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6e973d2c PM |
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/clkdev.h> | |
16 | #include <linux/clk-provider.h> | |
17 | #include <linux/err.h> | |
18 | #include <linux/of.h> | |
19 | #include <linux/of_address.h> | |
20 | ||
21 | #define to_clk_sp810_timerclken(_hw) \ | |
22 | container_of(_hw, struct clk_sp810_timerclken, hw) | |
23 | ||
24 | struct clk_sp810; | |
25 | ||
26 | struct clk_sp810_timerclken { | |
27 | struct clk_hw hw; | |
28 | struct clk *clk; | |
29 | struct clk_sp810 *sp810; | |
30 | int channel; | |
31 | }; | |
32 | ||
33 | struct clk_sp810 { | |
34 | struct device_node *node; | |
35 | int refclk_index, timclk_index; | |
36 | void __iomem *base; | |
37 | spinlock_t lock; | |
38 | struct clk_sp810_timerclken timerclken[4]; | |
39 | struct clk *refclk; | |
40 | struct clk *timclk; | |
41 | }; | |
42 | ||
43 | static u8 clk_sp810_timerclken_get_parent(struct clk_hw *hw) | |
44 | { | |
45 | struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw); | |
46 | u32 val = readl(timerclken->sp810->base + SCCTRL); | |
47 | ||
48 | return !!(val & (1 << SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel))); | |
49 | } | |
50 | ||
51 | static int clk_sp810_timerclken_set_parent(struct clk_hw *hw, u8 index) | |
52 | { | |
53 | struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw); | |
54 | struct clk_sp810 *sp810 = timerclken->sp810; | |
55 | u32 val, shift = SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel); | |
56 | unsigned long flags = 0; | |
57 | ||
58 | if (WARN_ON(index > 1)) | |
59 | return -EINVAL; | |
60 | ||
61 | spin_lock_irqsave(&sp810->lock, flags); | |
62 | ||
63 | val = readl(sp810->base + SCCTRL); | |
64 | val &= ~(1 << shift); | |
65 | val |= index << shift; | |
66 | writel(val, sp810->base + SCCTRL); | |
67 | ||
68 | spin_unlock_irqrestore(&sp810->lock, flags); | |
69 | ||
70 | return 0; | |
71 | } | |
72 | ||
73 | /* | |
74 | * FIXME - setting the parent every time .prepare is invoked is inefficient. | |
75 | * This is better handled by a dedicated clock tree configuration mechanism at | |
76 | * init-time. Revisit this later when such a mechanism exists | |
77 | */ | |
78 | static int clk_sp810_timerclken_prepare(struct clk_hw *hw) | |
79 | { | |
80 | struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw); | |
81 | struct clk_sp810 *sp810 = timerclken->sp810; | |
82 | struct clk *old_parent = __clk_get_parent(hw->clk); | |
83 | struct clk *new_parent; | |
84 | ||
85 | if (!sp810->refclk) | |
86 | sp810->refclk = of_clk_get(sp810->node, sp810->refclk_index); | |
87 | ||
88 | if (!sp810->timclk) | |
89 | sp810->timclk = of_clk_get(sp810->node, sp810->timclk_index); | |
90 | ||
91 | if (WARN_ON(IS_ERR(sp810->refclk) || IS_ERR(sp810->timclk))) | |
92 | return -ENOENT; | |
93 | ||
94 | /* Select fastest parent */ | |
95 | if (clk_get_rate(sp810->refclk) > clk_get_rate(sp810->timclk)) | |
96 | new_parent = sp810->refclk; | |
97 | else | |
98 | new_parent = sp810->timclk; | |
99 | ||
100 | /* Switch the parent if necessary */ | |
101 | if (old_parent != new_parent) { | |
102 | clk_prepare(new_parent); | |
103 | clk_set_parent(hw->clk, new_parent); | |
104 | clk_unprepare(old_parent); | |
105 | } | |
106 | ||
107 | return 0; | |
108 | } | |
109 | ||
110 | static void clk_sp810_timerclken_unprepare(struct clk_hw *hw) | |
111 | { | |
112 | struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw); | |
113 | struct clk_sp810 *sp810 = timerclken->sp810; | |
114 | ||
115 | clk_put(sp810->timclk); | |
116 | clk_put(sp810->refclk); | |
117 | } | |
118 | ||
119 | static const struct clk_ops clk_sp810_timerclken_ops = { | |
120 | .prepare = clk_sp810_timerclken_prepare, | |
121 | .unprepare = clk_sp810_timerclken_unprepare, | |
122 | .get_parent = clk_sp810_timerclken_get_parent, | |
123 | .set_parent = clk_sp810_timerclken_set_parent, | |
124 | }; | |
125 | ||
14b260ce | 126 | static struct clk *clk_sp810_timerclken_of_get(struct of_phandle_args *clkspec, |
6e973d2c PM |
127 | void *data) |
128 | { | |
129 | struct clk_sp810 *sp810 = data; | |
130 | ||
131 | if (WARN_ON(clkspec->args_count != 1 || clkspec->args[0] > | |
132 | ARRAY_SIZE(sp810->timerclken))) | |
133 | return NULL; | |
134 | ||
135 | return sp810->timerclken[clkspec->args[0]].clk; | |
136 | } | |
137 | ||
138 | void __init clk_sp810_of_setup(struct device_node *node) | |
139 | { | |
140 | struct clk_sp810 *sp810 = kzalloc(sizeof(*sp810), GFP_KERNEL); | |
141 | const char *parent_names[2]; | |
142 | char name[12]; | |
143 | struct clk_init_data init; | |
144 | int i; | |
145 | ||
146 | if (!sp810) { | |
147 | pr_err("Failed to allocate memory for SP810!\n"); | |
148 | return; | |
149 | } | |
150 | ||
151 | sp810->refclk_index = of_property_match_string(node, "clock-names", | |
152 | "refclk"); | |
153 | parent_names[0] = of_clk_get_parent_name(node, sp810->refclk_index); | |
154 | ||
155 | sp810->timclk_index = of_property_match_string(node, "clock-names", | |
156 | "timclk"); | |
157 | parent_names[1] = of_clk_get_parent_name(node, sp810->timclk_index); | |
158 | ||
159 | if (parent_names[0] <= 0 || parent_names[1] <= 0) { | |
160 | pr_warn("Failed to obtain parent clocks for SP810!\n"); | |
161 | return; | |
162 | } | |
163 | ||
164 | sp810->node = node; | |
165 | sp810->base = of_iomap(node, 0); | |
166 | spin_lock_init(&sp810->lock); | |
167 | ||
168 | init.name = name; | |
169 | init.ops = &clk_sp810_timerclken_ops; | |
170 | init.flags = CLK_IS_BASIC; | |
171 | init.parent_names = parent_names; | |
172 | init.num_parents = ARRAY_SIZE(parent_names); | |
173 | ||
174 | for (i = 0; i < ARRAY_SIZE(sp810->timerclken); i++) { | |
175 | snprintf(name, ARRAY_SIZE(name), "timerclken%d", i); | |
176 | ||
177 | sp810->timerclken[i].sp810 = sp810; | |
178 | sp810->timerclken[i].channel = i; | |
179 | sp810->timerclken[i].hw.init = &init; | |
180 | ||
181 | sp810->timerclken[i].clk = clk_register(NULL, | |
182 | &sp810->timerclken[i].hw); | |
183 | WARN_ON(IS_ERR(sp810->timerclken[i].clk)); | |
184 | } | |
185 | ||
186 | of_clk_add_provider(node, clk_sp810_timerclken_of_get, sp810); | |
187 | } | |
188 | CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup); |