[PATCH] clk: update clk_clean_rate_cache to use private clk struct

[Sean Anderson]

On 1/31/22 10:18 AM, Patrick Delaunay wrote:
> In clk_clean_rate_cache, clk->rate should update the private clock
> struct, in particular when CCF is activated, to save the cached
> rate value.
> 
> When clk_get_parent_rate is called, the cached information
> is read from pclk->rate, with pclk = clk_get_parent(clk).
> 
> As the cached is read from private clk data, the update should
> be done also on it.
> 
> Fixes: 6b7fd3128f7 ("clk: fix set_rate to clean up cached rates for the hierarchy")
> Signed-off-by: Patrick Delaunay <patrick.delaunay at foss.st.com>
> ---
> 
>   drivers/clk/clk-uclass.c | 20 +++++++++++++++++++-
>   1 file changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c
> index d245b672fa..62393b73e1 100644
> --- a/drivers/clk/clk-uclass.c
> +++ b/drivers/clk/clk-uclass.c
> @@ -576,6 +576,21 @@ ulong clk_round_rate(struct clk *clk, ulong rate)
>   	return ops->round_rate(clk, rate);
>   }
>   
> +static void clk_get_priv(struct clk *clk, struct clk **clkp)
> +{
> +	*clkp = NULL;
> +
> +	/* get private clock struct associated to the provided clock */
> +	if (CONFIG_IS_ENABLED(CLK_CCF)) {
> +		/* Take id 0 as a non-valid clk, such as dummy */
> +		if (clk->id)
> +			clk_get_by_id(clk->id, clkp);
> +	} else {
> +		*clkp = dev_get_clk_ptr(clk->dev);
> +	}

Does this even do anything without CCF? AFAIK those clocks are the only
ones which mirror the clock structure in udevices and keep their "real"
struct clock as their private data. IMO this whole system is broken
because most drivers do not/should not do this.

--Sean

> +}
> +
> +/* clean cache, called with private clock struct */
>   static void clk_clean_rate_cache(struct clk *clk)
>   {
>   	struct udevice *child_dev;
> @@ -595,6 +610,7 @@ static void clk_clean_rate_cache(struct clk *clk)
>   ulong clk_set_rate(struct clk *clk, ulong rate)
>   {
>   	const struct clk_ops *ops;
> +	struct clk *clkp;
>   
>   	debug("%s(clk=%p, rate=%lu)\n", __func__, clk, rate);
>   	if (!clk_valid(clk))
> @@ -604,8 +620,10 @@ ulong clk_set_rate(struct clk *clk, ulong rate)
>   	if (!ops->set_rate)
>   		return -ENOSYS;
>   
> +	/* get private clock struct used for cache */
> +	clk_get_priv(clk, &clkp);
>   	/* Clean up cached rates for us and all child clocks */
> -	clk_clean_rate_cache(clk);
> +	clk_clean_rate_cache(clkp);
>   
>   	return ops->set_rate(clk, rate);
>   }
>