iio: adc: at91: fix wrong channel number in triggered buffer mode

commit aea835f2dc8a682942b859179c49ad1841a6c8b9 upstream.

When channels are registered, the hardware channel number is not the
actual iio channel number.
This is because the driver is probed with a certain number of accessible
channels. Some pins are routed and some not, depending on the description of
the board in the DT.
Because of that, channels 0,1,2,3 can correspond to hardware channels
2,3,4,5 for example.
In the buffered triggered case, we need to do the translation accordingly.
Fixed the channel number to stop reading the wrong channel.

Fixes: 0e589d5fb ("ARM: AT91: IIO: Add AT91 ADC driver.")
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
index 5b8d6b60d45ac4d51fbb5569bdca5df260efef67..e3e2155b038652db151ee2b6d0540bc95ac1a06e 100644 (file)
--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -247,12 +247,14 @@ static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
        struct iio_poll_func *pf = p;
        struct iio_dev *idev = pf->indio_dev;
        struct at91_adc_state *st = iio_priv(idev);
+       struct iio_chan_spec const *chan;
        int i, j = 0;
 
        for (i = 0; i < idev->masklength; i++) {
                if (!test_bit(i, idev->active_scan_mask))
                        continue;
-               st->buffer[j] = at91_adc_readl(st, AT91_ADC_CHAN(st, i));
+               chan = idev->channels + i;
+               st->buffer[j] = at91_adc_readl(st, AT91_ADC_CHAN(st, chan->channel));
                j++;
        }