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From: Jonathan Cameron <jic23@kernel.org>
To: "Ardelean, Alexandru" <alexandru.Ardelean@analog.com>
Cc: "andrea.merello@gmail.com" <andrea.merello@gmail.com>,
	"Hennerich, Michael" <Michael.Hennerich@analog.com>,
	"lars@metafoo.de" <lars@metafoo.de>,
	"pmeerw@pmeerw.net" <pmeerw@pmeerw.net>,
	"knaack.h@gmx.de" <knaack.h@gmx.de>,
	"linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>
Subject: Re: [PATCH 1/4] iio: ad7949: kill pointless "readback"-handling code
Date: Sun, 15 Sep 2019 11:26:17 +0100
Message-ID: <20190915112617.7121665f@archlinux> (raw)
In-Reply-To: <e592cdc194cfa0ac0eb1a9539d890a1e5f70feb1.camel@analog.com>

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;
> >  }  


  reply index

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-12 14:43 [PATCH 0/4] Fixes for ad7949 Andrea Merello
2019-09-12 14:43 ` [PATCH 1/4] iio: ad7949: kill pointless "readback"-handling code Andrea Merello
2019-09-13  6:37   ` Ardelean, Alexandru
2019-09-15 10:26     ` Jonathan Cameron [this message]
2019-09-12 14:43 ` [PATCH 2/4] iio: ad7949: fix incorrect SPI xfer len Andrea Merello
2019-09-13  6:46   ` Ardelean, Alexandru
2019-09-13  7:56     ` Andrea Merello
2019-09-13  8:28       ` Ardelean, Alexandru
2019-09-15 10:36       ` Jonathan Cameron
2019-09-16  7:51         ` Ardelean, Alexandru
2019-09-21 17:16           ` Jonathan Cameron
2019-09-12 14:43 ` [PATCH 3/4] iio: ad7949: fix SPI xfer delays Andrea Merello
2019-09-13  6:59   ` Ardelean, Alexandru
2019-09-13  8:23     ` Andrea Merello
2019-09-13  8:43       ` Ardelean, Alexandru
2019-09-12 14:43 ` [PATCH 4/4] iio: ad7949: fix channels mixups Andrea Merello
2019-09-13  7:19   ` Ardelean, Alexandru
2019-09-13  8:30     ` Andrea Merello
2019-09-13 11:30       ` Couret Charles-Antoine
2019-09-13 11:40         ` Andrea Merello
2019-09-20  7:45         ` Andrea Merello
2019-09-21 17:12           ` Jonathan Cameron
2019-09-23  8:21             ` Andrea Merello
2019-10-05  9:55               ` Jonathan Cameron
     [not found]                 ` <CAN8YU5PRO5Y5EeEj2SZGm5XfuKSB1rtS7nKdu6wWxXYDOfexqw@mail.gmail.com>
2019-10-22  8:56                   ` Jonathan Cameron
2019-11-04 14:12                     ` Andrea Merello
2019-11-09 11:58                       ` Jonathan Cameron
2019-11-12 15:09                       ` Couret Charles-Antoine
2019-12-02 14:13                         ` [v2] " Andrea Merello
2019-12-02 15:36                           ` Couret Charles-Antoine
2019-12-04 11:06                             ` Jonathan Cameron
2019-12-04 11:13                               ` Couret Charles-Antoine
2019-12-06 16:45                                 ` Jonathan Cameron
2019-09-13  7:24 ` [PATCH 0/4] Fixes for ad7949 Ardelean, Alexandru
2019-09-13 14:00   ` Couret Charles-Antoine
2019-09-15 10:49     ` Jonathan Cameron
2019-09-16  7:39       ` Andrea Merello
2019-09-16  7:48         ` Ardelean, Alexandru
2019-09-16  7:50           ` Ardelean, Alexandru
2019-09-16  7:34     ` Andrea Merello

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