From: Sean Nyekjaer sean@geanix.com
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@geanix.com Reviewed-by: Olivier Moysan olivier.moysan@foss.st.com Link: https://lore.kernel.org/r/20230503162029.3654093-2-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 | 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)