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[PATCH RFC v4 06/12] clk: zte: Add regmap based clocks

From: Stefan Dösinger <stefandoesinger@gmail.com>
Date: 2026-06-16 20:27:29
Also in: linux-clk, linux-devicetree, lkml
Subsystem: common clk framework, the rest · Maintainers: Michael Turquette, Stephen Boyd, Linus Torvalds 

This is based on meson/clk-regmap.c, although slightly simplified. I
have kept the copyright lines at the top of the file to indicate its
origin.

I see that numerous clock drivers have their own incarnation of regmap
based mux/div/gate clocks. If there is any version of it that is likely
to be elevated to shared code liks clk-gate.c I'll copy that and try to
use it as unmodified as possible.

Signed-off-by: Stefan Dösinger <stefandoesinger@gmail.com>
---
 drivers/clk/zte/clk-regmap.c | 223 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 220 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/zte/clk-regmap.c b/drivers/clk/zte/clk-regmap.c
index 7908f1562f63..d9459417d17d 100644
--- a/drivers/clk/zte/clk-regmap.c
+++ b/drivers/clk/zte/clk-regmap.c
@@ -6,25 +6,242 @@
  * Author: Stefan Dösinger <stefandoesinger@gmail.com>
  */
 
+#include <linux/clk-provider.h>
+#include <linux/regmap.h>
+#include <linux/device.h>
+
 #include "clk-zx.h"
 
+struct zte_clk_regmap {
+	struct clk_hw	hw;
+	struct regmap	*map;
+	u16		reg;
+	u8		shift;
+	u8		size;
+};
+
+static inline struct zte_clk_regmap *to_zte_clk_regmap(struct clk_hw *hw)
+{
+	return container_of(hw, struct zte_clk_regmap, hw);
+}
+
+static int zte_clk_regmap_gate_enable(struct clk_hw *hw)
+{
+	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
+
+	return regmap_set_bits(clk->map, clk->reg, BIT(clk->shift));
+}
+
+static void zte_clk_regmap_gate_disable(struct clk_hw *hw)
+{
+	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
+
+	regmap_clear_bits(clk->map, clk->reg, BIT(clk->shift));
+}
+
+static int zte_clk_regmap_gate_is_enabled(struct clk_hw *hw)
+{
+	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
+	u32 val;
+
+	regmap_read(clk->map, clk->reg, &val);
+	return !!val;
+}
+
+static const struct clk_ops zte_clk_regmap_gate_ops = {
+	.enable		= zte_clk_regmap_gate_enable,
+	.disable	= zte_clk_regmap_gate_disable,
+	.is_enabled	= zte_clk_regmap_gate_is_enabled,
+};
+
 int zx_clk_register_gates(struct device *dev, struct regmap *regmap,
 			  const struct zx_gate_desc *desc, unsigned int num,
 			  struct clk_hw_onecell_data *clocks)
 {
-	return -ENODEV;
+	struct zte_clk_regmap *clk;
+	unsigned int i;
+	int res;
+
+	for (i = 0; i < num; ++i) {
+		struct clk_init_data init = {};
+
+		clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
+		if (!clk)
+			return -ENOMEM;
+
+		init.name = desc[i].name;
+		init.ops = &zte_clk_regmap_gate_ops;
+		init.parent_names = &desc[i].parent;
+		init.num_parents = 1;
+		init.flags = CLK_SET_RATE_PARENT | desc[i].flags;
+		clk->hw.init = &init;
+		clk->map = regmap;
+		clk->reg = desc[i].reg;
+		clk->shift = desc[i].shift;
+		clk->size = 1;
+
+		res = devm_clk_hw_register(dev, &clk->hw);
+		if (res)
+			return dev_err_probe(dev, res, "Failed to register clk %s\n", desc[i].name);
+
+		if (desc[i].id)
+			clocks->hws[desc[i].id] = &clk->hw;
+	}
+
+	return 0;
+}
+
+static unsigned long zte_clk_regmap_div_recalc_rate(struct clk_hw *hw,
+						unsigned long prate)
+{
+	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(clk->map, clk->reg, &val);
+	if (ret)
+		/* Gives a hint that something is wrong */
+		return 0;
+
+	val >>= clk->shift;
+	val &= clk_div_mask(clk->size);
+	return divider_recalc_rate(hw, prate, val, NULL, 0, clk->size);
 }
 
