xref: /linux/drivers/power/reset/syscon-poweroff.c (revision 8e1bb4a41aa78d6105e59186af3dcd545fc66e70)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Generic Syscon Poweroff Driver
4  *
5  * Copyright (c) 2015, National Instruments Corp.
6  * Author: Moritz Fischer <moritz.fischer@ettus.com>
7  */
8 
9 #include <linux/delay.h>
10 #include <linux/io.h>
11 #include <linux/notifier.h>
12 #include <linux/mfd/syscon.h>
13 #include <linux/of.h>
14 #include <linux/platform_device.h>
15 #include <linux/pm.h>
16 #include <linux/reboot.h>
17 #include <linux/regmap.h>
18 
19 struct syscon_poweroff_data {
20 	struct regmap *map;
21 	u32 offset;
22 	u32 value;
23 	u32 mask;
24 };
25 
26 static int syscon_poweroff(struct sys_off_data *off_data)
27 {
28 	struct syscon_poweroff_data *data = off_data->cb_data;
29 
30 	/* Issue the poweroff */
31 	regmap_update_bits(data->map, data->offset, data->mask, data->value);
32 
33 	mdelay(1000);
34 
35 	pr_emerg("Unable to poweroff system\n");
36 
37 	return NOTIFY_DONE;
38 }
39 
40 static int syscon_poweroff_probe(struct platform_device *pdev)
41 {
42 	struct device *dev = &pdev->dev;
43 	struct syscon_poweroff_data *data;
44 	int mask_err, value_err;
45 
46 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
47 	if (!data)
48 		return -ENOMEM;
49 
50 	data->map = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap");
51 	if (IS_ERR(data->map)) {
52 		data->map = syscon_node_to_regmap(dev->parent->of_node);
53 		if (IS_ERR(data->map)) {
54 			dev_err(dev, "unable to get syscon");
55 			return PTR_ERR(data->map);
56 		}
57 	}
58 
59 	if (of_property_read_u32(dev->of_node, "offset", &data->offset)) {
60 		dev_err(dev, "unable to read 'offset'");
61 		return -EINVAL;
62 	}
63 
64 	value_err = of_property_read_u32(dev->of_node, "value", &data->value);
65 	mask_err = of_property_read_u32(dev->of_node, "mask", &data->mask);
66 	if (value_err && mask_err) {
67 		dev_err(dev, "unable to read 'value' and 'mask'");
68 		return -EINVAL;
69 	}
70 
71 	if (value_err) {
72 		/* support old binding */
73 		data->value = data->mask;
74 		data->mask = 0xFFFFFFFF;
75 	} else if (mask_err) {
76 		/* support value without mask*/
77 		data->mask = 0xFFFFFFFF;
78 	}
79 
80 	return devm_register_sys_off_handler(&pdev->dev,
81 					     SYS_OFF_MODE_POWER_OFF,
82 					     SYS_OFF_PRIO_DEFAULT,
83 					     syscon_poweroff, data);
84 }
85 
86 static const struct of_device_id syscon_poweroff_of_match[] = {
87 	{ .compatible = "syscon-poweroff" },
88 	{}
89 };
90 
91 static struct platform_driver syscon_poweroff_driver = {
92 	.probe = syscon_poweroff_probe,
93 	.driver = {
94 		.name = "syscon-poweroff",
95 		.of_match_table = syscon_poweroff_of_match,
96 	},
97 };
98 builtin_platform_driver(syscon_poweroff_driver);
99