iio: mlx90614: Support devices with dual IR sensor

The model is detected by reading the EEPROM configuration during
probing.
Signed-off-by: Vianney le Clément de Saint-Marcq <vianney.leclement@essensium.com>
Cc: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/temperature/mlx90614.c

@@ -2,6 +2,7 @@
  * mlx90614.c - Support for Melexis MLX90614 contactless IR temperature sensor
  *
  * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
+ * Copyright (c) 2015 Essensium NV
  *
  * This file is subject to the terms and conditions of version 2 of
  * the GNU General Public License.  See the file COPYING in the main
@@ -59,26 +60,34 @@ static int mlx90614_read_raw(struct iio_dev *indio_dev,
 			    int *val2, long mask)
 {
 	struct mlx90614_data *data = iio_priv(indio_dev);
+	u8 cmd;
 	s32 ret;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW: /* 0.02K / LSB */
 		switch (channel->channel2) {
 		case IIO_MOD_TEMP_AMBIENT:
-			ret = i2c_smbus_read_word_data(data->client,
-			    MLX90614_TA);
-			if (ret < 0)
-				return ret;
+			cmd = MLX90614_TA;
 			break;
 		case IIO_MOD_TEMP_OBJECT:
-			ret = i2c_smbus_read_word_data(data->client,
-			    MLX90614_TOBJ1);
-			if (ret < 0)
-				return ret;
+			switch (channel->channel) {
+			case 0:
+				cmd = MLX90614_TOBJ1;
+				break;
+			case 1:
+				cmd = MLX90614_TOBJ2;
+				break;
+			default:
+				return -EINVAL;
+			}
 			break;
 		default:
 			return -EINVAL;
 		}
+
+		ret = i2c_smbus_read_word_data(data->client, cmd);
+		if (ret < 0)
+			return ret;
 		*val = ret;
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_OFFSET:
@@ -110,6 +119,16 @@ static const struct iio_chan_spec mlx90614_channels[] = {
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
 		    BIT(IIO_CHAN_INFO_SCALE),
 	},
+	{
+		.type = IIO_TEMP,
+		.indexed = 1,
+		.modified = 1,
+		.channel = 1,
+		.channel2 = IIO_MOD_TEMP_OBJECT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
+		    BIT(IIO_CHAN_INFO_SCALE),
+	},
 };
 
 static const struct iio_info mlx90614_info = {
@@ -117,11 +136,25 @@ static const struct iio_info mlx90614_info = {
 	.driver_module = THIS_MODULE,
 };
 
+/* Return 0 for single sensor, 1 for dual sensor, <0 on error. */
+static int mlx90614_probe_num_ir_sensors(struct i2c_client *client)
+{
+	s32 ret;
+
+	ret = i2c_smbus_read_word_data(client, MLX90614_CONFIG);
+
+	if (ret < 0)
+		return ret;
+
+	return (ret & MLX90614_CONFIG_DUAL_MASK) ? 1 : 0;
+}
+
 static int mlx90614_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
 	struct iio_dev *indio_dev;
 	struct mlx90614_data *data;
+	int ret;
 
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
 		return -ENODEV;
@@ -139,8 +172,21 @@ static int mlx90614_probe(struct i2c_client *client,
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->info = &mlx90614_info;
 
-	indio_dev->channels = mlx90614_channels;
-	indio_dev->num_channels = ARRAY_SIZE(mlx90614_channels);
+	ret = mlx90614_probe_num_ir_sensors(client);
+	switch (ret) {
+	case 0:
+		dev_dbg(&client->dev, "Found single sensor");
+		indio_dev->channels = mlx90614_channels;
+		indio_dev->num_channels = 2;
+		break;
+	case 1:
+		dev_dbg(&client->dev, "Found dual sensor");
+		indio_dev->channels = mlx90614_channels;
+		indio_dev->num_channels = 3;
+		break;
+	default:
+		return ret;
+	}
 
 	return iio_device_register(indio_dev);
 }
@@ -170,5 +216,6 @@ static struct i2c_driver mlx90614_driver = {
 module_i2c_driver(mlx90614_driver);
 
 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
+MODULE_AUTHOR("Vianney le Clément de Saint-Marcq <vianney.leclement@essensium.com>");
 MODULE_DESCRIPTION("Melexis MLX90614 contactless IR temperature sensor driver");
 MODULE_LICENSE("GPL");