[PATCH 2/2] hwmon: iio: Add labels from IIO channels

[Sean Anderson <sean.anderson@linux.dev>]

Add labels from IIO channels to our channels. This allows userspace to
display more meaningful names instead of "in0" or "temp5".

Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
---

 drivers/hwmon/iio_hwmon.c | 33 ++++++++++++++++++++++++++++++---
 1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/drivers/hwmon/iio_hwmon.c b/drivers/hwmon/iio_hwmon.c
index 4c8a80847891..588b64c18e63 100644
--- a/drivers/hwmon/iio_hwmon.c
+++ b/drivers/hwmon/iio_hwmon.c
@@ -33,6 +33,17 @@ struct iio_hwmon_state {
 	struct attribute **attrs;
 };
 
+static ssize_t iio_hwmon_read_label(struct device *dev,
+				  struct device_attribute *attr,
+				  char *buf)
+{
+	struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
+	struct iio_hwmon_state *state = dev_get_drvdata(dev);
+	struct iio_channel *chan = &state->channels[sattr->index];
+
+	return iio_read_channel_label(chan, buf);
+}
+
 /*
  * Assumes that IIO and hwmon operate in the same base units.
  * This is supposed to be true, but needs verification for
@@ -90,12 +101,12 @@ static int iio_hwmon_probe(struct platform_device *pdev)
 
 	st->channels = channels;
 
-	/* count how many attributes we have */
+	/* count how many channels we have */
 	while (st->channels[st->num_channels].indio_dev)
 		st->num_channels++;
 
 	st->attrs = devm_kcalloc(dev,
-				 st->num_channels + 1, sizeof(*st->attrs),
+				 2 * st->num_channels + 1, sizeof(*st->attrs),
 				 GFP_KERNEL);
 	if (st->attrs == NULL)
 		return -ENOMEM;
@@ -147,7 +158,23 @@ static int iio_hwmon_probe(struct platform_device *pdev)
 		a->dev_attr.show = iio_hwmon_read_val;
 		a->dev_attr.attr.mode = 0444;
 		a->index = i;
-		st->attrs[i] = &a->dev_attr.attr;
+		st->attrs[2 * i] = &a->dev_attr.attr;
+
+		a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL);
+		if (a == NULL)
+			return -ENOMEM;
+
+		sysfs_attr_init(&a->dev_attr.attr);
+		a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
+						       "%s%d_label",
+						       prefix, n);
+		if (!a->dev_attr.attr.name)
+			return -ENOMEM;
+
+		a->dev_attr.show = iio_hwmon_read_label;
+		a->dev_attr.attr.mode = 0444;
+		a->index = i;
+		st->attrs[2 * i + 1] = &a->dev_attr.attr;
 	}
 
 	st->attr_group.attrs = st->attrs;
-- 
2.35.1.1320.gc452695387.dirty