summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/clk/h8300/clk-h8s2678.c
blob: 6cf38dc1c9291e843f140e187b5dd0f0aadf6d4b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
/*
 * H8S2678 clock driver
 *
 * Copyright 2015 Yoshinori Sato <ysato@users.sourceforge.jp>
 */

#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/device.h>
#include <linux/of_address.h>
#include <linux/slab.h>

static DEFINE_SPINLOCK(clklock);

#define MAX_FREQ 33333333
#define MIN_FREQ  8000000

struct pll_clock {
	struct clk_hw hw;
	void __iomem *sckcr;
	void __iomem *pllcr;
};

#define to_pll_clock(_hw) container_of(_hw, struct pll_clock, hw)

static unsigned long pll_recalc_rate(struct clk_hw *hw,
		unsigned long parent_rate)
{
	struct pll_clock *pll_clock = to_pll_clock(hw);
	int mul = 1 << (readb(pll_clock->pllcr) & 3);

	return parent_rate * mul;
}

static long pll_round_rate(struct clk_hw *hw, unsigned long rate,
				unsigned long *prate)
{
	int i, m = -1;
	long offset[3];

	if (rate > MAX_FREQ)
		rate = MAX_FREQ;
	if (rate < MIN_FREQ)
		rate = MIN_FREQ;

	for (i = 0; i < 3; i++)
		offset[i] = abs(rate - (*prate * (1 << i)));
	for (i = 0; i < 3; i++)
		if (m < 0)
			m = i;
		else
			m = (offset[i] < offset[m])?i:m;

	return *prate * (1 << m);
}

static int pll_set_rate(struct clk_hw *hw, unsigned long rate,
			unsigned long parent_rate)
{
	int pll;
	unsigned char val;
	unsigned long flags;
	struct pll_clock *pll_clock = to_pll_clock(hw);

	pll = ((rate / parent_rate) / 2) & 0x03;
	spin_lock_irqsave(&clklock, flags);
	val = readb(pll_clock->sckcr);
	val |= 0x08;
	writeb(val, pll_clock->sckcr);
	val = readb(pll_clock->pllcr);
	val &= ~0x03;
	val |= pll;
	writeb(val, pll_clock->pllcr);
	spin_unlock_irqrestore(&clklock, flags);
	return 0;
}

static const struct clk_ops pll_ops = {
	.recalc_rate = pll_recalc_rate,
	.round_rate = pll_round_rate,
	.set_rate = pll_set_rate,
};

static void __init h8s2678_pll_clk_setup(struct device_node *node)
{
	int num_parents;
	struct clk *clk;
	const char *clk_name = node->name;
	const char *parent_name;
	struct pll_clock *pll_clock;
	struct clk_init_data init;

	num_parents = of_clk_get_parent_count(node);
	if (num_parents < 1) {
		pr_err("%s: no parent found", clk_name);
		return;
	}


	pll_clock = kzalloc(sizeof(*pll_clock), GFP_KERNEL);
	if (!pll_clock)
		return;

	pll_clock->sckcr = of_iomap(node, 0);
	if (pll_clock->sckcr == NULL) {
		pr_err("%s: failed to map divide register", clk_name);
		goto free_clock;
	}

	pll_clock->pllcr = of_iomap(node, 1);
	if (pll_clock->pllcr == NULL) {
		pr_err("%s: failed to map multiply register", clk_name);
		goto unmap_sckcr;
	}

	parent_name = of_clk_get_parent_name(node, 0);
	init.name = clk_name;
	init.ops = &pll_ops;
	init.flags = CLK_IS_BASIC;
	init.parent_names = &parent_name;
	init.num_parents = 1;
	pll_clock->hw.init = &init;

	clk = clk_register(NULL, &pll_clock->hw);
	if (IS_ERR(clk)) {
		pr_err("%s: failed to register %s div clock (%ld)\n",
		       __func__, clk_name, PTR_ERR(clk));
		goto unmap_pllcr;
	}

	of_clk_add_provider(node, of_clk_src_simple_get, clk);
	return;

unmap_pllcr:
	iounmap(pll_clock->pllcr);
unmap_sckcr:
	iounmap(pll_clock->sckcr);
free_clock:
	kfree(pll_clock);
}

CLK_OF_DECLARE(h8s2678_div_clk, "renesas,h8s2678-pll-clock",
	       h8s2678_pll_clk_setup);