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:

quoted

On Sat, Aug 9, 2025, at 12:00, Andy Shevchenko wrote:

quoted

On Fri, Aug 08, 2025 at 05:17:49PM +0200, Arnd Bergmann wrote:

quoted

From: Arnd Bergmann <arnd@arndb.de>

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.

quoted

--- 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).

quoted

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@gmail.com/ (local)

I do not have hardware so it probably is busted but if you could make it
work that would be great.

Thanks.

-- 
Dmitry