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From: shawn.guo@freescale.com (Shawn Guo)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: imx6: Fix procedure to switch the parent of LDB_DI_CLK
Date: Wed, 9 Apr 2014 22:59:38 +0800	[thread overview]
Message-ID: <20140409145936.GB2334@dragon> (raw)
In-Reply-To: <CAOMZO5CO8ucya8qmVXBo5kgRmuLqKGtpub07o1DuE9yh5LmmPQ@mail.gmail.com>

On Wed, Apr 09, 2014 at 11:20:28AM -0300, Fabio Estevam wrote:
> On Wed, Apr 9, 2014 at 10:34 AM, Shawn Guo <shawn.guo@freescale.com> wrote:
> 
> > I'm not sure this is a full/correct fix to the problem.  You assume that
> > the re-parenting only happens during boot for once?  What about the
> 
> Yes, correct. As far as I can see LDB parent is only set once in clk-imx6q.
> 
> > re-parenting triggered by the clk_set_parent() call?
> 
> Where do you see the LDB clock parent to change via clk_set_parent() call?
> 
> In imx_ldb.c we use clk_set_parent() to set the di parent, not ldb parent.

As long as you call clk_register_mux() to register a multiplexer, you
have to ensure that clk_set_parent() call always works properly on it,
no matter whether there is one actually calling into it right now.

Furthermore, some re-parenting happens in a way you may not be aware of.
See commit e366fdd (clk: clk-mux: implement remuxing on set_rate), for
example.

Shawn

  reply	other threads:[~2014-04-09 14:59 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-09 11:55 [PATCH] ARM: imx6: Fix procedure to switch the parent of LDB_DI_CLK Fabio Estevam
2014-04-09 13:34 ` Shawn Guo
2014-04-09 14:20   ` Fabio Estevam
2014-04-09 14:59     ` Shawn Guo [this message]
2014-04-09 15:28       ` Fabio Estevam
2014-04-10  1:21         ` Shawn Guo
2014-04-10  1:55           ` Fabio Estevam
2014-04-10  2:44             ` Shawn Guo
2014-04-09 13:35 ` Christian Gmeiner
2014-05-19  7:22 ` Dirk Behme
2014-05-19 17:07   ` Ranjani.Vaidyanathan at freescale.com
2014-05-19  9:25 ` Lothar Waßmann
2014-06-04 16:37 ` Dirk Behme
2014-06-04 17:29   ` Ranjani.Vaidyanathan at freescale.com
2014-06-04 17:49     ` Dirk Behme
2014-06-05 16:26       ` Ranjani.Vaidyanathan at freescale.com
2014-06-05 15:56     ` Dirk Behme

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