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>
>
> 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;
> }
