+				   ARRAY_SIZE(ina238_avg_samples));
+		adc_config = (data->adc_config & ~INA238_ADC_CONFIG_AVG_MASK) |
+			     (idx << INA238_ADC_CONFIG_AVG_SHIFT);
+		ret = regmap_write(data->regmap, INA238_ADC_CONFIG, adc_config);
+		if (ret)
+			return ret;
+		data->adc_config = adc_config;
+		return 0;
+	case hwmon_chip_update_interval:
+		/* Convert ms to us before passing to the shared helper */
+		val = clamp_val(val, 0, INT_MAX / 1000) * 1000;
+		return ina238_write_conv_time(data,
+			ina238_interval_us_to_conv_time((u32)val, ina238_samples(data)));
+	case hwmon_chip_update_interval_us:
+		val = clamp_val(val, 0, INT_MAX);
+		return ina238_write_conv_time(data,
+			ina238_interval_us_to_conv_time((u32)val, ina238_samples(data)));
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int ina238_read_in(struct device *dev, u32 attr, int channel,
+			  long *val)
+{
+	struct ina238_data *data = dev_get_drvdata(dev);
+	int reg, mask = 0;
+	int regval;
+	int err;
+
+	if (attr == hwmon_in_input)
+		return ina228_read_voltage(data, channel, val);
+
+	switch (channel) {
+	case 0:
+		switch (attr) {
+		case hwmon_in_max:
+			reg = INA238_SHUNT_OVER_VOLTAGE;
+			break;
+		case hwmon_in_min:
+			reg = INA238_SHUNT_UNDER_VOLTAGE;
+			break;
+		case hwmon_in_max_alarm:
+			reg = INA238_DIAG_ALERT;
+			mask = INA238_DIAG_ALERT_SHNTOL;
+			break;
+		case hwmon_in_min_alarm:
+			reg = INA238_DIAG_ALERT;
+			mask = INA238_DIAG_ALERT_SHNTUL;
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+		break;
+	case 1:
+		switch (attr) {
+		case hwmon_in_max:
+			reg = INA238_BUS_OVER_VOLTAGE;
+			break;
+		case hwmon_in_min:
+			reg = INA238_BUS_UNDER_VOLTAGE;
+			break;
+		case hwmon_in_max_alarm:
+			reg = INA238_DIAG_ALERT;
+			mask = INA238_DIAG_ALERT_BUSOL;
+			break;
+		case hwmon_in_min_alarm:
+			reg = INA238_DIAG_ALERT;
+			mask = INA238_DIAG_ALERT_BUSUL;
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	err = regmap_read(data->regmap, reg, &regval);
+	if (err < 0)
+		return err;
+
+	if (mask)
+		*val = !!(regval & mask);
+	else
+		*val = DIV_S64_ROUND_CLOSEST((s64)(s16)regval * data->voltage_lsb[channel],
+					     NUNIT_PER_MUNIT);
+
+	return 0;
+}
+
+static int ina238_write_in(struct device *dev, u32 attr, int channel, long val)
+{
+	struct ina238_data *data = dev_get_drvdata(dev);
+	static const int low_limits[2] = {-164, 0};
+	static const int high_limits[2] = {164, 150000};
+	static const u8 low_regs[2] = {INA238_SHUNT_UNDER_VOLTAGE, INA238_BUS_UNDER_VOLTAGE};
+	static const u8 high_regs[2] = {INA238_SHUNT_OVER_VOLTAGE, INA238_BUS_OVER_VOLTAGE};
+	int regval;
+
+	/* Initial clamp to avoid overflows */
+	val = clamp_val(val, low_limits[channel], high_limits[channel]);
+	val = DIV_S64_ROUND_CLOSEST((s64)val * NUNIT_PER_MUNIT, data->voltage_lsb[channel]);
+	/* Final clamp to register limits */
+	regval = clamp_val(val, S16_MIN, S16_MAX) & 0xffff;
+
+	switch (attr) {
+	case hwmon_in_min:
+		return regmap_write(data->regmap, low_regs[channel], regval);
+	case hwmon_in_max:
+		return regmap_write(data->regmap, high_regs[channel], regval);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int __ina238_read_curr(struct ina238_data *data, long *val)
+{
+	u32 lsb = data->current_lsb;
+	int err, regval;
+
+	if (data->config->has_20bit_voltage_current) {
+		err = ina238_read_field_s20(data->client, INA238_CURRENT, &regval);
+		if (err)
+			return err;
+		lsb /= 16;	/* Adjust accuracy */
+	} else {
