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/io.h>
20 #include <linux/of.h>
21 #include <linux/of_address.h>
22 
23 #define to_clk_sp810_timerclken(_hw) \
24 		container_of(_hw, struct clk_sp810_timerclken, hw)
25 
26 struct clk_sp810;
27 
28 struct clk_sp810_timerclken {
29 	struct clk_hw hw;
30 	struct clk *clk;
31 	struct clk_sp810 *sp810;
32 	int channel;
33 };
34 
35 struct clk_sp810 {
36 	struct device_node *node;
37 	void __iomem *base;
38 	spinlock_t lock;
39 	struct clk_sp810_timerclken timerclken[4];
40 };
41 
42 static u8 clk_sp810_timerclken_get_parent(struct clk_hw *hw)
43 {
44 	struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
45 	u32 val = readl(timerclken->sp810->base + SCCTRL);
46 
47 	return !!(val & (1 << SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel)));
48 }
49 
50 static int clk_sp810_timerclken_set_parent(struct clk_hw *hw, u8 index)
51 {
52 	struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
53 	struct clk_sp810 *sp810 = timerclken->sp810;
54 	u32 val, shift = SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel);
55 	unsigned long flags = 0;
56 
57 	if (WARN_ON(index > 1))
58 		return -EINVAL;
59 
60 	spin_lock_irqsave(&sp810->lock, flags);
61 
62 	val = readl(sp810->base + SCCTRL);
63 	val &= ~(1 << shift);
64 	val |= index << shift;
65 	writel(val, sp810->base + SCCTRL);
66 
67 	spin_unlock_irqrestore(&sp810->lock, flags);
68 
69 	return 0;
70 }
71 
72 static const struct clk_ops clk_sp810_timerclken_ops = {
73 	.get_parent = clk_sp810_timerclken_get_parent,
74 	.set_parent = clk_sp810_timerclken_set_parent,
75 };
76 
77 static struct clk *clk_sp810_timerclken_of_get(struct of_phandle_args *clkspec,
78 		void *data)
79 {
80 	struct clk_sp810 *sp810 = data;
81 
82 	if (WARN_ON(clkspec->args_count != 1 ||
83 		    clkspec->args[0] >=	ARRAY_SIZE(sp810->timerclken)))
84 		return NULL;
85 
86 	return sp810->timerclken[clkspec->args[0]].clk;
87 }
88 
89 static void __init clk_sp810_of_setup(struct device_node *node)
90 {
91 	struct clk_sp810 *sp810 = kzalloc(sizeof(*sp810), GFP_KERNEL);
92 	const char *parent_names[2];
93 	int num = ARRAY_SIZE(parent_names);
94 	char name[12];
95 	struct clk_init_data init;
96 	static int instance;
97 	int i;
98 	bool deprecated;
99 
100 	if (!sp810)
101 		return;
102 
103 	if (of_clk_parent_fill(node, parent_names, num) != num) {
104 		pr_warn("Failed to obtain parent clocks for SP810!\n");
105 		kfree(sp810);
106 		return;
107 	}
108 
109 	sp810->node = node;
110 	sp810->base = of_iomap(node, 0);
111 	spin_lock_init(&sp810->lock);
112 
113 	init.name = name;
114 	init.ops = &clk_sp810_timerclken_ops;
115 	init.flags = 0;
116 	init.parent_names = parent_names;
117 	init.num_parents = num;
118 
119 	deprecated = !of_find_property(node, "assigned-clock-parents", NULL);
120 
121 	for (i = 0; i < ARRAY_SIZE(sp810->timerclken); i++) {
122 		snprintf(name, sizeof(name), "sp810_%d_%d", instance, i);
123 
124 		sp810->timerclken[i].sp810 = sp810;
125 		sp810->timerclken[i].channel = i;
126 		sp810->timerclken[i].hw.init = &init;
127 
128 		/*
129 		 * If DT isn't setting the parent, force it to be
130 		 * the 1 MHz clock without going through the framework.
131 		 * We do this before clk_register() so that it can determine
132 		 * the parent and setup the tree properly.
133 		 */
134 		if (deprecated)
135 			init.ops->set_parent(&sp810->timerclken[i].hw, 1);
136 
137 		sp810->timerclken[i].clk = clk_register(NULL,
138 				&sp810->timerclken[i].hw);
139 		WARN_ON(IS_ERR(sp810->timerclken[i].clk));
140 	}
141 
142 	of_clk_add_provider(node, clk_sp810_timerclken_of_get, sp810);
143 	instance++;
144 }
145 CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup);
146