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09fb07bc FK |
1 | /* |
2 | * Generic Syscon Reboot Driver | |
3 | * | |
4 | * Copyright (c) 2013, Applied Micro Circuits Corporation | |
5 | * Author: Feng Kan <fkan@apm.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 | */ | |
afaebbdb | 17 | #include <linux/delay.h> |
09fb07bc | 18 | #include <linux/io.h> |
09fb07bc FK |
19 | #include <linux/notifier.h> |
20 | #include <linux/mfd/syscon.h> | |
afaebbdb FK |
21 | #include <linux/of_address.h> |
22 | #include <linux/of_device.h> | |
23 | #include <linux/platform_device.h> | |
09fb07bc | 24 | #include <linux/reboot.h> |
afaebbdb | 25 | #include <linux/regmap.h> |
09fb07bc FK |
26 | |
27 | struct syscon_reboot_context { | |
28 | struct regmap *map; | |
29 | u32 offset; | |
30 | u32 mask; | |
31 | struct notifier_block restart_handler; | |
32 | }; | |
33 | ||
09fb07bc FK |
34 | static int syscon_restart_handle(struct notifier_block *this, |
35 | unsigned long mode, void *cmd) | |
36 | { | |
afaebbdb FK |
37 | struct syscon_reboot_context *ctx = |
38 | container_of(this, struct syscon_reboot_context, | |
39 | restart_handler); | |
09fb07bc FK |
40 | |
41 | /* Issue the reboot */ | |
afaebbdb | 42 | regmap_write(ctx->map, ctx->offset, ctx->mask); |
09fb07bc | 43 | |
afaebbdb | 44 | mdelay(1000); |
09fb07bc FK |
45 | |
46 | pr_emerg("Unable to restart system\n"); | |
47 | return NOTIFY_DONE; | |
48 | } | |
49 | ||
50 | static int syscon_reboot_probe(struct platform_device *pdev) | |
51 | { | |
52 | struct syscon_reboot_context *ctx; | |
53 | struct device *dev = &pdev->dev; | |
54 | int err; | |
55 | ||
56 | ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL); | |
57 | if (!ctx) | |
58 | return -ENOMEM; | |
59 | ||
60 | ctx->map = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap"); | |
61 | if (IS_ERR(ctx->map)) | |
62 | return PTR_ERR(ctx->map); | |
63 | ||
64 | if (of_property_read_u32(pdev->dev.of_node, "offset", &ctx->offset)) | |
65 | return -EINVAL; | |
66 | ||
67 | if (of_property_read_u32(pdev->dev.of_node, "mask", &ctx->mask)) | |
68 | return -EINVAL; | |
69 | ||
70 | ctx->restart_handler.notifier_call = syscon_restart_handle; | |
b81180b3 | 71 | ctx->restart_handler.priority = 192; |
09fb07bc FK |
72 | err = register_restart_handler(&ctx->restart_handler); |
73 | if (err) | |
74 | dev_err(dev, "can't register restart notifier (err=%d)\n", err); | |
75 | ||
afaebbdb | 76 | return err; |
09fb07bc FK |
77 | } |
78 | ||
8fb08855 | 79 | static const struct of_device_id syscon_reboot_of_match[] = { |
09fb07bc FK |
80 | { .compatible = "syscon-reboot" }, |
81 | {} | |
82 | }; | |
83 | ||
84 | static struct platform_driver syscon_reboot_driver = { | |
85 | .probe = syscon_reboot_probe, | |
86 | .driver = { | |
87 | .name = "syscon-reboot", | |
88 | .of_match_table = syscon_reboot_of_match, | |
89 | }, | |
90 | }; | |
91 | module_platform_driver(syscon_reboot_driver); |