From: j.uzycki@elproma•com.pl (Janusz Użycki)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] gpio: mxs: implement get_direction callback
Date: Mon, 17 Nov 2014 16:58:15 +0100 [thread overview]
Message-ID: <546A1B17.4010600@elproma.com.pl> (raw)
In-Reply-To: <20141117155300.GI27002@pengutronix.de>
W dniu 2014-11-17 o 16:53, Uwe Kleine-K?nig pisze:
> Hello,
>
> On Mon, Nov 17, 2014 at 11:05:51AM +0100, Richard Genoud wrote:
>> 2014-11-17 10:59 GMT+01:00 Uwe Kleine-K?nig <u.kleine-koenig@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);
> Just in case you didn't notice: Your statement is right, but for the
> other caller to request_irq there is something fishy. He gets
> IRQ_NOAUTOEN without being able to notice ...
Likely the gpio interrupts will never shared. We can say mctrl_gpio is
the only owner
of a gpio after a request. So should we worry that IRQ_NOAUTOEN is hidden?
best regards
Janusz
>
> Best regards
> Uwe
>
next prev parent reply other threads:[~2014-11-17 15:58 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-14 22:27 [PATCH] gpio: mxs: implement get_direction callback Janusz Uzycki
2014-11-14 23:26 ` Uwe Kleine-König
2014-11-15 19:29 ` Janusz Użycki
2014-11-16 21:42 ` Uwe Kleine-König
2014-11-16 21:48 ` Uwe Kleine-König
2014-11-16 23:59 ` Janusz Użycki
2014-11-17 1:58 ` Janusz Użycki
2014-11-17 8:28 ` Uwe Kleine-König
2014-11-17 8:38 ` Alexander Shiyan
2014-11-17 8:44 ` Uwe Kleine-König
2014-11-17 8:53 ` Alexander Shiyan
2014-11-17 9:11 ` Janusz Użycki
2014-11-17 9:39 ` Uwe Kleine-König
2014-11-17 9:46 ` Richard Genoud
2014-11-17 9:59 ` Uwe Kleine-König
2014-11-17 10:05 ` Richard Genoud
2014-11-17 14:29 ` Janusz Użycki
2014-11-17 16:14 ` Richard Genoud
2014-11-17 15:53 ` Uwe Kleine-König
2014-11-17 15:58 ` Janusz Użycki [this message]
2014-11-17 16:02 ` Uwe Kleine-König
2014-11-17 16:04 ` Richard Genoud
2014-11-17 17:26 ` Janusz Użycki
2014-11-17 10:05 ` Alexander Shiyan
2014-11-17 10:09 ` Russell King - ARM Linux
2014-11-17 10:10 ` Richard Genoud
2014-11-17 10:17 ` Russell King - ARM Linux
2014-11-17 12:40 ` Janusz Użycki
2014-11-17 9:51 ` request an irq without enabling? [Was: Re: [PATCH] gpio: mxs: implement get_direction callback] Uwe Kleine-König
2014-11-17 9:57 ` Richard Genoud
2014-11-17 17:00 ` [PATCH] gpio: mxs: implement get_direction callback Janusz Użycki
2014-11-17 17:07 ` Janusz Użycki
2014-11-17 18:42 ` Uwe Kleine-König
2014-11-17 19:02 ` Janusz Użycki
2014-11-17 22:21 ` Uwe Kleine-König
2014-11-18 9:59 ` Janusz Użycki
2014-11-17 9:26 ` Richard Genoud
2014-11-17 14:45 ` Janusz Użycki
2014-11-17 15:59 ` Uwe Kleine-König
2014-11-17 8:31 ` Richard Genoud
2014-11-17 8:39 ` Uwe Kleine-König
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