LXR linux/arch/arm/mach-imx/clk-fixup-div.c

   1/*
   2 * Copyright (C) 2013 Freescale Semiconductor, Inc.
   3 *
   4 * The code contained herein is licensed under the GNU General Public
   5 * License. You may obtain a copy of the GNU General Public License
   6 * Version 2 or later at the following locations:
   7 *
   8 * http://www.opensource.org/licenses/gpl-license.html
   9 * http://www.gnu.org/copyleft/gpl.html
  10 */
  11
  12#include <linux/clk-provider.h>
  13#include <linux/err.h>
  14#include <linux/io.h>
  15#include <linux/slab.h>
  16#include "clk.h"
  17
  18#define to_clk_div(_hw) container_of(_hw, struct clk_divider, hw)
  19#define div_mask(d)     ((1 << (d->width)) - 1)
  20
  21/**
  22 * struct clk_fixup_div - imx integer fixup divider clock
  23 * @divider: the parent class
  24 * @ops: pointer to clk_ops of parent class
  25 * @fixup: a hook to fixup the write value
  26 *
  27 * The imx fixup divider clock is a subclass of basic clk_divider
  28 * with an addtional fixup hook.
  29 */
  30struct clk_fixup_div {
  31        struct clk_divider divider;
  32        const struct clk_ops *ops;
  33        void (*fixup)(u32 *val);
  34};
  35
  36static inline struct clk_fixup_div *to_clk_fixup_div(struct clk_hw *hw)
  37{
  38        struct clk_divider *divider = to_clk_div(hw);
  39
  40        return container_of(divider, struct clk_fixup_div, divider);
  41}
  42
  43static unsigned long clk_fixup_div_recalc_rate(struct clk_hw *hw,
  44                                         unsigned long parent_rate)
  45{
  46        struct clk_fixup_div *fixup_div = to_clk_fixup_div(hw);
  47
  48        return fixup_div->ops->recalc_rate(&fixup_div->divider.hw, parent_rate);
  49}
  50
  51static long clk_fixup_div_round_rate(struct clk_hw *hw, unsigned long rate,
  52                               unsigned long *prate)
  53{
  54        struct clk_fixup_div *fixup_div = to_clk_fixup_div(hw);
  55
  56        return fixup_div->ops->round_rate(&fixup_div->divider.hw, rate, prate);
  57}
  58
  59static int clk_fixup_div_set_rate(struct clk_hw *hw, unsigned long rate,
  60                            unsigned long parent_rate)
  61{
  62        struct clk_fixup_div *fixup_div = to_clk_fixup_div(hw);
  63        struct clk_divider *div = to_clk_div(hw);
  64        unsigned int divider, value;
  65        unsigned long flags = 0;
  66        u32 val;
  67
  68        divider = parent_rate / rate;
  69
  70        /* Zero based divider */
  71        value = divider - 1;
  72
  73        if (value > div_mask(div))
  74                value = div_mask(div);
  75
  76        spin_lock_irqsave(div->lock, flags);
  77
  78        val = readl(div->reg);
  79        val &= ~(div_mask(div) << div->shift);
  80        val |= value << div->shift;
  81        fixup_div->fixup(&val);
  82        writel(val, div->reg);
  83
  84        spin_unlock_irqrestore(div->lock, flags);
  85
  86        return 0;
  87}
  88
  89static const struct clk_ops clk_fixup_div_ops = {
  90        .recalc_rate = clk_fixup_div_recalc_rate,
  91        .round_rate = clk_fixup_div_round_rate,
  92        .set_rate = clk_fixup_div_set_rate,
  93};
  94
  95struct clk *imx_clk_fixup_divider(const char *name, const char *parent,
  96                                  void __iomem *reg, u8 shift, u8 width,
  97                                  void (*fixup)(u32 *val))
  98{
  99        struct clk_fixup_div *fixup_div;
 100        struct clk *clk;
 101        struct clk_init_data init;
 102
 103        if (!fixup)
 104                return ERR_PTR(-EINVAL);
 105
 106        fixup_div = kzalloc(sizeof(*fixup_div), GFP_KERNEL);
 107        if (!fixup_div)
 108                return ERR_PTR(-ENOMEM);
 109
 110        init.name = name;
 111        init.ops = &clk_fixup_div_ops;
 112        init.flags = CLK_SET_RATE_PARENT;
 113        init.parent_names = parent ? &parent : NULL;
 114        init.num_parents = parent ? 1 : 0;
 115
 116        fixup_div->divider.reg = reg;
 117        fixup_div->divider.shift = shift;
 118        fixup_div->divider.width = width;
 119        fixup_div->divider.lock = &imx_ccm_lock;
 120        fixup_div->divider.hw.init = &init;
 121        fixup_div->ops = &clk_divider_ops;
 122        fixup_div->fixup = fixup;
 123
 124        clk = clk_register(NULL, &fixup_div->divider.hw);
 125        if (IS_ERR(clk))
 126                kfree(fixup_div);
 127
 128        return clk;
 129}
 130