iio:ad5064: Add support for ltc2617 and similar devices

The Linear Technology LTC2606, LTC2607, LTC2609, LTC2616, LTC2617,
LTC2619, LTC2626, LTC2627 and LTC2629 devices are very similar
to the AD5064 device.

This patch adds support for those devices.

Datasheet for LTC devices:
LTC2606, LTC2616, LTC2626: http://www.linear.com/docs/6398
LTC2607, LTC2617, LTC2627: http://www.linear.com/docs/8977
LTC2709, LTC2619, LTC2629: http://www.linear.com/docs/8477

Signed-off-by: Marc Andre <marc.andre@netline.ch>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Documentation/ABI/testing/sysfs-bus-iio

@@ -496,6 +496,7 @@ Description:
 		1kohm_to_gnd: connected to ground via an 1kOhm resistor,
 		6kohm_to_gnd: connected to ground via a 6kOhm resistor,
 		20kohm_to_gnd: connected to ground via a 20kOhm resistor,
+		90kohm_to_gnd: connected to ground via a 90kOhm resistor,
 		100kohm_to_gnd: connected to ground via an 100kOhm resistor,
 		125kohm_to_gnd: connected to ground via an 125kOhm resistor,
 		500kohm_to_gnd: connected to ground via a 500kOhm resistor,

drivers/iio/dac/ad5064.c

@@ -1,6 +1,8 @@
 /*
  * AD5024, AD5025, AD5044, AD5045, AD5064, AD5064-1, AD5065, AD5628, AD5629R,
- * AD5648, AD5666, AD5668, AD5669R Digital to analog converters driver
+ * AD5648, AD5666, AD5668, AD5669R, LTC2606, LTC2607, LTC2609, LTC2616,
+ * LTC2617, LTC2619, LTC2626, LTC2627, LTC2629 Digital to analog converters
+ * driver
  *
  * Copyright 2011 Analog Devices Inc.
  *
@@ -126,6 +128,15 @@ enum ad5064_type {
 	ID_AD5668_2,
 	ID_AD5669_1,
 	ID_AD5669_2,
+	ID_LTC2606,
+	ID_LTC2607,
+	ID_LTC2609,
+	ID_LTC2616,
+	ID_LTC2617,
+	ID_LTC2619,
+	ID_LTC2626,
+	ID_LTC2627,
+	ID_LTC2629,
 };
 
 static int ad5064_write(struct ad5064_state *st, unsigned int cmd,
@@ -164,6 +175,10 @@ static const char * const ad5064_powerdown_modes[] = {
 	"three_state",
 };
 
+static const char * const ltc2617_powerdown_modes[] = {
+	"90kohm_to_gnd",
+};
+
 static int ad5064_get_powerdown_mode(struct iio_dev *indio_dev,
 	const struct iio_chan_spec *chan)
 {
@@ -194,6 +209,13 @@ static const struct iio_enum ad5064_powerdown_mode_enum = {
 	.set = ad5064_set_powerdown_mode,
 };
 
+static const struct iio_enum ltc2617_powerdown_mode_enum = {
+	.items = ltc2617_powerdown_modes,
+	.num_items = ARRAY_SIZE(ltc2617_powerdown_modes),
+	.get = ad5064_get_powerdown_mode,
+	.set = ad5064_set_powerdown_mode,
+};
+
 static ssize_t ad5064_read_dac_powerdown(struct iio_dev *indio_dev,
 	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 {
@@ -304,6 +326,18 @@ static const struct iio_chan_spec_ext_info ad5064_ext_info[] = {
 	{ },
 };
 
