[PATCH 0/2] hwmon: (ina3221) Apply _info API

[PATCH 0/2] hwmon: (ina3221) Apply _info API

[Nicolin Chen]

This series of patches applies _info API of hwmon core to
the ina3221 hwmon driver.

Nicolin Chen (2):
  hwmon: (core) Add hwmon_in_enable attribute
  hwmon: (ina3221) Use _info API to register hwmon device

 drivers/hwmon/hwmon.c   |   1 +
 drivers/hwmon/ina3221.c | 528 +++++++++++++++++++---------------------
 include/linux/hwmon.h   |   2 +
 3 files changed, 248 insertions(+), 283 deletions(-)

-- 
2.17.1

[PATCH 1/2] hwmon: (core) Add hwmon_in_enable attribute

[Nicolin Chen]

According to hwmon ABI, in%d_enable is a sysfs interface that
allows user space to enable and disable the input sensor. So
this patch just simply adds the attribute to the list.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---
 drivers/hwmon/hwmon.c | 1 +
 include/linux/hwmon.h | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index 33d51281272b..ac1cdf88840f 100644
--- a/drivers/hwmon/hwmon.c
+++ b/drivers/hwmon/hwmon.c
@@ -356,6 +356,7 @@ static const char * const hwmon_in_attr_templates[] = {
 	[hwmon_in_max_alarm] = "in%d_max_alarm",
 	[hwmon_in_lcrit_alarm] = "in%d_lcrit_alarm",
 	[hwmon_in_crit_alarm] = "in%d_crit_alarm",
+	[hwmon_in_enable] = "in%d_enable",
 };
 
 static const char * const hwmon_curr_attr_templates[] = {
diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
index 9493d4a388db..99e0c1b0b5fb 100644
--- a/include/linux/hwmon.h
+++ b/include/linux/hwmon.h
@@ -118,6 +118,7 @@ enum hwmon_in_attributes {
 	hwmon_in_max_alarm,
 	hwmon_in_lcrit_alarm,
 	hwmon_in_crit_alarm,
+	hwmon_in_enable,
 };
 
 #define HWMON_I_INPUT		BIT(hwmon_in_input)
@@ -135,6 +136,7 @@ enum hwmon_in_attributes {
 #define HWMON_I_MAX_ALARM	BIT(hwmon_in_max_alarm)
 #define HWMON_I_LCRIT_ALARM	BIT(hwmon_in_lcrit_alarm)
 #define HWMON_I_CRIT_ALARM	BIT(hwmon_in_crit_alarm)
+#define HWMON_I_ENABLE		BIT(hwmon_in_enable)
 
 enum hwmon_curr_attributes {
 	hwmon_curr_input,
-- 
2.17.1

[PATCH 2/2] hwmon: (ina3221) Use _info API to register hwmon device

[Nicolin Chen]

The hwmon core has a newer API which abstracts most of common
things in the core so as to simplify the hwmon device drivers.

This patch implements this _info API to ina3221 hwmon driver.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---
 drivers/hwmon/ina3221.c | 528 +++++++++++++++++++---------------------
 1 file changed, 245 insertions(+), 283 deletions(-)

diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c
index c3a497aed345..08cc0b4bc0ba 100644
--- a/drivers/hwmon/ina3221.c
+++ b/drivers/hwmon/ina3221.c
@@ -77,21 +77,6 @@ enum ina3221_channels {
 	INA3221_NUM_CHANNELS
 };
 
-static const unsigned int register_channel[] = {
-	[INA3221_BUS1] = INA3221_CHANNEL1,
-	[INA3221_BUS2] = INA3221_CHANNEL2,
-	[INA3221_BUS3] = INA3221_CHANNEL3,
-	[INA3221_SHUNT1] = INA3221_CHANNEL1,
-	[INA3221_SHUNT2] = INA3221_CHANNEL2,
-	[INA3221_SHUNT3] = INA3221_CHANNEL3,
-	[INA3221_CRIT1] = INA3221_CHANNEL1,
-	[INA3221_CRIT2] = INA3221_CHANNEL2,
-	[INA3221_CRIT3] = INA3221_CHANNEL3,
-	[INA3221_WARN1] = INA3221_CHANNEL1,
-	[INA3221_WARN2] = INA3221_CHANNEL2,
-	[INA3221_WARN3] = INA3221_CHANNEL3,
-};
-
 /**
  * struct ina3221_input - channel input source specific information
  * @label: label of channel input source
@@ -123,58 +108,6 @@ static inline bool ina3221_is_enabled(struct ina3221_data *ina, int channel)
 	return ina->reg_config & INA3221_CONFIG_CHx_EN(channel);
 }
 
-static ssize_t ina3221_show_label(struct device *dev,
-				  struct device_attribute *attr, char *buf)
-{
-	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
-	struct ina3221_data *ina = dev_get_drvdata(dev);
-	unsigned int channel = sd_attr->index;
-	struct ina3221_input *input = &ina->inputs[channel];
-
-	return snprintf(buf, PAGE_SIZE, "%s\n", input->label);
-}
-
-static ssize_t ina3221_show_enable(struct device *dev,
-				   struct device_attribute *attr, char *buf)
-{
-	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
-	struct ina3221_data *ina = dev_get_drvdata(dev);
-	unsigned int channel = sd_attr->index;
-
-	return snprintf(buf, PAGE_SIZE, "%d\n",
-			ina3221_is_enabled(ina, channel));
-}
-
-static ssize_t ina3221_set_enable(struct device *dev,
-				  struct device_attribute *attr,
-				  const char *buf, size_t count)
-{
-	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
-	struct ina3221_data *ina = dev_get_drvdata(dev);
-	unsigned int channel = sd_attr->index;
-	u16 config, mask = INA3221_CONFIG_CHx_EN(channel);
-	bool enable;
-	int ret;
-
-	ret = kstrtobool(buf, &enable);
-	if (ret)
-		return ret;
-
-	config = enable ? mask : 0;
-
-	/* Enable or disable the channel */
-	ret = regmap_update_bits(ina->regmap, INA3221_CONFIG, mask, config);
-	if (ret)
-		return ret;
-
-	/* Cache the latest config register value */
-	ret = regmap_read(ina->regmap, INA3221_CONFIG, &ina->reg_config);
-	if (ret)
-		return ret;
-
-	return count;
-}
-
 static int ina3221_read_value(struct ina3221_data *ina, unsigned int reg,
 			      int *val)
 {
@@ -190,94 +123,107 @@ static int ina3221_read_value(struct ina3221_data *ina, unsigned int reg,
 	return 0;
 }
 
-static ssize_t ina3221_show_bus_voltage(struct device *dev,
-					struct device_attribute *attr,
-					char *buf)
+static const u8 ina3221_in_reg[] = {
+	INA3221_BUS1,
+	INA3221_BUS2,
+	INA3221_BUS3,
+	INA3221_SHUNT1,
+	INA3221_SHUNT2,
+	INA3221_SHUNT3,
+};
+
+static int ina3221_read_in(struct device *dev, u32 attr, int channel, long *val)
 {
-	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
+	const bool is_shunt = channel > INA3221_CHANNEL3;
 	struct ina3221_data *ina = dev_get_drvdata(dev);
-	unsigned int reg = sd_attr->index;
-	unsigned int channel = register_channel[reg];
-	int val, voltage_mv, ret;
+	u8 reg = ina3221_in_reg[channel];
+	int regval, ret;
 
-	/* No data for read-only attribute if channel is disabled */
-	if (!attr->store && !ina3221_is_enabled(ina, channel))
-		return -ENODATA;
+	/* Translate shunt channel ID to sensor channel ID: 4->1, 5->2, 6->3 */
+	channel %= INA3221_NUM_CHANNELS;
 
-	ret = ina3221_read_value(ina, reg, &val);
-	if (ret)
-		return ret;
+	switch (attr) {
+	case hwmon_in_input:
+		if (!ina3221_is_enabled(ina, channel))
+			return -ENODATA;
 
-	voltage_mv = val * 8;
+		ret = ina3221_read_value(ina, reg, &regval);
+		if (ret)
+			return ret;
 
-	return snprintf(buf, PAGE_SIZE, "%d\n", voltage_mv);
+		/*
+		 * Scale of shunt voltage (uV): LSB is 40uV
+		 * Scale of bus voltage (mV): LSB is 8mV
+		 */
+		*val = regval * (is_shunt ? 40 : 8);
+		return 0;
+	case hwmon_in_enable:
+		*val = ina3221_is_enabled(ina, channel);
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
-static ssize_t ina3221_show_shunt_voltage(struct device *dev,
-					  struct device_attribute *attr,
-					  char *buf)
+static const u8 ina3221_curr_reg[][INA3221_NUM_CHANNELS] = {
+	[hwmon_curr_input] = { INA3221_SHUNT1, INA3221_SHUNT2, INA3221_SHUNT3 },
+	[hwmon_curr_max] = { INA3221_WARN1, INA3221_WARN2, INA3221_WARN3 },
+	[hwmon_curr_crit] = { INA3221_CRIT1, INA3221_CRIT2, INA3221_CRIT3 },
+	[hwmon_curr_max_alarm] = { F_WF1, F_WF2, F_WF3 },
+	[hwmon_curr_crit_alarm] = { F_CF1, F_CF2, F_CF3 },
+};
+
+static int ina3221_read_curr(struct device *dev, u32 attr,
+			     int channel, long *val)
 {
-	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
 	struct ina3221_data *ina = dev_get_drvdata(dev);
-	unsigned int reg = sd_attr->index;
-	unsigned int channel = register_channel[reg];
-	int val, voltage_uv, ret;
-
-	/* No data for read-only attribute if channel is disabled */
-	if (!attr->store && !ina3221_is_enabled(ina, channel))
-		return -ENODATA;
-
-	ret = ina3221_read_value(ina, reg, &val);
-	if (ret)
-		return ret;
-	voltage_uv = val * 40;
-
-	return snprintf(buf, PAGE_SIZE, "%d\n", voltage_uv);
-}
-
-static ssize_t ina3221_show_current(struct device *dev,
-				    struct device_attribute *attr, char *buf)
-{
-	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
-	struct ina3221_data *ina = dev_get_drvdata(dev);
-	unsigned int reg = sd_attr->index;
-	unsigned int channel = register_channel[reg];
 	struct ina3221_input *input = &ina->inputs[channel];
 	int resistance_uo = input->shunt_resistor;
-	int val, current_ma, voltage_nv, ret;
+	u8 reg = ina3221_curr_reg[attr][channel];
+	int regval, voltage_nv, ret;
 
-	/* No data for read-only attribute if channel is disabled */
-	if (!attr->store && !ina3221_is_enabled(ina, channel))
-		return -ENODATA;
+	switch (attr) {
+	case hwmon_curr_input:
+		if (!ina3221_is_enabled(ina, channel))
+			return -ENODATA;
+		/* fallthrough */
+	case hwmon_curr_crit:
+	case hwmon_curr_max:
+		ret = ina3221_read_value(ina, reg, &regval);
+		if (ret)
+			return ret;
 
