[PATCH v2 1/3] iio: adc: at91-sama5d2_adc: fix differential channels in triggered mode

Eugen.Hristev
2020-01-13T12:07:21Z

From: Eugen Hristev <eugen.hristev@microchip.com>

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.

Fixes: 5e1a1da0f8c9 ("iio: adc: at91-sama5d2_adc: add hw trigger and buffer support")
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
---
Changes in v2:
- moved to the start of the list

drivers/iio/adc/at91-sama5d2_adc.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index e1850f3..2a6950a 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -723,6 +723,7 @@ static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)

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;
@@ -732,6 +733,20 @@ static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
continue;

if (state) {
+ 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);
+ }
+
+ if (state) {
at91_adc_writel(st, AT91_SAMA5D2_CHER,
BIT(chan->channel));
/* enable irq only if not using DMA */
--
2.7.4