drivers/clk/h8300/clk-h8s2678.c

   1 /*
   2  * H8S2678 clock driver
   3  *
   4  * Copyright 2015 Yoshinori Sato <ysato@users.sourceforge.jp>
   5  */
   6
   7 #include <linux/clk-provider.h>
   8 #include <linux/err.h>
   9 #include <linux/device.h>
  10 #include <linux/of_address.h>
  11 #include <linux/slab.h>
  12
  13 static DEFINE_SPINLOCK(clklock);
  14
  15 #define MAX_FREQ 33333333
  16 #define MIN_FREQ  8000000
  17
  18 struct pll_clock {
  19         struct clk_hw hw;
  20         void __iomem *sckcr;
  21         void __iomem *pllcr;
  22 };
  23
  24 #define to_pll_clock(_hw) container_of(_hw, struct pll_clock, hw)
  25
  26 static unsigned long pll_recalc_rate(struct clk_hw *hw,
  27                 unsigned long parent_rate)
  28 {
  29         struct pll_clock *pll_clock = to_pll_clock(hw);
  30         int mul = 1 << (readb(pll_clock->pllcr) & 3);
  31
  32         return parent_rate * mul;
  33 }
  34
  35 static long pll_round_rate(struct clk_hw *hw, unsigned long rate,
  36                                 unsigned long *prate)
  37 {
  38         int i, m = -1;
  39         long offset[3];
  40
  41         if (rate > MAX_FREQ)
  42                 rate = MAX_FREQ;
  43         if (rate < MIN_FREQ)
  44                 rate = MIN_FREQ;
  45
  46         for (i = 0; i < 3; i++)
  47                 offset[i] = abs(rate - (*prate * (1 << i)));
  48         for (i = 0; i < 3; i++)
  49                 if (m < 0)
  50                         m = i;
  51                 else
  52                         m = (offset[i] < offset[m])?i:m;
  53
  54         return *prate * (1 << m);
  55 }
  56
  57 static int pll_set_rate(struct clk_hw *hw, unsigned long rate,
  58                         unsigned long parent_rate)
  59 {
  60         int pll;
  61         unsigned char val;
  62         unsigned long flags;
  63         struct pll_clock *pll_clock = to_pll_clock(hw);
  64
  65         pll = ((rate / parent_rate) / 2) & 0x03;
  66         spin_lock_irqsave(&clklock, flags);
  67         val = readb(pll_clock->sckcr);
  68         val |= 0x08;
  69         writeb(val, pll_clock->sckcr);
  70         val = readb(pll_clock->pllcr);
  71         val &= ~0x03;
  72         val |= pll;
  73         writeb(val, pll_clock->pllcr);
  74         spin_unlock_irqrestore(&clklock, flags);
  75         return 0;
  76 }
  77
  78 static const struct clk_ops pll_ops = {
  79         .recalc_rate = pll_recalc_rate,
  80         .round_rate = pll_round_rate,
  81         .set_rate = pll_set_rate,
  82 };
  83
  84 static void __init h8s2678_pll_clk_setup(struct device_node *node)
  85 {
  86         unsigned int num_parents;
  87         const char *clk_name = node->name;
  88         const char *parent_name;
  89         struct pll_clock *pll_clock;
  90         struct clk_init_data init;
  91         int ret;
  92
  93         num_parents = of_clk_get_parent_count(node);
  94         if (!num_parents) {
  95                 pr_err("%s: no parent found", clk_name);
  96                 return;
  97         }
  98
  99
 100         pll_clock = kzalloc(sizeof(*pll_clock), GFP_KERNEL);
 101         if (!pll_clock)
 102                 return;
 103
 104         pll_clock->sckcr = of_iomap(node, 0);
 105         if (pll_clock->sckcr == NULL) {
 106                 pr_err("%s: failed to map divide register", clk_name);
 107                 goto free_clock;
 108         }
 109
 110         pll_clock->pllcr = of_iomap(node, 1);
 111         if (pll_clock->pllcr == NULL) {
 112                 pr_err("%s: failed to map multiply register", clk_name);
 113                 goto unmap_sckcr;
 114         }
 115
 116         parent_name = of_clk_get_parent_name(node, 0);
 117         init.name = clk_name;
 118         init.ops = &pll_ops;
 119         init.flags = CLK_IS_BASIC;
 120         init.parent_names = &parent_name;
 121         init.num_parents = 1;
 122         pll_clock->hw.init = &init;
 123
 124         ret = clk_hw_register(NULL, &pll_clock->hw);
 125         if (ret) {
 126                 pr_err("%s: failed to register %s div clock (%d)\n",
 127                        __func__, clk_name, ret);
 128                 goto unmap_pllcr;
 129         }
 130
 131         of_clk_add_hw_provider(node, of_clk_hw_simple_get, &pll_clock->hw);
 132         return;
 133
 134 unmap_pllcr:
 135         iounmap(pll_clock->pllcr);
 136 unmap_sckcr:
 137         iounmap(pll_clock->sckcr);
 138 free_clock:
 139         kfree(pll_clock);
 140 }
 141
 142 CLK_OF_DECLARE(h8s2678_div_clk, "renesas,h8s2678-pll-clock",
 143                h8s2678_pll_clk_setup);