Re: [PATCH 4/4] clk: samsung: add infrastructure to add separate aliases

["Heiko Stübner" <heiko@sntech.de>]

Am Dienstag, 12. März 2013, 10:57:30 schrieb Thomas Abraham:
> On 12 March 2013 05:15, Heiko Stübner <heiko@sntech.de> wrote:
> > The current code adds aliases, if necessary, directly when adding the
> > clock, limiting the number of possible aliases to one.
> > 
> > Some platforms need more than one alias, like the hsmmc pclocks on
> > s3c2416 which need a "hsmmc" and "mmc_busclk.0" alias for the s3c-sdhci
> > driver.
> > 
> > Therefore add the possibility to separately add clock aliases for
> > previously created clocks.
> > 
> > Signed-off-by: Heiko Stuebner <heiko@sntech.de>
> > ---
> > change since the discussion: removed the list->alias check
> > 
> >  drivers/clk/samsung/clk.c |   33 +++++++++++++++++++++++++++++++++
> >  drivers/clk/samsung/clk.h |   21 +++++++++++++++++++++
> >  2 files changed, 54 insertions(+), 0 deletions(-)
> > 
> > diff --git a/drivers/clk/samsung/clk.c b/drivers/clk/samsung/clk.c
> > index 7c943f8..20ec566 100644
> > --- a/drivers/clk/samsung/clk.c
> > +++ b/drivers/clk/samsung/clk.c
> > @@ -94,6 +94,39 @@ void samsung_clk_add_lookup(struct clk *clk, unsigned
> > int id)
> > 
> >                 clk_table[id] = clk;
> >  
> >  }
> > 
> > +/* register a list of aliases */
> > +void __init samsung_clk_register_alias(struct samsung_clock_alias *list,
> > +                                       unsigned int nr_clk)
> > +{
> > +       struct clk *clk;
> > +       unsigned int idx, ret;
> > +
> > +       if (!clk_table) {
> > +               pr_err("%s: clock table missing\n", __func__);
> > +               return;
> > +       }
> > +
> > +       for (idx = 0; idx < nr_clk; idx++, list++) {
> > +               if (!list->id) {
> > +                       pr_err("%s: clock id missing for index %d\n",
> > __func__, +                               idx);
> > +                       continue;
> > +               }
> > +
> > +               clk = clk_table[list->id];
> > +               if (!clk) {
> > +                       pr_err("%s: failed to find clock %d\n", __func__,
> > +                               list->id);
> > +                       continue;
> > +               }
> > +
> > +               ret = clk_register_clkdev(clk, list->alias,
> > list->dev_name); +               if (ret)
> > +                       pr_err("%s: failed to register lookup %s\n",
> > +                                       __func__, list->alias);
> > +       }
> > +}
> > +
> > 
> >  /* register a list of fixed clocks */
> >  void __init samsung_clk_register_fixed_rate(
> >  
> >                 struct samsung_fixed_rate_clock *list, unsigned int
> >                 nr_clk)
> > 
> > diff --git a/drivers/clk/samsung/clk.h b/drivers/clk/samsung/clk.h
> > index 26a752b..6bacd6f 100644
> > --- a/drivers/clk/samsung/clk.h
> > +++ b/drivers/clk/samsung/clk.h
> > @@ -23,6 +23,25 @@
> > 
> >  #include <mach/map.h>
> >  
> >  /**
> > 
> > + * struct samsung_clock_alias: information about mux clock
> > + * @id: platform specific id of the clock.
> > + * @dev_name: name of the device to which this clock belongs.
> > + * @alias: optional clock alias name to be assigned to this clock.
> > + */
> > +struct samsung_clock_alias {
> > +       unsigned int            id;
> > +       const char              *dev_name;
> > +       const char              *alias;
> > +};
> > +
> > +#define ALIAS(_id, dname, a)   \
> > +       {                                                       \
> > +               .id             = _id,                          \
> > +               .dev_name       = dname,                        \
> > +               .alias          = a,                            \
> > +       }
> > +
> > +/**
> > 
> >   * struct samsung_fixed_rate_clock: information about fixed-rate clock
> >   * @id: platform specific id of the clock.
> >   * @name: name of this fixed-rate clock.
> > 
> > @@ -251,6 +270,8 @@ extern void __init samsung_clk_of_register_fixed_ext(
> > 
> >  extern void samsung_clk_add_lookup(struct clk *clk, unsigned int id);
> > 
> > +extern void samsung_clk_register_alias(struct samsung_clock_alias *list,
> > +               unsigned int nr_clk);
> > 
> >  extern void __init samsung_clk_register_fixed_rate(
> >  
> >                 struct samsung_fixed_rate_clock *clk_list, unsigned int
> >                 nr_clk);
> >  
> >  extern void __init samsung_clk_register_fixed_factor(
> > 
> > --
> > 1.7.2.3
> 
> This change looks fine but as discussed on 3/4 patch of this series,
> allocating clk_table for non-dt platforms would not be very helpful.

But how would we look up the previously registered clk otherwise?
Using clk_table for this lookup seemed like the best way to easily access 
these clocks.


Thanks
Heiko