From: Sean Nyekjaer <sean@xxxxxxxxxx>
commit 9c0d6ccd7d6bbd275e390b55a3390b4274291d95 upstream.
If no adc differential channels are defined driver will fail with EINVAL:
stm32-adc: probe of 48003000.adc:adc@0 failed with error -22
Fix this by skipping the initialization if no channels are defined.
This applies only to the legacy way of initializing adc channels.
Fixes: d7705f35448a ("iio: adc: stm32-adc: convert to device properties")
Signed-off-by: Sean Nyekjaer <sean@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230503162029.3654093-1-sean@xxxxxxxxxx
Cc: <Stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/iio/adc/stm32-adc.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -2006,16 +2006,15 @@ static int stm32_adc_get_legacy_chan_cou
* to get the *real* number of channels.
*/
ret = device_property_count_u32(dev, "st,adc-diff-channels");
- if (ret < 0)
- return ret;
-
- ret /= (int)(sizeof(struct stm32_adc_diff_channel) / sizeof(u32));
- if (ret > adc_info->max_channels) {
- dev_err(&indio_dev->dev, "Bad st,adc-diff-channels?\n");
- return -EINVAL;
- } else if (ret > 0) {
- adc->num_diff = ret;
- num_channels += ret;
+ if (ret > 0) {
+ ret /= (int)(sizeof(struct stm32_adc_diff_channel) / sizeof(u32));
+ if (ret > adc_info->max_channels) {
+ dev_err(&indio_dev->dev, "Bad st,adc-diff-channels?\n");
+ return -EINVAL;
+ } else if (ret > 0) {
+ adc->num_diff = ret;
+ num_channels += ret;
+ }
}
/* Optional sample time is provided either for each, or all channels */
