iio: adc: ad7887: Cleanup channel assignment

The channels specification assignment in chip info was simplified.
This patch makes supporting other devices by this driver easier.
Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ad7887.c

@@ -43,11 +43,17 @@ enum ad7887_channels {
 /**
  * struct ad7887_chip_info - chip specifc information
  * @int_vref_mv:	the internal reference voltage
- * @channel:		channel specification
+ * @channels:		channels specification
+ * @num_channels:	number of channels
+ * @dual_channels:	channels specification in dual mode
+ * @num_dual_channels:	number of channels in dual mode
  */
 struct ad7887_chip_info {
 	u16				int_vref_mv;
-	struct iio_chan_spec		channel[3];
+	const struct iio_chan_spec	*channels;
+	unsigned int			num_channels;
+	const struct iio_chan_spec	*dual_channels;
+	unsigned int			num_dual_channels;
 };
 
 struct ad7887_state {
@@ -183,45 +189,43 @@ static int ad7887_read_raw(struct iio_dev *indio_dev,
 	return -EINVAL;
 }
 
+#define AD7887_CHANNEL(x) { \
+	.type = IIO_VOLTAGE, \
+	.indexed = 1, \
+	.channel = (x), \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+	.address = (x), \
+	.scan_index = (x), \
+	.scan_type = { \
+		.sign = 'u', \
+		.realbits = 12, \
+		.storagebits = 16, \
+		.shift = 0, \
+		.endianness = IIO_BE, \
+	}, \
+}
+
+static const struct iio_chan_spec ad7887_channels[] = {
+	AD7887_CHANNEL(0),
+	IIO_CHAN_SOFT_TIMESTAMP(1),
+};
+
+static const struct iio_chan_spec ad7887_dual_channels[] = {
+	AD7887_CHANNEL(0),
+	AD7887_CHANNEL(1),
+	IIO_CHAN_SOFT_TIMESTAMP(2),
+};
 
 static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
 	/*
 	 * More devices added in future
 	 */
 	[ID_AD7887] = {
-		.channel[0] = {
-			.type = IIO_VOLTAGE,
-			.indexed = 1,
-			.channel = 1,
-			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-			.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
-			.address = 1,
-			.scan_index = 1,
-			.scan_type = {
-				.sign = 'u',
-				.realbits = 12,
-				.storagebits = 16,
-				.shift = 0,
-				.endianness = IIO_BE,
-			},
-		},
-		.channel[1] = {
-			.type = IIO_VOLTAGE,
-			.indexed = 1,
-			.channel = 0,
-			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-			.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
-			.address = 0,
-			.scan_index = 0,
-			.scan_type = {
-				.sign = 'u',
-				.realbits = 12,
-				.storagebits = 16,
-				.shift = 0,
-				.endianness = IIO_BE,
-			},
-		},
-		.channel[2] = IIO_CHAN_SOFT_TIMESTAMP(2),
+		.channels = ad7887_channels,
+		.num_channels = ARRAY_SIZE(ad7887_channels),
+		.dual_channels = ad7887_dual_channels,
+		.num_dual_channels = ARRAY_SIZE(ad7887_dual_channels),
 		.int_vref_mv = 2500,
 	},
 };
@@ -306,11 +310,11 @@ static int ad7887_probe(struct spi_device *spi)
 		spi_message_init(&st->msg[AD7887_CH1]);
 		spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);
 
-		indio_dev->channels = st->chip_info->channel;
-		indio_dev->num_channels = 3;
+		indio_dev->channels = st->chip_info->dual_channels;
+		indio_dev->num_channels = st->chip_info->num_dual_channels;
 	} else {
-		indio_dev->channels = &st->chip_info->channel[1];
-		indio_dev->num_channels = 2;
+		indio_dev->channels = st->chip_info->channels;
+		indio_dev->num_channels = st->chip_info->num_channels;
 	}
 
 	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,