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  */
  30 struct clk_fixup_div {
  31         struct clk_divider divider;
  32         const struct clk_ops *ops;
  33         void (*fixup)(u32 *val);
  34 };
  35
  36 static 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
  43 static 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
  51 static 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
  59 static 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
  89 static 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
  95 struct 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 }