[PATCH 4/7] clk: thead: th1520-ap: Support setting PLL rates

Yao Zi
2025-11-20T13:16:26Z

TH1520 ships several PLLs that could operate in either integer or
fractional mode. However, the TRM only lists a few configuration whose
stability is considered guaranteed.

Add a table-lookup rate determination logic to support PLL rate setting,
and fill up frequency-configuration tables for AP-subsystem PLLs.

Signed-off-by: Yao Zi <ziyao@disroot.org>
---
drivers/clk/thead/clk-th1520-ap.c | 142 ++++++++++++++++++++++++++++++
1 file changed, 142 insertions(+)

diff --git a/drivers/clk/thead/clk-th1520-ap.c b/drivers/clk/thead/clk-th1520-ap.c
index b820d47387bb..bf8e80c39a9e 100644
--- a/drivers/clk/thead/clk-th1520-ap.c
+++ b/drivers/clk/thead/clk-th1520-ap.c
@@ -22,6 +22,7 @@
#define TH1520_PLL_REFDIV GENMASK(5, 0)
#define TH1520_PLL_BYPASS BIT(30)
#define TH1520_PLL_VCO_RST BIT(29)
+#define TH1520_PLL_DACPD BIT(25)
#define TH1520_PLL_DSMPD BIT(24)
#define TH1520_PLL_FRAC GENMASK(23, 0)
#define TH1520_PLL_FRAC_BITS 24
@@ -72,9 +73,19 @@ struct ccu_div {
struct ccu_common common;
};

+struct ccu_pll_cfg {
+ unsigned long freq;
+ u32 fbdiv;
+ u32 frac;
+ u32 postdiv1;
+ u32 postdiv2;
+};
+
struct ccu_pll {
struct ccu_common common;
u32 lock_sts_mask;
+ int cfgnum;
+ const struct ccu_pll_cfg *cfgs;
};

#define TH_CCU_ARG(_shift, _width) \
@@ -391,17 +402,102 @@ static unsigned long ccu_pll_recalc_rate(struct clk_hw *hw,
return rate;
}

+static const struct ccu_pll_cfg *ccu_pll_lookup_best_cfg(struct ccu_pll *pll,
+ unsigned long rate)
+{
+ unsigned long best_delta = ULONG_MAX;
+ const struct ccu_pll_cfg *best_cfg;
+ int i;
+
+ for (i = 0; i < pll->cfgnum; i++) {
+ const struct ccu_pll_cfg *cfg = &pll->cfgs[i];
+ unsigned long delta;
+
+ delta = abs_diff(cfg->freq, rate);
+ if (delta < best_delta) {
+ best_delta = delta;
+ best_cfg = cfg;
+ }
+ }
+
+ return best_cfg;
+}
+
+static int ccu_pll_determine_rate(struct clk_hw *hw,
+ struct clk_rate_request *req)
+{
+ struct ccu_pll *pll = hw_to_ccu_pll(hw);
+
+ req->rate = ccu_pll_lookup_best_cfg(pll, req->rate)->freq;
+
+ return 0;
+}
+
+static int ccu_pll_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct ccu_pll *pll = hw_to_ccu_pll(hw);
+ const struct ccu_pll_cfg *cfg;
+
+ cfg = ccu_pll_lookup_best_cfg(pll, rate);
+
+ ccu_pll_disable(hw);
+
+ regmap_write(pll->common.map, pll->common.cfg0,
+ FIELD_PREP(TH1520_PLL_REFDIV, 1) |
+ FIELD_PREP(TH1520_PLL_FBDIV, cfg->fbdiv) |
+ FIELD_PREP(TH1520_PLL_POSTDIV1, cfg->postdiv1) |
+ FIELD_PREP(TH1520_PLL_POSTDIV2, cfg->postdiv2));
+
+ regmap_update_bits(pll->common.map, pll->common.cfg1,
+ TH1520_PLL_DACPD | TH1520_PLL_DSMPD |
+ TH1520_PLL_FRAC,
+ cfg->frac ? cfg->frac :
+ TH1520_PLL_DACPD | TH1520_PLL_DSMPD);
+
+ return ccu_pll_enable(hw);
+}
+
static const struct clk_ops clk_pll_ops = {
.disable = ccu_pll_disable,
.enable = ccu_pll_enable,
.is_enabled = ccu_pll_is_enabled,
.recalc_rate = ccu_pll_recalc_rate,
+ .determine_rate = ccu_pll_determine_rate,
+ .set_rate = ccu_pll_set_rate,
};

static const struct clk_parent_data osc_24m_clk[] = {
{ .index = 0 }
};

