Re: Why isn't IRQ shared for i2c-ocore
From: Lee Jones
Date: Fri May 08 2015 - 02:57:57 EST
On Fri, 08 May 2015, Geert Uytterhoeven wrote:
> On Thu, May 7, 2015 at 9:01 AM, Lee Jones <lee.jones@xxxxxxxxxx> wrote:
> >> I have a follow up question regarding interrupt. I see many I2C bus drivers
> >> request interrupt with flag = 0. Why not using IRQF_SHARED?
> > Probably because that particular IRQ is only used by the I2C
> > Controller. I'm not exactly sure that you're getting at? Why do you
> > think it should be shared? You should only flag it as shared if it
> > is.
> However, that's something the driver can't know.
> Sharing interrupts is an integration property. The same IP core may share its
> interrupt on one SoC, and not on another.
I guess that would depend on the IP. If this is part of an MFD, you'd
know if you only hand a single interrupt line coming into the chip or
not. If the IP can be moved around (copy & pasted) into different
chips, then yes, that might change.
How does one share an interrupt with other drivers if all them don't
know the IRQ is shared thought?
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