[PATCH v2 2/2] iio: adc: at91: fix wrong channel number in triggered buffer mode

On Tue, 25 Sep 2018 15:17:57 +0200
Ludovic Desroches [off-list ref] wrote:

On Mon, Sep 24, 2018 at 10:51:44AM +0300, Eugen Hristev wrote:

quoted

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 <redacted>
Signed-off-by: Eugen Hristev <redacted>  

Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>

Applied to the togreg branch of iio.git and pushed out as testing for the
autobuilders to play with it.

Thanks,

Jonathan

quoted

---
Changes in v2:
- Added 'const' spec to the declaration to avoid build warning

 drivers/iio/adc/at91_adc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
index e3be88e..75d2f73 100644
--- 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++;
 	}
 

-- 
2.7.4