iio: imu: inv_mpu6050: fix temperature reporting using bad unit

Temperature should be reported in milli-degrees, not degrees. Fix
scale and offset values to use the correct unit.

This is a fix for an issue that has been present for a long time.
The fixes tag reflects the point at which the code last changed in a
fashion that would make this fix patch no longer apply.  Backports
will be necessary to fix those elements that predate that patch.

Fixes: 1615fe41 ("iio: imu: mpu6050: Fix FIFO layout for ICM20602")
Cc: stable@vger.kernel.org
Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/inv_mpu6050/inv_mpu_core.c

@@ -117,6 +117,7 @@ static const struct inv_mpu6050_hw hw_info[] = {
 		.reg = &reg_set_6050,
 		.config = &chip_config_6050,
 		.fifo_size = 1024,
+		.temp = {INV_MPU6050_TEMP_OFFSET, INV_MPU6050_TEMP_SCALE},
 	},
 	{
 		.whoami = INV_MPU6500_WHOAMI_VALUE,
@@ -124,6 +125,7 @@ static const struct inv_mpu6050_hw hw_info[] = {
 		.reg = &reg_set_6500,
 		.config = &chip_config_6050,
 		.fifo_size = 512,
+		.temp = {INV_MPU6500_TEMP_OFFSET, INV_MPU6500_TEMP_SCALE},
 	},
 	{
 		.whoami = INV_MPU6515_WHOAMI_VALUE,
@@ -131,6 +133,7 @@ static const struct inv_mpu6050_hw hw_info[] = {
 		.reg = &reg_set_6500,
 		.config = &chip_config_6050,
 		.fifo_size = 512,
+		.temp = {INV_MPU6500_TEMP_OFFSET, INV_MPU6500_TEMP_SCALE},
 	},
 	{
 		.whoami = INV_MPU6000_WHOAMI_VALUE,
@@ -138,6 +141,7 @@ static const struct inv_mpu6050_hw hw_info[] = {
 		.reg = &reg_set_6050,
 		.config = &chip_config_6050,
 		.fifo_size = 1024,
+		.temp = {INV_MPU6050_TEMP_OFFSET, INV_MPU6050_TEMP_SCALE},
 	},
 	{
 		.whoami = INV_MPU9150_WHOAMI_VALUE,
@@ -145,6 +149,7 @@ static const struct inv_mpu6050_hw hw_info[] = {
 		.reg = &reg_set_6050,
 		.config = &chip_config_6050,
 		.fifo_size = 1024,
+		.temp = {INV_MPU6050_TEMP_OFFSET, INV_MPU6050_TEMP_SCALE},
 	},
 	{
 		.whoami = INV_MPU9250_WHOAMI_VALUE,
@@ -152,6 +157,7 @@ static const struct inv_mpu6050_hw hw_info[] = {
 		.reg = &reg_set_6500,
 		.config = &chip_config_6050,
 		.fifo_size = 512,
+		.temp = {INV_MPU6500_TEMP_OFFSET, INV_MPU6500_TEMP_SCALE},
 	},
 	{
 		.whoami = INV_MPU9255_WHOAMI_VALUE,
@@ -159,6 +165,7 @@ static const struct inv_mpu6050_hw hw_info[] = {
 		.reg = &reg_set_6500,
 		.config = &chip_config_6050,
 		.fifo_size = 512,
+		.temp = {INV_MPU6500_TEMP_OFFSET, INV_MPU6500_TEMP_SCALE},
 	},
 	{
 		.whoami = INV_ICM20608_WHOAMI_VALUE,
@@ -166,6 +173,7 @@ static const struct inv_mpu6050_hw hw_info[] = {
 		.reg = &reg_set_6500,
 		.config = &chip_config_6050,
 		.fifo_size = 512,
+		.temp = {INV_ICM20608_TEMP_OFFSET, INV_ICM20608_TEMP_SCALE},
 	},
 	{
 		.whoami = INV_ICM20602_WHOAMI_VALUE,
@@ -173,6 +181,7 @@ static const struct inv_mpu6050_hw hw_info[] = {
 		.reg = &reg_set_icm20602,
 		.config = &chip_config_6050,
 		.fifo_size = 1008,
+		.temp = {INV_ICM20608_TEMP_OFFSET, INV_ICM20608_TEMP_SCALE},
 	},
 };
 
