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/slab.h>
13 #include <linux/clk.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 	void __iomem *reg;
33 	u32 pmu_debug_save;
34 	struct clk_hw_onecell_data data;
35 };
36 
37 static struct exynos_clkout *clkout;
38 
39 static int exynos_clkout_suspend(void)
40 {
41 	clkout->pmu_debug_save = readl(clkout->reg + EXYNOS_PMU_DEBUG_REG);
42 
43 	return 0;
44 }
45 
46 static void exynos_clkout_resume(void)
47 {
48 	writel(clkout->pmu_debug_save, clkout->reg + EXYNOS_PMU_DEBUG_REG);
49 }
50 
51 static struct syscore_ops exynos_clkout_syscore_ops = {
52 	.suspend = exynos_clkout_suspend,
53 	.resume = exynos_clkout_resume,
54 };
55 
56 static void __init exynos_clkout_init(struct device_node *node, u32 mux_mask)
57 {
58 	const char *parent_names[EXYNOS_CLKOUT_PARENTS];
59 	struct clk *parents[EXYNOS_CLKOUT_PARENTS];
60 	int parent_count;
61 	int ret;
62 	int i;
63 
64 	clkout = kzalloc(sizeof(*clkout) +
65 			 sizeof(*clkout->data.hws) * EXYNOS_CLKOUT_NR_CLKS,
66 			 GFP_KERNEL);
67 	if (!clkout)
68 		return;
69 
70 	spin_lock_init(&clkout->slock);
71 
72 	parent_count = 0;
73 	for (i = 0; i < EXYNOS_CLKOUT_PARENTS; ++i) {
74 		char name[] = "clkoutXX";
75 
76 		snprintf(name, sizeof(name), "clkout%d", i);
77 		parents[i] = of_clk_get_by_name(node, name);
78 		if (IS_ERR(parents[i])) {
79 			parent_names[i] = "none";
80 			continue;
81 		}
82 
83 		parent_names[i] = __clk_get_name(parents[i]);
84 		parent_count = i + 1;
85 	}
86 
87 	if (!parent_count)
88 		goto free_clkout;
89 
90 	clkout->reg = of_iomap(node, 0);
91 	if (!clkout->reg)
92 		goto clks_put;
93 
94 	clkout->gate.reg = clkout->reg + EXYNOS_PMU_DEBUG_REG;
95 	clkout->gate.bit_idx = EXYNOS_CLKOUT_DISABLE_SHIFT;
96 	clkout->gate.flags = CLK_GATE_SET_TO_DISABLE;
97 	clkout->gate.lock = &clkout->slock;
98 
99 	clkout->mux.reg = clkout->reg + EXYNOS_PMU_DEBUG_REG;
100 	clkout->mux.mask = mux_mask;
101 	clkout->mux.shift = EXYNOS_CLKOUT_MUX_SHIFT;
102 	clkout->mux.lock = &clkout->slock;
103 
104 	clkout->data.hws[0] = clk_hw_register_composite(NULL, "clkout",
105 				parent_names, parent_count, &clkout->mux.hw,
106 				&clk_mux_ops, NULL, NULL, &clkout->gate.hw,
107 				&clk_gate_ops, CLK_SET_RATE_PARENT
108 				| CLK_SET_RATE_NO_REPARENT);
109 	if (IS_ERR(clkout->data.hws[0]))
110 		goto err_unmap;
111 
112 	clkout->data.num = EXYNOS_CLKOUT_NR_CLKS;
113 	ret = of_clk_add_hw_provider(node, of_clk_hw_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_hw_unregister(clkout->data.hws[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 /*
136  * We use CLK_OF_DECLARE_DRIVER initialization method to avoid setting
137  * the OF_POPULATED flag on the pmu device tree node, so later the
138  * Exynos PMU platform device can be properly probed with PMU driver.
139  */
140 
141 static void __init exynos4_clkout_init(struct device_node *node)
142 {
143 	exynos_clkout_init(node, EXYNOS4_CLKOUT_MUX_MASK);
144 }
145 CLK_OF_DECLARE_DRIVER(exynos4210_clkout, "samsung,exynos4210-pmu",
146 		exynos4_clkout_init);
147 CLK_OF_DECLARE_DRIVER(exynos4412_clkout, "samsung,exynos4412-pmu",
148 		exynos4_clkout_init);
149 CLK_OF_DECLARE_DRIVER(exynos3250_clkout, "samsung,exynos3250-pmu",
150 		exynos4_clkout_init);
151 
152 static void __init exynos5_clkout_init(struct device_node *node)
153 {
154 	exynos_clkout_init(node, EXYNOS5_CLKOUT_MUX_MASK);
155 }
156 CLK_OF_DECLARE_DRIVER(exynos5250_clkout, "samsung,exynos5250-pmu",
157 		exynos5_clkout_init);
158 CLK_OF_DECLARE_DRIVER(exynos5410_clkout, "samsung,exynos5410-pmu",
159 		exynos5_clkout_init);
160 CLK_OF_DECLARE_DRIVER(exynos5420_clkout, "samsung,exynos5420-pmu",
161 		exynos5_clkout_init);
162 CLK_OF_DECLARE_DRIVER(exynos5433_clkout, "samsung,exynos5433-pmu",
163 		exynos5_clkout_init);
164