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Subject[PATCH v2 1/2] clk: meson: mpll: add round closest support
Date
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;
--
2.14.3
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