-	ret = ina3221_read_value(ina, reg, &val);
-	if (ret)
-		return ret;
-	voltage_nv = val * 40000;
-
-	current_ma = DIV_ROUND_CLOSEST(voltage_nv, resistance_uo);
-
-	return snprintf(buf, PAGE_SIZE, "%d\n", current_ma);
+		/* Scale of shunt voltage: LSB is 40uV (40000nV) */
+		voltage_nv = regval * 40000;
+		/* Return current in mA */
+		*val = DIV_ROUND_CLOSEST(voltage_nv, resistance_uo);
+		return 0;
+	case hwmon_curr_crit_alarm:
+	case hwmon_curr_max_alarm:
+		ret = regmap_field_read(ina->fields[reg], &regval);
+		if (ret)
+			return ret;
+		*val = regval;
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
 }
 
-static ssize_t ina3221_set_current(struct device *dev,
-				   struct device_attribute *attr,
-				   const char *buf, size_t count)
+static int ina3221_write_curr(struct device *dev, u32 attr,
+			      int channel, long val)
 {
-	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
 	struct ina3221_data *ina = dev_get_drvdata(dev);
-	unsigned int reg = sd_attr->index;
-	unsigned int channel = register_channel[reg];
 	struct ina3221_input *input = &ina->inputs[channel];
 	int resistance_uo = input->shunt_resistor;
-	int val, current_ma, voltage_uv, ret;
+	u8 reg = ina3221_curr_reg[attr][channel];
+	int regval, current_ma, voltage_uv;
 
-	ret = kstrtoint(buf, 0, &current_ma);
-	if (ret)
-		return ret;
+	if (attr != hwmon_curr_crit && attr != hwmon_curr_max)
+		return -EOPNOTSUPP;
 
 	/* clamp current */
-	current_ma = clamp_val(current_ma,
+	current_ma = clamp_val(val,
 			       INT_MIN / resistance_uo,
 			       INT_MAX / resistance_uo);
 
@@ -287,15 +233,175 @@ static ssize_t ina3221_set_current(struct device *dev,
 	voltage_uv = clamp_val(voltage_uv, -163800, 163800);
 
 	/* 1 / 40uV(scale) << 3(register shift) = 5 */
-	val = DIV_ROUND_CLOSEST(voltage_uv, 5) & 0xfff8;
+	regval = DIV_ROUND_CLOSEST(voltage_uv, 5) & 0xfff8;
 
-	ret = regmap_write(ina->regmap, reg, val);
+	return regmap_write(ina->regmap, reg, regval);
+}
+
+static int ina3221_write_enable(struct device *dev, int channel, bool enable)
+{
+	struct ina3221_data *ina = dev_get_drvdata(dev);
+	u16 config, mask = INA3221_CONFIG_CHx_EN(channel);
+	int ret;
+
+	config = enable ? mask : 0;
+
+	/* Enable or disable the channel */
+	ret = regmap_update_bits(ina->regmap, INA3221_CONFIG, mask, config);
 	if (ret)
 		return ret;
 
-	return count;
+	/* Cache the latest config register value */
+	ret = regmap_read(ina->regmap, INA3221_CONFIG, &ina->reg_config);
+	if (ret)
+		return ret;
+
+	return 0;
 }
 
+static int ina3221_read(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
+{
+	switch (type) {
+	case hwmon_in:
+		return ina3221_read_in(dev, attr, channel - 1, val);
+	case hwmon_curr:
+		return ina3221_read_curr(dev, attr, channel, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int ina3221_write(struct device *dev, enum hwmon_sensor_types type,
+			 u32 attr, int channel, long val)
+{
+	switch (type) {
+	case hwmon_in:
+		if (attr != hwmon_in_enable)
+			return -EOPNOTSUPP;
+		return ina3221_write_enable(dev, channel - 1, val);
+	case hwmon_curr:
+		return ina3221_write_curr(dev, attr, channel, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int ina3221_read_string(struct device *dev, enum hwmon_sensor_types type,
+			       u32 attr, int channel, const char **str)
+{
+	struct ina3221_data *ina = dev_get_drvdata(dev);
+	int index = channel - 1;
+
+	if (type != hwmon_in || attr != hwmon_in_label)
+		return -EOPNOTSUPP;
+
+	/* Only 1-3 channels have hwmon_in_label */
+	if (channel < 1 || channel > 3)
+		return -EOPNOTSUPP;
+
+	*str = ina->inputs[index].label;
+
+	return 0;
+}
+
+static umode_t ina3221_is_visible(const void *drvdata,
+				  enum hwmon_sensor_types type,
+				  u32 attr, int channel)
+{
+	const struct ina3221_data *ina = drvdata;
+	const struct ina3221_input *input = NULL;
+
+	switch (type) {
+	case hwmon_in:
+		/* Ignore in0_ */
+		if (channel == 0)
+			return 0;
+
+		switch (attr) {
+		case hwmon_in_label:
+			if (channel - 1 <= INA3221_CHANNEL3)
+				input = &ina->inputs[channel - 1];
+			/* Hide label node if label is not provided */
+			return (input && input->label) ? 0444 : 0;
+		case hwmon_in_input:
+			return 0444;
+		case hwmon_in_enable:
+			return 0644;
+		default:
+			return 0;
+		}
+	case hwmon_curr:
+		switch (attr) {
+		case hwmon_curr_input:
+		case hwmon_curr_crit_alarm:
+		case hwmon_curr_max_alarm:
+			return 0444;
+		case hwmon_curr_crit:
+		case hwmon_curr_max:
+			return 0644;
+		default:
+			return 0;
+		}
+	default:
+		return 0;
+	}
+}
+
+static const u32 ina3221_in_config[] = {
+	/* 0: dummy, skipped in is_visible */
+	HWMON_I_INPUT,
+	/* 1-3: input voltage Channels */
+	HWMON_I_INPUT | HWMON_I_ENABLE | HWMON_I_LABEL,
+	HWMON_I_INPUT | HWMON_I_ENABLE | HWMON_I_LABEL,
+	HWMON_I_INPUT | HWMON_I_ENABLE | HWMON_I_LABEL,
+	/* 4-6: shunt voltage Channels */
+	HWMON_I_INPUT,
+	HWMON_I_INPUT,
+	HWMON_I_INPUT,
+	0
+};
+
+static const struct hwmon_channel_info ina3221_in = {
+	.type = hwmon_in,
+	.config = ina3221_in_config,
+};
+
+#define INA3221_HWMON_CURR_CONFIG (HWMON_C_INPUT | \
+				   HWMON_C_CRIT | HWMON_C_CRIT_ALARM | \
+				   HWMON_C_MAX | HWMON_C_MAX_ALARM)
+
+static const u32 ina3221_curr_config[] = {
+	INA3221_HWMON_CURR_CONFIG,
+	INA3221_HWMON_CURR_CONFIG,
+	INA3221_HWMON_CURR_CONFIG,
+	0
+};
+
+static const struct hwmon_channel_info ina3221_curr = {
+	.type = hwmon_curr,
+	.config = ina3221_curr_config,
+};
+
+static const struct hwmon_channel_info *ina3221_info[] = {
+	&ina3221_in,
+	&ina3221_curr,
+	NULL
+};
+
+static const struct hwmon_ops ina3221_hwmon_ops = {
+	.is_visible = ina3221_is_visible,
+	.read_string = ina3221_read_string,
+	.read = ina3221_read,
+	.write = ina3221_write,
+};
+
+static const struct hwmon_chip_info ina3221_chip_info = {
+	.ops = &ina3221_hwmon_ops,
+	.info = ina3221_info,
+};
+
+/* Extra attribute groups */
 static ssize_t ina3221_show_shunt(struct device *dev,
 				  struct device_attribute *attr, char *buf)
 {
@@ -329,54 +435,6 @@ static ssize_t ina3221_set_shunt(struct device *dev,
 	return count;
 }
 
-static ssize_t ina3221_show_alert(struct device *dev,
-				  struct device_attribute *attr, char *buf)
-{
-	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
-	struct ina3221_data *ina = dev_get_drvdata(dev);
-	unsigned int field = sd_attr->index;
-	unsigned int regval;
-	int ret;
-
-	ret = regmap_field_read(ina->fields[field], &regval);
-	if (ret)
-		return ret;
-
-	return snprintf(buf, PAGE_SIZE, "%d\n", regval);
-}
-
-/* input channel label */
-static SENSOR_DEVICE_ATTR(in1_label, 0444,
-		ina3221_show_label, NULL, INA3221_CHANNEL1);
-static SENSOR_DEVICE_ATTR(in2_label, 0444,
-		ina3221_show_label, NULL, INA3221_CHANNEL2);
-static SENSOR_DEVICE_ATTR(in3_label, 0444,
-		ina3221_show_label, NULL, INA3221_CHANNEL3);
-
-/* voltage channel enable */
-static SENSOR_DEVICE_ATTR(in1_enable, 0644,
-		ina3221_show_enable, ina3221_set_enable, INA3221_CHANNEL1);
-static SENSOR_DEVICE_ATTR(in2_enable, 0644,
-		ina3221_show_enable, ina3221_set_enable, INA3221_CHANNEL2);
-static SENSOR_DEVICE_ATTR(in3_enable, 0644,
-		ina3221_show_enable, ina3221_set_enable, INA3221_CHANNEL3);
-
-/* bus voltage */
-static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO,
-		ina3221_show_bus_voltage, NULL, INA3221_BUS1);
-static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO,
-		ina3221_show_bus_voltage, NULL, INA3221_BUS2);
-static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO,
-		ina3221_show_bus_voltage, NULL, INA3221_BUS3);
-
-/* calculated current */
-static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO,
-		ina3221_show_current, NULL, INA3221_SHUNT1);
-static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO,
-		ina3221_show_current, NULL, INA3221_SHUNT2);
-static SENSOR_DEVICE_ATTR(curr3_input, S_IRUGO,
-		ina3221_show_current, NULL, INA3221_SHUNT3);
-
 /* shunt resistance */
 static SENSOR_DEVICE_ATTR(shunt1_resistor, S_IRUGO | S_IWUSR,
 		ina3221_show_shunt, ina3221_set_shunt, INA3221_CHANNEL1);
@@ -385,109 +443,13 @@ static SENSOR_DEVICE_ATTR(shunt2_resistor, S_IRUGO | S_IWUSR,
 static SENSOR_DEVICE_ATTR(shunt3_resistor, S_IRUGO | S_IWUSR,
 		ina3221_show_shunt, ina3221_set_shunt, INA3221_CHANNEL3);
 
