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Date: Sun, 10 Mar 2024 12:35:23 +0100
Message-Id: <CZQ1EP61IDOC.1PPYGMIOINGND@gimli.ms.mff.cuni.cz>
Cc: "Lee Jones" <lee@kernel.org>, "Rob Herring" <robh+dt@kernel.org>,
 "Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>, "Conor Dooley"
 <conor+dt@kernel.org>, "Liam Girdwood" <lgirdwood@gmail.com>, "Mark Brown"
 <broonie@kernel.org>, <devicetree@vger.kernel.org>,
 <linux-kernel@vger.kernel.org>, <linux-input@vger.kernel.org>,
 =?utf-8?q?Duje_Mihanovi=C4=87?= <duje.mihanovic@skole.hr>,
 <~postmarketos/upstreaming@lists.sr.ht>, <phone-devel@vger.kernel.org>
Subject: Re: [RFC PATCH v3 4/5] input: add onkey driver for Marvell 88PM886
 PMIC
To: "Dmitry Torokhov" <dmitry.torokhov@gmail.com>
From: "Karel Balej" <karelb@gimli.ms.mff.cuni.cz>
References: <20240303101506.4187-1-karelb@gimli.ms.mff.cuni.cz>
 <20240303101506.4187-5-karelb@gimli.ms.mff.cuni.cz>
 <ZeTgEmjJc_VhYpLm@google.com>
 <CZL8ZSZAVEBI.349BV2Y6AKIPN@gimli.ms.mff.cuni.cz>
 <ZeZxI_spu4vwxrs7@google.com>
In-Reply-To: <ZeZxI_spu4vwxrs7@google.com>

Dmitry Torokhov, 2024-03-04T17:10:59-08:00:
> On Mon, Mar 04, 2024 at 09:28:45PM +0100, Karel Balej wrote:
> > Dmitry,
> >=20
> > Dmitry Torokhov, 2024-03-03T12:39:46-08:00:
> > > On Sun, Mar 03, 2024 at 11:04:25AM +0100, Karel Balej wrote:
> > > > From: Karel Balej <balejk@matfyz.cz>
> > > >=20
> > > > Marvell 88PM886 PMIC provides onkey among other things. Add client
> > > > driver to handle it. The driver currently only provides a basic sup=
port
> > > > omitting additional functions found in the vendor version, such as =
long
> > > > onkey and GPIO integration.
> > > >=20
> > > > Signed-off-by: Karel Balej <balejk@matfyz.cz>
> > > > ---
> > > >=20
> > > > Notes:
> > > >     RFC v3:
> > > >     - Drop wakeup-source.
> > > >     RFC v2:
> > > >     - Address Dmitry's feedback:
> > > >       - Sort includes alphabetically.
> > > >       - Drop onkey->irq.
> > > >       - ret -> err in irq_handler and no initialization.
> > > >       - Break long lines and other formatting.
> > > >       - Do not clobber platform_get_irq error.
> > > >       - Do not set device parent manually.
> > > >       - Use input_set_capability.
> > > >       - Use the wakeup-source DT property.
> > > >       - Drop of_match_table.
> > >
> > > I only said that you should not be using of_match_ptr(), but you stil=
l
> > > need to have of_match_table set and have MODULE_DEVICE_TABLE() for th=
e
> > > proper module loading support.
> >=20
> > I removed of_match_table because I no longer need compatible for this -=
-
> > there are no device tree properties and the driver is being instantiate=
d
> > by the MFD driver.
> >=20
> > Is the MODULE_DEVICE_TABLE() entry needed for the driver to probe when
> > compiled as module? If that is the case, given what I write above, am I
> > correct that MODULE_DEVICE_TABLE(platform,...) would be the right thing
> > to use here?
>
> Yes, if uevent generated for the device is "platform:<name>" then
> MODULE_DEVICE_TABLE(platform,...) will suffice. I am not sure how MFD
> sets it up (OF modalias or platform), but you should be able to check
> the format looking at the "uevent" attribute for your device in sysfs
> (/sys/devices/bus/platform/...).=20

The uevent is indeed platform.

But since there is only one device, perhaps having a device table is
superfluous and using `MODULE_ALIAS("platform:88pm886-onkey")` is more
fitting?

Although I don't understand why this is even necessary when the driver
name is such and the module is registered using
`module_platform_driver`...

Thank you, best regards,
K. B.