[PATCH 01/11] clk: sunxi-ng: mux: Fix determine_rate for mux clocks with pre-dividers

Maxime Ripard
2017-01-26T09:55:23Z

Hi Chen-Yu,

On Tue, Jan 24, 2017 at 10:32:20AM +0800, Chen-Yu Tsai wrote:
> The determine_rate helper used ccu_mux_helper_adjust_parent_for_prediv()
> to adjust the parent_rate to account for pre-dividers, but then passed
> the pristine parent clock rate from clk_hw_get_rate() to the round()
> callback, thereby ignoring the pre-divider adjustment. In addition,
> it was saving the adjusted parent rate back into struct
> clk_rate_request.
>
> This patch fixes this by saving the pristine parent clock rate, and
> adding a copy that is adjusted and passed to the round() callback.
> The pristine copy, if it is the best solution, would be saved back
> to struct clk_rate_request.
>
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
> drivers/clk/sunxi-ng/ccu_mux.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
> index 858a48621631..3445041894e7 100644
> --- a/drivers/clk/sunxi-ng/ccu_mux.c
> +++ b/drivers/clk/sunxi-ng/ccu_mux.c
> @@ -71,7 +71,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
> unsigned int i;
>
> for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
> - unsigned long tmp_rate, parent_rate;
> + unsigned long tmp_rate, parent_rate, adj_parent_rate;
> struct clk_hw *parent;
>
> parent = clk_hw_get_parent_by_index(hw, i);
> @@ -79,10 +79,11 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
> continue;
>
> parent_rate = clk_hw_get_rate(parent);
> + adj_parent_rate = parent_rate;
> ccu_mux_helper_adjust_parent_for_prediv(common, cm, i,
> - &parent_rate);
> + &adj_parent_rate);
>
> - tmp_rate = round(cm, clk_hw_get_rate(parent), req->rate, data);
> + tmp_rate = round(cm, parent_rate, req->rate, data);

Shouldn't you use the adjusted rate here too?

Thanks,
Maxime

--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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