-/* critical current */
-static SENSOR_DEVICE_ATTR(curr1_crit, S_IRUGO | S_IWUSR,
-		ina3221_show_current, ina3221_set_current, INA3221_CRIT1);
-static SENSOR_DEVICE_ATTR(curr2_crit, S_IRUGO | S_IWUSR,
-		ina3221_show_current, ina3221_set_current, INA3221_CRIT2);
-static SENSOR_DEVICE_ATTR(curr3_crit, S_IRUGO | S_IWUSR,
-		ina3221_show_current, ina3221_set_current, INA3221_CRIT3);
-
-/* critical current alert */
-static SENSOR_DEVICE_ATTR(curr1_crit_alarm, S_IRUGO,
-		ina3221_show_alert, NULL, F_CF1);
-static SENSOR_DEVICE_ATTR(curr2_crit_alarm, S_IRUGO,
-		ina3221_show_alert, NULL, F_CF2);
-static SENSOR_DEVICE_ATTR(curr3_crit_alarm, S_IRUGO,
-		ina3221_show_alert, NULL, F_CF3);
-
-/* warning current */
-static SENSOR_DEVICE_ATTR(curr1_max, S_IRUGO | S_IWUSR,
-		ina3221_show_current, ina3221_set_current, INA3221_WARN1);
-static SENSOR_DEVICE_ATTR(curr2_max, S_IRUGO | S_IWUSR,
-		ina3221_show_current, ina3221_set_current, INA3221_WARN2);
-static SENSOR_DEVICE_ATTR(curr3_max, S_IRUGO | S_IWUSR,
-		ina3221_show_current, ina3221_set_current, INA3221_WARN3);
-
-/* warning current alert */
-static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO,
-		ina3221_show_alert, NULL, F_WF1);
-static SENSOR_DEVICE_ATTR(curr2_max_alarm, S_IRUGO,
-		ina3221_show_alert, NULL, F_WF2);
-static SENSOR_DEVICE_ATTR(curr3_max_alarm, S_IRUGO,
-		ina3221_show_alert, NULL, F_WF3);
-
-/* shunt voltage */
-static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO,
-		ina3221_show_shunt_voltage, NULL, INA3221_SHUNT1);
-static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO,
-		ina3221_show_shunt_voltage, NULL, INA3221_SHUNT2);
-static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO,
-		ina3221_show_shunt_voltage, NULL, INA3221_SHUNT3);
-
 static struct attribute *ina3221_attrs[] = {
-	/* channel 1 -- make sure label at first */
-	&sensor_dev_attr_in1_label.dev_attr.attr,
-	&sensor_dev_attr_in1_enable.dev_attr.attr,
-	&sensor_dev_attr_in1_input.dev_attr.attr,
-	&sensor_dev_attr_curr1_input.dev_attr.attr,
 	&sensor_dev_attr_shunt1_resistor.dev_attr.attr,
-	&sensor_dev_attr_curr1_crit.dev_attr.attr,
-	&sensor_dev_attr_curr1_crit_alarm.dev_attr.attr,
-	&sensor_dev_attr_curr1_max.dev_attr.attr,
-	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
-	&sensor_dev_attr_in4_input.dev_attr.attr,
-
-	/* channel 2 -- make sure label at first */
-	&sensor_dev_attr_in2_label.dev_attr.attr,
-	&sensor_dev_attr_in2_enable.dev_attr.attr,
-	&sensor_dev_attr_in2_input.dev_attr.attr,
-	&sensor_dev_attr_curr2_input.dev_attr.attr,
 	&sensor_dev_attr_shunt2_resistor.dev_attr.attr,
-	&sensor_dev_attr_curr2_crit.dev_attr.attr,
-	&sensor_dev_attr_curr2_crit_alarm.dev_attr.attr,
-	&sensor_dev_attr_curr2_max.dev_attr.attr,
-	&sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
-	&sensor_dev_attr_in5_input.dev_attr.attr,
-
-	/* channel 3 -- make sure label at first */
-	&sensor_dev_attr_in3_label.dev_attr.attr,
-	&sensor_dev_attr_in3_enable.dev_attr.attr,
-	&sensor_dev_attr_in3_input.dev_attr.attr,
-	&sensor_dev_attr_curr3_input.dev_attr.attr,
 	&sensor_dev_attr_shunt3_resistor.dev_attr.attr,
-	&sensor_dev_attr_curr3_crit.dev_attr.attr,
-	&sensor_dev_attr_curr3_crit_alarm.dev_attr.attr,
-	&sensor_dev_attr_curr3_max.dev_attr.attr,
-	&sensor_dev_attr_curr3_max_alarm.dev_attr.attr,
-	&sensor_dev_attr_in6_input.dev_attr.attr,
-
 	NULL,
 };
-
-static umode_t ina3221_attr_is_visible(struct kobject *kobj,
-				       struct attribute *attr, int n)
-{
-	const int max_attrs = ARRAY_SIZE(ina3221_attrs) - 1;
-	const int num_attrs = max_attrs / INA3221_NUM_CHANNELS;
-	struct device *dev = kobj_to_dev(kobj);
-	struct ina3221_data *ina = dev_get_drvdata(dev);
-	enum ina3221_channels channel = n / num_attrs;
-	struct ina3221_input *input = &ina->inputs[channel];
-	int index = n % num_attrs;
-
-	/* Hide label node if label is not provided */
-	if (index == 0 && !input->label)
-		return 0;
-
-	return attr->mode;
-}
-
-static const struct attribute_group ina3221_group = {
-	.is_visible = ina3221_attr_is_visible,
-	.attrs = ina3221_attrs,
-};
-__ATTRIBUTE_GROUPS(ina3221);
+ATTRIBUTE_GROUPS(ina3221);
 
 static const struct regmap_range ina3221_yes_ranges[] = {
 	regmap_reg_range(INA3221_CONFIG, INA3221_BUS3),
@@ -620,9 +582,9 @@ static int ina3221_probe(struct i2c_client *client,
 
 	dev_set_drvdata(dev, ina);
 
-	hwmon_dev = devm_hwmon_device_register_with_groups(dev,
-							   client->name,
-							   ina, ina3221_groups);
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, ina,
+							 &ina3221_chip_info,
+							 ina3221_groups);
 	if (IS_ERR(hwmon_dev)) {
 		dev_err(dev, "Unable to register hwmon device\n");
 		return PTR_ERR(hwmon_dev);
-- 
2.17.1

Re: [PATCH 1/2] hwmon: (core) Add hwmon_in_enable attribute

[Guenter Roeck]

On Fri, Oct 05, 2018 at 04:59:04PM -0700, Nicolin Chen wrote:
> According to hwmon ABI, in%d_enable is a sysfs interface that
> allows user space to enable and disable the input sensor. So
> this patch just simply adds the attribute to the list.
> 
> Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>

Applied to hwmon-next.

Thanks,
Guenter

> ---
>  drivers/hwmon/hwmon.c | 1 +
>  include/linux/hwmon.h | 2 ++
>  2 files changed, 3 insertions(+)
> 
> diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
> index 33d51281272b..ac1cdf88840f 100644
> --- a/drivers/hwmon/hwmon.c
> +++ b/drivers/hwmon/hwmon.c
> @@ -356,6 +356,7 @@ static const char * const hwmon_in_attr_templates[] = {
>  	[hwmon_in_max_alarm] = "in%d_max_alarm",
>  	[hwmon_in_lcrit_alarm] = "in%d_lcrit_alarm",
>  	[hwmon_in_crit_alarm] = "in%d_crit_alarm",
> +	[hwmon_in_enable] = "in%d_enable",
>  };
>  
>  static const char * const hwmon_curr_attr_templates[] = {
> diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
> index 9493d4a388db..99e0c1b0b5fb 100644
> --- a/include/linux/hwmon.h
> +++ b/include/linux/hwmon.h
> @@ -118,6 +118,7 @@ enum hwmon_in_attributes {
>  	hwmon_in_max_alarm,
>  	hwmon_in_lcrit_alarm,
>  	hwmon_in_crit_alarm,
> +	hwmon_in_enable,
>  };
>  
>  #define HWMON_I_INPUT		BIT(hwmon_in_input)
> @@ -135,6 +136,7 @@ enum hwmon_in_attributes {
>  #define HWMON_I_MAX_ALARM	BIT(hwmon_in_max_alarm)
>  #define HWMON_I_LCRIT_ALARM	BIT(hwmon_in_lcrit_alarm)
>  #define HWMON_I_CRIT_ALARM	BIT(hwmon_in_crit_alarm)
> +#define HWMON_I_ENABLE		BIT(hwmon_in_enable)
>  
>  enum hwmon_curr_attributes {
>  	hwmon_curr_input,

Re: [PATCH 2/2] hwmon: (ina3221) Use _info API to register hwmon device

[Guenter Roeck]

Hi Nicolin,

On Fri, Oct 05, 2018 at 04:59:05PM -0700, Nicolin Chen wrote:
> The hwmon core has a newer API which abstracts most of common
> things in the core so as to simplify the hwmon device drivers.
> 
> This patch implements this _info API to ina3221 hwmon driver.
> 

$ size drivers/hwmon/ina*.o
   text	   data	    bss	    dec	    hex	filename
   9251	   3552	     64	  12867	   3243	drivers/hwmon/ina3221.o
  12959	   9256	     64	  22279	   5707	drivers/hwmon/ina3221-orig.o

It looks like this version is about 45% smaller. Surprising, isn't it ?

Something else I just noticed: When reading the shunt resistor
value from devicetree, the value range is not checked. A shunt
resistor value of 0 should result in a divide by zero error.
Also, the value read from dt is an u32, but assigned to an int.
A shunt resistor value of 0x80000000 or higher should yield quite
interesting results. Not that this makes sense, but we should not
accept bad values. Can you send a follow-up patch to fix that ?

Other comments inline.

