Re: [PATCH v2 2/4] iio: adc: add support for Allwinner SoCs ADC

From: Jonathan Cameron
Date: Sat Jul 23 2016 - 06:56:51 EST

On 21/07/16 14:15, Quentin Schulz wrote:
> On 20/07/2016 16:57, Jonathan Cameron wrote:
>> On 19/07/16 09:33, Quentin Schulz wrote:
>>> On 18/07/2016 15:18, Jonathan Cameron wrote:
>>>> On 15/07/16 10:59, Quentin Schulz wrote:
> [...]
>>>>> + enable_irq(info->temp_data_irq);
>>>> Is this hardware spitting out extra irqs? If not, much better to just
>>>> leave it enabled all the time and control whether it can occur or not
>>>> by controlling the device state..
>>> The temp_data_irq occurs every SUNXI_GPADC_TEMP_PERIOD(x) periods (in
>>> the current state of the driver: 2s). What do you mean by controlling
>>> the device state? Enabling or disabling the hardware part of the IP
>>> responsible of getting the temperature
>> Yes, or something along those lines if it wakes up fast enough.
> The ADC wakes up fast enough but resets its internal time clock (I don't
> know if it's the right term to use). Note that the temperature interrupt
> occurs by period of X seconds in this IP.
> This means that each time we disable the ADC on the hardware side, no
> temperature interrupt will occur within the first X seconds. I don't
> think this is what we want.
I'm guessing X is non trivial ;)

So fair enough. Could you add this justification as a comment in the
driver somewhere so that people coming back to this in a few years time
will know what the justification for this 'unusual' handling is.


> [...]
> Quentin
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