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8a577608 MF |
1 | /* |
2 | * Generic Syscon Poweroff Driver | |
3 | * | |
4 | * Copyright (c) 2015, National Instruments Corp. | |
5 | * Author: Moritz Fischer <moritz.fischer@ettus.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License as | |
9 | * published by the Free Software Foundation; either version 2 of | |
10 | * the License, or (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | */ | |
17 | ||
18 | #include <linux/kallsyms.h> | |
19 | #include <linux/delay.h> | |
20 | #include <linux/io.h> | |
21 | #include <linux/notifier.h> | |
22 | #include <linux/mfd/syscon.h> | |
23 | #include <linux/of_address.h> | |
24 | #include <linux/of_device.h> | |
25 | #include <linux/platform_device.h> | |
26 | #include <linux/pm.h> | |
27 | #include <linux/regmap.h> | |
28 | ||
29 | static struct regmap *map; | |
30 | static u32 offset; | |
31 | static u32 mask; | |
32 | ||
33 | void syscon_poweroff(void) | |
34 | { | |
35 | /* Issue the poweroff */ | |
36 | regmap_write(map, offset, mask); | |
37 | ||
38 | mdelay(1000); | |
39 | ||
40 | pr_emerg("Unable to poweroff system\n"); | |
41 | } | |
42 | ||
43 | static int syscon_poweroff_probe(struct platform_device *pdev) | |
44 | { | |
45 | char symname[KSYM_NAME_LEN]; | |
46 | ||
47 | map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "regmap"); | |
48 | if (IS_ERR(map)) { | |
49 | dev_err(&pdev->dev, "unable to get syscon"); | |
50 | return PTR_ERR(map); | |
51 | } | |
52 | ||
53 | if (of_property_read_u32(pdev->dev.of_node, "offset", &offset)) { | |
54 | dev_err(&pdev->dev, "unable to read 'offset'"); | |
55 | return -EINVAL; | |
56 | } | |
57 | ||
58 | if (of_property_read_u32(pdev->dev.of_node, "mask", &mask)) { | |
59 | dev_err(&pdev->dev, "unable to read 'mask'"); | |
60 | return -EINVAL; | |
61 | } | |
62 | ||
63 | if (pm_power_off) { | |
64 | lookup_symbol_name((ulong)pm_power_off, symname); | |
65 | dev_err(&pdev->dev, | |
66 | "pm_power_off already claimed %p %s", | |
67 | pm_power_off, symname); | |
68 | return -EBUSY; | |
69 | } | |
70 | ||
71 | pm_power_off = syscon_poweroff; | |
72 | ||
73 | return 0; | |
74 | } | |
75 | ||
76 | static int syscon_poweroff_remove(struct platform_device *pdev) | |
77 | { | |
78 | if (pm_power_off == syscon_poweroff) | |
79 | pm_power_off = NULL; | |
80 | ||
81 | return 0; | |
82 | } | |
83 | ||
84 | static const struct of_device_id syscon_poweroff_of_match[] = { | |
85 | { .compatible = "syscon-poweroff" }, | |
86 | {} | |
87 | }; | |
88 | ||
89 | static struct platform_driver syscon_poweroff_driver = { | |
90 | .probe = syscon_poweroff_probe, | |
91 | .remove = syscon_poweroff_remove, | |
92 | .driver = { | |
93 | .name = "syscon-poweroff", | |
94 | .of_match_table = syscon_poweroff_of_match, | |
95 | }, | |
96 | }; | |
97 | ||
98 | static int __init syscon_poweroff_register(void) | |
99 | { | |
100 | return platform_driver_register(&syscon_poweroff_driver); | |
101 | } | |
102 | device_initcall(syscon_poweroff_register); |