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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/drivers/clk/clk-gate.c
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/drivers/clk/clk-gate.c')
-rw-r--r--kernel/drivers/clk/clk-gate.c180
1 files changed, 180 insertions, 0 deletions
diff --git a/kernel/drivers/clk/clk-gate.c b/kernel/drivers/clk/clk-gate.c
new file mode 100644
index 000000000..3f0e4200c
--- /dev/null
+++ b/kernel/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);