Re: [PATCH v3 1/3] clk: Update API documentation related to clock disable

["Russell King (Oracle)" <linux@armlinux.org.uk>]

On Mon, Mar 18, 2024 at 11:08:40AM +0000, Biju Das wrote:
> 
> The API's related to clk disable operation does not explicitly
> states the synchoronous or asynchrous behaviour as it is driver
> dependent. So make this part clear in API documentation.
> 
> Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> v2->v3:
>  * No change.
> v2:
>  * New patch.
> ---
>  drivers/clk/clk.c            | 3 ++-
>  include/linux/clk-provider.h | 3 ++-
>  include/linux/clk.h          | 3 ++-
>  3 files changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 25371c91a58f..f5fa91a339d7 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -1010,7 +1010,8 @@ static void clk_core_unprepare_lock(struct clk_core *core)
>   * if the operation may sleep.  One example is a clk which is accessed over
>   * I2c.  In the complex case a clk gate operation may require a fast and a slow
>   * part.  It is this reason that clk_unprepare and clk_disable are not mutually
> - * exclusive.  In fact clk_disable must be called before clk_unprepare.
> + * exclusive.  In fact clk_disable must be called before clk_unprepare.  The
> + * synchronous or asynchronous clock gating operation is driver dependent.

What is important is that:

	clk_unprepare(clk);
	clk_prepare(clk);

must result in the prepare operation being completed before
clk_prepare() returns. The same applies to clk_disable(clk) followed
by clk_enable(clk).

Since these comment updates are aimed at the unprepare/disable
functionality, I think they're fine.

Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

Thanks!

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