linux-kernel - Re: [PATCH 2/5] clk: lpc32xx: read-only divider can propagate rate change

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Date:   Fri, 05 Jan 2018 20:40:25 +0100
From:   Jerome Brunet <jbrunet@...libre.com>
To:     Vladimir Zapolskiy <vz@...ia.com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        Michael Turquette <mturquette@...libre.com>,
        linux-clk@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org,
        Sylvain Lemieux <slemieux.tyco@...il.com>,
        Andy Gross <andy.gross@...aro.org>,
        David Brown <david.brown@...aro.org>
Subject: Re: [PATCH 2/5] clk: lpc32xx: read-only divider can propagate rate
 change

On Fri, 2018-01-05 at 20:12 +0200, Vladimir Zapolskiy wrote:
> Hi Jerome,
> 
> On 01/05/2018 07:09 PM, Jerome Brunet wrote:
> > When a divider clock has CLK_DIVIDER_READ_ONLY set, it means that the
> > register shall be left un-touched, but it does not mean the clock
> > should stop rate propagation if CLK_SET_RATE_PARENT is set
> > 
> 
> okay, the statement sounds correct, but there is no such clocks on LPC32xx,
> thus I hardly can confirm that adding dead/inapplicable code is a fix.
> 
> > This properly handled in qcom clk-regmap-divider but it was not in the
> > lpc32xx divider
> > 
> > Fixes: f7c82a60ba26 ("clk: lpc32xx: add common clock framework driver")
> > Signed-off-by: Jerome Brunet <jbrunet@...libre.com>
> 
> I would suggest to drop two LPC32xx clock driver changes from the series.

Hi Vladimir,

This is fine by me. Whether LPC32xx supports CLK_DIVIDER_READ_ONLY is up to you,
but you should be consistent about it.

I added the fix to LPC32xx because it looks like the generic divider (a lot) and
appears to support CLK_DIVIDER_READ_ONLY. If it does not, could you please kill
the related code ?

Regards
Jerome

> 
> --
> With best wishes,
> Vladimir