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SubjectRe: [PATCH v2 1/2] clk: meson: mpll: add round closest support
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On 15/05/2018 18:36, Jerome Brunet wrote:
> Allow the mpll driver to round the requested rate up if
> CLK_MESON_MPLL_ROUND_CLOSEST is set and it provides a rate closer to the
> requested rate.
>
> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> ---
> drivers/clk/meson/clk-mpll.c | 24 +++++++++++++++++++-----
> drivers/clk/meson/clkc.h | 3 +++
> 2 files changed, 22 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/clk/meson/clk-mpll.c b/drivers/clk/meson/clk-mpll.c
> index 0df1227b65b3..d233549de244 100644
> --- a/drivers/clk/meson/clk-mpll.c
> +++ b/drivers/clk/meson/clk-mpll.c
> @@ -89,10 +89,23 @@ static long rate_from_params(unsigned long parent_rate,
> static void params_from_rate(unsigned long requested_rate,
> unsigned long parent_rate,
> unsigned int *sdm,
> - unsigned int *n2)
> + unsigned int *n2,
> + u8 flags)
> {
> uint64_t div = parent_rate;
> - unsigned long rem = do_div(div, requested_rate);
> + uint64_t frac = do_div(div, requested_rate);
> +
> + frac *= SDM_DEN;
> +
> + if (flags & CLK_MESON_MPLL_ROUND_CLOSEST)
> + *sdm = DIV_ROUND_CLOSEST_ULL(frac, requested_rate);
> + else
> + *sdm = DIV_ROUND_UP_ULL(frac, requested_rate);
> +
> + if (*sdm == SDM_DEN) {
> + *sdm = 0;
> + div += 1;
> + }
>
> if (div < N2_MIN) {
> *n2 = N2_MIN;
> @@ -102,7 +115,6 @@ static void params_from_rate(unsigned long requested_rate,
> *sdm = SDM_DEN - 1;
> } else {
> *n2 = div;
> - *sdm = DIV_ROUND_UP_ULL((u64)rem * SDM_DEN, requested_rate);
> }
> }
>
> @@ -125,9 +137,11 @@ static long mpll_round_rate(struct clk_hw *hw,
> unsigned long rate,
> unsigned long *parent_rate)
> {
> + struct clk_regmap *clk = to_clk_regmap(hw);
> + struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
> unsigned int sdm, n2;
>
> - params_from_rate(rate, *parent_rate, &sdm, &n2);
> + params_from_rate(rate, *parent_rate, &sdm, &n2, mpll->flags);
> return rate_from_params(*parent_rate, sdm, n2);
> }
>
> @@ -140,7 +154,7 @@ static int mpll_set_rate(struct clk_hw *hw,
> unsigned int sdm, n2;
> unsigned long flags = 0;
>
> - params_from_rate(rate, parent_rate, &sdm, &n2);
> + params_from_rate(rate, parent_rate, &sdm, &n2, mpll->flags);
>
> if (mpll->lock)
> spin_lock_irqsave(mpll->lock, flags);
> diff --git a/drivers/clk/meson/clkc.h b/drivers/clk/meson/clkc.h
> index 8fe73c4edca8..8cc265cd3d2b 100644
> --- a/drivers/clk/meson/clkc.h
> +++ b/drivers/clk/meson/clkc.h
> @@ -97,8 +97,11 @@ struct meson_clk_mpll_data {
> struct parm ssen;
> struct parm misc;
> spinlock_t *lock;
> + u8 flags;
> };
>
> +#define CLK_MESON_MPLL_ROUND_CLOSEST BIT(0)
> +
> struct meson_clk_audio_div_data {
> struct parm div;
> u8 flags;
>

Acked-by: Neil Armstrong <narmstrong@baylibre.com>

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