+ Grant, Linus W and Jean-Christophe.
On Tue, Jul 2, 2013 at 1:44 PM, Torben Hohn <torb...@linutronix.de> wrote:
>
> Hi..
>
> I am running into Problems with a network adapter IRQ connected to an
> omap-gpio pin.
>
> omap-gpio expects gpio-request() to be called before i can use the pin.
> But this is abstracted via the DeviceTree bindings.
>
> I see 8d4c277e185c31359cf70573d8b0351fb7dd0dfe in mainline.
> This one just puts a warning into the exact place, i am dealing with.
> But i need to make this work, instead of bailing out.
>
This has been discussed extensively on the linux-omap mailing list and
the agreement is that it has to be handled by the IRQ core. So when a
GPIO line is mapped in the IRQ domain with irq_create_of_mapping(),
the core has to take care to request the GPIO and configure it as
input.
But until we have this general solution we have to do it on a per irq
chip driver basis and the less hack-ish solution is to have a custom
.map function handler that request the GPIO used as IRQ.
There is already a patch [1] queued in Linus Walleij linux-gpio tree
[2] for-next branch that implements this for OMAP GPIO. It would be
great if you can test it and give feedback.
> I have this fix in place, instead:
> ---------------------------------------------------------------------------------------
> commit 4ca17be8e7e24863cb98f440992fd89034aa34f5
> Author: Torben Hohn <torb...@linutronix.de>
> Date: Fri Jun 21 17:34:24 2013 +0200
>
> gpio omap: Fix for DT calling into gpio_irq_type without request_gpio()
>
> gpio_irq_type() requires that the GPIO is requested, do that.
>
> diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
> index f1fbedb2..57d956c 100644
> --- a/drivers/gpio/gpio-omap.c
> +++ b/drivers/gpio/gpio-omap.c
> @@ -87,6 +87,8 @@ struct gpio_bank {
> #define GPIO_BIT(bank, gpio) (1 << GPIO_INDEX(bank, gpio))
> #define GPIO_MOD_CTRL_BIT BIT(0)
>
> +static int omap_gpio_request(struct gpio_chip *chip, unsigned offset);
> +
> static int irq_to_gpio(struct gpio_bank *bank, unsigned int gpio_irq)
> {
> return gpio_irq - bank->irq_base + bank->chip.base;
> @@ -429,6 +431,9 @@ static int gpio_irq_type(struct irq_data *d, unsigned
> type)
> if (!gpio)
> gpio = irq_to_gpio(bank, d->irq);
>
> + if (!bank->mod_usage)
> + omap_gpio_request( &bank->chip, gpio );
> +
> if (type & ~IRQ_TYPE_SENSE_MASK)
> return -EINVAL;
>
>
> -----------------------------------------------------------------------------------------
>
>
> But now with RT i am running into a Problem, because gpio_irq_type() is called
> under a raw_spinlock() But its calling pm_runtime_suspend() which carries a
> normal spinlock.
>
>
> -----------------------------------------------------------------------------------------
> /**
> * irq_set_type - set the irq trigger type for an irq
> * @irq: irq number
> * @type: IRQ_TYPE_{LEVEL,EDGE}_* value - see include/linux/irq.h
> */
> int irq_set_irq_type(unsigned int irq, unsigned int type)
> {
> unsigned long flags;
> struct irq_desc *desc = irq_get_desc_buslock(irq, &flags,
> IRQ_GET_DESC_CHECK_GLOBAL);
> int ret = 0;
>
> if (!desc)
> return -EINVAL;
>
> type &= IRQ_TYPE_SENSE_MASK;
> ret = __irq_set_trigger(desc, irq, type);
> irq_put_desc_busunlock(desc, flags);
> return ret;
> }
> -----------------------------------------------------------------------------------------
>
> I think, i need a normal hook in the irq_chip, which "prepares" the irq, but
> i dont see one.
>
>
> --
> Mit freundlichen Grüßen
> Torben Hohn
>
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Thanks a lot and best regards,
Javier
[1]:
https://git.kernel.org/cgit/linux/kernel/git/linusw/linux-gpio.git/commit/?h=for-next&id=570c4bb53366157fa076922d0fc7e7adfd81cf42
[2]: git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio.git
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