linux-kernel - Re: [PATCH] clk: Don't write error code into divider register

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Date:   Thu, 31 Aug 2017 18:44:04 -0700
From:   Stephen Boyd <sboyd@...eaurora.org>
To:     Peter De Schrijver <pdeschrijver@...dia.com>
Cc:     Michael Turquette <mturquette@...libre.com>,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        Alex Frid <afrid@...dia.com>
Subject: Re: [PATCH] clk: Don't write error code into divider register

On 07/26, Peter De Schrijver wrote:
> On Tue, Jul 25, 2017 at 05:32:08PM -0700, Stephen Boyd wrote:
> > On 07/25, Peter De Schrijver wrote:
> > > From: Alex Frid <afrid@...dia.com>
> > > 
> > > Add a check for error returned by divider value calculation to avoid
> > > writing error code into hw register.
> > > 
> > > Signed-off-by: Alex Frid <afrid@...dia.com>
> > > Reviewed-by: Peter De Schrijver <pdeschrijver@...dia.com>
> > > Reviewed-by: Jon Mayo <jmayo@...dia.com>
> > > ---
> > 
> > Fixes: bca9690b9426 ("clk: divider: Make generic for usage elsewhere")
> > 
> > perhaps?
> > 
> > Also, curious how this got triggered? Presumably round_rate would
> > have failed before a set_rate call with something invalid came
> > through so that's why nobody has reported anything so far.
> > 
> 
> I don't really know. Aleks do you remember?
> 

Still wondering.

> > 	if ((s32)value < 0)
> > 
> > to see if there was an error. Sort of annoying that we've limited
> > the available space of divider_get_val() by combining the value
> > with the error code number space. We may want to not do that in
> > case people have huge dividers.
> > 
> 
> Yes. It would have been better to return the divider in a separate variable.
> There seem to be few users though, only 6.

Patches welcome.

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