linux-kernel - Re: [PATCH] platform/x86: Support for EC-connected GPIOs for identify LED/button on Barco P50 board

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Date:   Tue, 19 Oct 2021 17:14:02 +0200
From:   Peter Korsgaard <peter@...sgaard.com>
To:     Hans de Goede <hdegoede@...hat.com>
Cc:     Santosh Kumar Yadav <santoshkumar.yadav@...co.com>,
        santoshyadav30@...il.com, Mark Gross <mgross@...ux.intel.com>,
        Peter Korsgaard <peter.korsgaard@...co.com>,
        linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org
Subject: Re: [PATCH] platform/x86: Support for EC-connected GPIOs for identify LED/button on Barco P50 board

>>>>> "Hans" == Hans de Goede <hdegoede@...hat.com> writes:

 > Hi,
 > On 10/13/21 16:03, Santosh Kumar Yadav wrote:
 >> Add a driver providing access to the GPIOs for the identify button and led
 >> present on Barco P50 board, based on the pcengines-apuv2.c driver.
 >> 
 >> There is unfortunately no suitable ACPI entry for the EC communication
 >> interface, so instead bind to boards with "P50" as their DMI product family
 >> and hard code the I/O port number (0x299).
 >> 
 >> The driver also hooks up the leds-gpio and gpio-keys-polled drivers to the
 >> GPIOs, so they are finally exposed as:
 >> 
 >> LED:
 >> /sys/class/leds/identify
 >> 
 >> Button: (/proc/bus/input/devices)
 >> I: Bus=0019 Vendor=0001 Product=0001 Version=0100
 >> N: Name="identify"
 >> P: Phys=gpio-keys-polled/input0
 >> S: Sysfs=/devices/platform/barco-p50-gpio/gpio-keys-polled/input/input10
 >> U: Uniq=
 >> H: Handlers=event10
 >> B: PROP=0
 >> B: EV=3
 >> B: KEY=1000000 0 0 0 0 0 0
 >> 
 >> Signed-off-by: Santosh Kumar Yadav <santoshkumar.yadav@...co.com>
 >> Signed-off-by: Peter Korsgaard <peter@...sgaard.com>

 > Thanks, overall this looks pretty good. I've a couple of comments inline,
 > please send a v2 addresing this.

..

 >> +/* Board setup */
 >> +static const struct dmi_system_id dmi_ids[] __initconst = {
 >> +       {
 >> +               .matches = {
 >> +                       DMI_EXACT_MATCH(DMI_PRODUCT_FAMILY, "P50")
 >> +               },
 >> +       },

 > But I'm a bit worried about the DMI match, it seems a bit too generic.

 > E.g. Lenovo also has a P50 laptop series.

 > For v2 please make the DMI match also on e.g. sys_vendor.

Agreed, will add a match on vendor = Barco.


 > You should put a:

 > MODULE_DEVICE_TABLE(dmi, dmi_ids);

 > here, this will add a dmi based modalias to the module, so that it will
 > be automatically loaded at boot on systems which match the dmi_ids table.

Ok.


 >> +MODULE_SOFTDEP("pre: platform:leds-gpio platform:gpio-keys-polled");

 > Is this softdep really necessary ? I would expect things to work fine too if
 > the leds-gpio and gpio-keys-polled drivers are loaded automatically after
 > the platform_devices for them have been created .

True. This was copied over from pcengines-apuv2.c, but we'll drop it for
v2.

-- 
Bye, Peter Korsgaard