Re: [PATCH v5 RESEND 1/6] platform: x86-android-tablets: other: Add swnode for Xiaomi pad2 indicator LED

From: Kate Hsuan <hpa@redhat.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: "Pavel Machek" <pavel@ucw.cz>, "Lee Jones" <lee@kernel.org>,
	linux-leds@vger.kernel.org, platform-driver-x86@vger.kernel.org,
	"Hans de Goede" <hdegoede@redhat.com>,
	"Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>,
	"André Apitzsch" <git@apitzsch.eu>,
	linux-kernel@vger.kernel.org,
	"Sebastian Reichel" <sre@kernel.org>,
	linux-pm@vger.kernel.org
Subject: Re: [PATCH v5 RESEND 1/6] platform: x86-android-tablets: other: Add swnode for Xiaomi pad2 indicator LED
Date: Thu, 28 Mar 2024 17:14:21 +0800	[thread overview]
Message-ID: <CAEth8oH9iDm1fN1LyPRtvHt=w7z72kunpRssxg3-nPNAgOyoXg@mail.gmail.com> (raw)
In-Reply-To: <CAHp75VdQtmT0G1dFhdY7TrcBj2W6GhOaVv90_T1e3MdEtiduQQ@mail.gmail.com>

On Wed, Mar 27, 2024 at 7:06 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Wed, Mar 27, 2024 at 9:58 AM Kate Hsuan <hpa@redhat.com> wrote:
> > On Mon, Mar 25, 2024 at 3:30 AM Andy Shevchenko
> > <andy.shevchenko@gmail.com> wrote:
> > > On Sun, Mar 24, 2024 at 5:02 PM Kate Hsuan <hpa@redhat.com> wrote:
>
> ...
>
> > > > +/* main fwnode for ktd2026 */
> > > > +static const struct software_node ktd2026_node = {
> > > > +       .name = "ktd2026"
> > >
> > > Leave a comma, this is not a terminator.
> > >
> > > > +};
> > >
> > > When I asked about the name I relied on the fact that you have an idea
> > > how it works. So, assuming my understanding is correct, this platform
> > > may not have more than a single LED of this type. Dunno if we need a
> > > comment about this.
> >
> > I'll make a comment to describe the configuration.
> > This LED controller can be configured to an RGB LED like this. Also,
> > it can be configured as three single-color (RGB) LEDs to show red,
> > green, and blue only.
> > I think the name can be "ktd2026-multi-color". Is it good for you?
>
> My point here is that the name is static and if you have more than one
> LED in the system, the second one won't be registered due to sysfs
> name collisions. Question here is how many of these types of LEDs are
> possible on the platform? If more than one, the name has to be
> dropped. Writing this I think a comment would be good to have in any
> case.

Only one RGB LED controller on this platform so we can name it. I also
tested the LED with and without the name and the LED worked properly.
I think the name can be dropped and put a comment there to describe
the usage and configuration of the LED controller.

Thank you :)
>
> ...
>
> > > > +static int __init xiaomi_mipad2_init(void)
> > > > +{
> > > > +       return software_node_register_node_group(ktd2026_node_group);
> > > > +}
> > > > +
> > > > +static void xiaomi_mipad2_exit(void)
> > >
> > > __exit ?
> > No need.
> > x86-andriod-tablet is based on platform_driver and platform_device so
> > it doesn't need __exit.
> >
> > I put __exit and the compiler complained about the warning.
> > ===
> > WARNING: modpost:
> > drivers/platform/x86/x86-android-tablets/x86-android-tablets: section
> > mismatch in reference: xiaomi_mipad2_info+0x50 (section: .init.rodata)
> > -> xiaomi_mipad2_exit (section: .exit.text)
> > ===
>
> This is interesting. Why then do we call them symmetrically?
>
> Hans, do we need to have anything here been amended?
>
> --
> With Best Regards,
> Andy Shevchenko
>

-- 
BR,
Kate