+		err = regmap_read(data->regmap, INA238_CURRENT, &regval);
+		if (err)
+			return err;
+		regval = (s16)regval;
+	}
+
+	*val = DIV_S64_ROUND_CLOSEST((s64)regval * lsb, 1000);
+	return 0;
+}
+
+static int ina238_read_curr(struct device *dev, u32 attr, long *val)
+{
+	struct ina238_data *data = dev_get_drvdata(dev);
+	int reg, mask = 0;
+	int regval;
+	int err;
+
+	if (attr == hwmon_curr_input)
+		return __ina238_read_curr(data, val);
+
+	switch (attr) {
+	case hwmon_curr_min:
+		reg = INA238_SHUNT_UNDER_VOLTAGE;
+		break;
+	case hwmon_curr_min_alarm:
+		reg = INA238_DIAG_ALERT;
+		mask = INA238_DIAG_ALERT_SHNTUL;
+		break;
+	case hwmon_curr_max:
+		reg = INA238_SHUNT_OVER_VOLTAGE;
+		break;
+	case hwmon_curr_max_alarm:
+		reg = INA238_DIAG_ALERT;
+		mask = INA238_DIAG_ALERT_SHNTOL;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	err = regmap_read(data->regmap, reg, &regval);
+	if (err < 0)
+		return err;
+
+	if (mask)
+		*val = !!(regval & mask);
+	else
+		*val = DIV_S64_ROUND_CLOSEST((s64)(s16)regval * data->current_lsb, 1000);
+
+	return 0;
+}
+
+static int ina238_write_curr(struct device *dev, u32 attr, long val)
+{
+	struct ina238_data *data = dev_get_drvdata(dev);
+	int regval;
+
+	/* Set baseline range to avoid over/underflows */
+	val = clamp_val(val, -1000000, 1000000);
+	/* Scale */
+	val = DIV_ROUND_CLOSEST(val * 1000, data->current_lsb);
+	/* Clamp to register size */
+	regval = clamp_val(val, S16_MIN, S16_MAX) & 0xffff;
+
+	switch (attr) {
+	case hwmon_curr_min:
+		return regmap_write(data->regmap, INA238_SHUNT_UNDER_VOLTAGE,
+				    regval);
+	case hwmon_curr_max:
+		return regmap_write(data->regmap, INA238_SHUNT_OVER_VOLTAGE,
+				    regval);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int ina238_read_power(struct device *dev, u32 attr, long *val)
+{
+	struct ina238_data *data = dev_get_drvdata(dev);
+	long long power;
+	int regval;
+	int err;
+
+	switch (attr) {
+	case hwmon_power_input:
+		err = ina238_read_reg24(data->client, INA238_POWER, &regval);
+		if (err)
+			return err;
+
+		power = (long long)regval * data->power_lsb;
+		/* Clamp value to maximum value of long */
+		*val = clamp_val(power, 0, LONG_MAX);
+		break;
+	case hwmon_power_input_highest:
+		err = ina238_read_reg24(data->client, SQ52206_POWER_PEAK, &regval);
+		if (err)
+			return err;
+
+		power = (long long)regval * data->power_lsb;
+		/* Clamp value to maximum value of long */
+		*val = clamp_val(power, 0, LONG_MAX);
+		break;
+	case hwmon_power_max:
+		err = regmap_read(data->regmap, INA238_POWER_LIMIT, &regval);
+		if (err)
+			return err;
+
+		/*
+		 * Truncated 24-bit compare register, lower 8-bits are
+		 * truncated. Same conversion to/from uW as POWER register.
+		 */
+		power = ((long long)regval << 8) * data->power_lsb;
+		/* Clamp value to maximum value of long */
+		*val = clamp_val(power, 0, LONG_MAX);
+		break;
+	case hwmon_power_max_alarm:
+		err = regmap_read(data->regmap, INA238_DIAG_ALERT, &regval);
+		if (err)
+			return err;
+
+		*val = !!(regval & INA238_DIAG_ALERT_POL);
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int ina238_write_power_max(struct device *dev, long val)
+{
+	struct ina238_data *data = dev_get_drvdata(dev);
+
+	/*
+	 * Unsigned postive values. Compared against the 24-bit power register,
+	 * lower 8-bits are truncated. Same conversion to/from uW as POWER
+	 * register.
+	 * The first clamp_val() is to establish a baseline to avoid overflows.
