ARM: imx: add common clock support for fixup mux
One register may have several fields to control some clocks. It
is possible that the read/write values of some fields may map to
different real functional values, so writing to the other fields
in the same register may break a working clock tree. A real case
is the aclk_podf field in the register 'CCM Serial Clock Multiplexer
Register 1' of i.MX6Q/SDL SoC. This patch introduces a fixup hook
for multiplexer clock which is called before writing a value to
clock registers to support this kind of multiplexer clocks.
Signed-off-by: Liu Ying <Ying.Liu@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
diff --git a/arch/arm/mach-imx/clk-fixup-mux.c b/arch/arm/mach-imx/clk-fixup-mux.c
new file mode 100644
index 0000000..deb4b80
--- /dev/null
+++ b/arch/arm/mach-imx/clk-fixup-mux.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2013 Freescale Semiconductor, Inc.
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include "clk.h"
+
+#define to_clk_mux(_hw) container_of(_hw, struct clk_mux, hw)
+
+/**
+ * struct clk_fixup_mux - imx integer fixup multiplexer clock
+ * @mux: the parent class
+ * @ops: pointer to clk_ops of parent class
+ * @fixup: a hook to fixup the write value
+ *
+ * The imx fixup multiplexer clock is a subclass of basic clk_mux
+ * with an addtional fixup hook.
+ */
+struct clk_fixup_mux {
+ struct clk_mux mux;
+ const struct clk_ops *ops;
+ void (*fixup)(u32 *val);
+};
+
+static inline struct clk_fixup_mux *to_clk_fixup_mux(struct clk_hw *hw)
+{
+ struct clk_mux *mux = to_clk_mux(hw);
+
+ return container_of(mux, struct clk_fixup_mux, mux);
+}
+
+static u8 clk_fixup_mux_get_parent(struct clk_hw *hw)
+{
+ struct clk_fixup_mux *fixup_mux = to_clk_fixup_mux(hw);
+
+ return fixup_mux->ops->get_parent(&fixup_mux->mux.hw);
+}
+
+static int clk_fixup_mux_set_parent(struct clk_hw *hw, u8 index)
+{
+ struct clk_fixup_mux *fixup_mux = to_clk_fixup_mux(hw);
+ struct clk_mux *mux = to_clk_mux(hw);
+ unsigned long flags = 0;
+ u32 val;
+
+ spin_lock_irqsave(mux->lock, flags);
+
+ val = readl(mux->reg);
+ val &= ~(mux->mask << mux->shift);
+ val |= index << mux->shift;
+ fixup_mux->fixup(&val);
+ writel(val, mux->reg);
+
+ spin_unlock_irqrestore(mux->lock, flags);
+
+ return 0;
+}
+
+static const struct clk_ops clk_fixup_mux_ops = {
+ .get_parent = clk_fixup_mux_get_parent,
+ .set_parent = clk_fixup_mux_set_parent,
+};
+
+struct clk *imx_clk_fixup_mux(const char *name, void __iomem *reg,
+ u8 shift, u8 width, const char **parents,
+ int num_parents, void (*fixup)(u32 *val))
+{
+ struct clk_fixup_mux *fixup_mux;
+ struct clk *clk;
+ struct clk_init_data init;
+
+ if (!fixup)
+ return ERR_PTR(-EINVAL);
+
+ fixup_mux = kzalloc(sizeof(*fixup_mux), GFP_KERNEL);
+ if (!fixup_mux)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &clk_fixup_mux_ops;
+ init.parent_names = parents;
+ init.num_parents = num_parents;
+
+ fixup_mux->mux.reg = reg;
+ fixup_mux->mux.shift = shift;
+ fixup_mux->mux.mask = BIT(width) - 1;
+ fixup_mux->mux.lock = &imx_ccm_lock;
+ fixup_mux->mux.hw.init = &init;
+ fixup_mux->ops = &clk_mux_ops;
+ fixup_mux->fixup = fixup;
+
+ clk = clk_register(NULL, &fixup_mux->mux.hw);
+ if (IS_ERR(clk))
+ kfree(fixup_mux);
+
+ return clk;
+}