linux-kernel - Re: [PATCH 4/9] clk: imx: add pllv4 support

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Message-ID: <20170701003642.GS22780@codeaurora.org>
Date:   Fri, 30 Jun 2017 17:36:42 -0700
From:   Stephen Boyd <sboyd@...eaurora.org>
To:     Dong Aisheng <dongas86@...il.com>
Cc:     Dong Aisheng <aisheng.dong@....com>, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        mturquette@...libre.com, shawnguo@...nel.org, Anson.Huang@....com,
        ping.bai@....com
Subject: Re: [PATCH 4/9] clk: imx: add pllv4 support

On 06/20, Dong Aisheng wrote:
> On Mon, Jun 19, 2017 at 06:59:17PM -0700, Stephen Boyd wrote:
> > On 05/15, Dong Aisheng wrote:
> > > +
> > > +	if (clk_pllv4_is_enabled(hw)) {
> > > +		WARN(1, "clk_pllv4: can't change rate when pll is enabled");
> > > +		return -EINVAL;
> > 
> > Sad, CLK_SET_RATE_GATE isn't working for you I suppose?
> > 
> 
> CLK_SET_RATE_GATE can't work in early stage before running clk_disable_unused.
> At that point, the clock tree state is still not consistent with HW.
> e.g. prepare/enable count is still zero but it's actually enabled due to
> reset state or bootloader.
> 
> The code here is adding a double check in case user sets rate in early stage.
> 
> However, probably it could also be moved into clock core as it's not platform
> dependant behavior?
> 

Ok. It would be good to fix the core framework to synchronize the
prepared/enabled state at registration time so we don't need this
check in the driver.

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