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Commit a49e6c4b authored by Liu Ying's avatar Liu Ying Committed by Shawn Guo
Browse files

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: default avatarLiu Ying <Ying.Liu@freescale.com>
Signed-off-by: default avatarShawn Guo <shawn.guo@linaro.org>
parent cbe7fc8a

arch/arm/mach-imx/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/arm/mach-imx/clk-fixup-mux.c

0 → 100644
+107 −0
Original line number Diff line number Diff line 
/*

 * 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;

}

arch/arm/mach-imx/clk.h

+4 −0
Original line number Diff line number Diff line
@@ -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);