Re: [PATCH 1/4] iio: ad7949: kill pointless "readback"-handling code

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 13 Sep 2019 06:37:17 +0000
"Ardelean, Alexandru" <alexandru.Ardelean@analog.com> wrote:

> On Thu, 2019-09-12 at 16:43 +0200, Andrea Merello wrote:
> > [External]
> > 
> > The device could be configured to spit out also the configuration word
> > while reading the AD result value (in the same SPI xfer) - this is called
> > "readback" in the device datasheet.
> > 
> > The driver checks if readback is enabled and it eventually adjusts the SPI
> > xfer length and it applies proper shifts to still get the data, discarding
> > the configuration word.
> > 
> > The readback option is actually never enabled (the driver disables it), so
> > the said checks do not serve for any purpose.
> > 
> > Since enabling the readback option seems not to provide any advantage (the
> > driver entirely sets the configuration word without relying on any default
> > value), just kill the said, unused, code.  
> 
> Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>

Applied to the togreg branch of iio.git and pushed out as testing for
the autobuilders to poke at it.

Thanks,

Jonathan

> 
> > 
> > Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
> > ---
> >  drivers/iio/adc/ad7949.c | 27 +++------------------------
> >  1 file changed, 3 insertions(+), 24 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c
> > index ac0ffff6c5ae..518044c31a73 100644
> > --- a/drivers/iio/adc/ad7949.c
> > +++ b/drivers/iio/adc/ad7949.c
> > @@ -57,29 +57,11 @@ struct ad7949_adc_chip {
> >  	u32 buffer ____cacheline_aligned;
> >  };
> >  
> > -static bool ad7949_spi_cfg_is_read_back(struct ad7949_adc_chip *ad7949_adc)
> > -{
> > -	if (!(ad7949_adc->cfg & AD7949_CFG_READ_BACK))
> > -		return true;
> > -
> > -	return false;
> > -}
> > -
> > -static int ad7949_spi_bits_per_word(struct ad7949_adc_chip *ad7949_adc)
> > -{
> > -	int ret = ad7949_adc->resolution;
> > -
> > -	if (ad7949_spi_cfg_is_read_back(ad7949_adc))
> > -		ret += AD7949_CFG_REG_SIZE_BITS;
> > -
> > -	return ret;
> > -}
> > -
> >  static int ad7949_spi_write_cfg(struct ad7949_adc_chip *ad7949_adc, u16 val,
> >  				u16 mask)
> >  {
> >  	int ret;
> > -	int bits_per_word = ad7949_spi_bits_per_word(ad7949_adc);
> > +	int bits_per_word = ad7949_adc->resolution;
> >  	int shift = bits_per_word - AD7949_CFG_REG_SIZE_BITS;
> >  	struct spi_message msg;
> >  	struct spi_transfer tx[] = {
> > @@ -107,7 +89,7 @@ static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val,
> >  				   unsigned int channel)
> >  {
> >  	int ret;
> > -	int bits_per_word = ad7949_spi_bits_per_word(ad7949_adc);
> > +	int bits_per_word = ad7949_adc->resolution;
> >  	int mask = GENMASK(ad7949_adc->resolution, 0);
> >  	struct spi_message msg;
> >  	struct spi_transfer tx[] = {
> > @@ -138,10 +120,7 @@ static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val,
> >  
> >  	ad7949_adc->current_channel = channel;
> >  
> > -	if (ad7949_spi_cfg_is_read_back(ad7949_adc))
> > -		*val = (ad7949_adc->buffer >> AD7949_CFG_REG_SIZE_BITS) & mask;
> > -	else
> > -		*val = ad7949_adc->buffer & mask;
> > +	*val = ad7949_adc->buffer & mask;
> >  
> >  	return 0;
> >  }