iio: dac: ad5686: fix triggered buffer support

Sample for the first channel was repeated over all the channels.
Endianness conversion is already taken care inside the write function
implementation. Also, IIO_TRIGGERED_BUFFER dependency is missing in
Kconfig.

Signed-off-by: Rodrigo Alencar <rodrigo.alencar@analog.com>

Author: rodrigo455

drivers/iio/dac/Kconfig

@@ -224,6 +224,8 @@ config LTC2688
 
 config AD5686
 	tristate
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
 
 config AD5686_SPI
 	tristate "Analog Devices AD5686 and similar multi-channel DACs (SPI)"

drivers/iio/dac/ad5686.c

@@ -511,22 +511,18 @@ static irqreturn_t ad5686_trigger_handler(int irq, void *p)
 	const struct iio_chan_spec *chan;
 	struct iio_buffer *buffer = indio_dev->buffer;
 	struct ad5686_state *st = iio_priv(indio_dev);
-	u8 sample[2];
-	unsigned int i;
-	u16 val;
-	int ret;
+	u16 val[AD5686_MAX_CHANNELS];
+	int ret, ch, i = 0;
 
-	ret = iio_pop_from_buffer(buffer, sample);
+	ret = iio_pop_from_buffer(buffer, val);
 	if (ret < 0)
 		goto out;
 
 	mutex_lock(&st->lock);
-	iio_for_each_active_channel(indio_dev, i) {
-		val = (sample[1] << 8) + sample[0];
-
-		chan = &indio_dev->channels[i];
+	iio_for_each_active_channel(indio_dev, ch) {
+		chan = &indio_dev->channels[ch];
 		ret = st->write(st, AD5686_CMD_WRITE_INPUT_N_UPDATE_N,
-				chan->address, val << chan->scan_type.shift);
+				chan->address, val[i++] << chan->scan_type.shift);
 	}
 	mutex_unlock(&st->lock);
 

drivers/iio/dac/ad5686.h

@@ -25,6 +25,7 @@
 
 #define AD5686_ADDR_DAC(chan)			(0x1 << (chan))
 #define AD5686_ADDR_ALL_DAC			0xF
+#define AD5686_MAX_CHANNELS			16
 
 #define AD5686_CMD_NOOP				0x0
 #define AD5686_CMD_WRITE_INPUT_N		0x1