linux-kernel - Re: [PATCH v9 01/10] clk: fix initial state of critical clock's parents

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Date:	Fri, 12 Aug 2016 16:17:53 +0800
From:	James Liao <jamesjj.liao@...iatek.com>
To:	Stephen Boyd <sboyd@...eaurora.org>,
	Michael Turquette <mturquette@...libre.com>
CC:	Rob Herring <robh@...nel.org>,
	Philipp Zabel <p.zabel@...gutronix.de>,
	Arnd Bergmann <arnd@...db.de>, <devicetree@...r.kernel.org>,
	Erin Lo <erin.lo@...iatek.com>, <linux-kernel@...r.kernel.org>,
	<srv_heupstream@...iatek.com>,
	<linux-mediatek@...ts.infradead.org>,
	"Sascha Hauer" <kernel@...gutronix.de>,
	Matthias Brugger <matthias.bgg@...il.com>,
	<linux-clk@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v9 01/10] clk: fix initial state of critical clock's
 parents

On Wed, 2016-08-10 at 14:09 -0700, Stephen Boyd wrote:
> (Including lists)
> 
> On 08/09, James Liao wrote:
> > On Wed, 2016-08-03 at 13:46 +0800, James Liao wrote:
> >>
> >> Hi Mike,
> >>
> >> Do you have new patches to fix new clock parents? If not, I think we can
> >> use my patch first. Is it okay?
> >>
> >
> > Hi Stephen,
> >
> > Do you have comments for the bug fixing? I prefer to use my patch (clk:
> > fix initial state of critical clock's parents). How do you think?
> >
> 
> How about we recalc accuracies and rates in addition to the patch
> from Mike? That will fix everything?

Hi Stephen,

It works!

I'll send a new series of MT2701 clock support in few days. Should I
include this patch in my series? Or you'll merge it into clk-next
directly?


Best regards,

James

> ---8<----
> From: Michael Turquette <mturquette@...libre.com>
> Subject: [PATCH] clk: migrate ref counts when orphans are reunited
> 
> It's always nice to see families reunited, and this is equally true when
> talking about parent clocks and their children. However, if the orphan
> clk had a positive prepare_count or enable_count, then we would not
> migrate those counts up the parent chain correctly.
> 
> This has manifested with the recent critical clocks feature, which often
> enables clocks very early, before their parents have been registered.
> 
> Fixed by replacing the call to clk_core_reparent with calls to
> __clk_set_parent_{before,after}.
> 
> Cc: James Liao <jamesjj.liao@...iatek.com>
> Cc: Erin Lo <erin.lo@...iatek.com>
> Signed-off-by: Michael Turquette <mturquette@...libre.com>
> [sboyd@...eaurora.org: Recalc accuracies and rates too]
> Signed-off-by: Stephen Boyd <sboyd@...eaurora.org>
> ---
>  drivers/clk/clk.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 820a939fb6bb..dc3fff2bf839 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -2449,8 +2449,16 @@ static int __clk_core_init(struct clk_core *core)
>  	hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
>  		struct clk_core *parent = __clk_init_parent(orphan);
>  
> -		if (parent)
> -			clk_core_reparent(orphan, parent);
> +		/*
> +		 * we could call __clk_set_parent, but that would result in a
> +		 * reducant call to the .set_rate op, if it exists
> +		 */
> +		if (parent) {
> +			__clk_set_parent_before(orphan, parent);
> +			__clk_set_parent_after(orphan, parent, NULL);
> +			__clk_recalc_accuracies(orphan);
> +			__clk_recalc_rates(orphan, 0);
> +		}
>  	}
>  
>  	/*