Re: [PATCH] IIO: BME280: Updates to Humidity readings need ctrl_reg write!

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 28 Aug 2017 16:21:39 -0700
Colin Parker <colin.foeparker@aclima.io> wrote:

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

That's nasty.

> 
> 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@aclima.io>

I'd just like to leave a little more time for Andreas to respond to
this before I apply it.

Give me a bump if it looks like I have forgotten about it after next
weekend.

Thanks,

Jonathan

> ---
>  drivers/iio/pressure/bmp280-core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
> index 0d2ea3e..8f26428 100644
> --- a/drivers/iio/pressure/bmp280-core.c
> +++ b/drivers/iio/pressure/bmp280-core.c
> @@ -573,7 +573,7 @@ static int bmp280_chip_config(struct bmp280_data *data)
>  	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,