Thanks,
Guenter

> Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
> ---
>  drivers/hwmon/ina3221.c | 528 +++++++++++++++++++---------------------
>  1 file changed, 245 insertions(+), 283 deletions(-)
> 
> diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c
> index c3a497aed345..08cc0b4bc0ba 100644
> --- a/drivers/hwmon/ina3221.c
> +++ b/drivers/hwmon/ina3221.c
> @@ -77,21 +77,6 @@ enum ina3221_channels {
>  	INA3221_NUM_CHANNELS
>  };
>  
> -static const unsigned int register_channel[] = {
> -	[INA3221_BUS1] = INA3221_CHANNEL1,
> -	[INA3221_BUS2] = INA3221_CHANNEL2,
> -	[INA3221_BUS3] = INA3221_CHANNEL3,
> -	[INA3221_SHUNT1] = INA3221_CHANNEL1,
> -	[INA3221_SHUNT2] = INA3221_CHANNEL2,
> -	[INA3221_SHUNT3] = INA3221_CHANNEL3,
> -	[INA3221_CRIT1] = INA3221_CHANNEL1,
> -	[INA3221_CRIT2] = INA3221_CHANNEL2,
> -	[INA3221_CRIT3] = INA3221_CHANNEL3,
> -	[INA3221_WARN1] = INA3221_CHANNEL1,
> -	[INA3221_WARN2] = INA3221_CHANNEL2,
> -	[INA3221_WARN3] = INA3221_CHANNEL3,
> -};
> -
>  /**
>   * struct ina3221_input - channel input source specific information
>   * @label: label of channel input source
> @@ -123,58 +108,6 @@ static inline bool ina3221_is_enabled(struct ina3221_data *ina, int channel)
>  	return ina->reg_config & INA3221_CONFIG_CHx_EN(channel);
>  }
>  
> -static ssize_t ina3221_show_label(struct device *dev,
> -				  struct device_attribute *attr, char *buf)
> -{
> -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> -	struct ina3221_data *ina = dev_get_drvdata(dev);
> -	unsigned int channel = sd_attr->index;
> -	struct ina3221_input *input = &ina->inputs[channel];
> -
> -	return snprintf(buf, PAGE_SIZE, "%s\n", input->label);
> -}
> -
> -static ssize_t ina3221_show_enable(struct device *dev,
> -				   struct device_attribute *attr, char *buf)
> -{
> -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> -	struct ina3221_data *ina = dev_get_drvdata(dev);
> -	unsigned int channel = sd_attr->index;
> -
> -	return snprintf(buf, PAGE_SIZE, "%d\n",
> -			ina3221_is_enabled(ina, channel));
> -}
> -
> -static ssize_t ina3221_set_enable(struct device *dev,
> -				  struct device_attribute *attr,
> -				  const char *buf, size_t count)
> -{
> -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> -	struct ina3221_data *ina = dev_get_drvdata(dev);
> -	unsigned int channel = sd_attr->index;
> -	u16 config, mask = INA3221_CONFIG_CHx_EN(channel);
> -	bool enable;
> -	int ret;
> -
> -	ret = kstrtobool(buf, &enable);
> -	if (ret)
> -		return ret;
> -
> -	config = enable ? mask : 0;
> -
> -	/* Enable or disable the channel */
> -	ret = regmap_update_bits(ina->regmap, INA3221_CONFIG, mask, config);
> -	if (ret)
> -		return ret;
> -
> -	/* Cache the latest config register value */
> -	ret = regmap_read(ina->regmap, INA3221_CONFIG, &ina->reg_config);
> -	if (ret)
> -		return ret;
> -
> -	return count;
> -}
> -
>  static int ina3221_read_value(struct ina3221_data *ina, unsigned int reg,
>  			      int *val)
>  {
> @@ -190,94 +123,107 @@ static int ina3221_read_value(struct ina3221_data *ina, unsigned int reg,
>  	return 0;
>  }
>  
> -static ssize_t ina3221_show_bus_voltage(struct device *dev,
> -					struct device_attribute *attr,
> -					char *buf)
> +static const u8 ina3221_in_reg[] = {
> +	INA3221_BUS1,
> +	INA3221_BUS2,
> +	INA3221_BUS3,
> +	INA3221_SHUNT1,
> +	INA3221_SHUNT2,
> +	INA3221_SHUNT3,
> +};
> +
> +static int ina3221_read_in(struct device *dev, u32 attr, int channel, long *val)
>  {
> -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> +	const bool is_shunt = channel > INA3221_CHANNEL3;
>  	struct ina3221_data *ina = dev_get_drvdata(dev);
> -	unsigned int reg = sd_attr->index;
> -	unsigned int channel = register_channel[reg];
> -	int val, voltage_mv, ret;
> +	u8 reg = ina3221_in_reg[channel];
> +	int regval, ret;
>  
> -	/* No data for read-only attribute if channel is disabled */
> -	if (!attr->store && !ina3221_is_enabled(ina, channel))
> -		return -ENODATA;
> +	/* Translate shunt channel ID to sensor channel ID: 4->1, 5->2, 6->3 */

Misleading. The channel number as used here is 0-aligned, so it is 3 -> 0
etc.

I know the chip talks about channels 1..3, but that is not how "channel"
is used here. It took me a bit to find out that the calling code
subtracts 1 from the channel number and that the code is correct.
We don't want others to suffer the same fate.

> +	channel %= INA3221_NUM_CHANNELS;

3 % 3 = 0, not 1.

>  
> -	ret = ina3221_read_value(ina, reg, &val);
> -	if (ret)
> -		return ret;
> +	switch (attr) {
> +	case hwmon_in_input:
> +		if (!ina3221_is_enabled(ina, channel))
> +			return -ENODATA;
>  
> -	voltage_mv = val * 8;
> +		ret = ina3221_read_value(ina, reg, &regval);
> +		if (ret)
> +			return ret;
>  
> -	return snprintf(buf, PAGE_SIZE, "%d\n", voltage_mv);
> +		/*
> +		 * Scale of shunt voltage (uV): LSB is 40uV
> +		 * Scale of bus voltage (mV): LSB is 8mV
> +		 */
> +		*val = regval * (is_shunt ? 40 : 8);
> +		return 0;
> +	case hwmon_in_enable:
> +		*val = ina3221_is_enabled(ina, channel);
> +		return 0;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
>  }
>  
> -static ssize_t ina3221_show_shunt_voltage(struct device *dev,
> -					  struct device_attribute *attr,
> -					  char *buf)
> +static const u8 ina3221_curr_reg[][INA3221_NUM_CHANNELS] = {
> +	[hwmon_curr_input] = { INA3221_SHUNT1, INA3221_SHUNT2, INA3221_SHUNT3 },
> +	[hwmon_curr_max] = { INA3221_WARN1, INA3221_WARN2, INA3221_WARN3 },
> +	[hwmon_curr_crit] = { INA3221_CRIT1, INA3221_CRIT2, INA3221_CRIT3 },
> +	[hwmon_curr_max_alarm] = { F_WF1, F_WF2, F_WF3 },
> +	[hwmon_curr_crit_alarm] = { F_CF1, F_CF2, F_CF3 },
> +};
> +
> +static int ina3221_read_curr(struct device *dev, u32 attr,
> +			     int channel, long *val)
>  {
> -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
>  	struct ina3221_data *ina = dev_get_drvdata(dev);
> -	unsigned int reg = sd_attr->index;
> -	unsigned int channel = register_channel[reg];
> -	int val, voltage_uv, ret;
> -
> -	/* No data for read-only attribute if channel is disabled */
> -	if (!attr->store && !ina3221_is_enabled(ina, channel))
> -		return -ENODATA;
> -
> -	ret = ina3221_read_value(ina, reg, &val);
> -	if (ret)
> -		return ret;
> -	voltage_uv = val * 40;
> -
> -	return snprintf(buf, PAGE_SIZE, "%d\n", voltage_uv);
> -}
> -
> -static ssize_t ina3221_show_current(struct device *dev,
> -				    struct device_attribute *attr, char *buf)
> -{
> -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> -	struct ina3221_data *ina = dev_get_drvdata(dev);
> -	unsigned int reg = sd_attr->index;
> -	unsigned int channel = register_channel[reg];
>  	struct ina3221_input *input = &ina->inputs[channel];
>  	int resistance_uo = input->shunt_resistor;
> -	int val, current_ma, voltage_nv, ret;
> +	u8 reg = ina3221_curr_reg[attr][channel];
> +	int regval, voltage_nv, ret;
>  
> -	/* No data for read-only attribute if channel is disabled */
> -	if (!attr->store && !ina3221_is_enabled(ina, channel))
> -		return -ENODATA;
> +	switch (attr) {
> +	case hwmon_curr_input:
> +		if (!ina3221_is_enabled(ina, channel))
> +			return -ENODATA;
> +		/* fallthrough */

I think the official terminology is "fall through".
But then it looks like "fallthrough" is also widely used,
so maybe we are ok.

> +	case hwmon_curr_crit:
> +	case hwmon_curr_max:
> +		ret = ina3221_read_value(ina, reg, &regval);
> +		if (ret)
> +			return ret;
>  
> -	ret = ina3221_read_value(ina, reg, &val);
> -	if (ret)
> -		return ret;
> -	voltage_nv = val * 40000;
> -
> -	current_ma = DIV_ROUND_CLOSEST(voltage_nv, resistance_uo);
> -
> -	return snprintf(buf, PAGE_SIZE, "%d\n", current_ma);
> +		/* Scale of shunt voltage: LSB is 40uV (40000nV) */
> +		voltage_nv = regval * 40000;
> +		/* Return current in mA */
> +		*val = DIV_ROUND_CLOSEST(voltage_nv, resistance_uo);
> +		return 0;
> +	case hwmon_curr_crit_alarm:
> +	case hwmon_curr_max_alarm:
> +		ret = regmap_field_read(ina->fields[reg], &regval);
> +		if (ret)
> +			return ret;
> +		*val = regval;
> +		return 0;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
>  }
>  
> -static ssize_t ina3221_set_current(struct device *dev,
> -				   struct device_attribute *attr,
> -				   const char *buf, size_t count)
> +static int ina3221_write_curr(struct device *dev, u32 attr,
> +			      int channel, long val)
>  {
> -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
>  	struct ina3221_data *ina = dev_get_drvdata(dev);
> -	unsigned int reg = sd_attr->index;
> -	unsigned int channel = register_channel[reg];
>  	struct ina3221_input *input = &ina->inputs[channel];
>  	int resistance_uo = input->shunt_resistor;
> -	int val, current_ma, voltage_uv, ret;
> +	u8 reg = ina3221_curr_reg[attr][channel];
> +	int regval, current_ma, voltage_uv;
>  
> -	ret = kstrtoint(buf, 0, &current_ma);
> -	if (ret)
> -		return ret;
> +	if (attr != hwmon_curr_crit && attr != hwmon_curr_max)
> +		return -EOPNOTSUPP;

I don't think this is needed.

>  
>  	/* clamp current */
> -	current_ma = clamp_val(current_ma,
> +	current_ma = clamp_val(val,
>  			       INT_MIN / resistance_uo,
>  			       INT_MAX / resistance_uo);
>  
> @@ -287,15 +233,175 @@ static ssize_t ina3221_set_current(struct device *dev,
>  	voltage_uv = clamp_val(voltage_uv, -163800, 163800);
>  
>  	/* 1 / 40uV(scale) << 3(register shift) = 5 */
> -	val = DIV_ROUND_CLOSEST(voltage_uv, 5) & 0xfff8;
> +	regval = DIV_ROUND_CLOSEST(voltage_uv, 5) & 0xfff8;
>  
> -	ret = regmap_write(ina->regmap, reg, val);
> +	return regmap_write(ina->regmap, reg, regval);
> +}
> +
> +static int ina3221_write_enable(struct device *dev, int channel, bool enable)
> +{
> +	struct ina3221_data *ina = dev_get_drvdata(dev);
> +	u16 config, mask = INA3221_CONFIG_CHx_EN(channel);
> +	int ret;
> +
> +	config = enable ? mask : 0;
> +
> +	/* Enable or disable the channel */
> +	ret = regmap_update_bits(ina->regmap, INA3221_CONFIG, mask, config);
>  	if (ret)
>  		return ret;
>  
> -	return count;
> +	/* Cache the latest config register value */
> +	ret = regmap_read(ina->regmap, INA3221_CONFIG, &ina->reg_config);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
>  }
>  
> +static int ina3221_read(struct device *dev, enum hwmon_sensor_types type,
> +			u32 attr, int channel, long *val)
> +{
> +	switch (type) {
> +	case hwmon_in:
> +		return ina3221_read_in(dev, attr, channel - 1, val);
> +	case hwmon_curr:
> +		return ina3221_read_curr(dev, attr, channel, val);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static int ina3221_write(struct device *dev, enum hwmon_sensor_types type,
> +			 u32 attr, int channel, long val)
> +{
> +	switch (type) {
> +	case hwmon_in:
> +		if (attr != hwmon_in_enable)
> +			return -EOPNOTSUPP;

I think you can drop this.

> +		return ina3221_write_enable(dev, channel - 1, val);
> +	case hwmon_curr:
> +		return ina3221_write_curr(dev, attr, channel, val);
> +	default:
> +		return -EOPNOTSUPP;

I tend to have drivers return -EOPNOTSUPP for default: cases
since otherwise static checkers may complain about missing default
cases, but otherwise we should refrain from unnecessary checks.

