kernel/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 #define div_mask(width) ((1 << (width)) - 1)
  22
  23 /**
  24  * struct hi6220_clk_divider - divider clock for hi6220
  25  *
  26  * @hw:         handle between common and hardware-specific interfaces
  27  * @reg:        register containing divider
  28  * @shift:      shift to the divider bit field
  29  * @width:      width of the divider bit field
  30  * @mask:       mask for setting divider rate
  31  * @table:      the div table that the divider supports
  32  * @lock:       register lock
  33  */
  34 struct hi6220_clk_divider {
  35         struct clk_hw   hw;
  36         void __iomem    *reg;
  37         u8              shift;
  38         u8              width;
  39         u32             mask;
  40         const struct clk_div_table *table;
  41         spinlock_t      *lock;
  42 };
  43
  44 #define to_hi6220_clk_divider(_hw)      \
  45         container_of(_hw, struct hi6220_clk_divider, hw)
  46
  47 static unsigned long hi6220_clkdiv_recalc_rate(struct clk_hw *hw,
  48                                         unsigned long parent_rate)
  49 {
  50         unsigned int val;
  51         struct hi6220_clk_divider *dclk = to_hi6220_clk_divider(hw);
  52
  53         val = readl_relaxed(dclk->reg) >> dclk->shift;
  54         val &= div_mask(dclk->width);
  55
  56         return divider_recalc_rate(hw, parent_rate, val, dclk->table,
  57                                    CLK_DIVIDER_ROUND_CLOSEST);
  58 }
  59
  60 static long hi6220_clkdiv_round_rate(struct clk_hw *hw, unsigned long rate,
  61                                         unsigned long *prate)
  62 {
  63         struct hi6220_clk_divider *dclk = to_hi6220_clk_divider(hw);
  64
  65         return divider_round_rate(hw, rate, prate, dclk->table,
  66                                   dclk->width, CLK_DIVIDER_ROUND_CLOSEST);
  67 }
  68
  69 static int hi6220_clkdiv_set_rate(struct clk_hw *hw, unsigned long rate,
  70                                         unsigned long parent_rate)
  71 {
  72         int value;
  73         unsigned long flags = 0;
  74         u32 data;
  75         struct hi6220_clk_divider *dclk = to_hi6220_clk_divider(hw);
  76
  77         value = divider_get_val(rate, parent_rate, dclk->table,
  78                                 dclk->width, CLK_DIVIDER_ROUND_CLOSEST);
  79
  80         if (dclk->lock)
  81                 spin_lock_irqsave(dclk->lock, flags);
  82
  83         data = readl_relaxed(dclk->reg);
  84         data &= ~(div_mask(dclk->width) << dclk->shift);
  85         data |= value << dclk->shift;
  86         data |= dclk->mask;
  87
  88         writel_relaxed(data, dclk->reg);
  89
  90         if (dclk->lock)
  91                 spin_unlock_irqrestore(dclk->lock, flags);
  92
  93         return 0;
  94 }
  95
  96 static const struct clk_ops hi6220_clkdiv_ops = {
  97         .recalc_rate = hi6220_clkdiv_recalc_rate,
  98         .round_rate = hi6220_clkdiv_round_rate,
  99         .set_rate = hi6220_clkdiv_set_rate,
 100 };
 101
 102 struct clk *hi6220_register_clkdiv(struct device *dev, const char *name,
 103         const char *parent_name, unsigned long flags, void __iomem *reg,
 104         u8 shift, u8 width, u32 mask_bit, spinlock_t *lock)
 105 {
 106         struct hi6220_clk_divider *div;
 107         struct clk *clk;
 108         struct clk_init_data init;
 109         struct clk_div_table *table;
 110         u32 max_div, min_div;
 111         int i;
 112
 113         /* allocate the divider */
 114         div = kzalloc(sizeof(*div), GFP_KERNEL);
 115         if (!div)
 116                 return ERR_PTR(-ENOMEM);
 117
 118         /* Init the divider table */
 119         max_div = div_mask(width) + 1;
 120         min_div = 1;
 121
 122         table = kcalloc(max_div + 1, sizeof(*table), GFP_KERNEL);
 123         if (!table) {
 124                 kfree(div);
 125                 return ERR_PTR(-ENOMEM);
 126         }
 127
 128         for (i = 0; i < max_div; i++) {
 129                 table[i].div = min_div + i;
 130                 table[i].val = table[i].div - 1;
 131         }
 132
 133         init.name = name;
 134         init.ops = &hi6220_clkdiv_ops;
 135         init.flags = flags;
 136         init.parent_names = parent_name ? &parent_name : NULL;
 137         init.num_parents = parent_name ? 1 : 0;
 138
 139         /* struct hi6220_clk_divider assignments */
 140         div->reg = reg;
 141         div->shift = shift;
 142         div->width = width;
 143         div->mask = mask_bit ? BIT(mask_bit) : 0;
 144         div->lock = lock;
 145         div->hw.init = &init;
 146         div->table = table;
 147
 148         /* register the clock */
 149         clk = clk_register(dev, &div->hw);
 150         if (IS_ERR(clk)) {
 151                 kfree(table);
 152                 kfree(div);
 153         }
 154
 155         return clk;
 156 }