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SubjectRe: [PATCH v4 5/9] clk: at91: clk-generated: create function to find best_diff
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On 25/07/2017 at 09:37, Quentin Schulz wrote:
> The way to find the best_diff and do the appropriate process afterwards
> can be re-used.
>
> This patch prepares the driver for an upcoming patch that will allow
> clk_generated to determine the rate of the audio_pll.
>
> Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
> Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>

> ---
> drivers/clk/at91/clk-generated.c | 41 +++++++++++++++++++++------------
> 1 file changed, 27 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
> index ef4b4e0..7260e49 100644
> --- a/drivers/clk/at91/clk-generated.c
> +++ b/drivers/clk/at91/clk-generated.c
> @@ -99,15 +99,36 @@ clk_generated_recalc_rate(struct clk_hw *hw,
> return DIV_ROUND_CLOSEST(parent_rate, gck->gckdiv + 1);
> }
>
> +static void clk_generated_best_diff(struct clk_rate_request *req,
> + struct clk_hw *parent,
> + unsigned long parent_rate, u32 div,
> + int *best_diff, long *best_rate)
> +{
> + unsigned long tmp_rate;
> + int tmp_diff;
> +
> + if (!div)
> + tmp_rate = parent_rate;
> + else
> + tmp_rate = parent_rate / div;
> + tmp_diff = abs(req->rate - tmp_rate);
> +
> + if (*best_diff < 0 || *best_diff > tmp_diff) {
> + *best_rate = tmp_rate;
> + *best_diff = tmp_diff;
> + req->best_parent_rate = parent_rate;
> + req->best_parent_hw = parent;
> + }
> +}
> +
> static int clk_generated_determine_rate(struct clk_hw *hw,
> struct clk_rate_request *req)
> {
> struct clk_generated *gck = to_clk_generated(hw);
> struct clk_hw *parent = NULL;
> long best_rate = -EINVAL;
> - unsigned long tmp_rate, min_rate;
> + unsigned long min_rate;
> int best_diff = -1;
> - int tmp_diff;
> int i;
>
> for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
> @@ -125,18 +146,10 @@ static int clk_generated_determine_rate(struct clk_hw *hw,
> continue;
>
> div = DIV_ROUND_CLOSEST(parent_rate, req->rate);
> - if (!div)
> - tmp_rate = parent_rate;
> - else
> - tmp_rate = parent_rate / div;
> - tmp_diff = abs(req->rate - tmp_rate);
> -
> - if (best_diff < 0 || best_diff > tmp_diff) {
> - best_rate = tmp_rate;
> - best_diff = tmp_diff;
> - req->best_parent_rate = parent_rate;
> - req->best_parent_hw = parent;
> - }
> +
> + clk_generated_best_diff(req, parent, parent_rate, div,
> + &best_diff, &best_rate);
> +
>
> if (!best_diff)
> break;
>


--
Nicolas Ferre

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