> +	}
> +}
> +
> +static int ina3221_read_string(struct device *dev, enum hwmon_sensor_types type,
> +			       u32 attr, int channel, const char **str)
> +{
> +	struct ina3221_data *ina = dev_get_drvdata(dev);
> +	int index = channel - 1;
> +
> +	if (type != hwmon_in || attr != hwmon_in_label)
> +		return -EOPNOTSUPP;
> +
> +	/* Only 1-3 channels have hwmon_in_label */
> +	if (channel < 1 || channel > 3)
> +		return -EOPNOTSUPP;
> +
The above checks should be unnecessary.

> +	*str = ina->inputs[index].label;
> +
> +	return 0;
> +}
> +
> +static umode_t ina3221_is_visible(const void *drvdata,
> +				  enum hwmon_sensor_types type,
> +				  u32 attr, int channel)
> +{
> +	const struct ina3221_data *ina = drvdata;
> +	const struct ina3221_input *input = NULL;
> +
> +	switch (type) {
> +	case hwmon_in:
> +		/* Ignore in0_ */
> +		if (channel == 0)
> +			return 0;
> +
> +		switch (attr) {
> +		case hwmon_in_label:
> +			if (channel - 1 <= INA3221_CHANNEL3)
> +				input = &ina->inputs[channel - 1];
> +			/* Hide label node if label is not provided */
> +			return (input && input->label) ? 0444 : 0;
> +		case hwmon_in_input:
> +			return 0444;
> +		case hwmon_in_enable:
> +			return 0644;
> +		default:
> +			return 0;
> +		}
> +	case hwmon_curr:
> +		switch (attr) {
> +		case hwmon_curr_input:
> +		case hwmon_curr_crit_alarm:
> +		case hwmon_curr_max_alarm:
> +			return 0444;
> +		case hwmon_curr_crit:
> +		case hwmon_curr_max:
> +			return 0644;
> +		default:
> +			return 0;
> +		}
> +	default:
> +		return 0;
> +	}
> +}
> +
> +static const u32 ina3221_in_config[] = {
> +	/* 0: dummy, skipped in is_visible */
> +	HWMON_I_INPUT,
> +	/* 1-3: input voltage Channels */
> +	HWMON_I_INPUT | HWMON_I_ENABLE | HWMON_I_LABEL,
> +	HWMON_I_INPUT | HWMON_I_ENABLE | HWMON_I_LABEL,
> +	HWMON_I_INPUT | HWMON_I_ENABLE | HWMON_I_LABEL,
> +	/* 4-6: shunt voltage Channels */
> +	HWMON_I_INPUT,
> +	HWMON_I_INPUT,
> +	HWMON_I_INPUT,
> +	0
> +};
> +
> +static const struct hwmon_channel_info ina3221_in = {
> +	.type = hwmon_in,
> +	.config = ina3221_in_config,
> +};
> +
> +#define INA3221_HWMON_CURR_CONFIG (HWMON_C_INPUT | \
> +				   HWMON_C_CRIT | HWMON_C_CRIT_ALARM | \
> +				   HWMON_C_MAX | HWMON_C_MAX_ALARM)
> +
> +static const u32 ina3221_curr_config[] = {
> +	INA3221_HWMON_CURR_CONFIG,
> +	INA3221_HWMON_CURR_CONFIG,
> +	INA3221_HWMON_CURR_CONFIG,
> +	0
> +};
> +
> +static const struct hwmon_channel_info ina3221_curr = {
> +	.type = hwmon_curr,
> +	.config = ina3221_curr_config,
> +};
> +
> +static const struct hwmon_channel_info *ina3221_info[] = {
> +	&ina3221_in,
> +	&ina3221_curr,
> +	NULL
> +};
> +
> +static const struct hwmon_ops ina3221_hwmon_ops = {
> +	.is_visible = ina3221_is_visible,
> +	.read_string = ina3221_read_string,
> +	.read = ina3221_read,
> +	.write = ina3221_write,
> +};
> +
> +static const struct hwmon_chip_info ina3221_chip_info = {
> +	.ops = &ina3221_hwmon_ops,
> +	.info = ina3221_info,
> +};
> +
> +/* Extra attribute groups */
>  static ssize_t ina3221_show_shunt(struct device *dev,
>  				  struct device_attribute *attr, char *buf)
>  {
> @@ -329,54 +435,6 @@ static ssize_t ina3221_set_shunt(struct device *dev,
>  	return count;
>  }
>  
> -static ssize_t ina3221_show_alert(struct device *dev,
> -				  struct device_attribute *attr, char *buf)
> -{
> -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> -	struct ina3221_data *ina = dev_get_drvdata(dev);
> -	unsigned int field = sd_attr->index;
> -	unsigned int regval;
> -	int ret;
> -
> -	ret = regmap_field_read(ina->fields[field], &regval);
> -	if (ret)
> -		return ret;
> -
> -	return snprintf(buf, PAGE_SIZE, "%d\n", regval);
> -}
> -
> -/* input channel label */
> -static SENSOR_DEVICE_ATTR(in1_label, 0444,
> -		ina3221_show_label, NULL, INA3221_CHANNEL1);
> -static SENSOR_DEVICE_ATTR(in2_label, 0444,
> -		ina3221_show_label, NULL, INA3221_CHANNEL2);
> -static SENSOR_DEVICE_ATTR(in3_label, 0444,
> -		ina3221_show_label, NULL, INA3221_CHANNEL3);
> -
> -/* voltage channel enable */
> -static SENSOR_DEVICE_ATTR(in1_enable, 0644,
> -		ina3221_show_enable, ina3221_set_enable, INA3221_CHANNEL1);
> -static SENSOR_DEVICE_ATTR(in2_enable, 0644,
> -		ina3221_show_enable, ina3221_set_enable, INA3221_CHANNEL2);
> -static SENSOR_DEVICE_ATTR(in3_enable, 0644,
> -		ina3221_show_enable, ina3221_set_enable, INA3221_CHANNEL3);
> -
> -/* bus voltage */
> -static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO,
> -		ina3221_show_bus_voltage, NULL, INA3221_BUS1);
> -static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO,
> -		ina3221_show_bus_voltage, NULL, INA3221_BUS2);
> -static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO,
> -		ina3221_show_bus_voltage, NULL, INA3221_BUS3);
> -
> -/* calculated current */
> -static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO,
> -		ina3221_show_current, NULL, INA3221_SHUNT1);
> -static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO,
> -		ina3221_show_current, NULL, INA3221_SHUNT2);
> -static SENSOR_DEVICE_ATTR(curr3_input, S_IRUGO,
> -		ina3221_show_current, NULL, INA3221_SHUNT3);
> -
>  /* shunt resistance */
>  static SENSOR_DEVICE_ATTR(shunt1_resistor, S_IRUGO | S_IWUSR,
>  		ina3221_show_shunt, ina3221_set_shunt, INA3221_CHANNEL1);
> @@ -385,109 +443,13 @@ static SENSOR_DEVICE_ATTR(shunt2_resistor, S_IRUGO | S_IWUSR,
>  static SENSOR_DEVICE_ATTR(shunt3_resistor, S_IRUGO | S_IWUSR,
>  		ina3221_show_shunt, ina3221_set_shunt, INA3221_CHANNEL3);
>  
> -/* critical current */
> -static SENSOR_DEVICE_ATTR(curr1_crit, S_IRUGO | S_IWUSR,
> -		ina3221_show_current, ina3221_set_current, INA3221_CRIT1);
> -static SENSOR_DEVICE_ATTR(curr2_crit, S_IRUGO | S_IWUSR,
> -		ina3221_show_current, ina3221_set_current, INA3221_CRIT2);
> -static SENSOR_DEVICE_ATTR(curr3_crit, S_IRUGO | S_IWUSR,
> -		ina3221_show_current, ina3221_set_current, INA3221_CRIT3);
> -
> -/* critical current alert */
> -static SENSOR_DEVICE_ATTR(curr1_crit_alarm, S_IRUGO,
> -		ina3221_show_alert, NULL, F_CF1);
> -static SENSOR_DEVICE_ATTR(curr2_crit_alarm, S_IRUGO,
> -		ina3221_show_alert, NULL, F_CF2);
> -static SENSOR_DEVICE_ATTR(curr3_crit_alarm, S_IRUGO,
> -		ina3221_show_alert, NULL, F_CF3);
> -
> -/* warning current */
> -static SENSOR_DEVICE_ATTR(curr1_max, S_IRUGO | S_IWUSR,
> -		ina3221_show_current, ina3221_set_current, INA3221_WARN1);
> -static SENSOR_DEVICE_ATTR(curr2_max, S_IRUGO | S_IWUSR,
> -		ina3221_show_current, ina3221_set_current, INA3221_WARN2);
> -static SENSOR_DEVICE_ATTR(curr3_max, S_IRUGO | S_IWUSR,
> -		ina3221_show_current, ina3221_set_current, INA3221_WARN3);
> -
> -/* warning current alert */
> -static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO,
> -		ina3221_show_alert, NULL, F_WF1);
> -static SENSOR_DEVICE_ATTR(curr2_max_alarm, S_IRUGO,
> -		ina3221_show_alert, NULL, F_WF2);
> -static SENSOR_DEVICE_ATTR(curr3_max_alarm, S_IRUGO,
> -		ina3221_show_alert, NULL, F_WF3);
> -
> -/* shunt voltage */
> -static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO,
> -		ina3221_show_shunt_voltage, NULL, INA3221_SHUNT1);
> -static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO,
> -		ina3221_show_shunt_voltage, NULL, INA3221_SHUNT2);
> -static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO,
> -		ina3221_show_shunt_voltage, NULL, INA3221_SHUNT3);
> -
>  static struct attribute *ina3221_attrs[] = {
> -	/* channel 1 -- make sure label at first */
> -	&sensor_dev_attr_in1_label.dev_attr.attr,
> -	&sensor_dev_attr_in1_enable.dev_attr.attr,
> -	&sensor_dev_attr_in1_input.dev_attr.attr,
> -	&sensor_dev_attr_curr1_input.dev_attr.attr,
>  	&sensor_dev_attr_shunt1_resistor.dev_attr.attr,
> -	&sensor_dev_attr_curr1_crit.dev_attr.attr,
> -	&sensor_dev_attr_curr1_crit_alarm.dev_attr.attr,
> -	&sensor_dev_attr_curr1_max.dev_attr.attr,
> -	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
> -	&sensor_dev_attr_in4_input.dev_attr.attr,
> -
> -	/* channel 2 -- make sure label at first */
> -	&sensor_dev_attr_in2_label.dev_attr.attr,
> -	&sensor_dev_attr_in2_enable.dev_attr.attr,
> -	&sensor_dev_attr_in2_input.dev_attr.attr,
> -	&sensor_dev_attr_curr2_input.dev_attr.attr,
>  	&sensor_dev_attr_shunt2_resistor.dev_attr.attr,
> -	&sensor_dev_attr_curr2_crit.dev_attr.attr,
> -	&sensor_dev_attr_curr2_crit_alarm.dev_attr.attr,
> -	&sensor_dev_attr_curr2_max.dev_attr.attr,
> -	&sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
> -	&sensor_dev_attr_in5_input.dev_attr.attr,
> -
> -	/* channel 3 -- make sure label at first */
> -	&sensor_dev_attr_in3_label.dev_attr.attr,
> -	&sensor_dev_attr_in3_enable.dev_attr.attr,
> -	&sensor_dev_attr_in3_input.dev_attr.attr,
> -	&sensor_dev_attr_curr3_input.dev_attr.attr,
>  	&sensor_dev_attr_shunt3_resistor.dev_attr.attr,
> -	&sensor_dev_attr_curr3_crit.dev_attr.attr,
> -	&sensor_dev_attr_curr3_crit_alarm.dev_attr.attr,
> -	&sensor_dev_attr_curr3_max.dev_attr.attr,
> -	&sensor_dev_attr_curr3_max_alarm.dev_attr.attr,
> -	&sensor_dev_attr_in6_input.dev_attr.attr,
> -
>  	NULL,
>  };
> -
> -static umode_t ina3221_attr_is_visible(struct kobject *kobj,
> -				       struct attribute *attr, int n)
> -{
> -	const int max_attrs = ARRAY_SIZE(ina3221_attrs) - 1;
> -	const int num_attrs = max_attrs / INA3221_NUM_CHANNELS;
> -	struct device *dev = kobj_to_dev(kobj);
> -	struct ina3221_data *ina = dev_get_drvdata(dev);
> -	enum ina3221_channels channel = n / num_attrs;
> -	struct ina3221_input *input = &ina->inputs[channel];
> -	int index = n % num_attrs;
> -
> -	/* Hide label node if label is not provided */
> -	if (index == 0 && !input->label)
> -		return 0;
> -
> -	return attr->mode;
> -}
> -
> -static const struct attribute_group ina3221_group = {
> -	.is_visible = ina3221_attr_is_visible,
> -	.attrs = ina3221_attrs,
> -};
> -__ATTRIBUTE_GROUPS(ina3221);
> +ATTRIBUTE_GROUPS(ina3221);
>  
>  static const struct regmap_range ina3221_yes_ranges[] = {
>  	regmap_reg_range(INA3221_CONFIG, INA3221_BUS3),
> @@ -620,9 +582,9 @@ static int ina3221_probe(struct i2c_client *client,
>  
>  	dev_set_drvdata(dev, ina);
>  
> -	hwmon_dev = devm_hwmon_device_register_with_groups(dev,
> -							   client->name,
> -							   ina, ina3221_groups);
> +	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, ina,
> +							 &ina3221_chip_info,
> +							 ina3221_groups);
>  	if (IS_ERR(hwmon_dev)) {
>  		dev_err(dev, "Unable to register hwmon device\n");
>  		return PTR_ERR(hwmon_dev);

