[PATCH] gpio: mxs: implement get_direction callback

[Richard Genoud]

2014-11-17 10:59 GMT+01:00 Uwe Kleine-König <u.kleine-koenig at pengutronix.de>:
> Hello Richard,
>
>> >>>> So finally the prototypes would be:
>> >>>> int mctrl_gpio_request_irqs(struct mctrl_gpios*, struct
>> >>>> uart_port*, irqhandler_t);
>> >>>> void mctrl_gpio_free_irqs(struct mctrl_gpios*);
>> >>
>> >> I think:
>> >>
>> >>         struct mctrl_gpios {
>> >>                 struct uart_port *port;
>> >>                 struct {
>> >>                         gpio_desc *gpio;
>> >>                         unsigned int irq;
>> I think it's just "int irq;" there
> irqs are unsigned. Some functions returning an irq use "int", but
> depending on who you ask this only for error reporting or a relict.
> Use 0 for invalid/unused in mctrl_gpio*.
>
>> > Yes. I tried to assign irq value in mctrl_gpio_init() only.
>> > There was another issue if CONFIG_GPIOLIB is not defined but it looks mctrl_
>> > disable/enable_ms()
>> > and mctrl_ irq handler solve the problem.
>> >
>> >>   Not sure there is a corresponding request_irq variant for that.
>> >
>> >
>> > What would you propose?
>> In atmel_request_gpio_irq(), the function irq_set_status_flags(irq,
>> IRQ_NOAUTOEN); is used before request_irq to prevent the irq from
>> being enabled when requested.
> I'm not sure this is allowed. How do you handle request_irq failing? (I
> just checked: you don't.) Consider another thread just doing
> request_irq($yourirq, ...) between
>
>         irq_set_status_flags(irq[i], IRQ_NOAUTOEN);
>
> and
>
>         err = request_irq(irq[i], ...

well, in this case, request_irq() will fail and all the previously
requested irqs will be freed:
    /*
     * If something went wrong, rollback.
     */
    while (err && (--i >= 0))
        if (irq[i] >= 0)
            free_irq(irq[i], port);