Re: [PATCH 1/3] mfd: pm8921: Expose pm8xxx_read_irq_status

[Ivan T. Ivanov]

On Tue, 2014-07-08 at 16:43 -0700, Bjorn Andersson wrote:
> On Tue, Jul 8, 2014 at 4:20 PM, Stephen Boyd <sboyd@xxxxxxxxxxxxxx> wrote:
> > On 07/07/14 18:26, Bjorn Andersson wrote:

<snip>

> [...]
> > Sad, the header file came back. I guess there isn't a way to put the
> > pinctrl driver inside the core mfd driver? Then we wouldn't need to
> > expose an "irq read line" function.
> >
> 
> I continued my search and this needs to be accessed by gpio, mpp, adc,
> charger, bms and usb(?). So we have to expose it in some form.
> 
> > Actually Abhijeet proposed such an API in 2011 but it didn't go
> > anywhere[1]. If we had that API we should be able to call
> > read_irq_line() from the pinctrl driver whenever we want to get the
> > state of the gpio, plus the API is generic. We're going to need that API
> > anyway for things like USB insertion detection so it might make sense to
> > add it sooner rather than later.
> >
> > [1]
> > http://lists.infradead.org/pipermail/linux-arm-kernel/2011-April/048319.html
> 
> From what I can see of this thread it was exposed as a way for drivers
> to be able to query if an interrupt handler was called on raising or
> falling edge. And based on the locking limitations of the
> implementation we couldn't have used it anyways.
> 
> Our use case is different in that we're at any point in time
> interested in reading out the status of the irq line, as the only way
> of getting that status.

How about using extcon framework? 

Regards,
Ivan

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