Re: [PATCH v2 15/16] gpio: tegra: Use banked GPIO infrastructure

From: Grygorii Strashko
Date: Tue Oct 10 2017 - 15:32:09 EST




On 10/10/2017 05:27 AM, Thierry Reding wrote:
> On Mon, Oct 09, 2017 at 04:22:29PM -0500, Grygorii Strashko wrote:
>>
>>
>> On 09/28/2017 04:56 AM, Thierry Reding wrote:
>>> From: Thierry Reding <treding@xxxxxxxxxx>
>>>
>>> Convert the Tegra GPIO driver to use the banked GPIO infrastructure,
>>> which simplifies some parts of the driver.
>>>
>>> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
>>> ---
>>> drivers/gpio/Kconfig | 1 +
>>> drivers/gpio/gpio-tegra.c | 203 ++++++++++++++++++++++------------------------
>>> 2 files changed, 98 insertions(+), 106 deletions(-)
>>>
>>> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
>>> index db3e446ad9b3..458157d6d491 100644
>>> --- a/drivers/gpio/Kconfig
>>> +++ b/drivers/gpio/Kconfig
>>> @@ -439,6 +439,7 @@ config GPIO_TEGRA
>>> default ARCH_TEGRA
>>> depends on ARCH_TEGRA || COMPILE_TEST
>>
>> ...
>>
>>> @@ -616,76 +617,66 @@ static int tegra_gpio_probe(struct platform_device *pdev)
>>> tgi->ic.irq_set_wake = tegra_gpio_irq_set_wake;
>>> #endif
>>>
>>> + irq = &tgi->gc.irq;
>>> + irq->chip = &tgi->ic;
>>> + irq->handler = handle_simple_irq;
>>> + irq->lock_key = &tegra_gpio_lock_class;
>>
>> As per current gpiolib design lockdep lock_class_key is assigned
>> automatically and hidden from gpiolib users.
>> Why do you need to do the same manually?
>
> Can you elaborate? I don't see the lock class key getting set anywhere.
> gpiolib does set if for interrupts, but only if the drivers assigned it
> before adding the chip.
>

include/linux/gpio/driver.h

#ifdef CONFIG_LOCKDEP

/*
* Lockdep requires that each irqchip instance be created with a
* unique key so as to avoid unnecessary warnings. This upfront
* boilerplate static inlines provides such a key for each
* unique instance.
*/
static inline int gpiochip_irqchip_add(struct gpio_chip *gpiochip,
struct irq_chip *irqchip,
unsigned int first_irq,
irq_flow_handler_t handler,
unsigned int type)
{
static struct lock_class_key key;
^^^

return gpiochip_irqchip_add_key(gpiochip, irqchip, first_irq,
handler, type, false, &key);
}


--
regards,
-grygorii