[PATCH v2 3/5] iio: mcp9600: Add compatibility for mcp9601

[Ben Collins <bcollins@watter.com>]

MCP9601 is a super set of MCP9600. The drivers works without changes
on this chipset.

Signed-off-by: Ben Collins <bcollins@watter.com>
---
 drivers/iio/temperature/Kconfig   |  6 +++---
 drivers/iio/temperature/mcp9600.c | 31 +++++++++++++++++++++++--------
 2 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig
index 1244d8e17d504..2a5d04b1d1c87 100644
--- a/drivers/iio/temperature/Kconfig
+++ b/drivers/iio/temperature/Kconfig
@@ -173,11 +173,11 @@ config MAX31865
 	  will be called max31865.
 
 config MCP9600
-	tristate "MCP9600 thermocouple EMF converter"
+	tristate "MCP9600 and similar thermocouple EMF converters"
 	depends on I2C
 	help
-	  If you say yes here you get support for MCP9600
-	  thermocouple EMF converter connected via I2C.
+	  If you say yes here you get support for MCP9600, MCP9601, and
+	  similar thermocouple EMF converters connected via I2C.
 
 	  This driver can also be built as a module. If so, the module
 	  will be called mcp9600.
diff --git a/drivers/iio/temperature/mcp9600.c b/drivers/iio/temperature/mcp9600.c
index d53703c089031..104bc83de6da7 100644
--- a/drivers/iio/temperature/mcp9600.c
+++ b/drivers/iio/temperature/mcp9600.c
@@ -42,6 +42,7 @@
 
 /* MCP9600 device id value */
 #define MCP9600_DEVICE_ID_MCP9600	0x40
+#define MCP9600_DEVICE_ID_MCP9601	0x41
 
 #define MCP9600_ALERT_COUNT		4
 
@@ -418,14 +419,26 @@ static int mcp9600_probe(struct i2c_client *client)
 {
 	struct iio_dev *indio_dev;
 	struct mcp9600_data *data;
-	int ret, ch_sel;
+	int ret, ch_sel, dev_id;
+
+	dev_id = i2c_smbus_read_byte_data(client, MCP9600_DEVICE_ID);
+	if (dev_id < 0)
+		return dev_err_probe(&client->dev, dev_id,
+				     "Failed to read device ID\n");
+
+	switch (dev_id) {
+	case MCP9600_DEVICE_ID_MCP9600:
+	case MCP9600_DEVICE_ID_MCP9601:
+		if (dev_id != id->driver_data)
+			dev_warn(&client->dev,
+				 "Expected id %x but detected %x. Ensure dt is correct\n",
+				 (u8)id->driver_data, (u8)dev_id);
+		break;
 
-	ret = i2c_smbus_read_byte_data(client, MCP9600_DEVICE_ID);
-	if (ret < 0)
-		return dev_err_probe(&client->dev, ret, "Failed to read device ID\n");
-	if (ret != MCP9600_DEVICE_ID_MCP9600)
-		dev_warn(&client->dev, "Expected ID %x, got %x\n",
-				MCP9600_DEVICE_ID_MCP9600, ret);
+	default:
+		dev_warn(&client->dev, "Unknown id %x, using %x\n", (u8)dev_id,
+			(u8)id->driver_data);
+	}
 
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 	if (!indio_dev)
@@ -448,13 +461,15 @@ static int mcp9600_probe(struct i2c_client *client)
 }
 
 static const struct i2c_device_id mcp9600_id[] = {
-	{ "mcp9600" },
+	{ "mcp9600", MCP9600_DEVICE_ID_MCP9600 },
+	{ "mcp9601", MCP9600_DEVICE_ID_MCP9601 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, mcp9600_id);
 
 static const struct of_device_id mcp9600_of_match[] = {
 	{ .compatible = "microchip,mcp9600" },
+	{ .compatible = "microchip,mcp9601" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, mcp9600_of_match);
-- 
2.50.1