drivers/clk/versatile/clk-sp810.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *
   4  * Copyright (C) 2013 ARM Limited
   5  */
   6
   7 #include <linux/amba/sp810.h>
   8 #include <linux/slab.h>
   9 #include <linux/clk.h>
  10 #include <linux/clk-provider.h>
  11 #include <linux/err.h>
  12 #include <linux/io.h>
  13 #include <linux/of.h>
  14 #include <linux/of_address.h>
  15
  16 #define to_clk_sp810_timerclken(_hw) \
  17                 container_of(_hw, struct clk_sp810_timerclken, hw)
  18
  19 struct clk_sp810;
  20
  21 struct clk_sp810_timerclken {
  22         struct clk_hw hw;
  23         struct clk *clk;
  24         struct clk_sp810 *sp810;
  25         int channel;
  26 };
  27
  28 struct clk_sp810 {
  29         struct device_node *node;
  30         void __iomem *base;
  31         spinlock_t lock;
  32         struct clk_sp810_timerclken timerclken[4];
  33 };
  34
  35 static u8 clk_sp810_timerclken_get_parent(struct clk_hw *hw)
  36 {
  37         struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
  38         u32 val = readl(timerclken->sp810->base + SCCTRL);
  39
  40         return !!(val & (1 << SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel)));
  41 }
  42
  43 static int clk_sp810_timerclken_set_parent(struct clk_hw *hw, u8 index)
  44 {
  45         struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
  46         struct clk_sp810 *sp810 = timerclken->sp810;
  47         u32 val, shift = SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel);
  48         unsigned long flags = 0;
  49
  50         if (WARN_ON(index > 1))
  51                 return -EINVAL;
  52
  53         spin_lock_irqsave(&sp810->lock, flags);
  54
  55         val = readl(sp810->base + SCCTRL);
  56         val &= ~(1 << shift);
  57         val |= index << shift;
  58         writel(val, sp810->base + SCCTRL);
  59
  60         spin_unlock_irqrestore(&sp810->lock, flags);
  61
  62         return 0;
  63 }
  64
  65 static const struct clk_ops clk_sp810_timerclken_ops = {
  66         .get_parent = clk_sp810_timerclken_get_parent,
  67         .set_parent = clk_sp810_timerclken_set_parent,
  68 };
  69
  70 static struct clk *clk_sp810_timerclken_of_get(struct of_phandle_args *clkspec,
  71                 void *data)
  72 {
  73         struct clk_sp810 *sp810 = data;
  74
  75         if (WARN_ON(clkspec->args_count != 1 ||
  76                     clkspec->args[0] >= ARRAY_SIZE(sp810->timerclken)))
  77                 return NULL;
  78
  79         return sp810->timerclken[clkspec->args[0]].clk;
  80 }
  81
  82 static void __init clk_sp810_of_setup(struct device_node *node)
  83 {
  84         struct clk_sp810 *sp810 = kzalloc(sizeof(*sp810), GFP_KERNEL);
  85         const char *parent_names[2];
  86         int num = ARRAY_SIZE(parent_names);
  87         char name[12];
  88         struct clk_init_data init;
  89         static int instance;
  90         int i;
  91         bool deprecated;
  92
  93         if (!sp810)
  94                 return;
  95
  96         if (of_clk_parent_fill(node, parent_names, num) != num) {
  97                 pr_warn("Failed to obtain parent clocks for SP810!\n");
  98                 kfree(sp810);
  99                 return;
 100         }
 101
 102         sp810->node = node;
 103         sp810->base = of_iomap(node, 0);
 104         spin_lock_init(&sp810->lock);
 105
 106         init.name = name;
 107         init.ops = &clk_sp810_timerclken_ops;
 108         init.flags = 0;
 109         init.parent_names = parent_names;
 110         init.num_parents = num;
 111
 112         deprecated = !of_find_property(node, "assigned-clock-parents", NULL);
 113
 114         for (i = 0; i < ARRAY_SIZE(sp810->timerclken); i++) {
 115                 snprintf(name, sizeof(name), "sp810_%d_%d", instance, i);
 116
 117                 sp810->timerclken[i].sp810 = sp810;
 118                 sp810->timerclken[i].channel = i;
 119                 sp810->timerclken[i].hw.init = &init;
 120
 121                 /*
 122                  * If DT isn't setting the parent, force it to be
 123                  * the 1 MHz clock without going through the framework.
 124                  * We do this before clk_register() so that it can determine
 125                  * the parent and setup the tree properly.
 126                  */
 127                 if (deprecated)
 128                         init.ops->set_parent(&sp810->timerclken[i].hw, 1);
 129
 130                 sp810->timerclken[i].clk = clk_register(NULL,
 131                                 &sp810->timerclken[i].hw);
 132                 WARN_ON(IS_ERR(sp810->timerclken[i].clk));
 133         }
 134
 135         of_clk_add_provider(node, clk_sp810_timerclken_of_get, sp810);
 136         instance++;
 137 }
 138 CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup);