clk: mediatek: Add new clkmux register API

On both MT8183 & MT6765, there add "set/clr" register for
each clkmux setting, and one update register to trigger value change.
It is designed to prevent read-modify-write racing issue.
The sw design need to add a new API to handle this hw change with
a new mtk_clk_mux/mtk_mux struct in new file "clk-mux.c", "clk-mux.h".

Signed-off-by: Owen Chen <owen.chen@mediatek.com>
Signed-off-by: Weiyi Lu <weiyi.lu@mediatek.com>
Reviewed-by: James Liao <jamesjj.liao@mediatek.com>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
Tested-by: Nicolas Boichat <drinkcat@chromium.org>
[sboyd@kernel.org: Squash in flags=0 to silence warning]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

1 files changed, 223 insertions, 0 deletions

diff --git a/drivers/clk/mediatek/clk-mux.c b/drivers/clk/mediatek/clk-mux.c
new file mode 100644
index 000000000000..76f9cd039195
--- /dev/null
+++ b/drivers/clk/mediatek/clk-mux.c
@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018 MediaTek Inc.
+ * Author: Owen Chen <owen.chen@mediatek.com>
+ */
+
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/mfd/syscon.h>
+
+#include "clk-mtk.h"
+#include "clk-mux.h"
+
+static inline struct mtk_clk_mux *to_mtk_clk_mux(struct clk_hw *hw)
+{
+	return container_of(hw, struct mtk_clk_mux, hw);
+}
+
+static int mtk_clk_mux_enable(struct clk_hw *hw)
+{
+	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
+	u32 mask = BIT(mux->data->gate_shift);
+
+	return regmap_update_bits(mux->regmap, mux->data->mux_ofs,
+			mask, ~mask);
+}
+
+static void mtk_clk_mux_disable(struct clk_hw *hw)
+{
+	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
+	u32 mask = BIT(mux->data->gate_shift);
+
+	regmap_update_bits(mux->regmap, mux->data->mux_ofs, mask, mask);
+}
+
+static int mtk_clk_mux_enable_setclr(struct clk_hw *hw)
+{
+	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
+
+	return regmap_write(mux->regmap, mux->data->clr_ofs,
+			BIT(mux->data->gate_shift));
+}
+
+static void mtk_clk_mux_disable_setclr(struct clk_hw *hw)
+{
+	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
+
+	regmap_write(mux->regmap, mux->data->set_ofs,
+			BIT(mux->data->gate_shift));
+}
+
+static int mtk_clk_mux_is_enabled(struct clk_hw *hw)
+{
+	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
+	u32 val;
+
+	regmap_read(mux->regmap, mux->data->mux_ofs, &val);
+
+	return (val & BIT(mux->data->gate_shift)) == 0;
+}
+
+static u8 mtk_clk_mux_get_parent(struct clk_hw *hw)
+{
+	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
+	u32 mask = GENMASK(mux->data->mux_width - 1, 0);
+	u32 val;
+
+	regmap_read(mux->regmap, mux->data->mux_ofs, &val);
+	val = (val >> mux->data->mux_shift) & mask;
+
+	return val;
+}
+
+static int mtk_clk_mux_set_parent_lock(struct clk_hw *hw, u8 index)
+{
+	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
+	u32 mask = GENMASK(mux->data->mux_width - 1, 0);
+	unsigned long flags = 0;
+
+	if (mux->lock)
+		spin_lock_irqsave(mux->lock, flags);
+	else
+		__acquire(mux->lock);
+
+	regmap_update_bits(mux->regmap, mux->data->mux_ofs, mask,
+		index << mux->data->mux_shift);
+
+	if (mux->lock)
+		spin_unlock_irqrestore(mux->lock, flags);
+	else
