Initial import

1 files changed, 180 insertions, 0 deletions

diff --git a/drivers/clk/clk-gate.c b/drivers/clk/clk-gate.c
new file mode 100644
index 000000000..3f0e4200c
--- /dev/null
+++ b/drivers/clk/clk-gate.c
@@ -0,0 +1,180 @@
+/*
+ * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
+ * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Gated clock implementation
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/string.h>
+
+/**
+ * DOC: basic gatable clock which can gate and ungate it's ouput
+ *
+ * Traits of this clock:
+ * prepare - clk_(un)prepare only ensures parent is (un)prepared
+ * enable - clk_enable and clk_disable are functional & control gating
+ * rate - inherits rate from parent.  No clk_set_rate support
+ * parent - fixed parent.  No clk_set_parent support
+ */
+
+#define to_clk_gate(_hw) container_of(_hw, struct clk_gate, hw)
+
+/*
+ * It works on following logic:
+ *
+ * For enabling clock, enable = 1
+ *	set2dis = 1	-> clear bit	-> set = 0
+ *	set2dis = 0	-> set bit	-> set = 1
+ *
+ * For disabling clock, enable = 0
+ *	set2dis = 1	-> set bit	-> set = 1
+ *	set2dis = 0	-> clear bit	-> set = 0
+ *
+ * So, result is always: enable xor set2dis.
+ */
+static void clk_gate_endisable(struct clk_hw *hw, int enable)
+{
+	struct clk_gate *gate = to_clk_gate(hw);
+	int set = gate->flags & CLK_GATE_SET_TO_DISABLE ? 1 : 0;
+	unsigned long uninitialized_var(flags);
+	u32 reg;
+
+	set ^= enable;
+
+	if (gate->lock)
+		spin_lock_irqsave(gate->lock, flags);
+
+	if (gate->flags & CLK_GATE_HIWORD_MASK) {
+		reg = BIT(gate->bit_idx + 16);
+		if (set)
+			reg |= BIT(gate->bit_idx);
+	} else {
+		reg = clk_readl(gate->reg);
+
+		if (set)
+			reg |= BIT(gate->bit_idx);
+		else
+			reg &= ~BIT(gate->bit_idx);
+	}
+
+	clk_writel(reg, gate->reg);
+
+	if (gate->lock)
+		spin_unlock_irqrestore(gate->lock, flags);
+}
+
+static int clk_gate_enable(struct clk_hw *hw)
+{
+	clk_gate_endisable(hw, 1);
+
+	return 0;
+}
+
+static void clk_gate_disable(struct clk_hw *hw)
+{
+	clk_gate_endisable(hw, 0);
+}
+
+static int clk_gate_is_enabled(struct clk_hw *hw)
+{
+	u32 reg;
+	struct clk_gate *gate = to_clk_gate(hw);
+
+	reg = clk_readl(gate->reg);
+
+	/* if a set bit disables this clk, flip it before masking */
+	if (gate->flags & CLK_GATE_SET_TO_DISABLE)
+		reg ^= BIT(gate->bit_idx);
+
+	reg &= BIT(gate->bit_idx);
+
+	return reg ? 1 : 0;
+}
+
+const struct clk_ops clk_gate_ops = {
+	.enable = clk_gate_enable,
+	.disable = clk_gate_disable,
+	.is_enabled = clk_gate_is_enabled,
+};
+EXPORT_SYMBOL_GPL(clk_gate_ops);
+
+/**
+ * clk_register_gate - register a gate clock with the clock framework
+ * @dev: device that is registering this clock
+ * @name: name of this clock
+ * @parent_name: name of this clock's parent
+ * @flags: framework-specific flags for this clock
+ * @reg: register address to control gating of this clock
+ * @bit_idx: which bit in the register controls gating of this clock
+ * @clk_gate_flags: gate-specific flags for this clock
+ * @lock: shared register lock for this clock
+ */
+struct clk *clk_register_gate(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		void __iomem *reg, u8 bit_idx,
+		u8 clk_gate_flags, spinlock_t *lock)
+{
+	struct clk_gate *gate;
+	struct clk *clk;
+	struct clk_init_data init;
+
+	if (clk_gate_flags & CLK_GATE_HIWORD_MASK) {
+		if (bit_idx > 15) {
+			pr_err("gate bit exceeds LOWORD field\n");
+			return ERR_PTR(-EINVAL);
+		}
+	}
+
+	/* allocate the gate */
+	gate = kzalloc(sizeof(struct clk_gate), GFP_KERNEL);
+	if (!gate) {
+		pr_err("%s: could not allocate gated clk\n", __func__);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	init.name = name;
+	init.ops = &clk_gate_ops;
+	init.flags = flags | CLK_IS_BASIC;
+	init.parent_names = (parent_name ? &parent_name: NULL);
+	init.num_parents = (parent_name ? 1 : 0);
+
+	/* struct clk_gate assignments */
+	gate->reg = reg;
+	gate->bit_idx = bit_idx;
+	gate->flags = clk_gate_flags;
+	gate->lock = lock;
+	gate->hw.init = &init;
+
+	clk = clk_register(dev, &gate->hw);
+
+	if (IS_ERR(clk))
+		kfree(gate);
+
+	return clk;
+}
+EXPORT_SYMBOL_GPL(clk_register_gate);
+
+void clk_unregister_gate(struct clk *clk)
+{
+	struct clk_gate *gate;
+	struct clk_hw *hw;
+
+	hw = __clk_get_hw(clk);
+	if (!hw)
+		return;
+
+	gate = to_clk_gate(hw);
+
+	clk_unregister(clk);
+	kfree(gate);
+}
+EXPORT_SYMBOL_GPL(clk_unregister_gate);