Re: [RFC PATCH v2] clk: move check of CLK_SET_RATE_GATE flag to clk_propagate_rate_change()

[Jiada Wang]

Hello Michael

On 07/13/2016 07:29 AM, Michael Turquette wrote:
> Quoting jiada_wang@xxxxxxxxxx (2016-07-10 22:33:28)
> > From: Jiada Wang <jiada_wang@xxxxxxxxxx>
> >
> > Previously CLK_SET_RATE_GATE flag is only checked in clk_set_rate()
> > which only ensures the clock being called by clk_set_rate() won't
> > change rate when it has been prepared if CLK_SET_RATE_GATE flag is set.
> > But a clk_set_rate() request may propagate rate change to these clocks
> > from the requested clock's topmost parent clock to all its offsprings,
> > when any one of these clocks has CLK_SET_RATE_GATE flag set
> > and it has been prepared, the clk_set_rate() request should fail.
> >
> > This patch moves check of CLK_SET_RATE_GATE flag to
> > clk_propagate_rate_change() to ensure all affected clocks will
> > be checked if their rate will be changed after clk_set_rate().
> >
> > Signed-off-by: Jiada Wang <jiada_wang@xxxxxxxxxx>
> > ---
>
> What's different in version 2? It's tradition to put a little version
> changelog here, below the "---" line and above the "diff --git a/..."
> line.
version 2 resolves the following kernel warning
"
   drivers/clk/clk.c: In function 'clk_propagate_rate_change':
>> drivers/clk/clk.c:1441:3: warning: return makes pointer from integer 
without a cast
      return -EBUSY;
      ^
"
I forgot to add a changelog in v2 patch, sorry for the confusion caused.

Thanks,
Jiada
> Regards,
> Mike
>
> >   drivers/clk/clk.c |    6 +++---
> >   1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> > index 820a939..2f930c8 100644
> > --- a/drivers/clk/clk.c
> > +++ b/drivers/clk/clk.c
> > @@ -1437,6 +1437,9 @@ static struct clk_core *clk_propagate_rate_change(struct clk_core *core,
> >          if (core->rate == core->new_rate)
> >                  return NULL;
> >
> > +       if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count)
> > +               return core;
> > +
> >          if (core->notifier_count) {
> >                  ret = __clk_notify(core, event, core->rate, core->new_rate);
> >                  if (ret & NOTIFY_STOP_MASK)
> > @@ -1571,9 +1574,6 @@ static int clk_core_set_rate_nolock(struct clk_core *core,
> >          if (rate == clk_core_get_rate_nolock(core))
> >                  return 0;
> >
> > -       if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count)
> > -               return -EBUSY;
> > -
> >          /* calculate new rates and get the topmost changed clock */
> >          top = clk_calc_new_rates(core, rate);
> >          if (!top)
> > --
> > 1.7.9.5