Re: [RFC 3/5] clk: use struct clk only for external API

From: Stephen Warren
Date: Fri Jun 27 2014 - 18:37:54 EST


On 06/27/2014 01:57 AM, Tomeu Vizoso wrote:
> From: Rabin Vincent <rabin.vincent@xxxxxxxxxxxxxx>
>
> In order to provide per-user accounting, this separates the struct clk
> used in the common clock framework into two structures 'struct clk_core'
> and 'struct clk'. struct clk_core will be used for internal
> manipulation and struct clk will be used in the clock API
> implementation.
>
> In this patch, struct clk is simply renamed to struct clk_core and a new
> struct clk is implemented which simply wraps it. In the next patch, the
> new struct clk will be used to implement per-user clock enable
> accounting.

> diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h

> -struct clk {
> +struct clk_core {
> const char *name;
> const struct clk_ops *ops;
> struct clk_hw *hw;
> struct module *owner;
> - struct clk *parent;
> + struct clk_core *parent;
> const char **parent_names;
> - struct clk **parents;
> + struct clk_core **parents;
> u8 num_parents;
> u8 new_parent_index;
> unsigned long rate;
> unsigned long new_rate;
> - struct clk *new_parent;
> - struct clk *new_child;
> + struct clk_core *new_parent;
> + struct clk_core *new_child;
> unsigned long flags;
> unsigned int enable_count;
> unsigned int prepare_count;
> @@ -55,6 +55,10 @@ struct clk {
> struct kref ref;
> };
>
> +struct clk {
> + struct clk_core clk;
> +};

I'm confused why that field isn't a pointer instead. Don't we want to
end up with the following data structure:

(dev a's) struct clk --------v
struct clk_core -----> struct clk_hw
(dev b's) struct clk --------^

Where all 3 arrows are pointers? (and struct clk_core probably contains
a list of the struct clk that point at it).

Otherwise, we end up creating a whole struct clk_core for each client.
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