[PATCH v9 06/12] clk: zte: Add regmap-based clocks

[Stefan Dösinger]

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 like clk-gate.c I'll copy that and try to
use it as unmodified as possible.

Signed-off-by: Stefan Dösinger <stefandoesinger at gmail.com>

---

Version 9:
Register single clocks per function invocation, remove
ZX297520V3_CLK_NO_EXPORT again

Version 8: Use ZX297520V3_CLK_NO_EXPORT instead of 0 for unexported clocks.

Version 6: Remove stray regmap (Sashiko)

Version 5: Use regmap_test_bits in zte_clk_regmap_gate_is_enabled
---
 drivers/clk/zte/clk-regmap.c | 219 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 212 insertions(+), 7 deletions(-)

diff --git a/drivers/clk/zte/clk-regmap.c b/drivers/clk/zte/clk-regmap.c
index 80332dba97f6..022b2be7bb3d 100644
--- a/drivers/clk/zte/clk-regmap.c
+++ b/drivers/clk/zte/clk-regmap.c
@@ -1,32 +1,237 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
+ * Copyright (c) 2018 BayLibre, SAS.
  * Copyright (c) 2026 Stefan Dösinger
  */
 
+#include <linux/bits.h>
 #include <linux/clk-provider.h>
+#include <linux/container_of.h>
 #include <linux/device.h>
+#include <linux/err.h>
 #include <linux/errno.h>
 #include <linux/regmap.h>
+#include <linux/types.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);
+
+	return regmap_test_bits(clk->map, clk->reg, BIT(clk->shift));
+}
+
+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,
+};
+
 struct clk_hw *zx_clk_register_gate(struct device *dev, struct regmap *regmap,
-				    const struct zx_gate_desc *desc,
-				    struct clk_hw * const *clocks)
+				    const struct zx_gate_desc *desc, struct clk_hw * const *clocks)
+{
+	struct clk_parent_data parent = zx_get_parent(&desc->parent, clocks);
+	struct clk_init_data init = {};
+	struct zte_clk_regmap *clk;
+	int res;
+
+	clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
+	if (!clk)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = desc->name;
+	init.ops = &zte_clk_regmap_gate_ops;
+	init.parent_data = &parent;
+	init.num_parents = 1;
+	init.flags = CLK_SET_RATE_PARENT | desc->flags;
+	clk->hw.init = &init;
+	clk->map = regmap;
+	clk->reg = desc->reg;
+	clk->shift = desc->shift;
+	clk->size = 1;
+
+	res = devm_clk_hw_register(dev, &clk->hw);
+	if (res)
+		return ERR_PTR(res);
+
+	return &clk->hw;
+}
+
+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)
+		return 0; /* Gives a hint that something is wrong */
+
+	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)
 {
-	return ERR_PTR(-ENODEV);
+	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,
+};
+
 struct clk_hw *zx_clk_register_divider(struct device *dev, struct regmap *regmap,
 				       const struct zx_div_desc *desc,
 				       struct clk_hw * const *clocks)
 {
-	return ERR_PTR(-ENODEV);
+	struct clk_parent_data parent = zx_get_parent(&desc->parent, clocks);
+	struct clk_init_data init = {};
+	struct zte_clk_regmap *clk;
+	int res;
+
+	clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
+	if (!clk)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = desc->name;
+	init.ops = &zte_clk_regmap_divider_ops;
+	init.parent_data = &parent;
+	init.num_parents = 1;
+	init.flags = CLK_SET_RATE_PARENT;
+	clk->hw.init = &init;
+	clk->map = regmap;
+	clk->reg = desc->reg;
+	clk->shift = desc->shift;
+	clk->size = desc->size;
+
+	res = devm_clk_hw_register(dev, &clk->hw);
+	if (res)
+		return ERR_PTR(res);
+
+	return &clk->hw;
 }
 
+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,
+};
+
 struct clk_hw *zx_clk_register_mux(struct device *dev, struct regmap *regmap,
-				   const struct zx_mux_desc *desc,
-				   struct clk_hw * const *clocks)
+			  const struct zx_mux_desc *desc, struct clk_hw * const *clocks)
 {
-	return ERR_PTR(-ENODEV);
+	struct clk_parent_data parents[CLK_ZX_MAX_PARENTS];
+	struct clk_init_data init = {};
+	struct zte_clk_regmap *clk;
+	unsigned int i;
+	int res;
+
+	if (WARN_ON(desc->num_parents > ARRAY_SIZE(parents)))
+		return ERR_PTR(-EINVAL);
+
+	for (i = 0; i < desc->num_parents; ++i)
+		parents[i] = zx_get_parent(&desc->parents[i], clocks);
+
+	clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
+	if (!clk)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = desc->name;
+	init.ops = &zte_clk_regmap_mux_ops;
+	init.parent_data = parents;
+	init.num_parents = desc->num_parents;
+	clk->hw.init = &init;
+	clk->map = regmap;
+	clk->reg = desc->reg;
+	clk->shift = desc->shift;
+	clk->size = desc->size;
+
+	res = devm_clk_hw_register(dev, &clk->hw);
+	if (res)
+		return ERR_PTR(res);
+
+	return &clk->hw;
 }

-- 
2.54.0