+	 */
+	val = clamp_val(val, 0, LONG_MAX / 2);
+	val = DIV_ROUND_CLOSEST(val, data->power_lsb);
+	val = clamp_val(val >> 8, 0, U16_MAX);
+
+	return regmap_write(data->regmap, INA238_POWER_LIMIT, val);
+}
+
+static int ina238_temp_from_reg(s16 regval, u8 resolution)
+{
+	return ((regval >> (16 - resolution)) * 1000) >> (resolution - 9);
+}
+
+static int ina238_read_temp(struct device *dev, u32 attr, long *val)
+{
+	struct ina238_data *data = dev_get_drvdata(dev);
+	int regval;
+	int err;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		err = regmap_read(data->regmap, INA238_DIE_TEMP, &regval);
+		if (err)
+			return err;
+		*val = ina238_temp_from_reg(regval, data->config->temp_resolution);
+		break;
+	case hwmon_temp_max:
+		err = regmap_read(data->regmap, INA238_TEMP_LIMIT, &regval);
+		if (err)
+			return err;
+		/* Signed, result in mC */
+		*val = ina238_temp_from_reg(regval, data->config->temp_resolution);
+		break;
+	case hwmon_temp_max_alarm:
+		err = regmap_read(data->regmap, INA238_DIAG_ALERT, &regval);
+		if (err)
+			return err;
+
+		*val = !!(regval & INA238_DIAG_ALERT_TMPOL);
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static u16 ina238_temp_to_reg(long val, u8 resolution)
+{
+	int fraction = 1000 - DIV_ROUND_CLOSEST(1000, BIT(resolution - 9));
+
+	val = clamp_val(val, -255000 - fraction, 255000 + fraction);
+
+	return (DIV_ROUND_CLOSEST(val << (resolution - 9), 1000) << (16 - resolution)) & 0xffff;
+}
+
+static int ina238_write_temp_max(struct device *dev, long val)
+{
+	struct ina238_data *data = dev_get_drvdata(dev);
+	int regval;
+
+	regval = ina238_temp_to_reg(val, data->config->temp_resolution);
+	return regmap_write(data->regmap, INA238_TEMP_LIMIT, regval);
+}
+
+static int ina238_read_energy(struct device *dev, s64 *energy)
+{
+	struct ina238_data *data = dev_get_drvdata(dev);
+	u64 regval;
+	int ret;
+
+	ret = ina238_read_reg40(data->client, SQ52206_ENERGY, &regval);
+	if (ret)
+		return ret;
+
+	/* result in uJ */
+	*energy = regval * data->energy_lsb;
+	return 0;
+}
+
+static int ina238_read(struct device *dev, enum hwmon_sensor_types type,
+		       u32 attr, int channel, long *val)
+{
+	switch (type) {
+	case hwmon_chip:
+		return ina238_read_chip(dev, attr, val);
+	case hwmon_in:
+		return ina238_read_in(dev, attr, channel, val);
+	case hwmon_curr:
+		return ina238_read_curr(dev, attr, val);
+	case hwmon_power:
+		return ina238_read_power(dev, attr, val);
+	case hwmon_energy64:
+		return ina238_read_energy(dev, (s64 *)val);
+	case hwmon_temp:
+		return ina238_read_temp(dev, attr, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+	return 0;
+}
+
+static int ina238_write(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long val)
+{
+	switch (type) {
+	case hwmon_chip:
+		return ina238_write_chip(dev, attr, val);
+	case hwmon_in:
+		return ina238_write_in(dev, attr, channel, val);
+	case hwmon_curr:
+		return ina238_write_curr(dev, attr, val);
+	case hwmon_power:
+		return ina238_write_power_max(dev, val);
+	case hwmon_temp:
+		return ina238_write_temp_max(dev, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static umode_t ina238_is_visible(const void *drvdata,
+				 enum hwmon_sensor_types type,
+				 u32 attr, int channel)
+{
+	const struct ina238_data *data = drvdata;
+	bool has_power_highest = data->config->has_power_highest;
+	bool has_energy = data->config->has_energy;
+
+	switch (type) {
+	case hwmon_chip:
+		switch (attr) {
+		case hwmon_chip_samples:
+		case hwmon_chip_update_interval:
