On 03/02/2014 12:25, Boris BREZILLON :
> Implement the determine_rate callback to choose the best parent clk that
> fulfills the requested rate.
>
> Signed-off-by: Boris BREZILLON <b.brezil...@overkiz.com>
Acked-by: Nicolas Ferre <nicolas.fe...@atmel.com>
Nice feature, thanks!
> ---
> drivers/clk/at91/clk-programmable.c | 56
> +++++++++++++++++------------------
> 1 file changed, 28 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/clk/at91/clk-programmable.c
> b/drivers/clk/at91/clk-programmable.c
> index 02f62a0..8e242c7 100644
> --- a/drivers/clk/at91/clk-programmable.c
> +++ b/drivers/clk/at91/clk-programmable.c
> @@ -105,40 +105,40 @@ static unsigned long
> clk_programmable_recalc_rate(struct clk_hw *hw,
> return parent_rate >> prog->pres;
> }
>
> -static long clk_programmable_round_rate(struct clk_hw *hw, unsigned long
> rate,
> - unsigned long *parent_rate)
> +static long clk_programmable_determine_rate(struct clk_hw *hw,
> + unsigned long rate,
> + unsigned long *best_parent_rate,
> + struct clk **best_parent_clk)
> {
> - unsigned long best_rate = *parent_rate;
> - unsigned long best_diff;
> - unsigned long new_diff;
> - unsigned long cur_rate;
> - int shift = shift;
> -
> - if (rate > *parent_rate)
> - return *parent_rate;
> - else
> - best_diff = *parent_rate - rate;
> -
> - if (!best_diff)
> - return best_rate;
> + struct clk *parent = NULL;
> + long best_rate = -EINVAL;
> + unsigned long parent_rate;
> + unsigned long tmp_rate;
> + int shift;
> + int i;
>
> - for (shift = 1; shift < PROG_PRES_MASK; shift++) {
> - cur_rate = *parent_rate >> shift;
> + for (i = 0; i < __clk_get_num_parents(hw->clk); i++) {
> + parent = clk_get_parent_by_index(hw->clk, i);
> + if (!parent)
> + continue;
>
> - if (cur_rate > rate)
> - new_diff = cur_rate - rate;
> - else
> - new_diff = rate - cur_rate;
> + parent_rate = __clk_get_rate(parent);
> + for (shift = 0; shift < PROG_PRES_MASK; shift++) {
> + tmp_rate = parent_rate >> shift;
> + if (tmp_rate <= rate)
> + break;
> + }
>
> - if (!new_diff)
> - return cur_rate;
> + if (tmp_rate > rate)
> + continue;
>
> - if (new_diff < best_diff) {
> - best_diff = new_diff;
> - best_rate = cur_rate;
> + if (best_rate < 0 || (rate - tmp_rate) < (rate - best_rate)) {
> + best_rate = tmp_rate;
> + *best_parent_rate = parent_rate;
> + *best_parent_clk = parent;
> }
>
> - if (rate > cur_rate)
> + if (!best_rate)
> break;
> }
>
> @@ -231,7 +231,7 @@ static const struct clk_ops programmable_ops = {
> .prepare = clk_programmable_prepare,
> .is_prepared = clk_programmable_is_ready,
> .recalc_rate = clk_programmable_recalc_rate,
> - .round_rate = clk_programmable_round_rate,
> + .determine_rate = clk_programmable_determine_rate,
> .get_parent = clk_programmable_get_parent,
> .set_parent = clk_programmable_set_parent,
> .set_rate = clk_programmable_set_rate,
>
--
Nicolas Ferre
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