linux-kernel - Re: [PATCH v6 5/9] iio: adc: ad7173: refactor ain and vref selection

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Date: Fri, 07 Jun 2024 12:24:57 +0200
From: Nuno Sá <noname.nuno@...il.com>
To: "Ceclan, Dumitru" <mitrutzceclan@...il.com>, dumitru.ceclan@...log.com
Cc: Lars-Peter Clausen <lars@...afoo.de>, Michael Hennerich
 <Michael.Hennerich@...log.com>, Jonathan Cameron <jic23@...nel.org>, Rob
 Herring <robh@...nel.org>, Krzysztof Kozlowski
 <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>,
 David Lechner <dlechner@...libre.com>,  linux-iio@...r.kernel.org,
 devicetree@...r.kernel.org,  linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 5/9] iio: adc: ad7173: refactor ain and vref selection

On Fri, 2024-06-07 at 12:37 +0300, Ceclan, Dumitru wrote:
> On 07/06/2024 12:04, Nuno Sá wrote:
> > On Thu, 2024-06-06 at 19:07 +0300, Dumitru Ceclan via B4 Relay wrote:
> > > From: Dumitru Ceclan <dumitru.ceclan@...log.com>
> > > 
> > > Move validation of analog inputs and reference voltage selection to
> > > separate functions to reduce the size of the channel config parsing
> > > function and improve readability.
> > > Add defines for the number of analog inputs in a channel.
> > > 
> > > Signed-off-by: Dumitru Ceclan <dumitru.ceclan@...log.com>
> > > ---
> > >  drivers/iio/adc/ad7173.c | 68 +++++++++++++++++++++++++++++++++----------
> > > ----
> > > -
> > >  1 file changed, 47 insertions(+), 21 deletions(-)
> > > 
> > > diff --git a/drivers/iio/adc/ad7173.c b/drivers/iio/adc/ad7173.c
> > > index 8631f218b69e..4040edbd1c32 100644
> > > --- a/drivers/iio/adc/ad7173.c
> > > +++ b/drivers/iio/adc/ad7173.c
> > > @@ -60,6 +60,7 @@
> > >  #define AD7173_CH_SETUP_AINPOS_MASK	GENMASK(9, 5)
> > >  #define AD7173_CH_SETUP_AINNEG_MASK	GENMASK(4, 0)
> > >  
> > > +#define AD7173_NO_AINS_PER_CHANNEL	2
> > >  #define AD7173_CH_ADDRESS(pos, neg) \
> > >  	(FIELD_PREP(AD7173_CH_SETUP_AINPOS_MASK, pos) | \
> > >  	 FIELD_PREP(AD7173_CH_SETUP_AINNEG_MASK, neg))
> > > @@ -629,6 +630,7 @@ static int ad7173_setup(struct iio_dev *indio_dev)
> > >  static unsigned int ad7173_get_ref_voltage_milli(struct ad7173_state *st,
> > >  						 u8 reference_select)
> > >  {
> > > +	struct device *dev = &st->sd.spi->dev;
> > >  	int vref;
> > >  
> > >  	switch (reference_select) {
> > > @@ -652,9 +654,11 @@ static unsigned int
> > > ad7173_get_ref_voltage_milli(struct
> > > ad7173_state *st,
> > >  		return -EINVAL;
> > >  	}
> > >  
> > > -	if (vref < 0)
> > > +	if (vref < 0) {
> > > +		dev_err(dev, "Cannot use reference %u. Error:%d\n",
> > > +			reference_select, vref);
> > >  		return vref;
> > > -
> > > +	}
> > >  	return vref / (MICRO / MILLI);
> > >  }
> > 
> > unrelated?
> > 
> > - Nuno Sá
> > 
> 
> Hmm, maybe I misunderstood "Any error log needed should be done inside
> ad7173_get_ref_voltage_milli()"
> https://lore.kernel.org/all/71452f6882efe6a181d477914488617d28a38e2f.camel@gmail.com/
> 
> This change should be in a different patch or should it not've been done
> this way?

Ohh right... Mentioning this particular log change in the commit message would
avoid my question. Also, note that you're still doing:

ret = ad7173_get_ref_voltage_milli(st, ref_sel);
if (ret < 0)
	return ret;

instead of:

return ad7173_get_ref_voltage_milli(...)

which defeats the purpose of having the log inside
ad7173_get_ref_voltage_milli() 

But after stepping back I see ad7173_get_ref_voltage_milli() is also being used
in a non probe path. Hence, doing the log out of the function using
dev_err_probe() may be reason enough to keep things as you had before my
comments. Will leave that up to you (sorry for the noise).

- Nuno Sá