Hi Hans,
On Sun, Aug 10, 2025 at 05:12:46PM +0200, Hans de Goede wrote:
> Hi Arnd, Andy,
>
> On 9-Aug-25 9:44 PM, Arnd Bergmann wrote:
> > On Sat, Aug 9, 2025, at 12:00, Andy Shevchenko wrote:
> >> On Fri, Aug 08, 2025 at 05:17:49PM +0200, Arnd Bergmann wrote:
> >>> From: Arnd Bergmann <arnd@xxxxxxxx>
> >>>
> >>> A few old machines have not been converted away from the old-style
> >>> gpiolib interfaces. Make these select the new CONFIG_GPIOLIB_LEGACY
> >>> symbol so the code still works where it is needed but can be left
> >>> out otherwise.
> >>
> >>> --- a/drivers/platform/x86/x86-android-tablets/Kconfig
> >>> +++ b/drivers/platform/x86/x86-android-tablets/Kconfig
> >>> @@ -8,6 +8,7 @@ config X86_ANDROID_TABLETS
> >>> depends on I2C && SPI && SERIAL_DEV_BUS
> >>> depends on GPIOLIB && PMIC_OPREGION
> >>> depends on ACPI && EFI && PCI
> >>> + select GPIOLIB_LEGACY
> >>> select NEW_LEDS
> >>> select LEDS_CLASS
> >>> select POWER_SUPPLY
> >>
> >> Hmm... This is a surprising change. But I leave it to Hans.
>
> Yes I was surprised by this myself since I explicitly removed
> all legacy GPIO use from the x86-android-tablets code a while
> ago (or so I thought).
>
> > I think the only function that still needs it is
> > x86_android_tablet_probe() doing
> >
> > static struct gpio_keys_button *buttons;
> >
> > for (i = 0; i < dev_info->gpio_button_count; i++) {
> > ret = x86_android_tablet_get_gpiod(dev_info->gpio_button[i].chip,
> > dev_info->gpio_button[i].pin,
> > dev_info->gpio_button[i].button.desc,
> > false, GPIOD_IN, &gpiod);
> >
> > buttons[i] = dev_info->gpio_button[i].button;
> > buttons[i].gpio = desc_to_gpio(gpiod);
> > /* Release GPIO descriptor so that gpio-keys can request it */
> > devm_gpiod_put(&x86_android_tablet_device->dev, gpiod);
> > }
> >
> > So the driver itself uses gpio descriptors, but it passes
> > some of them into another driver by number. There is probably
> > an easy workaround that I did not see.
>
> Ah I see, so this is basically in the same boat as
> drivers/input/misc/soc_button_array.c which also first
> gets a gpio_desc and then calls desc_to_gpio() to store
> the GPIO number in struct gpio_keys_button which is passed
> as platform_data to drivers/input/keyboard/gpio_keys.c
>
> The gpio_keys driver then converts things back
> into a gpio_desc in gpio_keys_setup_key()
> using devm_gpio_request_one() + gpio_to_desc()
>
> So it looks like we need to add a gpiod member to
> struct gpio_keys_button (include/linux/gpio_keys.h)
> and modify gpio_keys.c to prefer that over using
> button->gpio, something like the attached patch
> basically.
>
> I won't have time to work on this until September,
> so if someone wants to take the attached patch and run
> with it go for it.
>
> Note the x86-android-tablets / soc_button_array code
> will become responsible for requesting / releasing
> the gpiod when using the new gpio_keys_button.gpiod
> member.
>
> For the x86-android-tablets code this is easy, just drop
> these 2 lines:
>
> /* Release GPIO descriptor so that gpio-keys can request it */
> devm_gpiod_put(&x86_android_tablet_device->dev, gpiod);
>
> And for soc_button_array.c it is _probably_ just a matter
> of switching to devm_gpiod_get_index() and drop the
> gpiod_put().
>
> I have hardware to test both the x86-android-tablets
> code as well as the soc_button_array code. I might be
> able to do a quick test on August 22nd or 29th.
I just sent out a v2 of my series from '23 converting
x86-android-tablets to use PROPERTY_ENTRY_GPIO(), including converting
buttons and switches:
https://lore.kernel.org/all/20250810-x86-andoroid-tablet-v2-0-9c7a1b3c32b2@xxxxxxxxx/
I do not have hardware so it probably is busted but if you could make it
work that would be great.
Thanks.
--
Dmitry
