linux-kernel - Re: [PATCH] gpio: gpio-stmpe: fully use convert probe to device-managed

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Date:   Thu, 20 May 2021 13:06:30 +0300
From:   Alexandru Ardelean <aardelean@...iqon.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linus.walleij@...aro.org" <linus.walleij@...aro.org>,
        "bgolaszewski@...libre.com" <bgolaszewski@...libre.com>,
        "alexandre.torgue@...s.st.com" <alexandre.torgue@...s.st.com>,
        "mcoquelin.stm32@...il.com" <mcoquelin.stm32@...il.com>
Subject: Re: [PATCH] gpio: gpio-stmpe: fully use convert probe to device-managed

On Thu, 20 May 2021 at 09:40, Andy Shevchenko <andy.shevchenko@...il.com> wrote:
>
>
>
> On Sunday, May 16, 2021, Alexandru Ardelean <aardelean@...iqon.com> wrote:
>>
>> The driver doesn't look like it can be built as a kmod, so leaks cannot
>> happen via a rmmod mechanism.
>> The remove hook was removed via commit 3b52bb960ec6 ("gpio: stmpe: make
>> it explicitly non-modular").
>>
>> The IRQ is registered via devm_request_threaded_irq(), making the driver
>> only partially device-managed.
>>
>> In any case all resources should be made device-managed, mostly as a good
>> practice. That way at least the unwinding on error is happening in reverse
>> order (as the probe).
>>
>> This change also removes platform_set_drvdata() since the information is
>> never retrieved to be used in the driver.
>
>
> Any driver can be unbind from device thru sysfs. The exception is when they (device drivers) specifically disable that.

Oh, I see.
Thanks for the info :)

>
>>
>> Signed-off-by: Alexandru Ardelean <aardelean@...iqon.com>
>> ---
>>
>> I'm not sure if this should be marked with a Fixes tag.
>> But if so, it should probably be for commit 3b52bb960ec6 (also mentioned in
>> the comment above).
>>
>>  drivers/gpio/gpio-stmpe.c | 32 +++++++++++++-------------------
>>  1 file changed, 13 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c
>> index b94ef8181428..dd4d58b4ae49 100644
>> --- a/drivers/gpio/gpio-stmpe.c
>> +++ b/drivers/gpio/gpio-stmpe.c
>> @@ -449,6 +449,11 @@ static void stmpe_init_irq_valid_mask(struct gpio_chip *gc,
>>         }
>>  }
>>
>> +static void stmpe_gpio_disable(void *stmpe)
>> +{
>> +       stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
>> +}
>> +
>>  static int stmpe_gpio_probe(struct platform_device *pdev)
>>  {
>>         struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
>> @@ -461,7 +466,7 @@ static int stmpe_gpio_probe(struct platform_device *pdev)
>>                 return -EINVAL;
>>         }
>>
>> -       stmpe_gpio = kzalloc(sizeof(*stmpe_gpio), GFP_KERNEL);
>> +       stmpe_gpio = devm_kzalloc(&pdev->dev, sizeof(*stmpe_gpio), GFP_KERNEL);
>>         if (!stmpe_gpio)
>>                 return -ENOMEM;
>>
>> @@ -489,7 +494,11 @@ static int stmpe_gpio_probe(struct platform_device *pdev)
>>
>>         ret = stmpe_enable(stmpe, STMPE_BLOCK_GPIO);
>>         if (ret)
>> -               goto out_free;
>> +               return ret;
>> +
>> +       ret = devm_add_action_or_reset(&pdev->dev, stmpe_gpio_disable, stmpe);
>> +       if (ret)
>> +               return ret;
>>
>>         if (irq > 0) {
>>                 struct gpio_irq_chip *girq;
>> @@ -499,7 +508,7 @@ static int stmpe_gpio_probe(struct platform_device *pdev)
>>                                 "stmpe-gpio", stmpe_gpio);
>>                 if (ret) {
>>                         dev_err(&pdev->dev, "unable to get irq: %d\n", ret);
>> -                       goto out_disable;
>> +                       return ret;
>>                 }
>>
>>                 girq = &stmpe_gpio->chip.irq;
>> @@ -514,22 +523,7 @@ static int stmpe_gpio_probe(struct platform_device *pdev)
>>                 girq->init_valid_mask = stmpe_init_irq_valid_mask;
>>         }
>>
>> -       ret = gpiochip_add_data(&stmpe_gpio->chip, stmpe_gpio);
>> -       if (ret) {
>> -               dev_err(&pdev->dev, "unable to add gpiochip: %d\n", ret);
>> -               goto out_disable;
>> -       }
>> -
>> -       platform_set_drvdata(pdev, stmpe_gpio);
>> -
>> -       return 0;
>> -
>> -out_disable:
>> -       stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
>> -       gpiochip_remove(&stmpe_gpio->chip);
>> -out_free:
>> -       kfree(stmpe_gpio);
>> -       return ret;
>> +       return devm_gpiochip_add_data(&pdev->dev, &stmpe_gpio->chip, stmpe_gpio);
>>  }
>>
>>  static struct platform_driver stmpe_gpio_driver = {
>> --
>> 2.31.1
>>
>
>
> --
> With Best Regards,
> Andy Shevchenko
>
>