[PATCH 04/16] clk: sunxi-ng: Add gate clock support

[Maxime Ripard]

Some clocks in the Allwinner SoCs clocks unit are just simple gates. Add
support for those clocks.

Since it's a feature that can also be found in more complex clocks, provide
a bunch of helpers that can be reused later on.

Signed-off-by: Maxime Ripard <maxime.ripard at free-electrons.com>
---
 drivers/clk/sunxi-ng/Makefile   |  1 +
 drivers/clk/sunxi-ng/ccu_gate.c | 82 +++++++++++++++++++++++++++++++++++++++++
 drivers/clk/sunxi-ng/ccu_gate.h | 53 ++++++++++++++++++++++++++
 3 files changed, 136 insertions(+)
 create mode 100644 drivers/clk/sunxi-ng/ccu_gate.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_gate.h

diff --git a/drivers/clk/sunxi-ng/Makefile b/drivers/clk/sunxi-ng/Makefile
index d76276736765..fc01127b3b45 100644
--- a/drivers/clk/sunxi-ng/Makefile
+++ b/drivers/clk/sunxi-ng/Makefile
@@ -2,3 +2,4 @@ obj-y += ccu_common.o
 obj-y += ccu_reset.o
 
 obj-y += ccu_fixed_factor.o
+obj-y += ccu_gate.o
diff --git a/drivers/clk/sunxi-ng/ccu_gate.c b/drivers/clk/sunxi-ng/ccu_gate.c
new file mode 100644
index 000000000000..1e98f8a33ac3
--- /dev/null
+++ b/drivers/clk/sunxi-ng/ccu_gate.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2016 Maxime Ripard
+ * Maxime Ripard <maxime.ripard at free-electrons.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#include <linux/clk-provider.h>
+
+#include "ccu_gate.h"
+
+void ccu_gate_helper_disable(struct ccu_common *common, u32 gate)
+{
+	unsigned long flags;
+	u32 reg;
+
+	if (!(common->features & CCU_FEATURE_GATE))
+		return;
+
+	spin_lock_irqsave(common->lock, flags);
+
+	reg = readl(common->base + common->reg);
+	writel(reg & ~gate, common->base + common->reg);
+
+	spin_unlock_irqrestore(common->lock, flags);
+}
+
+static void ccu_gate_disable(struct clk_hw *hw)
+{
+	struct ccu_gate *cg = hw_to_ccu_gate(hw);
+
+	return ccu_gate_helper_disable(&cg->common, cg->enable);
+}
+
+int ccu_gate_helper_enable(struct ccu_common *common, u32 gate)
+{
+	unsigned long flags;
+	u32 reg;
+
+	if (!(common->features & CCU_FEATURE_GATE))
+		return 0;
+
+	spin_lock_irqsave(common->lock, flags);
+
+	reg = readl(common->base + common->reg);
+	writel(reg | gate, common->base + common->reg);
+
+	spin_unlock_irqrestore(common->lock, flags);
+
+	return 0;
+}
+
+static int ccu_gate_enable(struct clk_hw *hw)
+{
+	struct ccu_gate *cg = hw_to_ccu_gate(hw);
+
+	return ccu_gate_helper_enable(&cg->common, cg->enable);
+}
+
+int ccu_gate_helper_is_enabled(struct ccu_common *common, u32 gate)
+{
+	if (!(common->features & CCU_FEATURE_GATE))
+		return 1;
+
+	return readl(common->base + common->reg) & gate;
+}
+
+static int ccu_gate_is_enabled(struct clk_hw *hw)
+{
+	struct ccu_gate *cg = hw_to_ccu_gate(hw);
+
+	return ccu_gate_helper_is_enabled(&cg->common, cg->enable);
+}
+
+const struct clk_ops ccu_gate_ops = {
+	.disable	= ccu_gate_disable,
+	.enable		= ccu_gate_enable,
+	.is_enabled	= ccu_gate_is_enabled,
+};
diff --git a/drivers/clk/sunxi-ng/ccu_gate.h b/drivers/clk/sunxi-ng/ccu_gate.h
new file mode 100644
index 000000000000..8e15fa17bcc1
--- /dev/null
+++ b/drivers/clk/sunxi-ng/ccu_gate.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2016 Maxime Ripard. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _CCU_GATE_H_
+#define _CCU_GATE_H_
+
+#include <linux/clk-provider.h>
+
+#include "ccu_common.h"
+
+struct ccu_gate {
+	u32			enable;
+
+	struct ccu_common	common;
+};
+
+#define SUNXI_CCU_GATE(_struct, _name, _parent, _reg, _gate, _flags)	\
+	struct ccu_gate _struct = {					\
+		.enable	= _gate,					\
+		.common	= {						\
+			.reg		= _reg,				\
+			.features	= CCU_FEATURE_GATE,		\
+			.hw.init	= SUNXI_HW_INIT(_name,		\
+							_parent,	\
+							&ccu_gate_ops,	\
+							_flags),	\
+		}							\
+	}
+
+static inline struct ccu_gate *hw_to_ccu_gate(struct clk_hw *hw)
+{
+	struct ccu_common *common = hw_to_ccu_common(hw);
+
+	return container_of(common, struct ccu_gate, common);
+}
+
+void ccu_gate_helper_disable(struct ccu_common *common, u32 gate);
+int ccu_gate_helper_enable(struct ccu_common *common, u32 gate);
+int ccu_gate_helper_is_enabled(struct ccu_common *common, u32 gate);
+
+extern const struct clk_ops ccu_gate_ops;
+
+#endif /* _CCU_GATE_H_ */
-- 
2.8.2