Re: [PATCH v6 3/8] clk: tegra: Have EMC clock implement determine_rate()

[Thierry Reding <thierry.reding@gmail.com>]

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On Tue, Mar 17, 2015 at 10:36:13AM +0100, Tomeu Vizoso wrote:
> instead of round_rate, so we can take rate constraints into account when
> choosing the best rate.
> 
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> ---
>  drivers/clk/tegra/clk-emc.c | 19 +++++++++++++++----
>  1 file changed, 15 insertions(+), 4 deletions(-)

Mike, Stephen,

I'd like to take this into the Tegra tree because other patches depend
on this (albeit as far as I can tell it's only a runtime dependency).
This patch also depends on the EMC frequency scaling patches (that Mike
Acked) that I have in a separate branch. Alternatively I can provide a
stable branch with my current stash of patches that you can pull into
the clk tree.

Thanks,
Thierry

> diff --git a/drivers/clk/tegra/clk-emc.c b/drivers/clk/tegra/clk-emc.c
> index 704fff7..615da43 100644
> --- a/drivers/clk/tegra/clk-emc.c
> +++ b/drivers/clk/tegra/clk-emc.c
> @@ -117,8 +117,11 @@ static unsigned long emc_recalc_rate(struct clk_hw *hw,
>   * safer since things have EMC rate floors. Also don't touch parent_rate
>   * since we don't want the CCF to play with our parent clocks.
>   */
> -static long emc_round_rate(struct clk_hw *hw, unsigned long rate,
> -		    unsigned long *parent_rate)
> +static long emc_determine_rate(struct clk_hw *hw, unsigned long rate,
> +			       unsigned long min_rate,
> +			       unsigned long max_rate,
> +			       unsigned long *best_parent_rate,
> +			       struct clk_hw **best_parent_hw)
>  {
>  	struct tegra_clk_emc *tegra;
>  	u8 ram_code = tegra_read_ram_code();
> @@ -133,7 +136,15 @@ static long emc_round_rate(struct clk_hw *hw, unsigned long rate,
>  
>                  timing = tegra->timings + i;
>  
> -                if (timing->rate >= rate)
> +		if (timing->rate > max_rate) {
> +			i = min(i, 1);
> +			return tegra->timings[i - 1].rate;
> +		}
> +
> +		if (timing->rate < min_rate)
> +			continue;
> +
> +		if (timing->rate >= rate)
>                          return timing->rate;
>          }
>  
> @@ -452,7 +463,7 @@ static int load_timings_from_dt(struct tegra_clk_emc *tegra,
>  
>  static const struct clk_ops tegra_clk_emc_ops = {
>  	.recalc_rate = emc_recalc_rate,
> -	.round_rate = emc_round_rate,
> +	.determine_rate = emc_determine_rate,
>  	.set_rate = emc_set_rate,
>  	.get_parent = emc_get_parent,
>  };
> -- 
> 2.1.0
> 

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