iio: max517: Add support for MAX520 and MAX521 chips.

MAX520 and MAX521 are protocol-compatible with the already supported
chips, just have more channels.
Signed-off-by: Antonio Fiol <antonio@fiol.es>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/dac/Kconfig

@@ -143,11 +143,16 @@ config AD7303
 	  ad7303.
 
 config MAX517
-	tristate "Maxim MAX517/518/519 DAC driver"
+	tristate "Maxim MAX517/518/519/520/521 DAC driver"
 	depends on I2C
 	help
-	  If you say yes here you get support for the Maxim chips MAX517,
-	  MAX518 and MAX519 (I2C 8-Bit DACs with rail-to-rail outputs).
+	  If you say yes here you get support for the following Maxim chips
+	  (I2C 8-Bit DACs with rail-to-rail outputs):
+	  MAX517 - Single channel, single reference
+	  MAX518 - Dual channel, ref=Vdd
+	  MAX519 - Dual channel, dual reference
+	  MAX520 - Quad channel, quad reference
+	  MAX521 - Octal channel, independent ref for ch0-3, shared ref for ch4-7
 
 	  This driver can also be built as a module.  If so, the module
 	  will be called max517.

drivers/iio/dac/max517.c

@@ -39,11 +39,13 @@ enum max517_device_ids {
 	ID_MAX517,
 	ID_MAX518,
 	ID_MAX519,
+	ID_MAX520,
+	ID_MAX521,
 };
 
 struct max517_data {
 	struct i2c_client	*client;
-	unsigned short		vref_mv[2];
+	unsigned short		vref_mv[8];
 };
 
 /*
@@ -149,7 +151,13 @@ static const struct iio_info max517_info = {
 
 static const struct iio_chan_spec max517_channels[] = {
 	MAX517_CHANNEL(0),
-	MAX517_CHANNEL(1)
+	MAX517_CHANNEL(1),
+	MAX517_CHANNEL(2),
+	MAX517_CHANNEL(3),
+	MAX517_CHANNEL(4),
+	MAX517_CHANNEL(5),
+	MAX517_CHANNEL(6),
+	MAX517_CHANNEL(7),
 };
 
 static int max517_probe(struct i2c_client *client,
@@ -158,6 +166,7 @@ static int max517_probe(struct i2c_client *client,
 	struct max517_data *data;
 	struct iio_dev *indio_dev;
 	struct max517_platform_data *platform_data = client->dev.platform_data;
+	int chan;
 
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 	if (!indio_dev)
@@ -169,11 +178,21 @@ static int max517_probe(struct i2c_client *client,
 	/* establish that the iio_dev is a child of the i2c device */
 	indio_dev->dev.parent = &client->dev;
 
-	/* reduced channel set for MAX517 */
-	if (id->driver_data == ID_MAX517)
-		indio_dev->num_channels = 1;
-	else
+	switch (id->driver_data) {
+	case ID_MAX521:
+		indio_dev->num_channels = 8;
+		break;
+	case ID_MAX520:
+		indio_dev->num_channels = 4;
+		break;
+	case ID_MAX519:
+	case ID_MAX518:
 		indio_dev->num_channels = 2;
+		break;
+	default:  /* single channel for MAX517 */
+		indio_dev->num_channels = 1;
+		break;
+	}
 	indio_dev->channels = max517_channels;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->info = &max517_info;
@@ -182,11 +201,11 @@ static int max517_probe(struct i2c_client *client,
 	 * Reference voltage on MAX518 and default is 5V, else take vref_mv
 	 * from platform_data
 	 */
-	if (id->driver_data == ID_MAX518 || !platform_data) {
-		data->vref_mv[0] = data->vref_mv[1] = 5000; /* mV */
-	} else {
-		data->vref_mv[0] = platform_data->vref_mv[0];
-		data->vref_mv[1] = platform_data->vref_mv[1];
+	for (chan = 0; chan < indio_dev->num_channels; chan++) {
+		if (id->driver_data == ID_MAX518 || !platform_data)
+			data->vref_mv[chan] = 5000; /* mV */
+		else
+			data->vref_mv[chan] = platform_data->vref_mv[chan];
 	}
 
 	return iio_device_register(indio_dev);
@@ -202,6 +221,8 @@ static const struct i2c_device_id max517_id[] = {
 	{ "max517", ID_MAX517 },
 	{ "max518", ID_MAX518 },
 	{ "max519", ID_MAX519 },
+	{ "max520", ID_MAX520 },
+	{ "max521", ID_MAX521 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, max517_id);
@@ -218,5 +239,5 @@ static struct i2c_driver max517_driver = {
 module_i2c_driver(max517_driver);
 
 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
-MODULE_DESCRIPTION("MAX517/MAX518/MAX519 8-bit DAC");
+MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC");
 MODULE_LICENSE("GPL");

include/linux/iio/dac/max517.h

@@ -9,7 +9,7 @@
 #define IIO_DAC_MAX517_H_
 
 struct max517_platform_data {
-	u16				vref_mv[2];
+	u16				vref_mv[8];
 };
 
 #endif /* IIO_DAC_MAX517_H_ */