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);
139