+static int zte_clk_regmap_div_determine_rate(struct clk_hw *hw,
+					 struct clk_rate_request *req)
+{
+	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
+
+	return divider_determine_rate(hw, req, NULL, clk->size, 0);
+}
+
+static int zte_clk_regmap_div_set_rate(struct clk_hw *hw, unsigned long rate,
+				   unsigned long parent_rate)
+{
+	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
+	unsigned int val;
+	int ret;
+
+	ret = divider_get_val(rate, parent_rate, NULL, clk->size, 0);
+	if (ret < 0)
+		return ret;
+
+	val = (unsigned int)ret << clk->shift;
+	return regmap_update_bits(clk->map, clk->reg, clk_div_mask(clk->size) << clk->shift, val);
+};
+
+static const struct clk_ops zte_clk_regmap_divider_ops = {
+	.recalc_rate = zte_clk_regmap_div_recalc_rate,
+	.determine_rate = zte_clk_regmap_div_determine_rate,
+	.set_rate = zte_clk_regmap_div_set_rate,
+};
+
 int zx_clk_register_dividers(struct device *dev, struct regmap *regmap,
 			     const struct zx_div_desc *desc, unsigned int num,
 			     struct clk_hw_onecell_data *clocks)
 {
-	return -ENODEV;
+	struct zte_clk_regmap *clk;
+	unsigned int i;
+	int res;
+
+	for (i = 0; i < num; ++i) {
+		struct clk_init_data init = {};
+
+		clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
+		if (!clk)
+			return -ENOMEM;
+
+		init.name = desc[i].name;
+		init.ops = &zte_clk_regmap_divider_ops;
+		init.parent_names = &desc[i].parent;
+		init.num_parents = 1;
+		init.flags = CLK_SET_RATE_PARENT;
+		clk->hw.init = &init;
+		clk->map = regmap;
+		clk->reg = desc[i].reg;
+		clk->shift = desc[i].shift;
+		clk->size = desc[i].size;
+
+		res = devm_clk_hw_register(dev, &clk->hw);
+		if (res)
+			return dev_err_probe(dev, res, "Failed to register clk %s\n", desc[i].name);
+
+		if (desc[i].id)
+			clocks->hws[desc[i].id] = &clk->hw;
+	}
+
+	return 0;
 }
 
+static u8 zte_clk_regmap_mux_get_parent(struct clk_hw *hw)
+{
+	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(clk->map, clk->reg, &val);
+	if (ret)
+		return 0xff;
+
+	val >>= clk->shift;
+	val &= GENMASK(clk->size - 1, 0);
+	return clk_mux_val_to_index(hw, NULL, 0, val);
+}
+
+static int zte_clk_regmap_mux_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
+	unsigned int val = clk_mux_index_to_val(NULL, 0, index);
+
+	return regmap_update_bits(clk->map, clk->reg,
+				  GENMASK(clk->size - 1, 0) << clk->shift,
+				  val << clk->shift);
+}
+
+static int zte_clk_regmap_mux_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
+{
+	return clk_mux_determine_rate_flags(hw, req, 0);
+}
+
+static const struct clk_ops zte_clk_regmap_mux_ops = {
+	.get_parent = zte_clk_regmap_mux_get_parent,
+	.set_parent = zte_clk_regmap_mux_set_parent,
+	.determine_rate = zte_clk_regmap_mux_determine_rate,
+};
+
 int zx_clk_register_muxes(struct device *dev, struct regmap *regmap,
 			  const struct zx_mux_desc *desc, unsigned int num,
 			  struct clk_hw_onecell_data *clocks)
 {
-	return -ENODEV;
+	struct zte_clk_regmap *clk;
+	unsigned int i;
+	int res;
+
+	for (i = 0; i < num; ++i) {
+		struct clk_init_data init = {};
+
+		clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
+		if (!clk)
+			return -ENOMEM;
+
+		init.name = desc[i].name;
+		init.ops = &zte_clk_regmap_mux_ops;
+		init.parent_names = desc[i].parents;
+		init.num_parents = desc[i].num_parents;
+		clk->hw.init = &init;
+		clk->map = regmap;
+		clk->reg = desc[i].reg;
+		clk->shift = desc[i].shift;
+		clk->size = desc[i].size;
+
+		res = devm_clk_hw_register(dev, &clk->hw);
+		if (res)
+			return dev_err_probe(dev, res, "Failed to register clk %s\n", desc[i].name);
+
+		if (desc[i].id)
+			clocks->hws[desc[i].id] = &clk->hw;
+	}
+
+	return 0;
 }

-- 
2.53.0
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