[RFC V1 1/8] clk: support static parent

[Mike Turquette]

Hi Richard,

Thanks for porting your platform so quickly!

On Wed, Nov 23, 2011 at 3:12 AM, Richard Zhao <richard.zhao at linaro.org> wrote:
> Signed-off-by: Richard Zhao <richard.zhao at linaro.org>
> ---
>  drivers/clk/clk.c |   10 ++++------
>  1 files changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 85dabdb31..ed557c9 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -519,13 +519,11 @@ void clk_init(struct device *dev, struct clk *clk)
>
>        mutex_lock(&prepare_lock);
>
> -       if (clk->ops->get_parent) {
> +       if (clk->ops->get_parent)
>                clk->parent = clk->ops->get_parent(clk);
> -               if (clk->parent)
> -                       hlist_add_head(&clk->child_node,
> -                                       &clk->parent->children);
> -       } else
> -               clk->parent = NULL;
> +       if (clk->parent)
> +               hlist_add_head(&clk->child_node,
> +                               &clk->parent->children);

I'll have to NACK this.  I don't think we should trust .parent in
struct clk for initialization.

Rather, if your clk has a fixed parent then I would prefer for you to
put that parent inside your struct clk_hw_whatever and have your
.get_parent callback return clk_hw_whatever->fixed_parent.

The reason for this is that some folks with mux clks might be tempted
to populate .parent statically, but maybe the bootloader changed it
and now it can't be trusted.  I'd prefer to rule out this possibility
entirely by always relying on a .get_parent function.

Check out the way that the simple fixed-rate clk and simple gateable
clk does this in drivers/clk/clk-basic.c

Regards,
Mike

>
>        if (clk->ops->recalc_rate)
>                clk->rate = clk->ops->recalc_rate(clk);
> --
> 1.7.5.4
>
>
>