+		__release(mux->lock);
+
+	return 0;
+}
+
+static int mtk_clk_mux_set_parent_setclr_lock(struct clk_hw *hw, u8 index)
+{
+	struct mtk_clk_mux *mux = to_mtk_clk_mux(hw);
+	u32 mask = GENMASK(mux->data->mux_width - 1, 0);
+	u32 val, orig;
+	unsigned long flags = 0;
+
+	if (mux->lock)
+		spin_lock_irqsave(mux->lock, flags);
+	else
+		__acquire(mux->lock);
+
+	regmap_read(mux->regmap, mux->data->mux_ofs, &orig);
+	val = (orig & ~(mask << mux->data->mux_shift))
+			| (index << mux->data->mux_shift);
+
+	if (val != orig) {
+		regmap_write(mux->regmap, mux->data->clr_ofs,
+				mask << mux->data->mux_shift);
+		regmap_write(mux->regmap, mux->data->set_ofs,
+				index << mux->data->mux_shift);
+
+		if (mux->data->upd_shift >= 0)
+			regmap_write(mux->regmap, mux->data->upd_ofs,
+					BIT(mux->data->upd_shift));
+	}
+
+	if (mux->lock)
+		spin_unlock_irqrestore(mux->lock, flags);
+	else
+		__release(mux->lock);
+
+	return 0;
+}
+
+const struct clk_ops mtk_mux_ops = {
+	.get_parent = mtk_clk_mux_get_parent,
+	.set_parent = mtk_clk_mux_set_parent_lock,
+};
+
+const struct clk_ops mtk_mux_clr_set_upd_ops = {
+	.get_parent = mtk_clk_mux_get_parent,
+	.set_parent = mtk_clk_mux_set_parent_setclr_lock,
+};
+
+const struct clk_ops mtk_mux_gate_ops = {
+	.enable = mtk_clk_mux_enable,
+	.disable = mtk_clk_mux_disable,
+	.is_enabled = mtk_clk_mux_is_enabled,
+	.get_parent = mtk_clk_mux_get_parent,
+	.set_parent = mtk_clk_mux_set_parent_lock,
+};
+
+const struct clk_ops mtk_mux_gate_clr_set_upd_ops = {
+	.enable = mtk_clk_mux_enable_setclr,
+	.disable = mtk_clk_mux_disable_setclr,
+	.is_enabled = mtk_clk_mux_is_enabled,
+	.get_parent = mtk_clk_mux_get_parent,
+	.set_parent = mtk_clk_mux_set_parent_setclr_lock,
+};
+
+struct clk *mtk_clk_register_mux(const struct mtk_mux *mux,
+				 struct regmap *regmap,
+				 spinlock_t *lock)
+{
+	struct mtk_clk_mux *clk_mux;
+	struct clk_init_data init;
+	struct clk *clk;
+
+	clk_mux = kzalloc(sizeof(*clk_mux), GFP_KERNEL);
+	if (!clk_mux)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = mux->name;
+	init.flags = mux->flags | CLK_SET_RATE_PARENT;
+	init.parent_names = mux->parent_names;
+	init.num_parents = mux->num_parents;
+	init.ops = mux->ops;
+
+	clk_mux->regmap = regmap;
+	clk_mux->data = mux;
+	clk_mux->lock = lock;
+	clk_mux->hw.init = &init;
+
+	clk = clk_register(NULL, &clk_mux->hw);
+	if (IS_ERR(clk)) {
+		kfree(clk_mux);
+		return clk;
+	}
+
+	return clk;
+}
+
+int mtk_clk_register_muxes(const struct mtk_mux *muxes,
+			   int num, struct device_node *node,
+			   spinlock_t *lock,
+			   struct clk_onecell_data *clk_data)
+{
+	struct regmap *regmap;
+	struct clk *clk;
+	int i;
+
+	regmap = syscon_node_to_regmap(node);
+	if (IS_ERR(regmap)) {
+		pr_err("Cannot find regmap for %pOF: %ld\n", node,
+		       PTR_ERR(regmap));
+		return PTR_ERR(regmap);
+	}
+
+	for (i = 0; i < num; i++) {
+		const struct mtk_mux *mux = &muxes[i];
+
+		if (IS_ERR_OR_NULL(clk_data->clks[mux->id])) {
+			clk = mtk_clk_register_mux(mux, regmap, lock);
+
+			if (IS_ERR(clk)) {
+				pr_err("Failed to register clk %s: %ld\n",
+				       mux->name, PTR_ERR(clk));
+				continue;
+			}
+
+			clk_data->clks[mux->id] = clk;
+		}
+	}
+
+	return 0;
+}