drivers: sensor: lsm303dlhc_mag: Fix gain factor

The magnetometer on the LSM303DLHC has a different gain conversion
factor for LSB to Gauss for the Z axis than it does for X, Y. This
commit takes into account the different conversion factors, and
adds the correct coefficients for each gain setting and axis.

Signed-off-by: Kevin Townsend <[email protected]>

Author: microbuilder

drivers/sensor/lsm303dlhc_magn/lsm303dlhc_magn.c

@@ -52,11 +52,18 @@ static int lsm303dlhc_sample_fetch(const struct device *dev,
 	return 0;
 }
 
-static void lsm303dlhc_convert(struct sensor_value *val,
+static void lsm303dlhc_convert_xy(struct sensor_value *val,
 			       int64_t raw_val)
 {
-	val->val1 = raw_val / LSM303DLHC_MAGN_LSB_GAUSS;
-	val->val2 = (1000000 * raw_val / LSM303DLHC_MAGN_LSB_GAUSS) % 1000000;
+	val->val1 = raw_val / LSM303DLHC_MAGN_LSB_GAUSS_XY;
+	val->val2 = (1000000 * raw_val / LSM303DLHC_MAGN_LSB_GAUSS_XY) % 1000000;
+}
+
+static void lsm303dlhc_convert_z(struct sensor_value *val,
+			       int64_t raw_val)
+{
+	val->val1 = raw_val / LSM303DLHC_MAGN_LSB_GAUSS_Z;
+	val->val2 = (1000000 * raw_val / LSM303DLHC_MAGN_LSB_GAUSS_Z) % 1000000;
 }
 
 static int lsm303dlhc_channel_get(const struct device *dev,
@@ -67,18 +74,18 @@ static int lsm303dlhc_channel_get(const struct device *dev,
 
 	switch (chan) {
 	case  SENSOR_CHAN_MAGN_X:
-		lsm303dlhc_convert(val, drv_data->magn_x);
+		lsm303dlhc_convert_xy(val, drv_data->magn_x);
 		break;
 	case SENSOR_CHAN_MAGN_Y:
-		lsm303dlhc_convert(val, drv_data->magn_y);
+		lsm303dlhc_convert_xy(val, drv_data->magn_y);
 		break;
 	case SENSOR_CHAN_MAGN_Z:
-		lsm303dlhc_convert(val, drv_data->magn_z);
+		lsm303dlhc_convert_z(val, drv_data->magn_z);
 		break;
 	case SENSOR_CHAN_MAGN_XYZ:
-		lsm303dlhc_convert(val, drv_data->magn_x);
-		lsm303dlhc_convert(val + 1, drv_data->magn_y);
-		lsm303dlhc_convert(val + 2, drv_data->magn_z);
+		lsm303dlhc_convert_xy(val, drv_data->magn_x);
+		lsm303dlhc_convert_xy(val + 1, drv_data->magn_y);
+		lsm303dlhc_convert_z(val + 2, drv_data->magn_z);
 		break;
 	default:
 		return -ENOTSUP;

drivers/sensor/lsm303dlhc_magn/lsm303dlhc_magn.h

@@ -37,19 +37,26 @@
 					LSM303DLHC_MAGN_ODR_SHIFT)
 
 #if	(CONFIG_LSM303DLHC_MAGN_RANGE == 1)
-	#define LSM303DLHC_MAGN_LSB_GAUSS	1100
+	#define LSM303DLHC_MAGN_LSB_GAUSS_XY    1100
+	#define LSM303DLHC_MAGN_LSB_GAUSS_Z     980
 #elif	(CONFIG_LSM303DLHC_MAGN_RANGE == 2)
-	#define LSM303DLHC_MAGN_LSB_GAUSS	760
+	#define LSM303DLHC_MAGN_LSB_GAUSS_XY    855
+	#define LSM303DLHC_MAGN_LSB_GAUSS_Z     760
 #elif	(CONFIG_LSM303DLHC_MAGN_RANGE == 3)
-	#define LSM303DLHC_MAGN_LSB_GAUSS	600
+	#define LSM303DLHC_MAGN_LSB_GAUSS_XY    670
+	#define LSM303DLHC_MAGN_LSB_GAUSS_Z     600
 #elif	(CONFIG_LSM303DLHC_MAGN_RANGE == 4)
-	#define LSM303DLHC_MAGN_LSB_GAUSS	400
+	#define LSM303DLHC_MAGN_LSB_GAUSS_XY    450
+	#define LSM303DLHC_MAGN_LSB_GAUSS_Z     400
 #elif	(CONFIG_LSM303DLHC_MAGN_RANGE == 5)
-	#define LSM303DLHC_MAGN_LSB_GAUSS	355
+	#define LSM303DLHC_MAGN_LSB_GAUSS_XY    400
+	#define LSM303DLHC_MAGN_LSB_GAUSS_Z     355
 #elif	(CONFIG_LSM303DLHC_MAGN_RANGE == 6)
-	#define LSM303DLHC_MAGN_LSB_GAUSS	295
+	#define LSM303DLHC_MAGN_LSB_GAUSS_XY    330
+	#define LSM303DLHC_MAGN_LSB_GAUSS_Z     295
 #elif	(CONFIG_LSM303DLHC_MAGN_RANGE == 7)
-	#define LSM303DLHC_MAGN_LSB_GAUSS	205
+	#define LSM303DLHC_MAGN_LSB_GAUSS_XY    230
+	#define LSM303DLHC_MAGN_LSB_GAUSS_Z     205
 #endif
 
 #define LSM303DLHC_MAGN_FS_SHIFT	5