1 /*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License version 2 as
4 * published by the Free Software Foundation.
5 *
6 * This program is distributed in the hope that it will be useful,
7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9 * GNU General Public License for more details.
10 *
11 * Copyright (C) 2013 ARM Limited
12 */
13
14 #include <linux/amba/sp810.h>
15 #include <linux/slab.h>
16 #include <linux/clk.h>
17 #include <linux/clk-provider.h>
18 #include <linux/err.h>
19 #include <linux/of.h>
20 #include <linux/of_address.h>
21
22 #define to_clk_sp810_timerclken(_hw) \
23 container_of(_hw, struct clk_sp810_timerclken, hw)
24
25 struct clk_sp810;
26
27 struct clk_sp810_timerclken {
28 struct clk_hw hw;
29 struct clk *clk;
30 struct clk_sp810 *sp810;
31 int channel;
32 };
33
34 struct clk_sp810 {
35 struct device_node *node;
36 void __iomem *base;
37 spinlock_t lock;
38 struct clk_sp810_timerclken timerclken[4];
39 };
40
clk_sp810_timerclken_get_parent(struct clk_hw * hw)41 static u8 clk_sp810_timerclken_get_parent(struct clk_hw *hw)
42 {
43 struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
44 u32 val = readl(timerclken->sp810->base + SCCTRL);
45
46 return !!(val & (1 << SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel)));
47 }
48
clk_sp810_timerclken_set_parent(struct clk_hw * hw,u8 index)49 static int clk_sp810_timerclken_set_parent(struct clk_hw *hw, u8 index)
50 {
51 struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
52 struct clk_sp810 *sp810 = timerclken->sp810;
53 u32 val, shift = SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel);
54 unsigned long flags = 0;
55
56 if (WARN_ON(index > 1))
57 return -EINVAL;
58
59 spin_lock_irqsave(&sp810->lock, flags);
60
61 val = readl(sp810->base + SCCTRL);
62 val &= ~(1 << shift);
63 val |= index << shift;
64 writel(val, sp810->base + SCCTRL);
65
66 spin_unlock_irqrestore(&sp810->lock, flags);
67
68 return 0;
69 }
70
71 static const struct clk_ops clk_sp810_timerclken_ops = {
72 .get_parent = clk_sp810_timerclken_get_parent,
73 .set_parent = clk_sp810_timerclken_set_parent,
74 };
75
clk_sp810_timerclken_of_get(struct of_phandle_args * clkspec,void * data)76 static struct clk *clk_sp810_timerclken_of_get(struct of_phandle_args *clkspec,
77 void *data)
78 {
79 struct clk_sp810 *sp810 = data;
80
81 if (WARN_ON(clkspec->args_count != 1 ||
82 clkspec->args[0] >= ARRAY_SIZE(sp810->timerclken)))
83 return NULL;
84
85 return sp810->timerclken[clkspec->args[0]].clk;
86 }
87
clk_sp810_of_setup(struct device_node * node)88 static void __init clk_sp810_of_setup(struct device_node *node)
89 {
90 struct clk_sp810 *sp810 = kzalloc(sizeof(*sp810), GFP_KERNEL);
91 const char *parent_names[2];
92 int num = ARRAY_SIZE(parent_names);
93 char name[12];
94 struct clk_init_data init;
95 static int instance;
96 int i;
97 bool deprecated;
98
99 if (!sp810)
100 return;
101
102 if (of_clk_parent_fill(node, parent_names, num) != num) {
103 pr_warn("Failed to obtain parent clocks for SP810!\n");
104 kfree(sp810);
105 return;
106 }
107
108 sp810->node = node;
109 sp810->base = of_iomap(node, 0);
110 spin_lock_init(&sp810->lock);
111
112 init.name = name;
113 init.ops = &clk_sp810_timerclken_ops;
114 init.flags = CLK_IS_BASIC;
115 init.parent_names = parent_names;
116 init.num_parents = num;
117
118 deprecated = !of_find_property(node, "assigned-clock-parents", NULL);
119
120 for (i = 0; i < ARRAY_SIZE(sp810->timerclken); i++) {
121 snprintf(name, sizeof(name), "sp810_%d_%d", instance, i);
122
123 sp810->timerclken[i].sp810 = sp810;
124 sp810->timerclken[i].channel = i;
125 sp810->timerclken[i].hw.init = &init;
126
127 /*
128 * If DT isn't setting the parent, force it to be
129 * the 1 MHz clock without going through the framework.
130 * We do this before clk_register() so that it can determine
131 * the parent and setup the tree properly.
132 */
133 if (deprecated)
134 init.ops->set_parent(&sp810->timerclken[i].hw, 1);
135
136 sp810->timerclken[i].clk = clk_register(NULL,
137 &sp810->timerclken[i].hw);
138 WARN_ON(IS_ERR(sp810->timerclken[i].clk));
139 }
140
141 of_clk_add_provider(node, clk_sp810_timerclken_of_get, sp810);
142 instance++;
143 }
144 CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup);
145