iio:dac:ad5686: Add AD5672R/76/76R/84R/86R support

The AD5684R/AD5686R are a family of 4 channel DACs with 12-bit, 14-bit and
16-bit precision respectively. The devices come either with a built-in
reference or no built-in reference.

The AD5672R/AD5676/AD5676R are similar, except that they have 8 channels
instead of 4.

Datasheets:
http://www.analog.com/media/en/technical-documentation/data-sheets/AD5672R_5676R.pdf
http://www.analog.com/media/en/technical-documentation/data-sheets/AD5686R_5685R_5684R.pdf

Signed-off-by: Stefan Popa <stefan.popa@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/dac/ad5686.c

@@ -87,9 +87,14 @@ struct ad5686_state {
  */
 
 enum ad5686_supported_device_ids {
+	ID_AD5672R,
+	ID_AD5676,
+	ID_AD5676R,
 	ID_AD5684,
+	ID_AD5684R,
 	ID_AD5685R,
 	ID_AD5686,
+	ID_AD5686R
 };
 static int ad5686_spi_write(struct ad5686_state *st,
 			     u8 cmd, u8 addr, u16 val, u8 shift)
@@ -293,15 +298,47 @@ static struct iio_chan_spec name[] = {				\
 		AD5868_CHANNEL(3, 8, bits, _shift),		\
 }
 
+#define DECLARE_AD5676_CHANNELS(name, bits, _shift)		\
+static struct iio_chan_spec name[] = {				\
+		AD5868_CHANNEL(0, 0, bits, _shift),		\
+		AD5868_CHANNEL(1, 1, bits, _shift),		\
+		AD5868_CHANNEL(2, 2, bits, _shift),		\
+		AD5868_CHANNEL(3, 3, bits, _shift),		\
+		AD5868_CHANNEL(4, 4, bits, _shift),		\
+		AD5868_CHANNEL(5, 5, bits, _shift),		\
+		AD5868_CHANNEL(6, 6, bits, _shift),		\
+		AD5868_CHANNEL(7, 7, bits, _shift),		\
+}
+
+DECLARE_AD5676_CHANNELS(ad5672_channels, 12, 4);
+DECLARE_AD5676_CHANNELS(ad5676_channels, 16, 0);
 DECLARE_AD5686_CHANNELS(ad5684_channels, 12, 4);
 DECLARE_AD5686_CHANNELS(ad5685r_channels, 14, 2);
 DECLARE_AD5686_CHANNELS(ad5686_channels, 16, 0);
 
 static const struct ad5686_chip_info ad5686_chip_info_tbl[] = {
+	[ID_AD5672R] = {
+		.channels = ad5672_channels,
+		.int_vref_mv = 2500,
+		.num_channels = 8,
+	},
+	[ID_AD5676] = {
+		.channels = ad5676_channels,
+		.num_channels = 8,
+	},
+	[ID_AD5676R] = {
+		.channels = ad5676_channels,
+		.int_vref_mv = 2500,
+		.num_channels = 8,
+	},
 	[ID_AD5684] = {
 		.channels = ad5684_channels,
 		.num_channels = 4,
+	},
+	[ID_AD5684R] = {
+		.channels = ad5684_channels,
 		.int_vref_mv = 2500,
+		.num_channels = 4,
 	},
 	[ID_AD5685R] = {
 		.channels = ad5685r_channels,
@@ -311,7 +348,11 @@ static const struct ad5686_chip_info ad5686_chip_info_tbl[] = {
 	[ID_AD5686] = {
 		.channels = ad5686_channels,
 		.num_channels = 4,
+	},
+	[ID_AD5686R] = {
+		.channels = ad5686_channels,
 		.int_vref_mv = 2500,
+		.num_channels = 4,
 	},
 };
 
@@ -391,10 +432,15 @@ static int ad5686_remove(struct spi_device *spi)
 }
 
 static const struct spi_device_id ad5686_id[] = {
+	{"ad5672r", ID_AD5672R},
+	{"ad5676", ID_AD5676},
+	{"ad5676r", ID_AD5676R},
 	{"ad5684", ID_AD5684},
+	{"ad5684r", ID_AD5684R},
 	{"ad5685", ID_AD5685R}, /* Does not exist */
 	{"ad5685r", ID_AD5685R},
 	{"ad5686", ID_AD5686},
+	{"ad5686r", ID_AD5686R},
 	{}
 };
 MODULE_DEVICE_TABLE(spi, ad5686_id);