From: Sean Nyekjaer <sean@xxxxxxxxxx>
commit 3e27ef0ced49f8ae7883c25fadf76a2086e99025 upstream.
If only adc differential channels are defined driver will fail with
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>
Reviewed-by: Olivier Moysan <olivier.moysan@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230503162029.3654093-2-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 | 42 +++++++++++++++++++++++-------------------
1 file changed, 23 insertions(+), 19 deletions(-)
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -2037,6 +2037,7 @@ static int stm32_adc_legacy_chan_init(st
struct stm32_adc_diff_channel diff[STM32_ADC_CH_MAX];
struct device *dev = &indio_dev->dev;
u32 num_diff = adc->num_diff;
+ int num_se = nchans - num_diff;
int size = num_diff * sizeof(*diff) / sizeof(u32);
int scan_index = 0, ret, i, c;
u32 smp = 0, smps[STM32_ADC_CH_MAX], chans[STM32_ADC_CH_MAX];
@@ -2063,29 +2064,32 @@ static int stm32_adc_legacy_chan_init(st
scan_index++;
}
}
-
- ret = device_property_read_u32_array(dev, "st,adc-channels", chans,
- nchans);
- if (ret)
- return ret;
-
- for (c = 0; c < nchans; c++) {
- if (chans[c] >= adc_info->max_channels) {
- dev_err(&indio_dev->dev, "Invalid channel %d\n",
- chans[c]);
- return -EINVAL;
+ if (num_se > 0) {
+ ret = device_property_read_u32_array(dev, "st,adc-channels", chans, num_se);
+ if (ret) {
+ dev_err(&indio_dev->dev, "Failed to get st,adc-channels %d\n", ret);
+ return ret;
}
- /* Channel can't be configured both as single-ended & diff */
- for (i = 0; i < num_diff; i++) {
- if (chans[c] == diff[i].vinp) {
- dev_err(&indio_dev->dev, "channel %d misconfigured\n", chans[c]);
+ for (c = 0; c < num_se; c++) {
+ if (chans[c] >= adc_info->max_channels) {
+ dev_err(&indio_dev->dev, "Invalid channel %d\n",
+ chans[c]);
return -EINVAL;
}
+
+ /* Channel can't be configured both as single-ended & diff */
+ for (i = 0; i < num_diff; i++) {
+ if (chans[c] == diff[i].vinp) {
+ dev_err(&indio_dev->dev, "channel %d misconfigured\n",
+ chans[c]);
+ return -EINVAL;
+ }
+ }
+ stm32_adc_chan_init_one(indio_dev, &channels[scan_index],
+ chans[c], 0, scan_index, false);
+ scan_index++;
}
- stm32_adc_chan_init_one(indio_dev, &channels[scan_index],
- chans[c], 0, scan_index, false);
- scan_index++;
}
if (adc->nsmps > 0) {
@@ -2306,7 +2310,7 @@ static int stm32_adc_chan_fw_init(struct
if (legacy)
ret = stm32_adc_legacy_chan_init(indio_dev, adc, channels,
- num_channels);
+ timestamping ? num_channels - 1 : num_channels);
else
ret = stm32_adc_generic_chan_init(indio_dev, adc, channels);
if (ret < 0)
