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>
This commit is contained in:
Liu Ying 2013-07-04 17:35:46 +08:00 committed by Shawn Guo
parent cbe7fc8aae
commit a49e6c4b82
3 changed files with 112 additions and 1 deletions

View file

@ -16,7 +16,7 @@ obj-$(CONFIG_SOC_IMX5) += cpu-imx5.o mm-imx5.o clk-imx51-imx53.o ehci-imx5.o $(i
obj-$(CONFIG_COMMON_CLK) += clk-pllv1.o clk-pllv2.o clk-pllv3.o clk-gate2.o \
clk-pfd.o clk-busy.o clk.o \
clk-fixup-div.o
clk-fixup-div.o clk-fixup-mux.o
obj-$(CONFIG_IMX_HAVE_IOMUX_V1) += iomux-v1.o
obj-$(CONFIG_ARCH_MXC_IOMUX_V3) += iomux-v3.o

View file

@ -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;
}

View file

@ -53,6 +53,10 @@ struct clk *imx_clk_fixup_divider(const char *name, const char *parent,
void __iomem *reg, u8 shift, u8 width,
void (*fixup)(u32 *val));
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));
static inline struct clk *imx_clk_fixed(const char *name, int rate)
{
return clk_register_fixed_rate(NULL, name, NULL, CLK_IS_ROOT, rate);