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

Guenter Roeck
2014-09-27T15:50:00Z

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