+		case hwmon_chip_update_interval_us:
+			return 0644;
+		default:
+			return 0;
+		}
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_input:
+		case hwmon_in_max_alarm:
+		case hwmon_in_min_alarm:
+			return 0444;
+		case hwmon_in_max:
+		case hwmon_in_min:
+			return 0644;
+		default:
+			return 0;
+		}
+	case hwmon_curr:
+		switch (attr) {
+		case hwmon_curr_input:
+		case hwmon_curr_max_alarm:
+		case hwmon_curr_min_alarm:
+			return 0444;
+		case hwmon_curr_max:
+		case hwmon_curr_min:
+			return 0644;
+		default:
+			return 0;
+		}
+	case hwmon_power:
+		switch (attr) {
+		case hwmon_power_input:
+		case hwmon_power_max_alarm:
+			return 0444;
+		case hwmon_power_max:
+			return 0644;
+		case hwmon_power_input_highest:
+			if (has_power_highest)
+				return 0444;
+			return 0;
+		default:
+			return 0;
+		}
+	case hwmon_energy64:
+		/* hwmon_energy_input */
+		if (has_energy)
+			return 0444;
+		return 0;
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+		case hwmon_temp_max_alarm:
+			return 0444;
+		case hwmon_temp_max:
+			return 0644;
+		default:
+			return 0;
+		}
+	default:
+		return 0;
+	}
+}
+
+#define INA238_HWMON_IN_CONFIG (HWMON_I_INPUT | \
+				HWMON_I_MAX | HWMON_I_MAX_ALARM | \
+				HWMON_I_MIN | HWMON_I_MIN_ALARM)
+
+static const struct hwmon_channel_info * const ina238_info[] = {
+	HWMON_CHANNEL_INFO(chip,
+			   HWMON_C_SAMPLES | HWMON_C_UPDATE_INTERVAL |
+			   HWMON_C_UPDATE_INTERVAL_US),
+	HWMON_CHANNEL_INFO(in,
+			   /* 0: shunt voltage */
+			   INA238_HWMON_IN_CONFIG,
+			   /* 1: bus voltage */
+			   INA238_HWMON_IN_CONFIG),
+	HWMON_CHANNEL_INFO(curr,
+			   /* 0: current through shunt */
+			   HWMON_C_INPUT | HWMON_C_MIN | HWMON_C_MIN_ALARM |
+			   HWMON_C_MAX | HWMON_C_MAX_ALARM),
+	HWMON_CHANNEL_INFO(power,
+			   /* 0: power */
+			   HWMON_P_INPUT | HWMON_P_MAX |
+			   HWMON_P_MAX_ALARM | HWMON_P_INPUT_HIGHEST),
+	HWMON_CHANNEL_INFO(energy64,
+			   HWMON_E_INPUT),
+	HWMON_CHANNEL_INFO(temp,
+			   /* 0: die temperature */
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_ALARM),
+	NULL
+};
+
+static const struct hwmon_ops ina238_hwmon_ops = {
+	.is_visible = ina238_is_visible,
+	.read = ina238_read,
+	.write = ina238_write,
+};
+
+static const struct hwmon_chip_info ina238_chip_info = {
+	.ops = &ina238_hwmon_ops,
+	.info = ina238_info,
+};
+
+static int ina238_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct device *hwmon_dev;
+	struct ina238_data *data;
+	enum ina238_ids chip;
+	int config;
+	int ret;
+
+	chip = (uintptr_t)i2c_get_match_data(client);
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	/* set the device type */
+	data->config = &ina238_config[chip];
+
+	data->regmap = devm_regmap_init_i2c(client, &ina238_regmap_config);
+	if (IS_ERR(data->regmap)) {
+		dev_err(dev, "failed to allocate register map\n");
+		return PTR_ERR(data->regmap);
+	}
+
+	/* Setup CONFIG register */
+	config = data->config->config_default;
+	if (data->config->current_lsb) {
+		data->voltage_lsb[0] = INA238_SHUNT_VOLTAGE_LSB;
+		data->current_lsb = data->config->current_lsb;
+	} else {
+		/* load shunt value */
+		if (device_property_read_u32(dev, "shunt-resistor", &data->rshunt) < 0)
+			data->rshunt = INA238_RSHUNT_DEFAULT;
+		if (data->rshunt == 0) {
+			dev_err(dev, "invalid shunt resister value %u\n", data->rshunt);
+			return -EINVAL;
+		}
+
+		/* load shunt gain value */
+		if (device_property_read_u32(dev, "ti,shunt-gain", &data->gain) < 0)
+			data->gain = 4;	/* Default of ADCRANGE = 0 */
