[PATCH] hwmon: (iio_hwmon) Add support for humidity and power sensors

[Guenter Roeck <linux@roeck-us.net>]

The iio subsystem supports power and humidity sensors, so it makes sense
to support those sensor types in the iio-hwmon bridge as well.

Cc: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
Compile tested only.

Question is if I got the scale conversion correct for power measurements.
I _assume_ that iio always reports processed values in milli-units,
but I am not entirely sure.

 drivers/hwmon/iio_hwmon.c | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/drivers/hwmon/iio_hwmon.c b/drivers/hwmon/iio_hwmon.c
index 14c82da..efc55a9 100644
--- a/drivers/hwmon/iio_hwmon.c
+++ b/drivers/hwmon/iio_hwmon.c
@@ -21,6 +21,8 @@
 /**
  * struct iio_hwmon_state - device instance state
  * @channels:		filled with array of channels from iio
+ * @scale:		array of multipliers to convert from iio to hwmon
+ *			resolution
  * @num_channels:	number of channels in channels (saves counting twice)
  * @hwmon_dev:		associated hwmon device
  * @attr_group:	the group of attributes
@@ -28,6 +30,7 @@
  */
 struct iio_hwmon_state {
 	struct iio_channel *channels;
+	int *scale;
 	int num_channels;
 	struct device *hwmon_dev;
 	struct attribute_group attr_group;
@@ -48,13 +51,16 @@ static ssize_t iio_hwmon_read_val(struct device *dev,
 	int ret;
 	struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
 	struct iio_hwmon_state *state = dev_get_drvdata(dev);
+	s64 result_64;
 
 	ret = iio_read_channel_processed(&state->channels[sattr->index],
-					&result);
+					 &result);
 	if (ret < 0)
 		return ret;
 
-	return sprintf(buf, "%d\n", result);
+	result_64 = (s64)result * state->scale[sattr->index];
+
+	return sprintf(buf, "%lld\n", result_64);
 }
 
 static int iio_hwmon_probe(struct platform_device *pdev)
@@ -63,7 +69,7 @@ static int iio_hwmon_probe(struct platform_device *pdev)
 	struct iio_hwmon_state *st;
 	struct sensor_device_attribute *a;
 	int ret, i;
-	int in_i = 1, temp_i = 1, curr_i = 1;
+	int in_i = 1, temp_i = 1, curr_i = 1, power_i = 1, humidity_i = 1;
 	enum iio_chan_type type;
 	struct iio_channel *channels;
 	const char *name = "iio_hwmon";
@@ -94,6 +100,12 @@ static int iio_hwmon_probe(struct platform_device *pdev)
 		ret = -ENOMEM;
 		goto error_release_channels;
 	}
+	st->scale = devm_kzalloc(dev, sizeof(*st->scale) * st->num_channels,
+				 GFP_KERNEL);
+	if (st->scale == NULL) {
+		ret = -ENOMEM;
+		goto error_release_channels;
+	}
 
 	for (i = 0; i < st->num_channels; i++) {
 		a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL);
@@ -107,6 +119,7 @@ static int iio_hwmon_probe(struct platform_device *pdev)
 		if (ret < 0)
 			goto error_release_channels;
 
+		st->scale[i] = 1;
 		switch (type) {
 		case IIO_VOLTAGE:
 			a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
@@ -123,6 +136,17 @@ static int iio_hwmon_probe(struct platform_device *pdev)
 							  "curr%d_input",
 							  curr_i++);
 			break;
+		case IIO_POWER:
+			st->scale[i] = 1000;
+			a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
+							  "power%d_input",
+							  power_i++);
+			break;
+		case IIO_HUMIDITYRELATIVE:
+			a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
+							  "humidity%d_input",
+							  humidity_i++);
+			break;
 		default:
 			ret = -EINVAL;
 			goto error_release_channels;
-- 
1.9.1