Re: [PATCH 01/16] clk: permit to define a custom parent for clk_hw_get_parent_index

Stephen Boyd
2022-03-15T17:55:22Z

Quoting Ansuel Smith (2022-03-13 12:04:04)
> Clk can have multiple parents. Some clk may require to get the cached
> index of other parent that are not current associated with the clk.
> Extend clk_hw_get_parent_index() with an optional parent to permit a
> driver to get the cached index. If parent is NULL, the parent associated
> with the provided hw clk is used.
>
> Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
> ---
> drivers/clk/clk.c | 14 +++++++++-----
> drivers/clk/tegra/clk-periph.c | 2 +-
> drivers/clk/tegra/clk-sdmmc-mux.c | 2 +-
> drivers/clk/tegra/clk-super.c | 4 ++--
> include/linux/clk-provider.h | 2 +-
> 5 files changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 8de6a22498e7..fe42f56bfbdf 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -1711,15 +1711,19 @@ static int clk_fetch_parent_index(struct clk_core *core,
> /**
> * clk_hw_get_parent_index - return the index of the parent clock
> * @hw: clk_hw associated with the clk being consumed
> + * @parent: optional clk_hw of the parent to be fetched
> *
> - * Fetches and returns the index of parent clock. Returns -EINVAL if the given
> - * clock does not have a current parent.
> + * Fetches and returns the index of parent clock. If parent is not
> + * provided the parent of hw is used.
> + * Returns -EINVAL if the given clock does not have a current parent.
> */
> -int clk_hw_get_parent_index(struct clk_hw *hw)
> +int clk_hw_get_parent_index(struct clk_hw *hw, struct clk_hw *parent)

Please introduce another API vs. tacking on an "output" argument to this
API. That makes the patch less invasive. And it can also return a
pointer instead of an integer in that case.

> {
> - struct clk_hw *parent = clk_hw_get_parent(hw);
> + /* With parent NULL get the current parent of hw */
> + if (!parent)
> + parent = clk_hw_get_parent(hw);