Re: [RFT PATCH 2/4] platform/x86: int3472: led: don't use gpiod_toggle_active_low()

Hans de Goede
2023-09-27T09:41:55Z

Hi,

On 9/26/23 16:59, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> Instead of acpi_get_and_request_gpiod() + gpiod_toggle_active_low(), use
> temporary lookup tables with appropriate lookup flags.
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> ---
> drivers/platform/x86/intel/int3472/led.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/platform/x86/intel/int3472/led.c b/drivers/platform/x86/intel/int3472/led.c
> index bca1ce7d0d0c..62e0cd5207a7 100644
> --- a/drivers/platform/x86/intel/int3472/led.c
> +++ b/drivers/platform/x86/intel/int3472/led.c
> @@ -25,18 +25,14 @@ int skl_int3472_register_pled(struct int3472_discrete_device *int3472,
> if (int3472->pled.classdev.dev)
> return -EBUSY;
>
> - int3472->pled.gpio = acpi_get_and_request_gpiod(path, agpio->pin_table[0],
> - "int3472,privacy-led");
> + int3472->pled.gpio = skl_int3472_gpiod_get_from_temp_lookup(
> + int3472->dev, path, agpio->pin_table[0],
> + "int3472,privacy-led", polarity,
> + GPIOD_OUT_LOW);

Yeah so this is not going to work, path here is an ACPI device path, e.g.
on my laptop (which actually uses the INT3472 glue code) the path-s of
the 2 GPIO controllers are: `\_SB_.GPI0` resp `\_SB_.PC00.XHCI.RHUB.HS08.VGPO`

Where as skl_int3472_gpiod_get_from_temp_lookup() stores the passed in path
in gpiod_lookup_table.table[0].key, which is the dev_name() of the GPIO
controller's parent dev which are `INTC1055:00` resp. `INTC1096:00` .

So we are going to need to add some code to INT3472 to go from path to
a correct value for gpiod_lookup_table.table[0].key which means partly
reproducing most of acpi_get_gpiod:

struct gpio_chip *chip;
acpi_handle handle;
acpi_status status;

status = acpi_get_handle(NULL, path, &handle);
if (ACPI_FAILURE(status))
return ERR_PTR(-ENODEV);

chip = gpiochip_find(handle, acpi_gpiochip_find);
if (!chip)
return ERR_PTR(-EPROBE_DEFER);

And then get the key from the chip. Which means using gpiochip_find
in the int3472 code now, which does not sound like an improvement.

I think that was is needed instead is adding an active_low flag
to acpi_get_and_request_gpiod() and then have that directly
set the active-low flag on the returned desc.

Regards,

Hans

> if (IS_ERR(int3472->pled.gpio))
> return dev_err_probe(int3472->dev, PTR_ERR(int3472->pled.gpio),
> "getting privacy LED GPIO\n");
>
> - if (polarity == GPIO_ACTIVE_LOW)
> - gpiod_toggle_active_low(int3472->pled.gpio);
> -
> - /* Ensure the pin is in output mode and non-active state */
> - gpiod_direction_output(int3472->pled.gpio, 0);
> -
> /* Generate the name, replacing the ':' in the ACPI devname with '_' */
> snprintf(int3472->pled.name, sizeof(int3472->pled.name),
> "%s::privacy_led", acpi_dev_name(int3472->sensor));