[PATCH v6 04/10] clk: realtek: Add support for phase locked loops (PLLs)

Yu-Chun Lin
2026-04-02T07:42:57Z

From: Cheng-Yu Lee <cylee12@realtek.com>

Provide a full set of PLL operations for programmable PLLs and a read-only
variant for fixed or hardware-managed PLLs.

Signed-off-by: Cheng-Yu Lee <cylee12@realtek.com>
Co-developed-by: Yu-Chun Lin <eleanor.lin@realtek.com>
Signed-off-by: Yu-Chun Lin <eleanor.lin@realtek.com>
---
Changes in v6:
- Add the headers used in c file to follow the "Include What You Use" principle.
- Move to_clk_pll() from clk-pll.h to clk-pll.c to limit its scope.
---
drivers/clk/realtek/Makefile | 2 +
drivers/clk/realtek/clk-pll.c | 164 +++++++++++++++++++++++++++++++
drivers/clk/realtek/clk-pll.h | 42 ++++++++
drivers/clk/realtek/freq_table.c | 36 +++++++
drivers/clk/realtek/freq_table.h | 21 ++++
5 files changed, 265 insertions(+)
create mode 100644 drivers/clk/realtek/clk-pll.c
create mode 100644 drivers/clk/realtek/clk-pll.h
create mode 100644 drivers/clk/realtek/freq_table.c
create mode 100644 drivers/clk/realtek/freq_table.h

diff --git a/drivers/clk/realtek/Makefile b/drivers/clk/realtek/Makefile
index 377ec776ee47..a89ad77993e9 100644
--- a/drivers/clk/realtek/Makefile
+++ b/drivers/clk/realtek/Makefile
@@ -2,3 +2,5 @@
obj-$(CONFIG_RTK_CLK_COMMON) += clk-rtk.o

