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

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Jonathan Cameron <jic23@xxxxxxxxxx> schrieb am Sun, 03. Sep 17:34:
> On Mon, 28 Aug 2017 16:21:39 -0700
> Colin Parker <colin.foeparker@xxxxxxxxx> wrote:
> 
> > From: Colin Parker <colin.parker@xxxxxxxxx>
> > 
> > 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@xxxxxxxxx>

Acked-by: Andreas Klinger <ak@xxxxxxxxxxxxx>

> 
> 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,
> 
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