--- /dev/null
+/*
+ * 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);
Code Review / kvmfornfv.git / blobdiff