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
25struct clk_sp810;
26
27struct clk_sp810_timerclken {
28	struct clk_hw hw;
29	struct clk *clk;
30	struct clk_sp810 *sp810;
31	int channel;
32};
33
34struct clk_sp810 {
35	struct device_node *node;
36	void __iomem *base;
37	spinlock_t lock;
38	struct clk_sp810_timerclken timerclken[4];
39};
40
41static 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
49static 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
71static 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
76static 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
88static 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		pr_err("Failed to allocate memory for SP810!\n");
101		return;
102	}
103
104	if (of_clk_parent_fill(node, parent_names, num) != num) {
105		pr_warn("Failed to obtain parent clocks for SP810!\n");
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 = CLK_IS_BASIC;
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}
145CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup);
146