drivers/clk/hisilicon/clkdivider-hi6220.c

   1 /*
   2  * Hisilicon hi6220 SoC divider clock driver
   3  *
   4  * Copyright (c) 2015 Hisilicon Limited.
   5  *
   6  * Author: Bintian Wang <bintian.wang@huawei.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/clk-provider.h>
  16 #include <linux/slab.h>
  17 #include <linux/io.h>
  18 #include <linux/err.h>
  19 #include <linux/spinlock.h>
  20
  21 #include "clk.h"
  22
  23 #define div_mask(width) ((1 << (width)) - 1)
  24
  25 /**
  26  * struct hi6220_clk_divider - divider clock for hi6220
  27  *
  28  * @hw:         handle between common and hardware-specific interfaces
  29  * @reg:        register containing divider
  30  * @shift:      shift to the divider bit field
  31  * @width:      width of the divider bit field
  32  * @mask:       mask for setting divider rate
  33  * @table:      the div table that the divider supports
  34  * @lock:       register lock
  35  */
  36 struct hi6220_clk_divider {
  37         struct clk_hw   hw;
  38         void __iomem    *reg;
  39         u8              shift;
  40         u8              width;
  41         u32             mask;
  42         const struct clk_div_table *table;
  43         spinlock_t      *lock;
  44 };
  45
  46 #define to_hi6220_clk_divider(_hw)      \
  47         container_of(_hw, struct hi6220_clk_divider, hw)
  48
  49 static unsigned long hi6220_clkdiv_recalc_rate(struct clk_hw *hw,
  50                                         unsigned long parent_rate)
  51 {
  52         unsigned int val;
  53         struct hi6220_clk_divider *dclk = to_hi6220_clk_divider(hw);
  54
  55         val = readl_relaxed(dclk->reg) >> dclk->shift;
  56         val &= div_mask(dclk->width);
  57
  58         return divider_recalc_rate(hw, parent_rate, val, dclk->table,
  59                                    CLK_DIVIDER_ROUND_CLOSEST);
  60 }
  61
  62 static long hi6220_clkdiv_round_rate(struct clk_hw *hw, unsigned long rate,
  63                                         unsigned long *prate)
  64 {
  65         struct hi6220_clk_divider *dclk = to_hi6220_clk_divider(hw);
  66
  67         return divider_round_rate(hw, rate, prate, dclk->table,
  68                                   dclk->width, CLK_DIVIDER_ROUND_CLOSEST);
  69 }
  70
  71 static int hi6220_clkdiv_set_rate(struct clk_hw *hw, unsigned long rate,
  72                                         unsigned long parent_rate)
  73 {
  74         int value;
  75         unsigned long flags = 0;
  76         u32 data;
  77         struct hi6220_clk_divider *dclk = to_hi6220_clk_divider(hw);
  78
  79         value = divider_get_val(rate, parent_rate, dclk->table,
  80                                 dclk->width, CLK_DIVIDER_ROUND_CLOSEST);
  81
  82         if (dclk->lock)
  83                 spin_lock_irqsave(dclk->lock, flags);
  84
  85         data = readl_relaxed(dclk->reg);
  86         data &= ~(div_mask(dclk->width) << dclk->shift);
  87         data |= value << dclk->shift;
  88         data |= dclk->mask;
  89
  90         writel_relaxed(data, dclk->reg);
  91
  92         if (dclk->lock)
  93                 spin_unlock_irqrestore(dclk->lock, flags);
  94
  95         return 0;
  96 }
  97
  98 static const struct clk_ops hi6220_clkdiv_ops = {
  99         .recalc_rate = hi6220_clkdiv_recalc_rate,
 100         .round_rate = hi6220_clkdiv_round_rate,
 101         .set_rate = hi6220_clkdiv_set_rate,
 102 };
 103
 104 struct clk *hi6220_register_clkdiv(struct device *dev, const char *name,
 105         const char *parent_name, unsigned long flags, void __iomem *reg,
 106         u8 shift, u8 width, u32 mask_bit, spinlock_t *lock)
 107 {
 108         struct hi6220_clk_divider *div;
 109         struct clk *clk;
 110         struct clk_init_data init;
 111         struct clk_div_table *table;
 112         u32 max_div, min_div;
 113         int i;
 114
 115         /* allocate the divider */
 116         div = kzalloc(sizeof(*div), GFP_KERNEL);
 117         if (!div)
 118                 return ERR_PTR(-ENOMEM);
 119
 120         /* Init the divider table */
 121         max_div = div_mask(width) + 1;
 122         min_div = 1;
 123
 124         table = kcalloc(max_div + 1, sizeof(*table), GFP_KERNEL);
 125         if (!table) {
 126                 kfree(div);
 127                 return ERR_PTR(-ENOMEM);
 128         }
 129
 130         for (i = 0; i < max_div; i++) {
 131                 table[i].div = min_div + i;
 132                 table[i].val = table[i].div - 1;
 133         }
 134
 135         init.name = name;
 136         init.ops = &hi6220_clkdiv_ops;
 137         init.flags = flags;
 138         init.parent_names = parent_name ? &parent_name : NULL;
 139         init.num_parents = parent_name ? 1 : 0;
 140
 141         /* struct hi6220_clk_divider assignments */
 142         div->reg = reg;
 143         div->shift = shift;
 144         div->width = width;
 145         div->mask = mask_bit ? BIT(mask_bit) : 0;
 146         div->lock = lock;
 147         div->hw.init = &init;
 148         div->table = table;
 149
 150         /* register the clock */
 151         clk = clk_register(dev, &div->hw);
 152         if (IS_ERR(clk)) {
 153                 kfree(table);
 154                 kfree(div);
 155         }
 156
 157         return clk;
 158 }