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

BugLink: https://bugs.launchpad.net/bugs/1836802
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>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
index 2f7cd28223164dcf06c8e82c9ccb8b7328fa902a..9cac79222008ba8ae1e92baf73f45b6ce7152b99 100644 (file)
--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -248,12 +248,14 @@ 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++;
        }