On Fri, 13 Sep 2019 06:37:17 +0000
"Ardelean, Alexandru" <alexandru.Ardelean@xxxxxxxxxx> 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@xxxxxxxxxx>
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@xxxxxxxxx>
> > ---
> > 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;
> > }
