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

[Russell King - ARM Linux <linux@arm.linux.org.uk>]

On Tue, Feb 05, 2013 at 11:22:52AM +0100, Hiroshi Doyu wrote:
> 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;

That just looks totally wrong.

Firstly, according to the hunk, this function has the prototype:

static u8 clk_composite_get_parent(struct clk_hw *hw)

What do you think is the effect of passing -EINVAL back as a 'u8' ?

Secondly, the whole "check mux_hw->clk for NULL, and then overwrite it"
looks really really really wrong.  If it's already set, then why does it
need to be changed?  If it isn't set, why do you need to error out?

Thirdly, why is a function called "get_parent" modifying anything (isn't
it supposed to be _get_ing something?