Re: [PATCH v3 2/3] ltc2471: ltc2461/ltc2463 compatible strings

[Jonathan Cameron <jic23@kernel.org>]

On Tue, 28 Jul 2020 06:24:03 +0000
"Berghe, Darius" <Darius.Berghe@analog.com> wrote:

> Hi Jonathan,
> 
> Thanks for review, comments inline.
> 
> > -----Original Message-----
> > From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> > Sent: Monday, July 27, 2020 8:27 PM
> > To: Berghe, Darius <Darius.Berghe@analog.com>
> > Cc: linux-iio@vger.kernel.org; linux-kernel@vger.kernel.org;
> > devicetree@vger.kernel.org; jic23@kernel.org; robh@kernel.org
> > Subject: Re: [PATCH v3 2/3] ltc2471: ltc2461/ltc2463 compatible strings
> > 
> > [External]
> > 
> > On Mon, 27 Jul 2020 16:58:33 +0300
> > Darius Berghe <darius.berghe@analog.com> wrote:
> >   
> > > Add compatible strings for these devices in the existing ltc2471
> > > driver.
> > >
> > > Signed-off-by: Darius Berghe <darius.berghe@analog.com>  
> > 
> > Hi Darius,
> > 
> > A few additional minor comments from me.
> >   
> > > ---
> > >  drivers/iio/adc/ltc2471.c | 16 ++++++++++++----
> > >  1 file changed, 12 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/iio/adc/ltc2471.c b/drivers/iio/adc/ltc2471.c
> > > index e1c4e966524d..8c57203b1fe4 100644
> > > --- a/drivers/iio/adc/ltc2471.c
> > > +++ b/drivers/iio/adc/ltc2471.c
> > > @@ -1,5 +1,7 @@
> > >  /*
> > > - * Driver for Linear Technology LTC2471 and LTC2473 voltage monitors
> > > + * Driver for Linear Technology LTC2461, LTC2463, LTC2471 and LTC2473
> > > + voltage
> > > + * monitors.
> > > + * The LTC2463 is identical to the 2461, but reports a differential signal.
> > >   * The LTC2473 is identical to the 2471, but reports a differential signal.
> > >   *
> > >   * Copyright (C) 2017 Topic Embedded Products @@ -17,8 +19,10 @@
> > > #include <linux/mod_devicetable.h>
> > >
> > >  enum ltc2471_chips {
> > > +	ltc2461,
> > > +	ltc2463,
> > >  	ltc2471,
> > > -	ltc2473,
> > > +	ltc2473  
> > 
> > Why drop the comma?  We've just added two new devices. Seems possible
> > there may be more in the future!
> >   
> 
> Ok, will leave it there in v4.
> 
> > >  };
> > >
> > >  struct ltc2471_data {
> > > @@ -122,7 +126,7 @@ static int ltc2471_i2c_probe(struct i2c_client  
> > *client,  
> > >  	indio_dev->name = id->name;
> > >  	indio_dev->info = &ltc2471_info;
> > >  	indio_dev->modes = INDIO_DIRECT_MODE;
> > > -	if (id->driver_data == ltc2473)
> > > +	if (id->driver_data == ltc2473 || id->driver_data == ltc2463)  
> > If the only use of driver_data is going to be this check, then just set it to 2473
> > for the 2463 and 2473.  It's not uncommon to do this when we have a bunch
> > of devices that look the same to software.  
> 
> Yes the chips are similar but there is at least one feature which requires this level 
> of distinguishing them: the sampling rate (60sps for ltc2461/3 and selectable 208/833sps 
> for ltc2471/3). It's not used anywhere for now but I can see it being implemented
> as standard IIO dev attribute sampling frequency.

Fair enough.  Perhaps a note in the patch description so no one asks the question
on the next version?

> 
> >   
> > >  		indio_dev->channels = ltc2473_channel;
> > >  	else
> > >  		indio_dev->channels = ltc2471_channel; @@ -139,6 +143,8  
> > @@ static  
> > > int ltc2471_i2c_probe(struct i2c_client *client,  }
> > >
> > >  static const struct i2c_device_id ltc2471_i2c_id[] = {
> > > +	{ "ltc2461", ltc2461 },
> > > +	{ "ltc2463", ltc2463 },
> > >  	{ "ltc2471", ltc2471 },
> > >  	{ "ltc2473", ltc2473 },
> > >  	{}
> > > @@ -146,6 +152,8 @@ static const struct i2c_device_id ltc2471_i2c_id[]
> > > = {  MODULE_DEVICE_TABLE(i2c, ltc2471_i2c_id);
> > >
> > >  static const struct of_device_id ltc2471_of_match[] = {
> > > +	{ .compatible = "adi,ltc2461" },
> > > +	{ .compatible = "adi,ltc2463" },
> > >  	{ .compatible = "adi,ltc2471" },
> > >  	{ .compatible = "adi,ltc2473" },
> > >  	{}
> > > @@ -163,6 +171,6 @@ static struct i2c_driver ltc2471_i2c_driver = {
> > >
> > >  module_i2c_driver(ltc2471_i2c_driver);
> > >
> > > -MODULE_DESCRIPTION("LTC2471/LTC2473 ADC driver");
> > > +MODULE_DESCRIPTION("LTC2461/LTC2463/LTC2471/LTC2473 ADC  
> > driver");  
> > >  MODULE_AUTHOR("Topic Embedded Products");  MODULE_LICENSE("GPL  
> > v2");  
>