iio: adc: ti-ads8344: Fix channel selection

During initial submission the selection of the channel was done using
the scan_index member of the iio_chan_spec structure. It was an abuse
because this member is supposed to be used with a buffer so it was
removed.

However there was still the need to be able to known how to select a
channel, the correct member to store this information is address.

Thanks to this it is possible to select any other channel than the
channel 0.

Fixes: 8dd2d7c0 ("iio: adc: Add driver for the TI ADS8344 A/DC chips")
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ti-ads8344.c

@@ -32,16 +32,17 @@ struct ads8344 {
 	u8 rx_buf[3];
 };
 
-#define ADS8344_VOLTAGE_CHANNEL(chan, si)				\
+#define ADS8344_VOLTAGE_CHANNEL(chan, addr)				\
 	{								\
 		.type = IIO_VOLTAGE,					\
 		.indexed = 1,						\
 		.channel = chan,					\
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+		.address = addr,					\
 	}
 
-#define ADS8344_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si)			\
+#define ADS8344_VOLTAGE_CHANNEL_DIFF(chan1, chan2, addr)		\
 	{								\
 		.type = IIO_VOLTAGE,					\
 		.indexed = 1,						\
@@ -50,6 +51,7 @@ struct ads8344 {
 		.differential = 1,					\
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+		.address = addr,					\
 	}
 
 static const struct iio_chan_spec ads8344_channels[] = {
@@ -105,7 +107,7 @@ static int ads8344_read_raw(struct iio_dev *iio,
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		mutex_lock(&adc->lock);
-		*value = ads8344_adc_conversion(adc, channel->scan_index,
+		*value = ads8344_adc_conversion(adc, channel->address,
 						channel->differential);
 		mutex_unlock(&adc->lock);
 		if (*value < 0)