@@ -481,12 +490,8 @@ inv_mpu6050_read_raw(struct iio_dev *indio_dev,
 
 			return IIO_VAL_INT_PLUS_MICRO;
 		case IIO_TEMP:
-			*val = 0;
-			if (st->chip_type == INV_ICM20602)
-				*val2 = INV_ICM20602_TEMP_SCALE;
-			else
-				*val2 = INV_MPU6050_TEMP_SCALE;
-
+			*val = st->hw->temp.scale / 1000000;
+			*val2 = st->hw->temp.scale % 1000000;
 			return IIO_VAL_INT_PLUS_MICRO;
 		case IIO_MAGN:
 			return inv_mpu_magn_get_scale(st, chan, val, val2);
@@ -496,11 +501,7 @@ inv_mpu6050_read_raw(struct iio_dev *indio_dev,
 	case IIO_CHAN_INFO_OFFSET:
 		switch (chan->type) {
 		case IIO_TEMP:
-			if (st->chip_type == INV_ICM20602)
-				*val = INV_ICM20602_TEMP_OFFSET;
-			else
-				*val = INV_MPU6050_TEMP_OFFSET;
-
+			*val = st->hw->temp.offset;
 			return IIO_VAL_INT;
 		default:
 			return -EINVAL;

drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h

@@ -107,6 +107,7 @@ struct inv_mpu6050_chip_config {
  *  @reg:   register map of the chip.
  *  @config:    configuration of the chip.
  *  @fifo_size:	size of the FIFO in bytes.
+ *  @temp:	offset and scale to apply to raw temperature.
  */
 struct inv_mpu6050_hw {
 	u8 whoami;
@@ -114,6 +115,10 @@ struct inv_mpu6050_hw {
 	const struct inv_mpu6050_reg_map *reg;
 	const struct inv_mpu6050_chip_config *config;
 	size_t fifo_size;
+	struct {
+		int offset;
+		int scale;
+	} temp;
 };
 
 /*
@@ -279,16 +284,19 @@ struct inv_mpu6050_state {
 #define INV_MPU6050_REG_UP_TIME_MIN          5000
 #define INV_MPU6050_REG_UP_TIME_MAX          10000
 
-#define INV_MPU6050_TEMP_OFFSET	             12421
-#define INV_MPU6050_TEMP_SCALE               2941
+#define INV_MPU6050_TEMP_OFFSET	             12420
+#define INV_MPU6050_TEMP_SCALE               2941176
 #define INV_MPU6050_MAX_GYRO_FS_PARAM        3
 #define INV_MPU6050_MAX_ACCL_FS_PARAM        3
 #define INV_MPU6050_THREE_AXIS               3
 #define INV_MPU6050_GYRO_CONFIG_FSR_SHIFT    3
 #define INV_MPU6050_ACCL_CONFIG_FSR_SHIFT    3
 
-#define INV_ICM20602_TEMP_OFFSET	     8170
-#define INV_ICM20602_TEMP_SCALE		     3060
+#define INV_MPU6500_TEMP_OFFSET              7011
+#define INV_MPU6500_TEMP_SCALE               2995178
+
+#define INV_ICM20608_TEMP_OFFSET	     8170
+#define INV_ICM20608_TEMP_SCALE		     3059976
 
 /* 6 + 6 + 7 (for MPU9x50) = 19 round up to 24 and plus 8 */
 #define INV_MPU6050_OUTPUT_DATA_SIZE         32