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author | Liu Ying <Ying.Liu@freescale.com> | 2013-07-04 17:22:26 +0800 |
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committer | Shawn Guo <shawn.guo@linaro.org> | 2013-08-16 13:11:24 +0800 |
commit | cbe7fc8aaeefc71a75c2688602ba5bb570c0a265 (patch) | |
tree | fbe1e589b95e361002b0f481a4b013c4f30b2d39 /arch/arm/mach-imx | |
parent | f025569322b899a723990774bbe7a625a7e7da2c (diff) | |
download | op-kernel-dev-cbe7fc8aaeefc71a75c2688602ba5bb570c0a265.zip op-kernel-dev-cbe7fc8aaeefc71a75c2688602ba5bb570c0a265.tar.gz |
ARM: imx: add common clock support for fixup div
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 divider clock which is called before writing a value to clock
registers to support this kind of divider clocks.
Signed-off-by: Liu Ying <Ying.Liu@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Diffstat (limited to 'arch/arm/mach-imx')
-rw-r--r-- | arch/arm/mach-imx/Makefile | 3 | ||||
-rw-r--r-- | arch/arm/mach-imx/clk-fixup-div.c | 129 | ||||
-rw-r--r-- | arch/arm/mach-imx/clk.h | 4 |
3 files changed, 135 insertions, 1 deletions
diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile index e20f22d..92b91a2 100644 --- a/arch/arm/mach-imx/Makefile +++ b/arch/arm/mach-imx/Makefile @@ -15,7 +15,8 @@ imx5-pm-$(CONFIG_PM) += pm-imx5.o obj-$(CONFIG_SOC_IMX5) += cpu-imx5.o mm-imx5.o clk-imx51-imx53.o ehci-imx5.o $(imx5-pm-y) obj-$(CONFIG_COMMON_CLK) += clk-pllv1.o clk-pllv2.o clk-pllv3.o clk-gate2.o \ - clk-pfd.o clk-busy.o clk.o + clk-pfd.o clk-busy.o clk.o \ + clk-fixup-div.o obj-$(CONFIG_IMX_HAVE_IOMUX_V1) += iomux-v1.o obj-$(CONFIG_ARCH_MXC_IOMUX_V3) += iomux-v3.o diff --git a/arch/arm/mach-imx/clk-fixup-div.c b/arch/arm/mach-imx/clk-fixup-div.c new file mode 100644 index 0000000..21db020 --- /dev/null +++ b/arch/arm/mach-imx/clk-fixup-div.c @@ -0,0 +1,129 @@ +/* + * 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_div(_hw) container_of(_hw, struct clk_divider, hw) +#define div_mask(d) ((1 << (d->width)) - 1) + +/** + * struct clk_fixup_div - imx integer fixup divider clock + * @divider: the parent class + * @ops: pointer to clk_ops of parent class + * @fixup: a hook to fixup the write value + * + * The imx fixup divider clock is a subclass of basic clk_divider + * with an addtional fixup hook. + */ +struct clk_fixup_div { + struct clk_divider divider; + const struct clk_ops *ops; + void (*fixup)(u32 *val); +}; + +static inline struct clk_fixup_div *to_clk_fixup_div(struct clk_hw *hw) +{ + struct clk_divider *divider = to_clk_div(hw); + + return container_of(divider, struct clk_fixup_div, divider); +} + +static unsigned long clk_fixup_div_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_fixup_div *fixup_div = to_clk_fixup_div(hw); + + return fixup_div->ops->recalc_rate(&fixup_div->divider.hw, parent_rate); +} + +static long clk_fixup_div_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + struct clk_fixup_div *fixup_div = to_clk_fixup_div(hw); + + return fixup_div->ops->round_rate(&fixup_div->divider.hw, rate, prate); +} + +static int clk_fixup_div_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_fixup_div *fixup_div = to_clk_fixup_div(hw); + struct clk_divider *div = to_clk_div(hw); + unsigned int divider, value; + unsigned long flags = 0; + u32 val; + + divider = parent_rate / rate; + + /* Zero based divider */ + value = divider - 1; + + if (value > div_mask(div)) + value = div_mask(div); + + spin_lock_irqsave(div->lock, flags); + + val = readl(div->reg); + val &= ~(div_mask(div) << div->shift); + val |= value << div->shift; + fixup_div->fixup(&val); + writel(val, div->reg); + + spin_unlock_irqrestore(div->lock, flags); + + return 0; +} + +static const struct clk_ops clk_fixup_div_ops = { + .recalc_rate = clk_fixup_div_recalc_rate, + .round_rate = clk_fixup_div_round_rate, + .set_rate = clk_fixup_div_set_rate, +}; + +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_fixup_div *fixup_div; + struct clk *clk; + struct clk_init_data init; + + if (!fixup) + return ERR_PTR(-EINVAL); + + fixup_div = kzalloc(sizeof(*fixup_div), GFP_KERNEL); + if (!fixup_div) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &clk_fixup_div_ops; + init.flags = CLK_SET_RATE_PARENT; + init.parent_names = parent ? &parent : NULL; + init.num_parents = parent ? 1 : 0; + + fixup_div->divider.reg = reg; + fixup_div->divider.shift = shift; + fixup_div->divider.width = width; + fixup_div->divider.lock = &imx_ccm_lock; + fixup_div->divider.hw.init = &init; + fixup_div->ops = &clk_divider_ops; + fixup_div->fixup = fixup; + + clk = clk_register(NULL, &fixup_div->divider.hw); + if (IS_ERR(clk)) + kfree(fixup_div); + + return clk; +} diff --git a/arch/arm/mach-imx/clk.h b/arch/arm/mach-imx/clk.h index 0e4e8bb..51eb3853 100644 --- a/arch/arm/mach-imx/clk.h +++ b/arch/arm/mach-imx/clk.h @@ -49,6 +49,10 @@ struct clk *imx_clk_busy_mux(const char *name, void __iomem *reg, u8 shift, u8 width, void __iomem *busy_reg, u8 busy_shift, const char **parent_names, int num_parents); +struct clk *imx_clk_fixup_divider(const char *name, const char *parent, + void __iomem *reg, u8 shift, u8 width, + 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); |