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
syscon_poweroff(struct sys_off_data * off_data)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
syscon_poweroff_probe(struct platform_device * pdev)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