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Subject: Re: [PATCH v5] gpiolib: Bind gpio_device to a driver to enable
 fw_devlink=on by default
To:     Saravana Kannan <saravanak@google.com>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Marc Zyngier <maz@kernel.org>,
        Jisheng Zhang <Jisheng.Zhang@synaptics.com>,
        Kever Yang <kever.yang@rock-chips.com>,
        Android Kernel Team <kernel-team@android.com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>
References: <20210122193600.1415639-1-saravanak@google.com>
 <544ad0e4-0954-274c-8e77-866aaa5661a8@gmail.com>
 <CAGETcx_CYKczo+geD7yDo+T2+_-tgGYwtjR-2sMPQYHuz-wAgw@mail.gmail.com>
 <09502076-02e9-39ee-e432-24260696a927@gmail.com>
 <CAGETcx9fqnCZTC=afDUHnS6gES8WW4SwFNmH5sWaGVRYiysOMQ@mail.gmail.com>
From:   Dmitry Osipenko <digetx@gmail.com>
Message-ID: <c21d1a6b-5464-b59d-3967-c75c5a16136c@gmail.com>
Date:   Tue, 2 Feb 2021 00:15:42 +0300
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01.02.2021 23:15, Saravana Kannan пишет:
> On Mon, Feb 1, 2021 at 8:49 AM Dmitry Osipenko <digetx@gmail.com> wrote:
>>
>> 01.02.2021 00:28, Saravana Kannan пишет:
>>>> This patch causes these new errors on NVIDIA Tegra30 Nexus 7 using recent linux-next:
>>>>
>>>>  gpio-1022 (cpu-pwr-req-hog): hogged as input
>>>>  max77620-pinctrl max77620-pinctrl: pin gpio4 already requested by max77620-pinctrl; cannot claim for gpiochip1
>>>>  max77620-pinctrl max77620-pinctrl: pin-4 (gpiochip1) status -22
>>>>  max77620-pinctrl max77620-pinctrl: could not request pin 4 (gpio4) from group gpio4  on device max77620-pinctrl
>>>>  gpio_stub_drv gpiochip1: Error applying setting, reverse things back
>>>>  gpio_stub_drv: probe of gpiochip1 failed with error -22
>>>>
>>>> Please fix, thanks in advance.
>>> I have a partial guess on why this is happening. So can you try this patch?
>>>
>>> Thanks,
>>> Saravana
>>>
>>> --- a/drivers/gpio/gpiolib.c
>>> +++ b/drivers/gpio/gpiolib.c
>>> @@ -4213,6 +4213,8 @@ static int gpio_stub_drv_probe(struct device *dev)
>>>          * gpio_device of the GPIO chip with the firmware node and then simply
>>>          * bind it to this stub driver.
>>>          */
>>> +       if (dev->fwnode && dev->fwnode->dev != dev)
>>> +               return -EBUSY;
>>>         return 0;
>>>  }
>>
>> This change doesn't help, exactly the same errors are still there.
> 
> Sorry, I see what's happening. Try this instead. If it works, I'll
> send out a proper patch.
> 
> Thanks,
> Saravana
> 
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 8e0564c50840..f3d0ffe8a930 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -56,8 +56,10 @@
>  static DEFINE_IDA(gpio_ida);
>  static dev_t gpio_devt;
>  #define GPIO_DEV_MAX 256 /* 256 GPIO chip devices supported */
> +static int gpio_bus_match(struct device *dev, struct device_driver *drv);
>  static struct bus_type gpio_bus_type = {
>         .name = "gpio",
> +       .match = gpio_bus_match,
>  };
> 
>  /*
> @@ -4199,6 +4201,14 @@ void gpiod_put_array(struct gpio_descs *descs)
>  }
>  EXPORT_SYMBOL_GPL(gpiod_put_array);
> 
> +
> +static int gpio_bus_match(struct device *dev, struct device_driver *drv)
> +{
> +       if (dev->fwnode && dev->fwnode->dev != dev)
> +               return 0;
> +       return 1;
> +}
> +
>  static int gpio_stub_drv_probe(struct device *dev)
>  {
>         /*
> 

This works, thank you!

Tested-by: Dmitry Osipenko <digetx@gmail.com>