Messages in this thread |  | | Date | Tue, 25 Feb 2014 10:47:27 +0100 | Subject | Re: [PATCH v4 2/8] at91: pinctrl: don't request GPIOs used for interrupts but lock them as IRQ | From | Jean-Jacques Hiblot <> |
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2014-02-25 10:35 GMT+01:00 Jean-Jacques Hiblot <jjhiblot@traphandler.com>: > Hi Linus, > > 2014-02-24 14:25 GMT+01:00 Linus Walleij <linus.walleij@linaro.org>: >> On Wed, Feb 12, 2014 at 11:06 AM, Jean-Jacques Hiblot >> <jjhiblot@traphandler.com> wrote: >> >>> During the xlate stage of the DT interrupt parsing, the at91 pinctrl driver >>> requests the GPIOs that are described as interrupt sources. This prevents a >>> driver to request the gpio later to get its electrical value. >>> This patch replaces the gpio_request with a gpio_lock_as_irq to prevent the >>> gpio to be set as an ouput while allowing a subsequent gpio_request to succeed >>> >>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com> >> >> OK, but is this really correct: >> >>> @@ -1478,18 +1478,17 @@ static int at91_gpio_irq_domain_xlate(struct irq_domain *d, >>> { >>> struct at91_gpio_chip *at91_gpio = d->host_data; >>> int ret; >>> - int pin = at91_gpio->chip.base + intspec[0]; >>> >>> if (WARN_ON(intsize < 2)) >>> return -EINVAL; >>> *out_hwirq = intspec[0]; >>> *out_type = intspec[1] & IRQ_TYPE_SENSE_MASK; >>> >>> - ret = gpio_request(pin, ctrlr->full_name); >>> + ret = gpio_lock_as_irq(&at91_gpio->chip, intspec[0]); >> >> So when resolving an IRQ resource, we take for granted that it will be used >> for IRQs and IRQs only? Is it not possible that this resolution is done >> and then the driver using it unloads or whatever and it is still marked >> as IRQ? > No, once it's reserved for irq, it'll be for irq only. >> >> I don't think the xlate function should have such side effects on >> the gpio_chip internal state. I think it should just translate. > > I agree but I choose to only replace the gpio_request by a > lock_as_irq(), not rework the whole thing. It seemed it would have > more chance to be accepted this way. IMO the right time to do this is > at the time of the request_irq() >> >> The line is locked for IRQ the moment its startup() callback is >> called, is it not? >> >>> - ret = gpio_direction_input(pin); >>> + ret = at91_gpio_direction_input(&at91_gpio->chip, intspec[0]); >> >> I actually don't like this either. This kind of thing was causing >> problems in the OMAP driver like hell. > But calling gpio_direction_input() defeats the purpose of removing the > gpio_request() because it ensures that the gpio is requested. >> >> I think this should be deleted from xlate and at91_gpio_direction_input() >> be called from the irqchip's .startup() or even .unmask() function >> instead. > irq_startup and irq_shutdown seem the right place for this because > they're called when requesting and freeing the interrupt. It'll > require a change to __setup_irq() though to check the return value of > irq_startup.
Linux,
Sorry, for the noise. You can forget this proposed patch and my previous email. I just saw that the patch where this was done in startup and shutdown was applied. I thought it had been rejected . I'm sorry for the confusion.
Jean-Jacques >> >> Yours, >> Linus Walleij
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