Re: [PATCH V2] clk: Add composite clock type

[Prashant Gaikwad]

On Wednesday 06 February 2013 11:40 AM, Hiroshi Doyu wrote:
> Prashant Gaikwad <pgaikwad@xxxxxxxxxx> wrote @ Wed, 6 Feb 2013 03:55:00 +0100:
>
> > > > No, clk_ops depends on the clocks you are using. There could be a clock
> > > > with mux and gate while another one with mux and div.
> > > You are right. What about the following? We don't have to have similar
> > > copy of clk_composite_ops for each instances.
> > Clock framework takes decision depending on the ops availability and it
> > does not know if the clock is mux or gate.
> >
> > For example,
> >
> >                   if (clk->ops->enable) {
> >                           ret = clk->ops->enable(clk->hw);
> >                           if (ret) {
> >                                   __clk_disable(clk->parent);
> >                                   return ret;
> >                           }
> >                   }
> >
> > in above case if clk_composite does not have gate clock then as per your
> > suggestion if it returns error value then it will fail and it is wrong.
> Ok, now I understand. Thank you for explanation.
>
> We always need to allocate clk_composite_ops for each clk_composite,
> right? If so what about having "struct clk_ops ops" in "struct
> clk_composite"?
>
> diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite.c
> index f30fb4b..5240e24 100644
> --- a/drivers/clk/clk-composite.c
> +++ b/drivers/clk/clk-composite.c
> @@ -129,20 +129,13 @@ struct clk *clk_register_composite(struct device *dev, const char *name,
>                  pr_err("%s: could not allocate composite clk\n", __func__);
>                  return ERR_PTR(-ENOMEM);
>          }
> +       clk_composite_ops = &composite->ops;
>   
>          init.name = name;
>          init.flags = flags | CLK_IS_BASIC;
>          init.parent_names = parent_names;
>          init.num_parents = num_parents;
>   
> -       /* allocate the clock ops */
> -       clk_composite_ops = kzalloc(sizeof(*clk_composite_ops), GFP_KERNEL);
> -       if (!clk_composite_ops) {
> -               pr_err("%s: could not allocate clk ops\n", __func__);
> -               kfree(composite);
> -               return ERR_PTR(-ENOMEM);
> -       }
> -
>          if (mux_hw && mux_ops) {
>                  if (!mux_ops->get_parent || !mux_ops->set_parent) {
>                          clk = ERR_PTR(-EINVAL);
> @@ -202,7 +195,6 @@ struct clk *clk_register_composite(struct device *dev, const char *name,
>          return clk;
>   
>   err:
> -       kfree(clk_composite_ops);
>          kfree(composite);
>          return clk;
>   }
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index f0ac818..bb5d36a 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -346,6 +346,8 @@ struct clk_composite {
>          const struct clk_ops    *mux_ops;
>          const struct clk_ops    *div_ops;
>          const struct clk_ops    *gate_ops;
> +
> +       const struct clk_ops    ops;
>   };
>   
>   struct clk *clk_register_composite(struct device *dev, const char *name,

This will work, but there is no harm in allocating dynamically. What is 
preferred?

> > > diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite.c
> > > index f30fb4b..8f88805 100644
> > > --- a/drivers/clk/clk-composite.c
> > > +++ b/drivers/clk/clk-composite.c
> > > @@ -27,6 +27,9 @@ static u8 clk_composite_get_parent(struct clk_hw *hw)
> > >           const struct clk_ops *mux_ops = composite->mux_ops;
> > >           struct clk_hw *mux_hw = composite->mux_hw;
> > >    
> > > +       if (!mux_hw->clk)
> > > +	       return -EINVAL;
> > > +
> > >           mux_hw->clk = hw->clk;
> > It is wrong.
> Will the above "mux_hw->clk = hw->clk" be removed from the original?

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