From: Sean Nyekjaer sean@geanix.com
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@geanix.com Link: https://lore.kernel.org/r/20230503162029.3654093-1-sean@geanix.com Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -1882,16 +1882,15 @@ 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 */