[PATCH v3 1/3] clk: meson: Support PLL with fixed fractional denominators

From: Chuan Liu via B4 Relay
Date: Mon Sep 09 2024 - 06:09:29 EST


From: Chuan Liu <chuan.liu@xxxxxxxxxxx>

Some PLLS with fractional multipliers have fractional denominators with
fixed values, instead of the previous "(1 << pll-> frc.width)".

Signed-off-by: Chuan Liu <chuan.liu@xxxxxxxxxxx>
---
drivers/clk/meson/clk-pll.c | 8 +++++---
drivers/clk/meson/clk-pll.h | 1 +
2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c
index bc570a2ff3a3..89f0f04a16ab 100644
--- a/drivers/clk/meson/clk-pll.c
+++ b/drivers/clk/meson/clk-pll.c
@@ -57,12 +57,13 @@ static unsigned long __pll_params_to_rate(unsigned long parent_rate,
struct meson_clk_pll_data *pll)
{
u64 rate = (u64)parent_rate * m;
+ unsigned int frac_max = pll->frac_max ? pll->frac_max :
+ (1 << pll->frac.width);

if (frac && MESON_PARM_APPLICABLE(&pll->frac)) {
u64 frac_rate = (u64)parent_rate * frac;

- rate += DIV_ROUND_UP_ULL(frac_rate,
- (1 << pll->frac.width));
+ rate += DIV_ROUND_UP_ULL(frac_rate, frac_max);
}

return DIV_ROUND_UP_ULL(rate, n);
@@ -100,7 +101,8 @@ static unsigned int __pll_params_with_frac(unsigned long rate,
unsigned int n,
struct meson_clk_pll_data *pll)
{
- unsigned int frac_max = (1 << pll->frac.width);
+ unsigned int frac_max = pll->frac_max ? pll->frac_max :
+ (1 << pll->frac.width);
u64 val = (u64)rate * n;

/* Bail out if we are already over the requested rate */
diff --git a/drivers/clk/meson/clk-pll.h b/drivers/clk/meson/clk-pll.h
index 7b6b87274073..949157fb7bf5 100644
--- a/drivers/clk/meson/clk-pll.h
+++ b/drivers/clk/meson/clk-pll.h
@@ -43,6 +43,7 @@ struct meson_clk_pll_data {
unsigned int init_count;
const struct pll_params_table *table;
const struct pll_mult_range *range;
+ unsigned int frac_max;
u8 flags;
};


--
2.42.0