linux-kernel - Re: Why isn't IRQ shared for i2c-ocore

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Message-ID: <CAMuHMdWXFmPWsL4QyjwV+X-mruS0pU2Uzj7aSSxTQDJ=K+32XA@mail.gmail.com>
Date:	Fri, 8 May 2015 08:47:44 +0200
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Lee Jones <lee.jones@...aro.org>
Cc:	York Sun <yorksun@...escale.com>,
	Julia Lawall <Julia.Lawall@...6.fr>,
	Linux I2C <linux-i2c@...r.kernel.org>, wolfram@...-dreams.de,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Why isn't IRQ shared for i2c-ocore

On Thu, May 7, 2015 at 9:01 AM, Lee Jones <lee.jones@...aro.org> 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.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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