linux-kernel - Re: [RFT PATCH 2/4] platform/x86: int3472: led: don't use gpiod_toggle_active

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Message-ID: <3f8760f8-ae8c-c0b0-19d7-76fbbf5d25de@redhat.com>
Date:   Wed, 27 Sep 2023 15:08:24 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     Bartosz Golaszewski <brgl@...ev.pl>
Cc:     Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Daniel Scally <djrscally@...il.com>,
        Mark Gross <markgross@...nel.org>, linux-gpio@...r.kernel.org,
        linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
        platform-driver-x86@...r.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [RFT PATCH 2/4] platform/x86: int3472: led: don't use
 gpiod_toggle_active_low()

Hi Bart,

On 9/27/23 12:44, Bartosz Golaszewski wrote:
> On Wed, Sep 27, 2023 at 11:40 AM Hans de Goede <hdegoede@...hat.com> wrote:
>>
>> Hi,
>>
>> On 9/26/23 16:59, Bartosz Golaszewski wrote:
>>> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.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@...aro.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.
>>
> 
> Ultimately I'd like everyone to use gpiod_get() for getting
> descriptors but for now I get it's enough. Are you find with this
> being done in a single patch across GPIO and this driver?

Yes doing this in a single patch is fine.

Also I'm fine with merging such a patch through the gpio tree .

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));
>>
>