4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Colin Parker <colin.par...@aclima.io>

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.par...@aclima.io>
Acked-by: Andreas Klinger <a...@it-klinger.de>
Signed-off-by: Jonathan Cameron <jonathan.came...@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 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,


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