+static const struct ccu_pll_cfg cpu_pll_cfgs[] = {
+ { 125000000, 125, 0, 6, 4 },
+ { 200000000, 125, 0, 5, 3 },
+ { 300000000, 125, 0, 5, 2 },
+ { 400000000, 100, 0, 3, 2 },
+ { 500000000, 125, 0, 6, 1 },
+ { 600000000, 125, 0, 5, 1 },
+ { 702000000, 117, 0, 4, 1 },
+ { 800000000, 100, 0, 3, 1 },
+ { 900000000, 75, 0, 2, 1 },
+ { 1000000000, 125, 0, 3, 1 },
+ { 1104000000, 92, 0, 2, 1 },
+ { 1200000000, 100, 0, 2, 1 },
+ { 1296000000, 108, 0, 2, 1 },
+ { 1404000000, 117, 0, 2, 1 },
+ { 1500000000, 125, 0, 2, 1 },
+ { 1608000000, 67, 0, 1, 1 },
+ { 1704000000, 71, 0, 1, 1 },
+ { 1800000000, 75, 0, 1, 1 },
+ { 1896000000, 79, 0, 1, 1 },
+ { 1992000000, 83, 0, 1, 1 },
+ { 2112000000, 88, 0, 1, 1 },
+ { 2208000000, 92, 0, 1, 1 },
+ { 2304000000, 96, 0, 1, 1 },
+ { 2400000000, 100, 0, 1, 1 },
+};
+
static struct ccu_pll cpu_pll0_clk = {
.common = {
.clkid = CLK_CPU_PLL0,
@@ -413,6 +509,8 @@ static struct ccu_pll cpu_pll0_clk = {
CLK_IS_CRITICAL),
},
.lock_sts_mask = BIT(1),
+ .cfgnum = ARRAY_SIZE(cpu_pll_cfgs),
+ .cfgs = cpu_pll_cfgs,
};

static struct ccu_pll cpu_pll1_clk = {
@@ -426,6 +524,16 @@ static struct ccu_pll cpu_pll1_clk = {
CLK_IS_CRITICAL),
},
.lock_sts_mask = BIT(4),
+ .cfgnum = ARRAY_SIZE(cpu_pll_cfgs),
+ .cfgs = cpu_pll_cfgs,
+};
+
+static const struct ccu_pll_cfg gmac_pll_cfg = {
+ .freq = 1000000000,
+ .fbdiv = 125,
+ .frac = 0,
+ .postdiv1 = 3,
+ .postdiv2 = 1,
};

static struct ccu_pll gmac_pll_clk = {
@@ -439,6 +547,8 @@ static struct ccu_pll gmac_pll_clk = {
CLK_IS_CRITICAL),
},
.lock_sts_mask = BIT(3),
+ .cfgnum = 1,
+ .cfgs = &gmac_pll_cfg,
};

static const struct clk_hw *gmac_pll_clk_parent[] = {
@@ -449,6 +559,14 @@ static const struct clk_parent_data gmac_pll_clk_pd[] = {
{ .hw = &gmac_pll_clk.common.hw }
};

+static const struct ccu_pll_cfg video_pll_cfg = {
+ .freq = 792000000,
+ .fbdiv = 99,
+ .frac = 0,
+ .postdiv1 = 3,
+ .postdiv2 = 1,
+};
+
static struct ccu_pll video_pll_clk = {
.common = {
.clkid = CLK_VIDEO_PLL,
@@ -460,6 +578,8 @@ static struct ccu_pll video_pll_clk = {
CLK_IS_CRITICAL),
},
.lock_sts_mask = BIT(7),
+ .cfgnum = 1,
+ .cfgs = &video_pll_cfg,
};

static const struct clk_hw *video_pll_clk_parent[] = {
@@ -470,6 +590,14 @@ static const struct clk_parent_data video_pll_clk_pd[] = {
{ .hw = &video_pll_clk.common.hw }
};

+static const struct ccu_pll_cfg dpu_pll_cfg = {
+ .freq = 1188000000,
+ .fbdiv = 99,
+ .frac = 0,
+ .postdiv1 = 2,
+ .postdiv2 = 1,
+};
+
static struct ccu_pll dpu0_pll_clk = {
.common = {
.clkid = CLK_DPU0_PLL,
@@ -481,6 +609,8 @@ static struct ccu_pll dpu0_pll_clk = {
0),
},
.lock_sts_mask = BIT(8),
+ .cfgnum = 1,
+ .cfgs = &dpu_pll_cfg,
};

static const struct clk_hw *dpu0_pll_clk_parent[] = {
@@ -498,12 +628,22 @@ static struct ccu_pll dpu1_pll_clk = {
0),
},
.lock_sts_mask = BIT(9),
+ .cfgnum = 1,
+ .cfgs = &dpu_pll_cfg,
};

static const struct clk_hw *dpu1_pll_clk_parent[] = {
&dpu1_pll_clk.common.hw
};

+static const struct ccu_pll_cfg tee_pll_cfg = {
+ .freq = 792000000,
+ .fbdiv = 99,
+ .frac = 0,
+ .postdiv1 = 3,
+ .postdiv2 = 1,
+};
+
static struct ccu_pll tee_pll_clk = {
.common = {
.clkid = CLK_TEE_PLL,
@@ -515,6 +655,8 @@ static struct ccu_pll tee_pll_clk = {
CLK_IS_CRITICAL),
},
.lock_sts_mask = BIT(10),
+ .cfgnum = 1,
+ .cfgs = &tee_pll_cfg,
};

static const struct clk_parent_data c910_i0_parents[] = {
--
2.51.2