Re: [PATCH] input: make gpio-keys use IRQF_SHARED

[Ferenc Wagner <wferi@niif.hu>]

Dmitry Torokhov <dmitry.torokhov@gmail.com> writes:

> On Wed, Sep 16, 2009 at 07:03:18PM +0400, Dmitry Eremin-Solenikov wrote:
>> There is nothing that disallows gpio-keys to share it's IRQ line
>> w/ other drivers. Make it use IRQF_SHARED in request_irq().
>> 
>> An example of other driver with which I'd like to share IRQ line
>> for GPIO buttons is ledtrig-gpio.
>> 
>> Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
>> ---
>>  drivers/input/keyboard/gpio_keys.c |    1 +
>>  1 files changed, 1 insertions(+), 0 deletions(-)
>> 
>> diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
>> index efed0c9..9fc2fab 100644
>> --- a/drivers/input/keyboard/gpio_keys.c
>> +++ b/drivers/input/keyboard/gpio_keys.c
>> @@ -147,6 +147,7 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev)
>>  		}
>>  
>>  		error = request_irq(irq, gpio_keys_isr,
>> +				    IRQF_SHARED |
>>  				    IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
>>  				    button->desc ? button->desc : "gpio_keys",
>>  				    bdata);
>
> How will you determine which device generated the interrupt? Because you
> can't return IRQ_HANDLED unconditionally and expect both devices work
> reliably.

It would be possible, but commit
da0d03fe6cecde837f113a8a587f5a872d0fade0 states that:

    The gpio_get_value function may sleep, so it should not be called in a
    timer function.

But I don't see why it could sleep, is that really the case?  Because
that makes acknowledging the interrupt very hard.  Actually, I need
and tested interrupt sharing.  What are the "cansleep wrappers" in
asm-generic/gpio.h if these function can sleep as well?  I'd be
grateful for some explanation.  Also, commit
57ffe9d539e0eb741bb9ca8f2834d210e70ee2e3 removed the possibility of
telling apart different keys, so that should be reverted during the
process.  I already asked Uwe Kleine-König about the whys, but didn't
get a reply.
-- 
Regards,
Feri.
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