linux-kernel - Re: [PATCH v2 6/8] media: i2c: ds90ub953: Restructure clkout management

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Message-ID: <ZLqL1LinK21Pkx+K@smile.fi.intel.com>
Date:   Fri, 21 Jul 2023 16:44:52 +0300
From:   Andy Shevchenko <andriy.shevchenko@...el.com>
To:     Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Luca Ceresoli <luca.ceresoli@...tlin.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Hans Verkuil <hverkuil@...all.nl>,
        Satish Nagireddy <satish.nagireddy@...cruise.com>,
        Matti Vaittinen <mazziesaccount@...il.com>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 6/8] media: i2c: ds90ub953: Restructure clkout
 management

On Fri, Jul 21, 2023 at 04:23:54PM +0300, Tomi Valkeinen wrote:
> On 21/07/2023 13:29, Andy Shevchenko wrote:
> > On Thu, Jul 20, 2023 at 01:30:37PM +0300, Tomi Valkeinen wrote:

...

> > > +struct ub953_clkout_data {
> > > +	u32 hs_div;
> > > +	u32 m;
> > > +	u32 n;
> > 
> > I don't think it makes driver worse. The V4L2 UAPI has similar struct which is
> > used widely, hence I see no issues in using u32_fract here.
> 
> I think it makes sense to use u32_fract in common code. My argument for not
> using it here is:
> 
> - There is no actual functionality that u32_fract brings, so it's really
> only about field naming
> - m and n matches the terms in the HW documentation, making it easier to
> compare the code and the docs
> - This is private to the driver
> - I'm (currently) the most likely person to edit the driver, and I would
> have to check which one that numerator/denominator was again when looking at
> this part of the code (but maybe I would learn eventually)
> 
> So, in my view, the change doesn't really have any pros but does have cons.
> 
> That said, it's not a biggie. If others chime in and say it's a good idea to
> use u32_fract, I'm fine doing that change.

Thank you for a good summary of your point of view.
I agree that others, esp. maintainers, can decide
on how to proceed with this suggestion.

-- 
With Best Regards,
Andy Shevchenko