linux-kernel - Re: [PATCH v2 2/2] iio: adc: ad9467: support write/read offset

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Message-ID: <a6194f8f0b8506283d2941a869961fd4f284634d.camel@gmail.com>
Date: Tue, 02 Dec 2025 15:05:09 +0000
From: Nuno Sá <noname.nuno@...il.com>
To: Tomas Melin <tomas.melin@...sala.com>, Lars-Peter Clausen
 <lars@...afoo.de>,  Michael Hennerich <Michael.Hennerich@...log.com>, Nuno
 Sa <nuno.sa@...log.com>, Jonathan Cameron <jic23@...nel.org>,  David
 Lechner <dlechner@...libre.com>, Andy Shevchenko <andy@...nel.org>,
 Alexandru Ardelean	 <alexandru.ardelean@...log.com>
Cc: Jonathan Cameron <Jonathan.Cameron@...wei.com>,
 linux-iio@...r.kernel.org, 	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] iio: adc: ad9467: support write/read offset

On Tue, 2025-12-02 at 16:52 +0200, Tomas Melin wrote:
> Hi,
> 
> On 02/12/2025 15:47, Nuno Sá wrote:
> > On Tue, 2025-12-02 at 12:53 +0000, Tomas Melin wrote:
> 
> > >  static const struct iio_chan_spec ad9434_channels[] = {
> > > -	AD9467_CHAN(0, BIT(IIO_CHAN_INFO_SCALE), 0, 12, 's'),
> > > +	{
> > > +		.type = IIO_VOLTAGE,
> > > +		.indexed = 1,
> > > +		.channel = 0,
> > > +		.info_mask_shared_by_type =
> > > +		BIT(IIO_CHAN_INFO_SCALE) |
> > > +		BIT(IIO_CHAN_INFO_SAMP_FREQ) |
> > > +		BIT(IIO_CHAN_INFO_CALIBBIAS),
> > > +		.info_mask_shared_by_type_available =
> > > +		BIT(IIO_CHAN_INFO_SCALE) |
> > > +		BIT(IIO_CHAN_INFO_CALIBBIAS),
> > 
> > Odd style for info_mask_shared_by_type_available and info_mask_shared_by_type. Seems we have
> > more line breaks than needed.
> > 
> Looking at existing code, there seems to many different ways to indent
> these kind of lines. Can you please provide your preferred style?
> 

Looking at the same driver I would expect something like:

https://elixir.bootlin.com/linux/v6.18/source/drivers/iio/adc/ad9467.c#L289

So, just break the line when the col limit is reached.

> 
> > 
> > > +		.scan_index = 0,
> > > +		.scan_type = {
> > > +			.sign = 's',
> > > +			.realbits = 12,
> > > +			.storagebits = 16,
> > > +		},
> > > +	},
> > >  };
> > >  
> > >  static const struct iio_chan_spec ad9467_channels[] = {
> > > @@ -367,6 +389,7 @@ static const struct ad9467_chip_info ad9434_chip_tbl = {
> > >  	.default_output_mode = AD9434_DEF_OUTPUT_MODE,
> > >  	.vref_mask = AD9434_REG_VREF_MASK,
> > >  	.num_lanes = 6,
> > > +	.offset_range = ad9434_offset_range,
> > >  };
> > >  
> > >  static const struct ad9467_chip_info ad9265_chip_tbl = {
> > > @@ -499,6 +522,33 @@ static int ad9467_set_scale(struct ad9467_state *st, int val, int val2)
> > >  	return -EINVAL;
> > >  }
> > >  
> > > +static int ad9467_get_offset(struct ad9467_state *st, int *val)
> > > +{
> > > +	int ret;
> > > +
> > > +	ret = ad9467_spi_read(st, AN877_ADC_REG_OFFSET);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +	*val = ret;
> > > +
> > > +	return IIO_VAL_INT;
> > > +}
> > > +
> > > +static int ad9467_set_offset(struct ad9467_state *st, int val)
> > > +{
> > > +	int ret;
> > > +
> > > +	if (val < st->info->offset_range[0] || val > st->info->offset_range[2])
> > > +		return -EINVAL;
> > > +
> > > +	ret = ad9467_spi_write(st, AN877_ADC_REG_OFFSET, val);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +	/* Sync registers */
> > 
> > I think this is not what David meant by adding a comment. IMHO, the comment as-is does not
> > bring any added value.
> The sync operation is needed in several places and is not commented in
> other locations either. Do you prefer no comment or even more elaborate
> comment for this particular sync operation?
> 

I know. I'm just stating the comment, as is, does not bring much value. But I was not the one asking
for it so I guess you should ask David :)

- Nuno Sá