+		if (data->gain != 1 && data->gain != 2 && data->gain != 4) {
+			dev_err(dev, "invalid shunt gain value %u\n", data->gain);
+			return -EINVAL;
+		}
+
+		/* Setup SHUNT_CALIBRATION register with fixed value */
+		ret = regmap_write(data->regmap, INA238_SHUNT_CALIBRATION,
+				   INA238_CALIBRATION_VALUE);
+		if (ret < 0) {
+			dev_err(dev, "error configuring the device: %d\n", ret);
+			return -ENODEV;
+		}
+		if (chip == sq52206) {
+			if (data->gain == 1)		/* ADCRANGE = 10/11 is /1 */
+				config |= SQ52206_CONFIG_ADCRANGE_HIGH;
+			else if (data->gain == 2)	/* ADCRANGE = 01 is /2 */
+				config |= SQ52206_CONFIG_ADCRANGE_LOW;
+		} else if (data->gain == 1) {		/* ADCRANGE = 1 is /1 */
+			config |= INA238_CONFIG_ADCRANGE;
+		}
+		data->voltage_lsb[0] = INA238_SHUNT_VOLTAGE_LSB * data->gain / 4;
+		data->current_lsb = DIV_U64_ROUND_CLOSEST(250ULL * INA238_FIXED_SHUNT * data->gain,
+							  data->rshunt);
+	}
+
+	ret = regmap_write(data->regmap, INA238_CONFIG, config);
+	if (ret < 0) {
+		dev_err(dev, "error configuring the device: %d\n", ret);
+		return -ENODEV;
+	}
+
+	/* Setup ADC_CONFIG register */
+	data->adc_config = INA238_ADC_CONFIG_DEFAULT;
+	ret = regmap_write(data->regmap, INA238_ADC_CONFIG, data->adc_config);
+	if (ret < 0) {
+		dev_err(dev, "error configuring the device: %d\n", ret);
+		return -ENODEV;
+	}
+
+	/* Setup alert/alarm configuration */
+	config = INA238_DIAG_ALERT_DEFAULT;
+	if (device_property_read_bool(dev, "ti,alert-polarity-active-high"))
+		config |= INA238_DIAG_ALERT_APOL;
+
+	ret = regmap_write(data->regmap, INA238_DIAG_ALERT, config);
+	if (ret < 0) {
+		dev_err(dev, "error configuring the device: %d\n", ret);
+		return -ENODEV;
+	}
+
+	data->voltage_lsb[1] = data->config->bus_voltage_lsb;
+
+	data->power_lsb = DIV_ROUND_CLOSEST(data->current_lsb *
+					    data->config->power_calculate_factor,
+					    100);
+
+	data->energy_lsb = data->power_lsb * 16;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
+							 &ina238_chip_info, NULL);
+	if (IS_ERR(hwmon_dev))
+		return PTR_ERR(hwmon_dev);
+
+	if (data->rshunt)
+		dev_info(dev, "power monitor %s (Rshunt = %u uOhm, gain = %u)\n",
+			 client->name, data->rshunt, data->gain);
+
+	return 0;
+}
+
+static const struct i2c_device_id ina238_id[] = {
+	{ .name = "ina228", .driver_data = ina228 },
+	{ .name = "ina237", .driver_data = ina237 },
+	{ .name = "ina238", .driver_data = ina238 },
+	{ .name = "ina700", .driver_data = ina700 },
+	{ .name = "ina780", .driver_data = ina780 },
+	{ .name = "sq52206", .driver_data = sq52206 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ina238_id);
+
+static const struct of_device_id __maybe_unused ina238_of_match[] = {
+	{
+		.compatible = "ti,ina228",
+		.data = (void *)ina228
+	},
+	{
+		.compatible = "ti,ina237",
+		.data = (void *)ina237
+	},
+	{
+		.compatible = "ti,ina238",
+		.data = (void *)ina238
+	},
+	{
+		.compatible = "ti,ina700",
+		.data = (void *)ina700
+	},
+	{
+		.compatible = "ti,ina780",
+		.data = (void *)ina780
+	},
+	{
+		.compatible = "silergy,sq52206",
+		.data = (void *)sq52206
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ina238_of_match);
+
+static struct i2c_driver ina238_driver = {
+	.driver = {
+		.name	= "ina238",
+		.of_match_table = of_match_ptr(ina238_of_match),
+	},
+	.probe		= ina238_probe,
+	.id_table	= ina238_id,
+};
+
+module_i2c_driver(ina238_driver);
+
+MODULE_AUTHOR("Nathan Rossi <nathan.rossi@digi.com>");
+MODULE_DESCRIPTION("ina238 driver");
+MODULE_LICENSE("GPL");