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
19struct clk_sp810;
20
21struct clk_sp810_timerclken {
22	struct clk_hw hw;
23	struct clk *clk;
24	struct clk_sp810 *sp810;
25	int channel;
26};
27
28struct clk_sp810 {
29	struct device_node *node;
30	void __iomem *base;
31	spinlock_t lock;
32	struct clk_sp810_timerclken timerclken[4];
33};
34
35static 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
43static 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
65static const struct clk_ops clk_sp810_timerclken_ops = {
66	.determine_rate = clk_hw_determine_rate_no_reparent,
67	.get_parent = clk_sp810_timerclken_get_parent,
68	.set_parent = clk_sp810_timerclken_set_parent,
69};
70
71static struct clk *clk_sp810_timerclken_of_get(struct of_phandle_args *clkspec,
72		void *data)
73{
74	struct clk_sp810 *sp810 = data;
75
76	if (WARN_ON(clkspec->args_count != 1 ||
77		    clkspec->args[0] >=	ARRAY_SIZE(sp810->timerclken)))
78		return NULL;
79
80	return sp810->timerclken[clkspec->args[0]].clk;
81}
82
83static void __init clk_sp810_of_setup(struct device_node *node)
84{
85	struct clk_sp810 *sp810 = kzalloc(sizeof(*sp810), GFP_KERNEL);
86	const char *parent_names[2];
87	int num = ARRAY_SIZE(parent_names);
88	char name[12];
89	struct clk_init_data init;
90	static int instance;
91	int i;
92	bool deprecated;
93
94	if (!sp810)
95		return;
96
97	if (of_clk_parent_fill(node, parent_names, num) != num) {
98		pr_warn("Failed to obtain parent clocks for SP810!\n");
99		kfree(sp810);
100		return;
101	}
102
103	sp810->node = node;
104	sp810->base = of_iomap(node, 0);
105	spin_lock_init(&sp810->lock);
106
107	init.name = name;
108	init.ops = &clk_sp810_timerclken_ops;
109	init.flags = 0;
110	init.parent_names = parent_names;
111	init.num_parents = num;
112
113	deprecated = !of_find_property(node, "assigned-clock-parents", NULL);
114
115	for (i = 0; i < ARRAY_SIZE(sp810->timerclken); i++) {
116		snprintf(name, sizeof(name), "sp810_%d_%d", instance, i);
117
118		sp810->timerclken[i].sp810 = sp810;
119		sp810->timerclken[i].channel = i;
120		sp810->timerclken[i].hw.init = &init;
121
122		/*
123		 * If DT isn't setting the parent, force it to be
124		 * the 1 MHz clock without going through the framework.
125		 * We do this before clk_register() so that it can determine
126		 * the parent and setup the tree properly.
127		 */
128		if (deprecated)
129			init.ops->set_parent(&sp810->timerclken[i].hw, 1);
130
131		sp810->timerclken[i].clk = clk_register(NULL,
132				&sp810->timerclken[i].hw);
133		WARN_ON(IS_ERR(sp810->timerclken[i].clk));
134	}
135
136	of_clk_add_provider(node, clk_sp810_timerclken_of_get, sp810);
137	instance++;
138}
139CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup);
140