On 12/05/2012 11:20 PM, Roland Stigge wrote:
> Hi Wolfgang,
>
> On 05/12/12 20:01, Wolfgang Grandegger wrote:
>>> + for (i = 0; i < block->ngpio; i++) {
>>> + status = gpio_request(block->gpio[i], "gpioblock dev");
>>
>> You could use the name of the GPIO block.
>
> OK.
>
>>> + if (status)
>>> + goto err1;
>>> +
>>> + irq = gpio_to_irq(block->gpio[i]);
>>> + if (irq >= 0 &&
>>> + !test_bit(FLAG_IS_OUT, &gpio_desc[block->gpio[i]].flags) &&
>>> + !gpio_block_is_irq_duplicate(block, i)) {
>>> + status = request_irq(irq, gpio_block_irq_handler,
>>> + IRQF_TRIGGER_FALLING,
>>> + block->name, block);
>>> + if (status)
>>> + goto err2;
>>> +
>>> + block->irq_controlled = true;
>>> + }
>>> + }
>>
>> There is no need to request IRQs if "O_NONBLOCK" is specified.
>
> Sure? Regarding this, I found: "The poll() function shall not be
> affected by the O_NONBLOCK flag." [1]
Ah, didn't know that.
>> I observed that the read returns once immediately (without blocking)
>> after reboot. I did not look into that yet.
>
> Didn't happen to me. Can you tell how this can be reproduced?
I think there is an interrupt pending for some reason. It might not be
the case with your setup.
Feel free to add my:
"Tested by: Wolfgang Grandegger <w...@grandegger.com>".
Will do some more tests when time permits, especially with mixed GPIO
input and output.
Wolfgang.
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