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
19struct syscon_poweroff_data {
20 struct regmap *map;
21 u32 offset;
22 u32 value;
23 u32 mask;
24};
25
26static 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(map: data->map, reg: data->offset, mask: data->mask, val: data->value);
32
33 mdelay(1000);
34
35 pr_emerg("Unable to poweroff system\n");
36
37 return NOTIFY_DONE;
38}
39
40static 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, size: sizeof(*data), GFP_KERNEL);
47 if (!data)
48 return -ENOMEM;
49
50 data->map = syscon_regmap_lookup_by_phandle(np: dev->of_node, property: "regmap");
51 if (IS_ERR(ptr: data->map)) {
52 data->map = syscon_node_to_regmap(np: dev->parent->of_node);
53 if (IS_ERR(ptr: data->map)) {
54 dev_err(dev, "unable to get syscon");
55 return PTR_ERR(ptr: data->map);
56 }
57 }
58
59 if (of_property_read_u32(np: dev->of_node, propname: "offset", out_value: &data->offset)) {
60 dev_err(dev, "unable to read 'offset'");
61 return -EINVAL;
62 }
63
64 value_err = of_property_read_u32(np: dev->of_node, propname: "value", out_value: &data->value);
65 mask_err = of_property_read_u32(np: dev->of_node, propname: "mask", out_value: &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(dev: &pdev->dev,
81 mode: SYS_OFF_MODE_POWER_OFF,
82 SYS_OFF_PRIO_DEFAULT,
83 callback: syscon_poweroff, cb_data: data);
84}
85
86static const struct of_device_id syscon_poweroff_of_match[] = {
87 { .compatible = "syscon-poweroff" },
88 {}
89};
90
91static 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};
98builtin_platform_driver(syscon_poweroff_driver);
99

source code of linux/drivers/power/reset/syscon-poweroff.c