linux-kernel - Re: [PATCH] clk: fix clock global name usage.

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Date:   Wed, 12 Jun 2019 16:00:36 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Alexandre Mergnat <amergnat@...libre.com>,
        wens Tsai <wens213@...il.com>
Cc:     Mike Turquette <mturquette@...libre.com>,
        linux-clk <linux-clk@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        baylibre-upstreaming@...ups.io,
        Jerome Brunet <jbrunet@...libre.com>
Subject: Re: [PATCH] clk: fix clock global name usage.

Quoting wens Tsai (2019-06-10 23:46:17)
> On Fri, May 24, 2019 at 3:29 PM Alexandre Mergnat <amergnat@...libre.com> wrote:
> >
> > A recent patch allows the clock framework to specify the parent
> > relationship with either the clk_hw pointer, the global name or through
> > Device Tree name.
> >
> > But the global name isn't handled by the clk framework because the DT name
> > is considered valid even if it's NULL, so of_clk_get_hw() returns an
> > unexpected clock (the first clock specified in DT).
> >
> > This can be fixed by calling of_clk_get_hw() only when DT name is not NULL.
> >
> > Fixes: fc0c209c147f ("clk: Allow parents to be specified without string names")
> > Cc: Jerome Brunet <jbrunet@...libre.com>
> > Signed-off-by: Alexandre Mergnat <amergnat@...libre.com>
> > ---
> >  drivers/clk/clk.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> > index bdb077ba59b9..9624a75e5a8d 100644
> > --- a/drivers/clk/clk.c
> > +++ b/drivers/clk/clk.c
> > @@ -368,7 +368,7 @@ static struct clk_core *clk_core_get(struct clk_core *core, u8 p_index)
> >         const char *dev_id = dev ? dev_name(dev) : NULL;
> >         struct device_node *np = core->of_node;
> >
> > -       if (np && index >= 0)
> > +       if (name && np && index >= 0)
> 
> I think the opposite should be the case. If either the name or index is valid,
> and there's a device node backing it, the code path should be entered.
> 
> This is implied by the description of struct clk_parent_data:
> 
>     @index: parent index local to provider registering clk (if @fw_name absent)
> 
> So the code path should be valid regardless of the value of .index.
> 
> That would make it
> 
>         if (np && (name || index >= 0)) ...
> 

Sure. I'll post my fix and pick the patch into clk-fixes so that this
works.