clk-rtk-y += common.o
+clk-rtk-y += clk-pll.o
+clk-rtk-y += freq_table.o
diff --git a/drivers/clk/realtek/clk-pll.c b/drivers/clk/realtek/clk-pll.c
new file mode 100644
index 000000000000..44730b22a94c
--- /dev/null
+++ b/drivers/clk/realtek/clk-pll.c
@@ -0,0 +1,164 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2024 Realtek Semiconductor Corporation
+ * Author: Cheng-Yu Lee <cylee12@realtek.com>
+ */
+
+#include <linux/regmap.h>
+#include "clk-pll.h"
+
+#define TIMEOUT 2000
+
+static inline struct clk_pll *to_clk_pll(struct clk_hw *hw)
+{
+ struct clk_regmap *clkr = to_clk_regmap(hw);
+
+ return container_of(clkr, struct clk_pll, clkr);
+}
+
+static int wait_freq_ready(struct clk_pll *clkp)
+{
+ u32 pollval;
+
+ if (!clkp->freq_ready_valid)
+ return 0;
+
+ return regmap_read_poll_timeout_atomic(clkp->clkr.regmap, clkp->freq_ready_reg, pollval,
+ (pollval & clkp->freq_ready_mask)
+ == clkp->freq_ready_val, 0, TIMEOUT);
+}
+
+static bool is_power_on(struct clk_pll *clkp)
+{
+ u32 val;
+
+ if (!clkp->power_reg)
+ return true;
+
+ if (regmap_read(clkp->clkr.regmap, clkp->power_reg, &val))
+ return true;
+
+ return (val & clkp->power_mask) == clkp->power_val_on;
+}
+
+static void clk_pll_disable(struct clk_hw *hw)
+{
+ struct clk_pll *clkp = to_clk_pll(hw);
+
+ if (!clkp->seq_power_off)
+ return;
+
+ regmap_multi_reg_write(clkp->clkr.regmap, clkp->seq_power_off,
+ clkp->num_seq_power_off);
+}
+
+static int clk_pll_is_enabled(struct clk_hw *hw)
+{
+ struct clk_pll *clkp = to_clk_pll(hw);
+
+ return is_power_on(clkp);
+}
+
+static int clk_pll_determine_rate(struct clk_hw *hw,
+ struct clk_rate_request *req)
+{
+ struct clk_pll *clkp = to_clk_pll(hw);
+ const struct freq_table *ftblv = NULL;
+
+ ftblv = ftbl_find_by_rate(clkp->freq_tbl, req->rate);
+ if (!ftblv)
+ return -EINVAL;
+
+ req->rate = ftblv->rate;
+ return 0;
+}
+
+static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_pll *clkp = to_clk_pll(hw);
+ const struct freq_table *fv;
+ u32 freq_val;
+
+ if (regmap_read(clkp->clkr.regmap, clkp->freq_reg, &freq_val))
+ return 0;
+
+ freq_val &= clkp->freq_mask;
+
+ fv = ftbl_find_by_val_with_mask(clkp->freq_tbl, clkp->freq_mask,
+ freq_val);
+ return fv ? fv->rate : 0;
+}
+
+static int clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_pll *clkp = to_clk_pll(hw);
+ const struct freq_table *fv;
+ int ret;
+
+ fv = ftbl_find_by_rate(clkp->freq_tbl, rate);
+ if (!fv || fv->rate != rate)
+ return -EINVAL;
+
+ if (clkp->seq_pre_set_freq) {
+ ret = regmap_multi_reg_write(clkp->clkr.regmap, clkp->seq_pre_set_freq,
+ clkp->num_seq_pre_set_freq);
+ if (ret)
+ return ret;
+ }
+
+ ret = regmap_update_bits(clkp->clkr.regmap, clkp->freq_reg,
+ clkp->freq_mask, fv->val);
+ if (ret)
+ return ret;
+
+ if (clkp->seq_post_set_freq) {
+ ret = regmap_multi_reg_write(clkp->clkr.regmap, clkp->seq_post_set_freq,
+ clkp->num_seq_post_set_freq);
+ if (ret)
+ return ret;
+ }
+
+ if (is_power_on(clkp)) {
+ ret = wait_freq_ready(clkp);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int clk_pll_enable(struct clk_hw *hw)
+{
+ struct clk_pll *clkp = to_clk_pll(hw);
+ int ret;
+
+ if (!clkp->seq_power_on)
+ return 0;
+
+ if (is_power_on(clkp))
+ return 0;
+
+ ret = regmap_multi_reg_write(clkp->clkr.regmap, clkp->seq_power_on,
+ clkp->num_seq_power_on);
+ if (ret)
+ return ret;
+
+ return wait_freq_ready(clkp);
+}
+
+const struct clk_ops rtk_clk_pll_ops = {
+ .enable = clk_pll_enable,
+ .disable = clk_pll_disable,
+ .is_enabled = clk_pll_is_enabled,
+ .recalc_rate = clk_pll_recalc_rate,
+ .determine_rate = clk_pll_determine_rate,
+ .set_rate = clk_pll_set_rate,
+};
+EXPORT_SYMBOL_NS_GPL(rtk_clk_pll_ops, "REALTEK_CLK");
+
+const struct clk_ops rtk_clk_pll_ro_ops = {
+ .recalc_rate = clk_pll_recalc_rate,
+};
+EXPORT_SYMBOL_NS_GPL(rtk_clk_pll_ro_ops, "REALTEK_CLK");
diff --git a/drivers/clk/realtek/clk-pll.h b/drivers/clk/realtek/clk-pll.h
new file mode 100644
index 000000000000..00884585a242
--- /dev/null
+++ b/drivers/clk/realtek/clk-pll.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2017-2019 Realtek Semiconductor Corporation
+ * Author: Cheng-Yu Lee <cylee12@realtek.com>
+ */
+
+#ifndef __CLK_REALTEK_CLK_PLL_H
+#define __CLK_REALTEK_CLK_PLL_H
+
+#include "common.h"
+#include "freq_table.h"
+
+struct reg_sequence;
+
+struct clk_pll {
+ struct clk_regmap clkr;
+ const struct reg_sequence *seq_power_on;
+ u32 num_seq_power_on;
+ const struct reg_sequence *seq_power_off;
+ u32 num_seq_power_off;
+ const struct reg_sequence *seq_pre_set_freq;
+ u32 num_seq_pre_set_freq;
+ const struct reg_sequence *seq_post_set_freq;
+ u32 num_seq_post_set_freq;
+ const struct freq_table *freq_tbl;
+ u32 freq_reg;
+ u32 freq_mask;
+ u32 freq_ready_valid;
+ u32 freq_ready_mask;
+ u32 freq_ready_reg;
+ u32 freq_ready_val;
+ u32 power_reg;
+ u32 power_mask;
+ u32 power_val_on;
+};
+
+#define __clk_pll_hw(_ptr) __clk_regmap_hw(&(_ptr)->clkr)
+
+extern const struct clk_ops rtk_clk_pll_ops;
+extern const struct clk_ops rtk_clk_pll_ro_ops;
+
+#endif /* __CLK_REALTEK_CLK_PLL_H */
diff --git a/drivers/clk/realtek/freq_table.c b/drivers/clk/realtek/freq_table.c
new file mode 100644
index 000000000000..272a10e75a54
--- /dev/null
+++ b/drivers/clk/realtek/freq_table.c
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/bitops.h>
+#include "freq_table.h"
+
+const struct freq_table *ftbl_find_by_rate(const struct freq_table *ftbl,
+ unsigned long rate)
+{
+ unsigned long best_rate = 0;
+ const struct freq_table *best = NULL;
+
+ for (; !IS_FREQ_TABLE_END(ftbl); ftbl++) {
+ if (ftbl->rate == rate)
+ return ftbl;
+
+ if (ftbl->rate > rate)
+ continue;
+
+ if (ftbl->rate > best_rate) {
+ best_rate = ftbl->rate;
+ best = ftbl;
+ }
+ }
+
+ return best;
+}
+
+const struct freq_table *
+ftbl_find_by_val_with_mask(const struct freq_table *ftbl, u32 mask, u32 value)
+{
+ for (; !IS_FREQ_TABLE_END(ftbl); ftbl++) {
+ if ((ftbl->val & mask) == (value & mask))
+ return ftbl;
+ }
+ return NULL;
+};
diff --git a/drivers/clk/realtek/freq_table.h b/drivers/clk/realtek/freq_table.h
new file mode 100644
index 000000000000..6d9116651105
--- /dev/null
+++ b/drivers/clk/realtek/freq_table.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+struct freq_table {
+ u32 val;
+ unsigned long rate;
+};
+
+/* ofs check */
+#define CLK_OFS_INVALID -1
+#define CLK_OFS_IS_VALID(_ofs) ((_ofs) != CLK_OFS_INVALID)
+
+#define FREQ_TABLE_END \
+ { \
+ .rate = 0 \
+ }
+#define IS_FREQ_TABLE_END(_f) ((_f)->rate == 0)
+
+const struct freq_table *ftbl_find_by_rate(const struct freq_table *ftbl,
+ unsigned long rate);
+const struct freq_table *
+ftbl_find_by_val_with_mask(const struct freq_table *ftbl, u32 mask, u32 value);
--
2.34.1