From cbe7fc8aaeefc71a75c2688602ba5bb570c0a265 Mon Sep 17 00:00:00 2001 From: Liu Ying Date: Thu, 4 Jul 2013 17:22:26 +0800 Subject: 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 Signed-off-by: Shawn Guo --- arch/arm/mach-imx/clk-fixup-div.c | 129 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 129 insertions(+) create mode 100644 arch/arm/mach-imx/clk-fixup-div.c (limited to 'arch/arm/mach-imx/clk-fixup-div.c') 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 000000000000..21db020b1f2d --- /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 +#include +#include +#include +#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; +} -- cgit v1.2.3