From: Simon Horman <horms@verge.net.au>
To: linux-sh@vger.kernel.org
Subject: Re: [PATCH 1/2] ARM: shmobile: r8a7740 legacy: Correct IIC0 parent clock
Date: Wed, 12 Nov 2014 09:10:23 +0000 [thread overview]
Message-ID: <20141112091022.GA9007@verge.net.au> (raw)
In-Reply-To: <1415181874-21549-1-git-send-email-geert+renesas@glider.be>
On Wed, Nov 12, 2014 at 10:06:34AM +0100, Geert Uytterhoeven wrote:
> Hi Simon,
>
> On Wed, Nov 12, 2014 at 3:27 AM, Simon Horman <horms@verge.net.au> wrote:
> > On Wed, Nov 12, 2014 at 09:34:23AM +0900, Simon Horman wrote:
> >> On Mon, Nov 10, 2014 at 09:52:38AM +0900, Simon Horman wrote:
> >> > On Wed, Nov 05, 2014 at 11:04:33AM +0100, Geert Uytterhoeven wrote:
> >> > > According to the datasheet, the operating clock for IIC0 is the HPP
> >> > > (RT Peri) clock, not the SUB (Peri) clock. Both clocks run at the same
> >> > > speed (50 Mhz).
> >> > >
> >> > > This is consistent with IIC0 being located in the A4R PM domain, and
> >> > > IIC1 in the A3SP PM domain.
> >> >
> >> > Thanks, I have queued this up.
> >>
> >> Hi Geert,
> >>
> >> As this appears to be a bug fix I would like to accompany this patch with
> >> some text describing when the problem was introduced and what its effects
> >> are. In short a rough guide to if it should be applied to -stable. To that
> >> end I prepared the following which I would appreciate your feedback on.
> >>
> >> * ARM: shmobile: r8a7740 legacy: Correct IIC0 parent clock
> >>
> >> This problem appears to have been introduced when IIC0 support was
> >> added to the r8a7740 by 6831f3a9184a1c540 ("ARM: mach-shmobile: r8a7740:
> >> add i2c support") in v3.2.
>
> That's the commit where it became effective. The bug was introduced in
> commit 6c01ba445cecb2d8 ("ARM: mach-shmobile: R-Mobile A1 support.").
Thanks, I have updated my description accordingly.
> > s/v3.2/v3.3/
> >
> >
> >> I am not aware of any run-time effect of this problem
>
> Indeed. Both clocks run at the same frequency, and TTBOMK the HPP clock
> cannot be disabled (is that correct?), so the IIC0 clock cannot be inadvertently
> be disabled because the common part is disabled through another clock.
That sounds like a question for Morimoto-san :)
prev parent reply other threads:[~2014-11-12 9:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-05 10:04 [PATCH 1/2] ARM: shmobile: r8a7740 legacy: Correct IIC0 parent clock Geert Uytterhoeven
2014-11-10 0:52 ` Simon Horman
2014-11-12 0:34 ` Simon Horman
2014-11-12 2:27 ` Simon Horman
2014-11-12 9:06 ` Geert Uytterhoeven
2014-11-12 9:10 ` Simon Horman [this message]
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