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 
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 
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 
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 
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