1 files changed, 150 insertions, 0 deletions

diff --git a/drivers/clk/clk-gate.c b/drivers/clk/clk-gate.c
new file mode 100644
index 000000000000..b5902e2ef2fd
--- /dev/null
+++ b/drivers/clk/clk-gate.c
@@ -0,0 +1,150 @@
+/*
+ * 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)
+
+static void clk_gate_set_bit(struct clk_gate *gate)
+{
+        u32 reg;
+        unsigned long flags = 0;
+
+        if (gate->lock)
+                spin_lock_irqsave(gate->lock, flags);
+
+        reg = readl(gate->reg);
+        reg |= BIT(gate->bit_idx);
+        writel(reg, gate->reg);
+
+        if (gate->lock)
+                spin_unlock_irqrestore(gate->lock, flags);
+}
+
+static void clk_gate_clear_bit(struct clk_gate *gate)
+{
+        u32 reg;
+        unsigned long flags = 0;
+
+        if (gate->lock)
+                spin_lock_irqsave(gate->lock, flags);
+
+        reg = readl(gate->reg);
+        reg &= ~BIT(gate->bit_idx);
+        writel(reg, gate->reg);
+
+        if (gate->lock)
+                spin_unlock_irqrestore(gate->lock, flags);
+}
+
+static int clk_gate_enable(struct clk_hw *hw)
+{
+        struct clk_gate *gate = to_clk_gate(hw);
+
+        if (gate->flags & CLK_GATE_SET_TO_DISABLE)
+                clk_gate_clear_bit(gate);
+        else
+                clk_gate_set_bit(gate);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(clk_gate_enable);
+
+static void clk_gate_disable(struct clk_hw *hw)
+{
+        struct clk_gate *gate = to_clk_gate(hw);
+
+        if (gate->flags & CLK_GATE_SET_TO_DISABLE)
+                clk_gate_set_bit(gate);
+        else
+                clk_gate_clear_bit(gate);
+}
+EXPORT_SYMBOL_GPL(clk_gate_disable);
+
+static int clk_gate_is_enabled(struct clk_hw *hw)
+{
+        u32 reg;
+        struct clk_gate *gate = to_clk_gate(hw);
+
+        reg = 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;
+}
+EXPORT_SYMBOL_GPL(clk_gate_is_enabled);
+
+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);
+
+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;
+
+        gate = kzalloc(sizeof(struct clk_gate), GFP_KERNEL);
+
+        if (!gate) {
+                pr_err("%s: could not allocate gated clk\n", __func__);
+                return NULL;
+        }
+
+        /* struct clk_gate assignments */
+        gate->reg = reg;
+        gate->bit_idx = bit_idx;
+        gate->flags = clk_gate_flags;
+        gate->lock = lock;
+
+        if (parent_name) {
+                gate->parent[0] = kstrdup(parent_name, GFP_KERNEL);
+                if (!gate->parent[0])
+                        goto out;
+        }
+
+        clk = clk_register(dev, name,
+                        &clk_gate_ops, &gate->hw,
+                        gate->parent,
+                        (parent_name ? 1 : 0),
+                        flags);
+        if (clk)
+                return clk;
+out:
+        kfree(gate->parent[0]);
+        kfree(gate);
+
+        return NULL;
+}