[PATCH 07/10] iio: adc: at91-sama5d2_adc: fix differential channels in triggered mode

[Eugen.Hristev]

From: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx>

The differential channels require writing the channel offset register (COR).
Otherwise they do not work in differential mode.
The configuration of COR is missing in triggered mode.

Signed-off-by: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx>
---
 drivers/iio/adc/at91-sama5d2_adc.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index a6b4dff..ccffa48 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -900,6 +900,7 @@ static int at91_adc_buffer_postenable(struct iio_dev *indio)
 
 	for_each_set_bit(bit, indio->active_scan_mask, indio->num_channels) {
 		struct iio_chan_spec const *chan = at91_adc_chan_get(indio, bit);
+		u32 cor;
 
 		if (!chan)
 			continue;
@@ -908,6 +909,17 @@ static int at91_adc_buffer_postenable(struct iio_dev *indio)
 		    chan->type == IIO_PRESSURE)
 			continue;
 
+		cor = at91_adc_readl(st, AT91_SAMA5D2_COR);
+
+		if (chan->differential)
+			cor |= (BIT(chan->channel) | BIT(chan->channel2)) <<
+			       AT91_SAMA5D2_COR_DIFF_OFFSET;
+		else
+			cor &= ~(BIT(chan->channel) <<
+			       AT91_SAMA5D2_COR_DIFF_OFFSET);
+
+		at91_adc_writel(st, AT91_SAMA5D2_COR, cor);
+
 		at91_adc_writel(st, AT91_SAMA5D2_CHER, BIT(chan->channel));
 		if (use_irq) {
 			at91_adc_writel(st, AT91_SAMA5D2_IER,
-- 
2.7.4