4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Colin Parker <colin.parker@xxxxxxxxx> commit 4b1f0c31f96c45e8521dd84aae50f2aa4aecfb7b upstream. The ctrl_reg register needs to be written after any write to the humidity registers. The value written to the ctrl_reg register does not necessarily need to change, but a write operation must occur. The regmap_update_bits functions will not write to a register if the register value matches the value to be written. This saves unnecessary bus operations. The change in this patch forces a bus write during the chip_config operation by switching to regmap_write_bits. This will fix issues where the Humidity Sensor Oversampling bits are not updated after initialization. Signed-off-by: Colin Parker <colin.parker@xxxxxxxxx> Acked-by: Andreas Klinger <ak@xxxxxxxxxxxxx> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/iio/pressure/bmp280-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/iio/pressure/bmp280-core.c +++ b/drivers/iio/pressure/bmp280-core.c @@ -558,7 +558,7 @@ static int bmp280_chip_config(struct bmp u8 osrs = BMP280_OSRS_TEMP_X(data->oversampling_temp + 1) | BMP280_OSRS_PRESS_X(data->oversampling_press + 1); - ret = regmap_update_bits(data->regmap, BMP280_REG_CTRL_MEAS, + ret = regmap_write_bits(data->regmap, BMP280_REG_CTRL_MEAS, BMP280_OSRS_TEMP_MASK | BMP280_OSRS_PRESS_MASK | BMP280_MODE_MASK,