[PATCH v3 4/4] iio: adc: ltc2497: add LTC2493 support

[Andrei Stancovici via B4 Relay]

From: Andrei Stancovici <andrei.stancovici@xxxxxxxxxx>

The LTC2493 is the 4-channel member of the LTC2499 family: 4 single-ended
inputs or 2 differential pairs, 24-bit result, and the same command
format, internal PTAT temperature sensor, 2x speed mode and line-frequency
rejection as the LTC2499.

Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/2493fe.pdf
Signed-off-by: Andrei Stancovici <andrei.stancovici@xxxxxxxxxx>

---
Changes in v3:
- The channel-set mechanism moved to the preceding patch, so this one
  adds only the LTC2493: its channel table and channel set, its
  chip_info entry, and the I2C and OF identifiers. No chip_info entry of
  an already supported part is touched (Nuno Sá).
- The LTC2493 channel table is defined once, for the speed-mode layout
  the part actually uses; v2 also generated a second variant that
  nothing selected.
- Revalidated on hardware with the full series applied: LTC2493 41/41,
  LTC2499 36/36, LTC2497 24/24.
---
 drivers/iio/adc/ltc2497-core.c | 20 ++++++++++++++++++++
 drivers/iio/adc/ltc2497.c      | 11 +++++++++++
 drivers/iio/adc/ltc2497.h      |  1 +
 3 files changed, 32 insertions(+)

diff --git a/drivers/iio/adc/ltc2497-core.c b/drivers/iio/adc/ltc2497-core.c
index 576a7c0a0f9b..6659f848256c 100644
--- a/drivers/iio/adc/ltc2497-core.c
+++ b/drivers/iio/adc/ltc2497-core.c
@@ -420,6 +420,20 @@ static const struct iio_chan_spec _name[] = {                           \
 LTC2497_DEFINE_CHANNELS(ltc2497core_channel, 0);
 LTC2497_DEFINE_CHANNELS(ltc2497core_channel_samp_freq, BIT(IIO_CHAN_INFO_SAMP_FREQ));
 
+static const struct iio_chan_spec ltc2493_channel[] = {
+	LTC2497_CHAN(0, LTC2497_SGL, "CH0", BIT(IIO_CHAN_INFO_SAMP_FREQ)),
+	LTC2497_CHAN(1, LTC2497_SGL, "CH1", BIT(IIO_CHAN_INFO_SAMP_FREQ)),
+	LTC2497_CHAN(2, LTC2497_SGL, "CH2", BIT(IIO_CHAN_INFO_SAMP_FREQ)),
+	LTC2497_CHAN(3, LTC2497_SGL, "CH3", BIT(IIO_CHAN_INFO_SAMP_FREQ)),
+	LTC2497_CHAN_DIFF(0, LTC2497_DIFF, BIT(IIO_CHAN_INFO_SAMP_FREQ)),
+	LTC2497_CHAN_DIFF(1, LTC2497_DIFF, BIT(IIO_CHAN_INFO_SAMP_FREQ)),
+	LTC2497_CHAN_DIFF(0, LTC2497_DIFF | LTC2497_SIGN,
+			  BIT(IIO_CHAN_INFO_SAMP_FREQ)),
+	LTC2497_CHAN_DIFF(1, LTC2497_DIFF | LTC2497_SIGN,
+			  BIT(IIO_CHAN_INFO_SAMP_FREQ)),
+	LTC2497_TEMP_CHANNEL,
+};
+
 /*
  * The temperature channel is the last entry of each table, so a part without
  * the sensor stops one short of it.
@@ -436,6 +450,12 @@ const struct ltc2497_channel_set ltc2497_chanset_ltc2499 = {
 };
 EXPORT_SYMBOL_NS_GPL(ltc2497_chanset_ltc2499, "LTC2497");
 
+const struct ltc2497_channel_set ltc2497_chanset_ltc2493 = {
+	.channels	= ltc2493_channel,
+	.num_channels	= ARRAY_SIZE(ltc2493_channel),
+};
+EXPORT_SYMBOL_NS_GPL(ltc2497_chanset_ltc2493, "LTC2497");
+
 static const struct iio_info ltc2497core_info = {
 	.read_raw = ltc2497core_read_raw,
 	.read_avail = ltc2497core_read_avail,
diff --git a/drivers/iio/adc/ltc2497.c b/drivers/iio/adc/ltc2497.c
index 984f15eb06f6..3bbb6d91d41c 100644
--- a/drivers/iio/adc/ltc2497.c
+++ b/drivers/iio/adc/ltc2497.c
@@ -19,6 +19,7 @@
 #include "ltc2497.h"
 
 enum ltc2497_chip_type {
+	TYPE_LTC2493,
 	TYPE_LTC2497,
 	TYPE_LTC2499,
 };
@@ -173,6 +174,14 @@ static void ltc2497_remove(struct i2c_client *client)
 }
 
 static const struct ltc2497_chip_info ltc2497_info[] = {
+	[TYPE_LTC2493] = {
+		.resolution = 24,
+		.name = "ltc2493",
+		.channel_set = &ltc2497_chanset_ltc2493,
+		.has_temp = true,
+		.has_speed_mode = true,
+		.has_rejection_mode = true,
+	},
 	[TYPE_LTC2497] = {
 		.resolution = 16,
 		.name = NULL,
@@ -189,6 +198,7 @@ static const struct ltc2497_chip_info ltc2497_info[] = {
 };
 
 static const struct i2c_device_id ltc2497_id[] = {
+	{ .name = "ltc2493", .driver_data = (kernel_ulong_t)&ltc2497_info[TYPE_LTC2493] },
 	{ .name = "ltc2497", .driver_data = (kernel_ulong_t)&ltc2497_info[TYPE_LTC2497] },
 	{ .name = "ltc2499", .driver_data = (kernel_ulong_t)&ltc2497_info[TYPE_LTC2499] },
 	{ }
@@ -196,6 +206,7 @@ static const struct i2c_device_id ltc2497_id[] = {
 MODULE_DEVICE_TABLE(i2c, ltc2497_id);
 
 static const struct of_device_id ltc2497_of_match[] = {
+	{ .compatible = "lltc,ltc2493", .data = &ltc2497_info[TYPE_LTC2493] },
 	{ .compatible = "lltc,ltc2497", .data = &ltc2497_info[TYPE_LTC2497] },
 	{ .compatible = "lltc,ltc2499", .data = &ltc2497_info[TYPE_LTC2499] },
 	{ }
diff --git a/drivers/iio/adc/ltc2497.h b/drivers/iio/adc/ltc2497.h
index 7335c6c0af84..8de35df74f28 100644
--- a/drivers/iio/adc/ltc2497.h
+++ b/drivers/iio/adc/ltc2497.h
@@ -55,6 +55,7 @@ struct ltc2497_channel_set {
 
 extern const struct ltc2497_channel_set ltc2497_chanset_ltc2497;
 extern const struct ltc2497_channel_set ltc2497_chanset_ltc2499;
+extern const struct ltc2497_channel_set ltc2497_chanset_ltc2493;
 
 struct ltc2497_chip_info {
 	const char *name;

-- 
2.43.0