Re: gpio_get_value in atomic context (was: make gpio-keys use IRQF_SHARED)

["Arve Hjønnevåg" <arve@android.com>]

2009/10/14 Ferenc Wagner <wferi@niif.hu>:
> Dmitry Torokhov <dmitry.torokhov@gmail.com> writes:
>
>> On Mon, Oct 12, 2009 at 07:09:50PM +0200, Ferenc Wagner wrote:
>>
>>>     The gpio_get_value function may sleep, so it should not be
>>>     called in a timer function.
>>>
>>> So is drivers/staging/dream/gpio_input.c in error, too?
>>
>> I guess so. Initially gpio method did not sleep but that has
>> changed.
>
> Let's make Arve aware of this then (even though it may not affect
> Android in practice).

If gpio_get_value may sleep, then what is gpio_get_value_cansleep for?
The gpio documentation claims gpio_get_value and gpio_set_value are
safe to use from interrupt context, but a call to gpio_cansleep is
probably needed in probe.

The matrix driver also need to change the direction of the gpio from
the timer, so it would be useful to have a standard way to check if
this is allowed as well.

-- 
Arve Hjønnevåg
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