* Tomi Valkeinen <[email protected]> [140116 23:47]:
> omap2_dpll_round_rate() doesn't actually round the given rate, even if
> the name and the description so hints. Instead it only tries to find an
> exact rate match, or if that fails, return ~0 as an error.
>
> What this basically means is that the user of the clock needs to know
> what rates the dpll can support, which obviously isn't right.
>
> This patch adds a simple method of rounding: during the iteration, the
> code keeps track of the closest rate match. If no exact match is found,
> the closest is returned.
>
> Signed-off-by: Tomi Valkeinen <[email protected]>
Paul & Tero, please ack if you want me to queue this.
Tony
> ---
> arch/arm/mach-omap2/clkt_dpll.c | 17 ++++++++++++-----
> 1 file changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/clkt_dpll.c b/arch/arm/mach-omap2/clkt_dpll.c
> index 1f1708ef77bb..1b4e68dfb713 100644
> --- a/arch/arm/mach-omap2/clkt_dpll.c
> +++ b/arch/arm/mach-omap2/clkt_dpll.c
> @@ -298,6 +298,7 @@ long omap2_dpll_round_rate(struct clk_hw *hw, unsigned
> long target_rate,
> struct dpll_data *dd;
> unsigned long ref_rate;
> const char *clk_name;
> + unsigned long diff, closest_diff = ~0;
>
> if (!clk || !clk->dpll_data)
> return ~0;
> @@ -345,20 +346,26 @@ long omap2_dpll_round_rate(struct clk_hw *hw, unsigned
> long target_rate,
> pr_debug("clock: %s: m = %d: n = %d: new_rate = %lu\n",
> clk_name, m, n, new_rate);
>
> - if (target_rate == new_rate) {
> + diff = max(target_rate, new_rate) - min(target_rate, new_rate);
> +
> + if (diff < closest_diff) {
> + closest_diff = diff;
> +
> dd->last_rounded_m = m;
> dd->last_rounded_n = n;
> - dd->last_rounded_rate = target_rate;
> - break;
> + dd->last_rounded_rate = new_rate;
> +
> + if (diff == 0)
> + break;
> }
> }
>
> - if (target_rate != new_rate) {
> + if (closest_diff == ~0) {
> pr_debug("clock: %s: cannot round to rate %lu\n",
> clk_name, target_rate);
> return ~0;
> }
>
> - return target_rate;
> + return dd->last_rounded_rate;
> }
>
> --
> 1.8.3.2
>
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