+static const struct iio_chan_spec_ext_info ltc2617_ext_info[] = {
+	{
+		.name = "powerdown",
+		.read = ad5064_read_dac_powerdown,
+		.write = ad5064_write_dac_powerdown,
+		.shared = IIO_SEPARATE,
+	},
+	IIO_ENUM("powerdown_mode", IIO_SEPARATE, &ltc2617_powerdown_mode_enum),
+	IIO_ENUM_AVAILABLE("powerdown_mode", &ltc2617_powerdown_mode_enum),
+	{ },
+};
+
 #define AD5064_CHANNEL(chan, addr, bits, _shift, _ext_info) {		\
 	.type = IIO_VOLTAGE,					\
 	.indexed = 1,						\
@@ -350,6 +384,10 @@ static DECLARE_AD5065_CHANNELS(ad5065_channels, 16, 4, ad5064_ext_info);
 static DECLARE_AD5064_CHANNELS(ad5629_channels, 12, 4, ad5064_ext_info);
 static DECLARE_AD5064_CHANNELS(ad5669_channels, 16, 0, ad5064_ext_info);
 
+static DECLARE_AD5064_CHANNELS(ltc2607_channels, 16, 0, ltc2617_ext_info);
+static DECLARE_AD5064_CHANNELS(ltc2617_channels, 14, 2, ltc2617_ext_info);
+static DECLARE_AD5064_CHANNELS(ltc2627_channels, 12, 4, ltc2617_ext_info);
+
 static const struct ad5064_chip_info ad5064_chip_info_tbl[] = {
 	[ID_AD5024] = {
 		.shared_vref = false,
@@ -458,6 +496,69 @@ static const struct ad5064_chip_info ad5064_chip_info_tbl[] = {
 		.channels = ad5669_channels,
 		.num_channels = 8,
 	},
+	[ID_LTC2606] = {
+		.shared_vref = true,
+		.internal_vref = 0,
+		.channels = ltc2607_channels,
+		.num_channels = 1,
+		.powerdown_ltc = true,
+	},
+	[ID_LTC2607] = {
+		.shared_vref = true,
+		.internal_vref = 0,
+		.channels = ltc2607_channels,
+		.num_channels = 2,
+		.powerdown_ltc = true,
+	},
+	[ID_LTC2609] = {
+		.shared_vref = false,
+		.internal_vref = 0,
+		.channels = ltc2607_channels,
+		.num_channels = 4,
+		.powerdown_ltc = true,
+	},
+	[ID_LTC2616] = {
+		.shared_vref = true,
+		.internal_vref = 0,
+		.channels = ltc2617_channels,
+		.num_channels = 1,
+		.powerdown_ltc = true,
+	},
+	[ID_LTC2617] = {
+		.shared_vref = true,
+		.internal_vref = 0,
+		.channels = ltc2617_channels,
+		.num_channels = 2,
+		.powerdown_ltc = true,
+	},
+	[ID_LTC2619] = {
+		.shared_vref = false,
+		.internal_vref = 0,
+		.channels = ltc2617_channels,
+		.num_channels = 4,
+		.powerdown_ltc = true,
+	},
+	[ID_LTC2626] = {
+		.shared_vref = true,
+		.internal_vref = 0,
+		.channels = ltc2627_channels,
+		.num_channels = 1,
+		.powerdown_ltc = true,
+	},
+	[ID_LTC2627] = {
+		.shared_vref = true,
+		.internal_vref = 0,
+		.channels = ltc2627_channels,
+		.num_channels = 2,
+		.powerdown_ltc = true,
+	},
+	[ID_LTC2629] = {
+		.shared_vref = false,
+		.internal_vref = 0,
+		.channels = ltc2627_channels,
+		.num_channels = 4,
+		.powerdown_ltc = true,
+	},
 };
 
 static inline unsigned int ad5064_num_vref(struct ad5064_state *st)
@@ -668,6 +769,15 @@ static const struct i2c_device_id ad5064_i2c_ids[] = {
 	{"ad5669-1", ID_AD5669_1},
 	{"ad5669-2", ID_AD5669_2},
 	{"ad5669-3", ID_AD5669_2}, /* similar enough to ad5669-2 */
+	{"ltc2606", ID_LTC2606},
+	{"ltc2607", ID_LTC2607},
+	{"ltc2609", ID_LTC2609},
+	{"ltc2616", ID_LTC2616},
+	{"ltc2617", ID_LTC2617},
+	{"ltc2619", ID_LTC2619},
+	{"ltc2626", ID_LTC2626},
+	{"ltc2627", ID_LTC2627},
+	{"ltc2629", ID_LTC2629},
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, ad5064_i2c_ids);