Re: [PATCH v2] gpio: convince line to become input in irq helper

[Bjorn Andersson <bjorn.andersson@linaro.org>]

On Wed 22 Jun 14:25 PDT 2016, Linus Walleij wrote:

> The generic IRQ helper library just checks if the IRQ line is
> set as input before activating it for interrupts. As we
> recently started to check things better with .get_dir() it
> turns out that it's good to try to convince the line to become
> an input before attempting to lock it as IRQ.
> 
> Cc: Björn Andersson <bjorn.andersson@linaro.org>

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> ChangeLog v1->v2:
> - Propagate the error from .direction_input() so we can rely on
>   it being used.
> ---
>  drivers/gpio/gpiolib.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 5a21a6acf8af..b195ec406ff4 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -1505,6 +1505,25 @@ static int gpiochip_irq_reqres(struct irq_data *d)
>  	if (!try_module_get(chip->gpiodev->owner))
>  		return -ENODEV;
>  
> +	/*
> +	 * If it is possible to switch this GPIO to an input
> +	 * this is a good time to do it.
> +	 */
> +	if (chip->direction_input) {
> +		struct gpio_desc *desc;
> +		int ret;
> +
> +		desc = gpiochip_get_desc(chip, d->hwirq);
> +		if (IS_ERR(desc))
> +			return PTR_ERR(desc);
> +
> +	        ret = chip->direction_input(chip, d->hwirq);
> +		if (ret)
> +			return ret;
> +
> +		clear_bit(FLAG_IS_OUT, &desc->flags);
> +	}
> +
>  	if (gpiochip_lock_as_irq(chip, d->hwirq)) {
>  		chip_err(chip,
>  			"unable to lock HW IRQ %lu for IRQ\n",
> -- 
> 2.4.11
> 
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