[PATCH V2] clk: Add composite clock type

Tomasz Figa
2013-02-05T10:38:46Z

On Tuesday 05 of February 2013 11:22:52 Hiroshi Doyu wrote:
> Prashant Gaikwad <pgaikwad@nvidia.com> wrote @ Tue, 5 Feb 2013 09:33:41
+0100:
> > > The members of "clk_composite_ops" seems to be always assigned
> > > statically. Istead of dynamically allocating/assigning, can't we
> > > just
> > > have "clk_composite_ops" statically as below?
> > >
> > > static struct clk_ops clk_composite_ops = {
> > >
> > > .get_parent = clk_composite_get_parent;
> > > .set_parent = clk_composite_set_parent;
> > > .recalc_rate = clk_composite_recalc_rate;
> > > .round_rate = clk_composite_round_rate;
> > > .set_rate = clk_composite_set_rate;
> > > .is_enabled = clk_composite_is_enabled;
> > > .enable = clk_composite_enable;
> > > .disable = clk_composite_disable;
> > >
> > > };
> > >
> > > struct clk *clk_register_composite(struct device *dev, const char
> > > *name,> >
> > > const char **parent_names, int num_parents,
> > > struct clk_hw *mux_hw, const struct clk_ops
*mux_ops,
> > > struct clk_hw *div_hw, const struct clk_ops
*div_ops,
> > > struct clk_hw *gate_hw, const struct clk_ops
*gate_ops,
> > > unsigned long flags)
> > >
> > > {
> > >
> > > .....
> > >
> > > init.ops = &clk_composite_ops;
> >
> > 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.
>
> 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;
> +

Or maybe even:

if (!mux_ops)

This would be more self-explanatory and save one dereference.

Best regards,
--
Tomasz Figa
Samsung Poland R&D Center
SW Solution Development, Linux Platform