1 /*
2  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
3  * Author: Tomasz Figa <t.figa@samsung.com>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  *
9  * Clock driver for Exynos clock output
10  */
11 
12 #include <linux/clk.h>
13 #include <linux/clkdev.h>
14 #include <linux/clk-provider.h>
15 #include <linux/of.h>
16 #include <linux/of_address.h>
17 #include <linux/syscore_ops.h>
18 
19 #define EXYNOS_CLKOUT_NR_CLKS		1
20 #define EXYNOS_CLKOUT_PARENTS		32
21 
22 #define EXYNOS_PMU_DEBUG_REG		0xa00
23 #define EXYNOS_CLKOUT_DISABLE_SHIFT	0
24 #define EXYNOS_CLKOUT_MUX_SHIFT		8
25 #define EXYNOS4_CLKOUT_MUX_MASK		0xf
26 #define EXYNOS5_CLKOUT_MUX_MASK		0x1f
27 
28 struct exynos_clkout {
29 	struct clk_gate gate;
30 	struct clk_mux mux;
31 	spinlock_t slock;
32 	struct clk_onecell_data data;
33 	struct clk *clk_table[EXYNOS_CLKOUT_NR_CLKS];
34 	void __iomem *reg;
35 	u32 pmu_debug_save;
36 };
37 
38 static struct exynos_clkout *clkout;
39 
40 static int exynos_clkout_suspend(void)
41 {
42 	clkout->pmu_debug_save = readl(clkout->reg + EXYNOS_PMU_DEBUG_REG);
43 
44 	return 0;
45 }
46 
47 static void exynos_clkout_resume(void)
48 {
49 	writel(clkout->pmu_debug_save, clkout->reg + EXYNOS_PMU_DEBUG_REG);
50 }
51 
52 static struct syscore_ops exynos_clkout_syscore_ops = {
53 	.suspend = exynos_clkout_suspend,
54 	.resume = exynos_clkout_resume,
55 };
56 
57 static void __init exynos_clkout_init(struct device_node *node, u32 mux_mask)
58 {
59 	const char *parent_names[EXYNOS_CLKOUT_PARENTS];
60 	struct clk *parents[EXYNOS_CLKOUT_PARENTS];
61 	int parent_count;
62 	int ret;
63 	int i;
64 
65 	clkout = kzalloc(sizeof(*clkout), GFP_KERNEL);
66 	if (!clkout)
67 		return;
68 
69 	spin_lock_init(&clkout->slock);
70 
71 	parent_count = 0;
72 	for (i = 0; i < EXYNOS_CLKOUT_PARENTS; ++i) {
73 		char name[] = "clkoutXX";
74 
75 		snprintf(name, sizeof(name), "clkout%d", i);
76 		parents[i] = of_clk_get_by_name(node, name);
77 		if (IS_ERR(parents[i])) {
78 			parent_names[i] = "none";
79 			continue;
80 		}
81 
82 		parent_names[i] = __clk_get_name(parents[i]);
83 		parent_count = i + 1;
84 	}
85 
86 	if (!parent_count)
87 		goto free_clkout;
88 
89 	clkout->reg = of_iomap(node, 0);
90 	if (!clkout->reg)
91 		goto clks_put;
92 
93 	clkout->gate.reg = clkout->reg + EXYNOS_PMU_DEBUG_REG;
94 	clkout->gate.bit_idx = EXYNOS_CLKOUT_DISABLE_SHIFT;
95 	clkout->gate.flags = CLK_GATE_SET_TO_DISABLE;
96 	clkout->gate.lock = &clkout->slock;
97 
98 	clkout->mux.reg = clkout->reg + EXYNOS_PMU_DEBUG_REG;
99 	clkout->mux.mask = mux_mask;
100 	clkout->mux.shift = EXYNOS_CLKOUT_MUX_SHIFT;
101 	clkout->mux.lock = &clkout->slock;
102 
103 	clkout->clk_table[0] = clk_register_composite(NULL, "clkout",
104 				parent_names, parent_count, &clkout->mux.hw,
105 				&clk_mux_ops, NULL, NULL, &clkout->gate.hw,
106 				&clk_gate_ops, CLK_SET_RATE_PARENT
107 				| CLK_SET_RATE_NO_REPARENT);
108 	if (IS_ERR(clkout->clk_table[0]))
109 		goto err_unmap;
110 
111 	clkout->data.clks = clkout->clk_table;
112 	clkout->data.clk_num = EXYNOS_CLKOUT_NR_CLKS;
113 	ret = of_clk_add_provider(node, of_clk_src_onecell_get, &clkout->data);
114 	if (ret)
115 		goto err_clk_unreg;
116 
117 	register_syscore_ops(&exynos_clkout_syscore_ops);
118 
119 	return;
120 
121 err_clk_unreg:
122 	clk_unregister(clkout->clk_table[0]);
123 err_unmap:
124 	iounmap(clkout->reg);
125 clks_put:
126 	for (i = 0; i < EXYNOS_CLKOUT_PARENTS; ++i)
127 		if (!IS_ERR(parents[i]))
128 			clk_put(parents[i]);
129 free_clkout:
130 	kfree(clkout);
131 
132 	pr_err("%s: failed to register clkout clock\n", __func__);
133 }
134 
135 static void __init exynos4_clkout_init(struct device_node *node)
136 {
137 	exynos_clkout_init(node, EXYNOS4_CLKOUT_MUX_MASK);
138 }
139 CLK_OF_DECLARE(exynos4210_clkout, "samsung,exynos4210-pmu",
140 		exynos4_clkout_init);
141 CLK_OF_DECLARE(exynos4212_clkout, "samsung,exynos4212-pmu",
142 		exynos4_clkout_init);
143 CLK_OF_DECLARE(exynos4412_clkout, "samsung,exynos4412-pmu",
144 		exynos4_clkout_init);
145 
146 static void __init exynos5_clkout_init(struct device_node *node)
147 {
148 	exynos_clkout_init(node, EXYNOS5_CLKOUT_MUX_MASK);
149 }
150 CLK_OF_DECLARE(exynos5250_clkout, "samsung,exynos5250-pmu",
151 		exynos5_clkout_init);
152 CLK_OF_DECLARE(exynos5420_clkout, "samsung,exynos5420-pmu",
153 		exynos5_clkout_init);
154