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author | Liu Ying <Ying.Liu@freescale.com> | 2013-07-04 17:35:46 +0800 |
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committer | Shawn Guo <shawn.guo@linaro.org> | 2013-08-16 13:11:24 +0800 |
commit | a49e6c4b820488b79ada6da9ce609fa8611d3e00 (patch) | |
tree | ac05da5efae2363c81decfdbe941537fcf4d4996 /arch/arm/mach-imx/clk-fixup-mux.c | |
parent | cbe7fc8aaeefc71a75c2688602ba5bb570c0a265 (diff) | |
download | op-kernel-dev-a49e6c4b820488b79ada6da9ce609fa8611d3e00.zip op-kernel-dev-a49e6c4b820488b79ada6da9ce609fa8611d3e00.tar.gz |
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>
Diffstat (limited to 'arch/arm/mach-imx/clk-fixup-mux.c')
-rw-r--r-- | arch/arm/mach-imx/clk-fixup-mux.c | 107 |
1 files changed, 107 insertions, 0 deletions
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; +} |