linux-kernel - [PATCH 6/9] clk: realtek: Add support for mux clock

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Message-ID: <20251229075313.27254-7-eleanor.lin@realtek.com>
Date: Mon, 29 Dec 2025 15:53:10 +0800
From: Yu-Chun Lin <eleanor.lin@...ltek.com>
To: <mturquette@...libre.com>, <sboyd@...nel.org>, <robh@...nel.org>,
        <krzk+dt@...nel.org>, <conor+dt@...nel.org>, <p.zabel@...gutronix.de>,
        <cylee12@...ltek.com>, <jyanchou@...ltek.com>
CC: <devicetree@...r.kernel.org>, <linux-clk@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <james.tai@...ltek.com>,
        <cy.huang@...ltek.com>, <stanley_chang@...ltek.com>,
        <eleanor.lin@...ltek.com>
Subject: [PATCH 6/9] clk: realtek: Add support for mux clock

Add a simple regmap-based clk_ops implementation for Realtek mux clocks.

The implementation supports parent selection and rate determination through
regmap-backed register access.

Signed-off-by: Cheng-Yu Lee <cylee12@...ltek.com>
Signed-off-by: Yu-Chun Lin <eleanor.lin@...ltek.com>
---
 drivers/clk/realtek/Makefile         |  1 +
 drivers/clk/realtek/clk-regmap-mux.c | 46 ++++++++++++++++++++++++++++
 drivers/clk/realtek/clk-regmap-mux.h | 43 ++++++++++++++++++++++++++
 3 files changed, 90 insertions(+)
 create mode 100644 drivers/clk/realtek/clk-regmap-mux.c
 create mode 100644 drivers/clk/realtek/clk-regmap-mux.h

diff --git a/drivers/clk/realtek/Makefile b/drivers/clk/realtek/Makefile
index 97058d48a176..b40dd5a26653 100644
--- a/drivers/clk/realtek/Makefile
+++ b/drivers/clk/realtek/Makefile
@@ -5,5 +5,6 @@ clk-rtk-y += common.o
 
 clk-rtk-y += clk-pll.o
 clk-rtk-y += clk-regmap-gate.o
+clk-rtk-y += clk-regmap-mux.o
 clk-rtk-y += freq_table.o
 clk-rtk-y += reset.o
diff --git a/drivers/clk/realtek/clk-regmap-mux.c b/drivers/clk/realtek/clk-regmap-mux.c
new file mode 100644
index 000000000000..10f677b3f26d
--- /dev/null
+++ b/drivers/clk/realtek/clk-regmap-mux.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2017 Realtek Semiconductor Corporation
+ * Author: Cheng-Yu Lee <cylee12@...ltek.com>
+ */
+
+#include "clk-regmap-mux.h"
+
+static u8 clk_regmap_mux_get_parent(struct clk_hw *hw)
+{
+	struct clk_regmap_mux *clkm = to_clk_regmap_mux(hw);
+	int num_parents = clk_hw_get_num_parents(hw);
+	u32 val;
+	int ret;
+
+	ret = regmap_read(clkm->clkr.regmap, clkm->mux_ofs, &val);
+	if (ret)
+		return ret;
+
+	val = val >> clkm->shift & clkm->mask;
+
+	if (val >= num_parents)
+		return -EINVAL;
+
+	return val;
+}
+
+static int clk_regmap_mux_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct clk_regmap_mux *clkm = to_clk_regmap_mux(hw);
+
+	return regmap_update_bits(clkm->clkr.regmap, clkm->mux_ofs,
+				  clkm->mask << clkm->shift, index << clkm->shift);
+}
+
+const struct clk_ops clk_regmap_mux_ops = {
+	.set_parent = clk_regmap_mux_set_parent,
+	.get_parent = clk_regmap_mux_get_parent,
+	.determine_rate = __clk_mux_determine_rate,
+};
+EXPORT_SYMBOL_GPL(clk_regmap_mux_ops);
+
+const struct clk_ops clk_regmap_mux_ro_ops = {
+	.get_parent = clk_regmap_mux_get_parent,
+};
+EXPORT_SYMBOL_GPL(clk_regmap_mux_ro_ops);
diff --git a/drivers/clk/realtek/clk-regmap-mux.h b/drivers/clk/realtek/clk-regmap-mux.h
new file mode 100644
index 000000000000..4855d4e94bc2
--- /dev/null
+++ b/drivers/clk/realtek/clk-regmap-mux.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2017 Realtek Semiconductor Corporation
+ * Author: Cheng-Yu Lee <cylee12@...ltek.com>
+ */
+
+#ifndef __CLK_REALTEK_CLK_REGMAP_MUX_H
+#define __CLK_REALTEK_CLK_REGMAP_MUX_H
+
+#include "common.h"
+
+struct clk_regmap_mux {
+	struct clk_regmap clkr;
+	int mux_ofs;
+	unsigned int mask;
+	unsigned int shift;
+};
+
+#define __clk_regmap_mux_hw(_p) __clk_regmap_hw(&(_p)->clkr)
+
+#define __CLK_REGMAP_MUX(_name, _parents, _ops, _flags, _ofs, _sft, _mask)   \
+	struct clk_regmap_mux _name = {                                      \
+		.clkr.hw.init =                                              \
+			CLK_HW_INIT_PARENTS(#_name, _parents, _ops, _flags), \
+		.mux_ofs = _ofs,                                             \
+		.shift = _sft,                                               \
+		.mask = _mask,                                               \
+	}
+
+#define CLK_REGMAP_MUX(_name, _parents, _flags, _ofs, _sft, _mask)           \
+	__CLK_REGMAP_MUX(_name, _parents, &clk_regmap_mux_ops, _flags, _ofs, \
+			 _sft, _mask)
+
+static inline struct clk_regmap_mux *to_clk_regmap_mux(struct clk_hw *hw)
+{
+	struct clk_regmap *clkr = to_clk_regmap(hw);
+
+	return container_of(clkr, struct clk_regmap_mux, clkr);
+}
+
+extern const struct clk_ops clk_regmap_mux_ops;
+
+#endif /* __CLK_REALTEK_CLK_REGMAP_MUX_H */
-- 
2.34.1