Re: [PATCH 2/2] hwmon: (ina3221) Use _info API to register hwmon device

[Nicolin Chen]

On Sat, Oct 06, 2018 at 01:05:27PM -0700, Guenter Roeck wrote:
> Hi Nicolin,
> 
> On Fri, Oct 05, 2018 at 04:59:05PM -0700, Nicolin Chen wrote:
> > The hwmon core has a newer API which abstracts most of common
> > things in the core so as to simplify the hwmon device drivers.
> > 
> > This patch implements this _info API to ina3221 hwmon driver.
> > 
> 
> $ size drivers/hwmon/ina*.o
>    text	   data	    bss	    dec	    hex	filename
>    9251	   3552	     64	  12867	   3243	drivers/hwmon/ina3221.o
>   12959	   9256	     64	  22279	   5707	drivers/hwmon/ina3221-orig.o
> 
> It looks like this version is about 45% smaller. Surprising, isn't it ?

I was thinking about adding a memory saving report like this in
the commit log until I noticed that the actual saving of binary
size is 7~8KB on my side and there seems to be no difference at
the size showed in the lsmod list (I built the driver with =m).

Yet, I agree the saving is proportionally huge.

> Something else I just noticed: When reading the shunt resistor
> value from devicetree, the value range is not checked. A shunt
> resistor value of 0 should result in a divide by zero error.
> Also, the value read from dt is an u32, but assigned to an int.
> A shunt resistor value of 0x80000000 or higher should yield quite
> interesting results. Not that this makes sense, but we should not
> accept bad values. Can you send a follow-up patch to fix that ?

Will send a separate fix in the next version.

> Other comments inline.

Will fix them too.

