Initial import

1 files changed, 195 insertions, 0 deletions

diff --git a/drivers/clk/clk-mux.c b/drivers/clk/clk-mux.c
new file mode 100644
index 000000000..69a094c37
--- /dev/null
+++ b/drivers/clk/clk-mux.c
@@ -0,0 +1,195 @@
+/*
+ * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
+ * Copyright (C) 2011 Richard Zhao, Linaro <richard.zhao@linaro.org>
+ * 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.
+ *
+ * Simple multiplexer clock implementation
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+
+/*
+ * DOC: basic adjustable multiplexer clock that cannot gate
+ *
+ * Traits of this clock:
+ * prepare - clk_prepare only ensures that parents are prepared
+ * enable - clk_enable only ensures that parents are enabled
+ * rate - rate is only affected by parent switching.  No clk_set_rate support
+ * parent - parent is adjustable through clk_set_parent
+ */
+
+#define to_clk_mux(_hw) container_of(_hw, struct clk_mux, hw)
+
+static u8 clk_mux_get_parent(struct clk_hw *hw)
+{
+	struct clk_mux *mux = to_clk_mux(hw);
+	int num_parents = __clk_get_num_parents(hw->clk);
+	u32 val;
+
+	/*
+	 * FIXME need a mux-specific flag to determine if val is bitwise or numeric
+	 * e.g. sys_clkin_ck's clksel field is 3 bits wide, but ranges from 0x1
+	 * to 0x7 (index starts at one)
+	 * OTOH, pmd_trace_clk_mux_ck uses a separate bit for each clock, so
+	 * val = 0x4 really means "bit 2, index starts at bit 0"
+	 */
+	val = clk_readl(mux->reg) >> mux->shift;
+	val &= mux->mask;
+
+	if (mux->table) {
+		int i;
+
+		for (i = 0; i < num_parents; i++)
+			if (mux->table[i] == val)
+				return i;
+		return -EINVAL;
+	}
+
+	if (val && (mux->flags & CLK_MUX_INDEX_BIT))
+		val = ffs(val) - 1;
+
+	if (val && (mux->flags & CLK_MUX_INDEX_ONE))
+		val--;
+
+	if (val >= num_parents)
+		return -EINVAL;
+
+	return val;
+}
+
+static int clk_mux_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct clk_mux *mux = to_clk_mux(hw);
+	u32 val;
+	unsigned long flags = 0;
+
+	if (mux->table)
+		index = mux->table[index];
+
+	else {
+		if (mux->flags & CLK_MUX_INDEX_BIT)
+			index = 1 << index;
+
+		if (mux->flags & CLK_MUX_INDEX_ONE)
+			index++;
+	}
+
+	if (mux->lock)
+		spin_lock_irqsave(mux->lock, flags);
+
+	if (mux->flags & CLK_MUX_HIWORD_MASK) {
+		val = mux->mask << (mux->shift + 16);
+	} else {
+		val = clk_readl(mux->reg);
+		val &= ~(mux->mask << mux->shift);
+	}
+	val |= index << mux->shift;
+	clk_writel(val, mux->reg);
+
+	if (mux->lock)
+		spin_unlock_irqrestore(mux->lock, flags);
+
+	return 0;
+}
+
+const struct clk_ops clk_mux_ops = {
+	.get_parent = clk_mux_get_parent,
+	.set_parent = clk_mux_set_parent,
+	.determine_rate = __clk_mux_determine_rate,
+};
+EXPORT_SYMBOL_GPL(clk_mux_ops);
+
+const struct clk_ops clk_mux_ro_ops = {
+	.get_parent = clk_mux_get_parent,
+};
+EXPORT_SYMBOL_GPL(clk_mux_ro_ops);
+
+struct clk *clk_register_mux_table(struct device *dev, const char *name,
+		const char **parent_names, u8 num_parents, unsigned long flags,
+		void __iomem *reg, u8 shift, u32 mask,
+		u8 clk_mux_flags, u32 *table, spinlock_t *lock)
+{
+	struct clk_mux *mux;
+	struct clk *clk;
+	struct clk_init_data init;
+	u8 width = 0;
+
+	if (clk_mux_flags & CLK_MUX_HIWORD_MASK) {
+		width = fls(mask) - ffs(mask) + 1;
+		if (width + shift > 16) {
+			pr_err("mux value exceeds LOWORD field\n");
+			return ERR_PTR(-EINVAL);
+		}
+	}
+
+	/* allocate the mux */
+	mux = kzalloc(sizeof(struct clk_mux), GFP_KERNEL);
+	if (!mux) {
+		pr_err("%s: could not allocate mux clk\n", __func__);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	init.name = name;
+	if (clk_mux_flags & CLK_MUX_READ_ONLY)
+		init.ops = &clk_mux_ro_ops;
+	else
+		init.ops = &clk_mux_ops;
+	init.flags = flags | CLK_IS_BASIC;
+	init.parent_names = parent_names;
+	init.num_parents = num_parents;
+
+	/* struct clk_mux assignments */
+	mux->reg = reg;
+	mux->shift = shift;
+	mux->mask = mask;
+	mux->flags = clk_mux_flags;
+	mux->lock = lock;
+	mux->table = table;
+	mux->hw.init = &init;
+
+	clk = clk_register(dev, &mux->hw);
+
+	if (IS_ERR(clk))
+		kfree(mux);
+
+	return clk;
+}
+EXPORT_SYMBOL_GPL(clk_register_mux_table);
+
+struct clk *clk_register_mux(struct device *dev, const char *name,
+		const char **parent_names, u8 num_parents, unsigned long flags,
+		void __iomem *reg, u8 shift, u8 width,
+		u8 clk_mux_flags, spinlock_t *lock)
+{
+	u32 mask = BIT(width) - 1;
+
+	return clk_register_mux_table(dev, name, parent_names, num_parents,
+				      flags, reg, shift, mask, clk_mux_flags,
+				      NULL, lock);
+}
+EXPORT_SYMBOL_GPL(clk_register_mux);
+
+void clk_unregister_mux(struct clk *clk)
+{
+	struct clk_mux *mux;
+	struct clk_hw *hw;
+
+	hw = __clk_get_hw(clk);
+	if (!hw)
+		return;
+
+	mux = to_clk_mux(hw);
+
+	clk_unregister(clk);
+	kfree(mux);
+}
+EXPORT_SYMBOL_GPL(clk_unregister_mux);