[PATCH 2/2] hwmon: lm75: Add support for label

[Flaviu Nistor <flaviu.nistor@gmail.com>]

Add support for label sysfs attribute similar to other hwmon devices.
This is particularly useful for systems with multiple sensors on the
same board, where identifying individual sensors is much easier since
labels can be defined via device tree.

Signed-off-by: Flaviu Nistor <flaviu.nistor@gmail.com>
---
 drivers/hwmon/lm75.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index eda93a8c23c9..66178ac63e4f 100644
--- a/drivers/hwmon/lm75.c
+++ b/drivers/hwmon/lm75.c
@@ -108,6 +108,7 @@ static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
 #define PCT2075_REG_IDLE	0x04
 
 struct lm75_data {
+	const char *label;
 	struct regmap			*regmap;
 	u16				orig_conf;
 	u8				resolution;	/* In bits, 9 to 16 */
@@ -363,6 +364,16 @@ static irqreturn_t lm75_alarm_handler(int irq, void *private)
 	return IRQ_HANDLED;
 }
 
+static int lm75_read_string(struct device *dev, enum hwmon_sensor_types type,
+			    u32 attr, int channel, const char **str)
+{
+	struct lm75_data *data = dev_get_drvdata(dev);
+
+	*str = data->label;
+
+	return 0;
+}
+
 static int lm75_read(struct device *dev, enum hwmon_sensor_types type,
 		     u32 attr, int channel, long *val)
 {
@@ -534,6 +545,9 @@ static umode_t lm75_is_visible(const void *data, enum hwmon_sensor_types type,
 		switch (attr) {
 		case hwmon_temp_input:
 			return 0444;
+		case hwmon_temp_label:
+		/* Hide label node if label is not provided */
+			return (config_data->label) ? 0444 : 0;
 		case hwmon_temp_max:
 		case hwmon_temp_max_hyst:
 			return 0644;
@@ -553,13 +567,14 @@ static const struct hwmon_channel_info * const lm75_info[] = {
 	HWMON_CHANNEL_INFO(chip,
 			   HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
 	HWMON_CHANNEL_INFO(temp,
-			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST |
+			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_MAX | HWMON_T_MAX_HYST |
 			   HWMON_T_ALARM),
 	NULL
 };
 
 static const struct hwmon_ops lm75_hwmon_ops = {
 	.is_visible = lm75_is_visible,
+	.read_string = lm75_read_string,
 	.read = lm75_read,
 	.write = lm75_write,
 };
@@ -721,6 +736,9 @@ static int lm75_generic_probe(struct device *dev, const char *name,
 	/* needed by custom regmap callbacks */
 	dev_set_drvdata(dev, data);
 
+	/* Save the connected input label if available */
+	of_property_read_string(dev->of_node, "label", &data->label);
+
 	data->kind = kind;
 	data->regmap = regmap;
 
-- 
2.43.0