Thank you
Nicolin

--------

> Thanks,
> Guenter
> 
> > Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
> > ---
> >  drivers/hwmon/ina3221.c | 528 +++++++++++++++++++---------------------
> >  1 file changed, 245 insertions(+), 283 deletions(-)
> > 
> > diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c
> > index c3a497aed345..08cc0b4bc0ba 100644
> > --- a/drivers/hwmon/ina3221.c
> > +++ b/drivers/hwmon/ina3221.c
> > @@ -77,21 +77,6 @@ enum ina3221_channels {
> >  	INA3221_NUM_CHANNELS
> >  };
> >  
> > -static const unsigned int register_channel[] = {
> > -	[INA3221_BUS1] = INA3221_CHANNEL1,
> > -	[INA3221_BUS2] = INA3221_CHANNEL2,
> > -	[INA3221_BUS3] = INA3221_CHANNEL3,
> > -	[INA3221_SHUNT1] = INA3221_CHANNEL1,
> > -	[INA3221_SHUNT2] = INA3221_CHANNEL2,
> > -	[INA3221_SHUNT3] = INA3221_CHANNEL3,
> > -	[INA3221_CRIT1] = INA3221_CHANNEL1,
> > -	[INA3221_CRIT2] = INA3221_CHANNEL2,
> > -	[INA3221_CRIT3] = INA3221_CHANNEL3,
> > -	[INA3221_WARN1] = INA3221_CHANNEL1,
> > -	[INA3221_WARN2] = INA3221_CHANNEL2,
> > -	[INA3221_WARN3] = INA3221_CHANNEL3,
> > -};
> > -
> >  /**
> >   * struct ina3221_input - channel input source specific information
> >   * @label: label of channel input source
> > @@ -123,58 +108,6 @@ static inline bool ina3221_is_enabled(struct ina3221_data *ina, int channel)
> >  	return ina->reg_config & INA3221_CONFIG_CHx_EN(channel);
> >  }
> >  
> > -static ssize_t ina3221_show_label(struct device *dev,
> > -				  struct device_attribute *attr, char *buf)
> > -{
> > -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> > -	struct ina3221_data *ina = dev_get_drvdata(dev);
> > -	unsigned int channel = sd_attr->index;
> > -	struct ina3221_input *input = &ina->inputs[channel];
> > -
> > -	return snprintf(buf, PAGE_SIZE, "%s\n", input->label);
> > -}
> > -
> > -static ssize_t ina3221_show_enable(struct device *dev,
> > -				   struct device_attribute *attr, char *buf)
> > -{
> > -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> > -	struct ina3221_data *ina = dev_get_drvdata(dev);
> > -	unsigned int channel = sd_attr->index;
> > -
> > -	return snprintf(buf, PAGE_SIZE, "%d\n",
> > -			ina3221_is_enabled(ina, channel));
> > -}
> > -
> > -static ssize_t ina3221_set_enable(struct device *dev,
> > -				  struct device_attribute *attr,
> > -				  const char *buf, size_t count)
> > -{
> > -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> > -	struct ina3221_data *ina = dev_get_drvdata(dev);
> > -	unsigned int channel = sd_attr->index;
> > -	u16 config, mask = INA3221_CONFIG_CHx_EN(channel);
> > -	bool enable;
> > -	int ret;
> > -
> > -	ret = kstrtobool(buf, &enable);
> > -	if (ret)
> > -		return ret;
> > -
> > -	config = enable ? mask : 0;
> > -
> > -	/* Enable or disable the channel */
> > -	ret = regmap_update_bits(ina->regmap, INA3221_CONFIG, mask, config);
> > -	if (ret)
> > -		return ret;
> > -
> > -	/* Cache the latest config register value */
> > -	ret = regmap_read(ina->regmap, INA3221_CONFIG, &ina->reg_config);
> > -	if (ret)
> > -		return ret;
> > -
> > -	return count;
> > -}
> > -
> >  static int ina3221_read_value(struct ina3221_data *ina, unsigned int reg,
> >  			      int *val)
> >  {
> > @@ -190,94 +123,107 @@ static int ina3221_read_value(struct ina3221_data *ina, unsigned int reg,
> >  	return 0;
> >  }
> >  
> > -static ssize_t ina3221_show_bus_voltage(struct device *dev,
> > -					struct device_attribute *attr,
> > -					char *buf)
> > +static const u8 ina3221_in_reg[] = {
> > +	INA3221_BUS1,
> > +	INA3221_BUS2,
> > +	INA3221_BUS3,
> > +	INA3221_SHUNT1,
> > +	INA3221_SHUNT2,
> > +	INA3221_SHUNT3,
> > +};
> > +
> > +static int ina3221_read_in(struct device *dev, u32 attr, int channel, long *val)
> >  {
> > -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> > +	const bool is_shunt = channel > INA3221_CHANNEL3;
> >  	struct ina3221_data *ina = dev_get_drvdata(dev);
> > -	unsigned int reg = sd_attr->index;
> > -	unsigned int channel = register_channel[reg];
> > -	int val, voltage_mv, ret;
> > +	u8 reg = ina3221_in_reg[channel];
> > +	int regval, ret;
> >  
> > -	/* No data for read-only attribute if channel is disabled */
> > -	if (!attr->store && !ina3221_is_enabled(ina, channel))
> > -		return -ENODATA;
> > +	/* Translate shunt channel ID to sensor channel ID: 4->1, 5->2, 6->3 */
> 
> Misleading. The channel number as used here is 0-aligned, so it is 3 -> 0
> etc.
> 
> I know the chip talks about channels 1..3, but that is not how "channel"
> is used here. It took me a bit to find out that the calling code
> subtracts 1 from the channel number and that the code is correct.
> We don't want others to suffer the same fate.
> 
> > +	channel %= INA3221_NUM_CHANNELS;
> 
> 3 % 3 = 0, not 1.
> 
> >  
> > -	ret = ina3221_read_value(ina, reg, &val);
> > -	if (ret)
> > -		return ret;
> > +	switch (attr) {
> > +	case hwmon_in_input:
> > +		if (!ina3221_is_enabled(ina, channel))
> > +			return -ENODATA;
> >  
> > -	voltage_mv = val * 8;
> > +		ret = ina3221_read_value(ina, reg, &regval);
> > +		if (ret)
> > +			return ret;
> >  
> > -	return snprintf(buf, PAGE_SIZE, "%d\n", voltage_mv);
> > +		/*
> > +		 * Scale of shunt voltage (uV): LSB is 40uV
> > +		 * Scale of bus voltage (mV): LSB is 8mV
> > +		 */
> > +		*val = regval * (is_shunt ? 40 : 8);
> > +		return 0;
> > +	case hwmon_in_enable:
> > +		*val = ina3221_is_enabled(ina, channel);
> > +		return 0;
> > +	default:
> > +		return -EOPNOTSUPP;
> > +	}
> >  }
> >  
> > -static ssize_t ina3221_show_shunt_voltage(struct device *dev,
> > -					  struct device_attribute *attr,
> > -					  char *buf)
> > +static const u8 ina3221_curr_reg[][INA3221_NUM_CHANNELS] = {
> > +	[hwmon_curr_input] = { INA3221_SHUNT1, INA3221_SHUNT2, INA3221_SHUNT3 },
> > +	[hwmon_curr_max] = { INA3221_WARN1, INA3221_WARN2, INA3221_WARN3 },
> > +	[hwmon_curr_crit] = { INA3221_CRIT1, INA3221_CRIT2, INA3221_CRIT3 },
> > +	[hwmon_curr_max_alarm] = { F_WF1, F_WF2, F_WF3 },
> > +	[hwmon_curr_crit_alarm] = { F_CF1, F_CF2, F_CF3 },
> > +};
> > +
> > +static int ina3221_read_curr(struct device *dev, u32 attr,
> > +			     int channel, long *val)
> >  {
> > -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> >  	struct ina3221_data *ina = dev_get_drvdata(dev);
> > -	unsigned int reg = sd_attr->index;
> > -	unsigned int channel = register_channel[reg];
> > -	int val, voltage_uv, ret;
> > -
> > -	/* No data for read-only attribute if channel is disabled */
> > -	if (!attr->store && !ina3221_is_enabled(ina, channel))
> > -		return -ENODATA;
> > -
> > -	ret = ina3221_read_value(ina, reg, &val);
> > -	if (ret)
> > -		return ret;
> > -	voltage_uv = val * 40;
> > -
> > -	return snprintf(buf, PAGE_SIZE, "%d\n", voltage_uv);
> > -}
> > -
> > -static ssize_t ina3221_show_current(struct device *dev,
> > -				    struct device_attribute *attr, char *buf)
> > -{
> > -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> > -	struct ina3221_data *ina = dev_get_drvdata(dev);
> > -	unsigned int reg = sd_attr->index;
> > -	unsigned int channel = register_channel[reg];
> >  	struct ina3221_input *input = &ina->inputs[channel];
> >  	int resistance_uo = input->shunt_resistor;
> > -	int val, current_ma, voltage_nv, ret;
> > +	u8 reg = ina3221_curr_reg[attr][channel];
> > +	int regval, voltage_nv, ret;
> >  
> > -	/* No data for read-only attribute if channel is disabled */
> > -	if (!attr->store && !ina3221_is_enabled(ina, channel))
> > -		return -ENODATA;
> > +	switch (attr) {
> > +	case hwmon_curr_input:
> > +		if (!ina3221_is_enabled(ina, channel))
> > +			return -ENODATA;
> > +		/* fallthrough */
> 
> I think the official terminology is "fall through".
> But then it looks like "fallthrough" is also widely used,
> so maybe we are ok.
> 
> > +	case hwmon_curr_crit:
> > +	case hwmon_curr_max:
> > +		ret = ina3221_read_value(ina, reg, &regval);
> > +		if (ret)
> > +			return ret;
> >  
> > -	ret = ina3221_read_value(ina, reg, &val);
> > -	if (ret)
> > -		return ret;
> > -	voltage_nv = val * 40000;
> > -
> > -	current_ma = DIV_ROUND_CLOSEST(voltage_nv, resistance_uo);
> > -
> > -	return snprintf(buf, PAGE_SIZE, "%d\n", current_ma);
> > +		/* Scale of shunt voltage: LSB is 40uV (40000nV) */
> > +		voltage_nv = regval * 40000;
> > +		/* Return current in mA */
> > +		*val = DIV_ROUND_CLOSEST(voltage_nv, resistance_uo);
> > +		return 0;
> > +	case hwmon_curr_crit_alarm:
> > +	case hwmon_curr_max_alarm:
> > +		ret = regmap_field_read(ina->fields[reg], &regval);
> > +		if (ret)
> > +			return ret;
> > +		*val = regval;
> > +		return 0;
> > +	default:
> > +		return -EOPNOTSUPP;
> > +	}
> >  }
> >  
> > -static ssize_t ina3221_set_current(struct device *dev,
> > -				   struct device_attribute *attr,
> > -				   const char *buf, size_t count)
> > +static int ina3221_write_curr(struct device *dev, u32 attr,
> > +			      int channel, long val)
> >  {
> > -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> >  	struct ina3221_data *ina = dev_get_drvdata(dev);
> > -	unsigned int reg = sd_attr->index;
> > -	unsigned int channel = register_channel[reg];
> >  	struct ina3221_input *input = &ina->inputs[channel];
> >  	int resistance_uo = input->shunt_resistor;
> > -	int val, current_ma, voltage_uv, ret;
> > +	u8 reg = ina3221_curr_reg[attr][channel];
> > +	int regval, current_ma, voltage_uv;
> >  
> > -	ret = kstrtoint(buf, 0, &current_ma);
> > -	if (ret)
> > -		return ret;
> > +	if (attr != hwmon_curr_crit && attr != hwmon_curr_max)
> > +		return -EOPNOTSUPP;
> 
> I don't think this is needed.
> 
> >  
> >  	/* clamp current */
> > -	current_ma = clamp_val(current_ma,
> > +	current_ma = clamp_val(val,
> >  			       INT_MIN / resistance_uo,
> >  			       INT_MAX / resistance_uo);
> >  
> > @@ -287,15 +233,175 @@ static ssize_t ina3221_set_current(struct device *dev,
> >  	voltage_uv = clamp_val(voltage_uv, -163800, 163800);
> >  
> >  	/* 1 / 40uV(scale) << 3(register shift) = 5 */
> > -	val = DIV_ROUND_CLOSEST(voltage_uv, 5) & 0xfff8;
> > +	regval = DIV_ROUND_CLOSEST(voltage_uv, 5) & 0xfff8;
> >  
> > -	ret = regmap_write(ina->regmap, reg, val);
> > +	return regmap_write(ina->regmap, reg, regval);
> > +}
> > +
> > +static int ina3221_write_enable(struct device *dev, int channel, bool enable)
> > +{
> > +	struct ina3221_data *ina = dev_get_drvdata(dev);
> > +	u16 config, mask = INA3221_CONFIG_CHx_EN(channel);
> > +	int ret;
> > +
> > +	config = enable ? mask : 0;
> > +
> > +	/* Enable or disable the channel */
> > +	ret = regmap_update_bits(ina->regmap, INA3221_CONFIG, mask, config);
> >  	if (ret)
> >  		return ret;
> >  
> > -	return count;
> > +	/* Cache the latest config register value */
> > +	ret = regmap_read(ina->regmap, INA3221_CONFIG, &ina->reg_config);
> > +	if (ret)
> > +		return ret;
> > +
> > +	return 0;
> >  }
> >  
> > +static int ina3221_read(struct device *dev, enum hwmon_sensor_types type,
> > +			u32 attr, int channel, long *val)
> > +{
> > +	switch (type) {
> > +	case hwmon_in:
> > +		return ina3221_read_in(dev, attr, channel - 1, val);
> > +	case hwmon_curr:
> > +		return ina3221_read_curr(dev, attr, channel, val);
> > +	default:
> > +		return -EOPNOTSUPP;
> > +	}
> > +}
> > +
> > +static int ina3221_write(struct device *dev, enum hwmon_sensor_types type,
> > +			 u32 attr, int channel, long val)
> > +{
> > +	switch (type) {
> > +	case hwmon_in:
> > +		if (attr != hwmon_in_enable)
> > +			return -EOPNOTSUPP;
> 
> I think you can drop this.
> 
> > +		return ina3221_write_enable(dev, channel - 1, val);
> > +	case hwmon_curr:
> > +		return ina3221_write_curr(dev, attr, channel, val);
> > +	default:
> > +		return -EOPNOTSUPP;
> 
> I tend to have drivers return -EOPNOTSUPP for default: cases
> since otherwise static checkers may complain about missing default
> cases, but otherwise we should refrain from unnecessary checks.
> 
> > +	}
> > +}
> > +
> > +static int ina3221_read_string(struct device *dev, enum hwmon_sensor_types type,
> > +			       u32 attr, int channel, const char **str)
> > +{
> > +	struct ina3221_data *ina = dev_get_drvdata(dev);
> > +	int index = channel - 1;
> > +
> > +	if (type != hwmon_in || attr != hwmon_in_label)
> > +		return -EOPNOTSUPP;
> > +
> > +	/* Only 1-3 channels have hwmon_in_label */
> > +	if (channel < 1 || channel > 3)
> > +		return -EOPNOTSUPP;
> > +
> The above checks should be unnecessary.
> 
> > +	*str = ina->inputs[index].label;
> > +
> > +	return 0;
> > +}
> > +
> > +static umode_t ina3221_is_visible(const void *drvdata,
> > +				  enum hwmon_sensor_types type,
> > +				  u32 attr, int channel)
> > +{
> > +	const struct ina3221_data *ina = drvdata;
> > +	const struct ina3221_input *input = NULL;
> > +
> > +	switch (type) {
> > +	case hwmon_in:
> > +		/* Ignore in0_ */
> > +		if (channel == 0)
> > +			return 0;
> > +
> > +		switch (attr) {
> > +		case hwmon_in_label:
> > +			if (channel - 1 <= INA3221_CHANNEL3)
> > +				input = &ina->inputs[channel - 1];
> > +			/* Hide label node if label is not provided */
> > +			return (input && input->label) ? 0444 : 0;
> > +		case hwmon_in_input:
> > +			return 0444;
> > +		case hwmon_in_enable:
> > +			return 0644;
> > +		default:
> > +			return 0;
> > +		}
> > +	case hwmon_curr:
> > +		switch (attr) {
> > +		case hwmon_curr_input:
> > +		case hwmon_curr_crit_alarm:
> > +		case hwmon_curr_max_alarm:
> > +			return 0444;
> > +		case hwmon_curr_crit:
> > +		case hwmon_curr_max:
> > +			return 0644;
> > +		default:
> > +			return 0;
> > +		}
> > +	default:
> > +		return 0;
> > +	}
> > +}
> > +
> > +static const u32 ina3221_in_config[] = {
> > +	/* 0: dummy, skipped in is_visible */
> > +	HWMON_I_INPUT,
> > +	/* 1-3: input voltage Channels */
> > +	HWMON_I_INPUT | HWMON_I_ENABLE | HWMON_I_LABEL,
> > +	HWMON_I_INPUT | HWMON_I_ENABLE | HWMON_I_LABEL,
> > +	HWMON_I_INPUT | HWMON_I_ENABLE | HWMON_I_LABEL,
> > +	/* 4-6: shunt voltage Channels */
> > +	HWMON_I_INPUT,
> > +	HWMON_I_INPUT,
> > +	HWMON_I_INPUT,
> > +	0
> > +};
> > +
> > +static const struct hwmon_channel_info ina3221_in = {
> > +	.type = hwmon_in,
> > +	.config = ina3221_in_config,
> > +};
> > +
> > +#define INA3221_HWMON_CURR_CONFIG (HWMON_C_INPUT | \
> > +				   HWMON_C_CRIT | HWMON_C_CRIT_ALARM | \
> > +				   HWMON_C_MAX | HWMON_C_MAX_ALARM)
> > +
> > +static const u32 ina3221_curr_config[] = {
> > +	INA3221_HWMON_CURR_CONFIG,
> > +	INA3221_HWMON_CURR_CONFIG,
> > +	INA3221_HWMON_CURR_CONFIG,
> > +	0
> > +};
> > +
> > +static const struct hwmon_channel_info ina3221_curr = {
> > +	.type = hwmon_curr,
> > +	.config = ina3221_curr_config,
> > +};
> > +
> > +static const struct hwmon_channel_info *ina3221_info[] = {
> > +	&ina3221_in,
> > +	&ina3221_curr,
> > +	NULL
> > +};
> > +
> > +static const struct hwmon_ops ina3221_hwmon_ops = {
> > +	.is_visible = ina3221_is_visible,
> > +	.read_string = ina3221_read_string,
> > +	.read = ina3221_read,
> > +	.write = ina3221_write,
> > +};
> > +
> > +static const struct hwmon_chip_info ina3221_chip_info = {
> > +	.ops = &ina3221_hwmon_ops,
> > +	.info = ina3221_info,
> > +};
> > +
> > +/* Extra attribute groups */
> >  static ssize_t ina3221_show_shunt(struct device *dev,
> >  				  struct device_attribute *attr, char *buf)
> >  {
> > @@ -329,54 +435,6 @@ static ssize_t ina3221_set_shunt(struct device *dev,
> >  	return count;
> >  }
> >  
> > -static ssize_t ina3221_show_alert(struct device *dev,
> > -				  struct device_attribute *attr, char *buf)
> > -{
> > -	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
> > -	struct ina3221_data *ina = dev_get_drvdata(dev);
> > -	unsigned int field = sd_attr->index;
> > -	unsigned int regval;
> > -	int ret;
> > -
> > -	ret = regmap_field_read(ina->fields[field], &regval);
> > -	if (ret)
> > -		return ret;
> > -
> > -	return snprintf(buf, PAGE_SIZE, "%d\n", regval);
> > -}
> > -
> > -/* input channel label */
> > -static SENSOR_DEVICE_ATTR(in1_label, 0444,
> > -		ina3221_show_label, NULL, INA3221_CHANNEL1);
> > -static SENSOR_DEVICE_ATTR(in2_label, 0444,
> > -		ina3221_show_label, NULL, INA3221_CHANNEL2);
> > -static SENSOR_DEVICE_ATTR(in3_label, 0444,
> > -		ina3221_show_label, NULL, INA3221_CHANNEL3);
> > -
> > -/* voltage channel enable */
> > -static SENSOR_DEVICE_ATTR(in1_enable, 0644,
> > -		ina3221_show_enable, ina3221_set_enable, INA3221_CHANNEL1);
> > -static SENSOR_DEVICE_ATTR(in2_enable, 0644,
> > -		ina3221_show_enable, ina3221_set_enable, INA3221_CHANNEL2);
> > -static SENSOR_DEVICE_ATTR(in3_enable, 0644,
> > -		ina3221_show_enable, ina3221_set_enable, INA3221_CHANNEL3);
> > -
> > -/* bus voltage */
> > -static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO,
> > -		ina3221_show_bus_voltage, NULL, INA3221_BUS1);
> > -static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO,
> > -		ina3221_show_bus_voltage, NULL, INA3221_BUS2);
> > -static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO,
> > -		ina3221_show_bus_voltage, NULL, INA3221_BUS3);
> > -
> > -/* calculated current */
> > -static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO,
> > -		ina3221_show_current, NULL, INA3221_SHUNT1);
> > -static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO,
> > -		ina3221_show_current, NULL, INA3221_SHUNT2);
> > -static SENSOR_DEVICE_ATTR(curr3_input, S_IRUGO,
> > -		ina3221_show_current, NULL, INA3221_SHUNT3);
> > -
> >  /* shunt resistance */
> >  static SENSOR_DEVICE_ATTR(shunt1_resistor, S_IRUGO | S_IWUSR,
> >  		ina3221_show_shunt, ina3221_set_shunt, INA3221_CHANNEL1);
> > @@ -385,109 +443,13 @@ static SENSOR_DEVICE_ATTR(shunt2_resistor, S_IRUGO | S_IWUSR,
> >  static SENSOR_DEVICE_ATTR(shunt3_resistor, S_IRUGO | S_IWUSR,
> >  		ina3221_show_shunt, ina3221_set_shunt, INA3221_CHANNEL3);
> >  
> > -/* critical current */
> > -static SENSOR_DEVICE_ATTR(curr1_crit, S_IRUGO | S_IWUSR,
> > -		ina3221_show_current, ina3221_set_current, INA3221_CRIT1);
> > -static SENSOR_DEVICE_ATTR(curr2_crit, S_IRUGO | S_IWUSR,
> > -		ina3221_show_current, ina3221_set_current, INA3221_CRIT2);
> > -static SENSOR_DEVICE_ATTR(curr3_crit, S_IRUGO | S_IWUSR,
> > -		ina3221_show_current, ina3221_set_current, INA3221_CRIT3);
> > -
> > -/* critical current alert */
> > -static SENSOR_DEVICE_ATTR(curr1_crit_alarm, S_IRUGO,
> > -		ina3221_show_alert, NULL, F_CF1);
> > -static SENSOR_DEVICE_ATTR(curr2_crit_alarm, S_IRUGO,
> > -		ina3221_show_alert, NULL, F_CF2);
> > -static SENSOR_DEVICE_ATTR(curr3_crit_alarm, S_IRUGO,
> > -		ina3221_show_alert, NULL, F_CF3);
> > -
> > -/* warning current */
> > -static SENSOR_DEVICE_ATTR(curr1_max, S_IRUGO | S_IWUSR,
> > -		ina3221_show_current, ina3221_set_current, INA3221_WARN1);
> > -static SENSOR_DEVICE_ATTR(curr2_max, S_IRUGO | S_IWUSR,
> > -		ina3221_show_current, ina3221_set_current, INA3221_WARN2);
> > -static SENSOR_DEVICE_ATTR(curr3_max, S_IRUGO | S_IWUSR,
> > -		ina3221_show_current, ina3221_set_current, INA3221_WARN3);
> > -
> > -/* warning current alert */
> > -static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO,
> > -		ina3221_show_alert, NULL, F_WF1);
> > -static SENSOR_DEVICE_ATTR(curr2_max_alarm, S_IRUGO,
> > -		ina3221_show_alert, NULL, F_WF2);
> > -static SENSOR_DEVICE_ATTR(curr3_max_alarm, S_IRUGO,
> > -		ina3221_show_alert, NULL, F_WF3);
> > -
> > -/* shunt voltage */
> > -static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO,
> > -		ina3221_show_shunt_voltage, NULL, INA3221_SHUNT1);
> > -static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO,
> > -		ina3221_show_shunt_voltage, NULL, INA3221_SHUNT2);
> > -static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO,
> > -		ina3221_show_shunt_voltage, NULL, INA3221_SHUNT3);
> > -
> >  static struct attribute *ina3221_attrs[] = {
> > -	/* channel 1 -- make sure label at first */
> > -	&sensor_dev_attr_in1_label.dev_attr.attr,
> > -	&sensor_dev_attr_in1_enable.dev_attr.attr,
> > -	&sensor_dev_attr_in1_input.dev_attr.attr,
> > -	&sensor_dev_attr_curr1_input.dev_attr.attr,
> >  	&sensor_dev_attr_shunt1_resistor.dev_attr.attr,
> > -	&sensor_dev_attr_curr1_crit.dev_attr.attr,
> > -	&sensor_dev_attr_curr1_crit_alarm.dev_attr.attr,
> > -	&sensor_dev_attr_curr1_max.dev_attr.attr,
> > -	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
> > -	&sensor_dev_attr_in4_input.dev_attr.attr,
> > -
> > -	/* channel 2 -- make sure label at first */
> > -	&sensor_dev_attr_in2_label.dev_attr.attr,
> > -	&sensor_dev_attr_in2_enable.dev_attr.attr,
> > -	&sensor_dev_attr_in2_input.dev_attr.attr,
> > -	&sensor_dev_attr_curr2_input.dev_attr.attr,
> >  	&sensor_dev_attr_shunt2_resistor.dev_attr.attr,
> > -	&sensor_dev_attr_curr2_crit.dev_attr.attr,
> > -	&sensor_dev_attr_curr2_crit_alarm.dev_attr.attr,
> > -	&sensor_dev_attr_curr2_max.dev_attr.attr,
> > -	&sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
> > -	&sensor_dev_attr_in5_input.dev_attr.attr,
> > -
> > -	/* channel 3 -- make sure label at first */
> > -	&sensor_dev_attr_in3_label.dev_attr.attr,
> > -	&sensor_dev_attr_in3_enable.dev_attr.attr,
> > -	&sensor_dev_attr_in3_input.dev_attr.attr,
> > -	&sensor_dev_attr_curr3_input.dev_attr.attr,
> >  	&sensor_dev_attr_shunt3_resistor.dev_attr.attr,
> > -	&sensor_dev_attr_curr3_crit.dev_attr.attr,
> > -	&sensor_dev_attr_curr3_crit_alarm.dev_attr.attr,
> > -	&sensor_dev_attr_curr3_max.dev_attr.attr,
> > -	&sensor_dev_attr_curr3_max_alarm.dev_attr.attr,
> > -	&sensor_dev_attr_in6_input.dev_attr.attr,
> > -
> >  	NULL,
> >  };
> > -
> > -static umode_t ina3221_attr_is_visible(struct kobject *kobj,
> > -				       struct attribute *attr, int n)
> > -{
> > -	const int max_attrs = ARRAY_SIZE(ina3221_attrs) - 1;
> > -	const int num_attrs = max_attrs / INA3221_NUM_CHANNELS;
> > -	struct device *dev = kobj_to_dev(kobj);
> > -	struct ina3221_data *ina = dev_get_drvdata(dev);
> > -	enum ina3221_channels channel = n / num_attrs;
> > -	struct ina3221_input *input = &ina->inputs[channel];
> > -	int index = n % num_attrs;
> > -
> > -	/* Hide label node if label is not provided */
> > -	if (index == 0 && !input->label)
> > -		return 0;
> > -
> > -	return attr->mode;
> > -}
> > -
> > -static const struct attribute_group ina3221_group = {
> > -	.is_visible = ina3221_attr_is_visible,
> > -	.attrs = ina3221_attrs,
> > -};
> > -__ATTRIBUTE_GROUPS(ina3221);
> > +ATTRIBUTE_GROUPS(ina3221);
> >  
> >  static const struct regmap_range ina3221_yes_ranges[] = {
> >  	regmap_reg_range(INA3221_CONFIG, INA3221_BUS3),
> > @@ -620,9 +582,9 @@ static int ina3221_probe(struct i2c_client *client,
> >  
> >  	dev_set_drvdata(dev, ina);
> >  
> > -	hwmon_dev = devm_hwmon_device_register_with_groups(dev,
> > -							   client->name,
> > -							   ina, ina3221_groups);
> > +	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, ina,
> > +							 &ina3221_chip_info,
> > +							 ina3221_groups);
> >  	if (IS_ERR(hwmon_dev)) {
> >  		dev_err(dev, "Unable to register hwmon device\n");
> >  		return PTR_ERR(hwmon_dev);