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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/regmap.h>
17
18static struct regmap *map;
19static u32 offset;
20static u32 value;
21static u32 mask;
22
23static void syscon_poweroff(void)
24{
25 /* Issue the poweroff */
26 regmap_update_bits(map, offset, mask, value);
27
28 mdelay(1000);
29
30 pr_emerg("Unable to poweroff system\n");
31}
32
33static int syscon_poweroff_probe(struct platform_device *pdev)
34{
35 struct device *dev = &pdev->dev;
36 int mask_err, value_err;
37
38 map = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap");
39 if (IS_ERR(map)) {
40 map = syscon_node_to_regmap(dev->parent->of_node);
41 if (IS_ERR(map)) {
42 dev_err(dev, "unable to get syscon");
43 return PTR_ERR(map);
44 }
45 }
46
47 if (of_property_read_u32(dev->of_node, "offset", &offset)) {
48 dev_err(dev, "unable to read 'offset'");
49 return -EINVAL;
50 }
51
52 value_err = of_property_read_u32(dev->of_node, "value", &value);
53 mask_err = of_property_read_u32(dev->of_node, "mask", &mask);
54 if (value_err && mask_err) {
55 dev_err(dev, "unable to read 'value' and 'mask'");
56 return -EINVAL;
57 }
58
59 if (value_err) {
60 /* support old binding */
61 value = mask;
62 mask = 0xFFFFFFFF;
63 } else if (mask_err) {
64 /* support value without mask*/
65 mask = 0xFFFFFFFF;
66 }
67
68 if (pm_power_off) {
69 dev_err(dev, "pm_power_off already claimed for %ps",
70 pm_power_off);
71 return -EBUSY;
72 }
73
74 pm_power_off = syscon_poweroff;
75
76 return 0;
77}
78
79static void syscon_poweroff_remove(struct platform_device *pdev)
80{
81 if (pm_power_off == syscon_poweroff)
82 pm_power_off = NULL;
83}
84
85static const struct of_device_id syscon_poweroff_of_match[] = {
86 { .compatible = "syscon-poweroff" },
87 {}
88};
89
90static struct platform_driver syscon_poweroff_driver = {
91 .probe = syscon_poweroff_probe,
92 .remove_new = syscon_poweroff_remove,
93 .driver = {
94 .name = "syscon-poweroff",
95 .of_match_table = syscon_poweroff_of_match,
96 },
97};
98builtin_platform_driver(syscon_poweroff_driver);
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
29static struct regmap *map;
30static u32 offset;
31static u32 value;
32static u32 mask;
33
34static void syscon_poweroff(void)
35{
36 /* Issue the poweroff */
37 regmap_update_bits(map, offset, mask, value);
38
39 mdelay(1000);
40
41 pr_emerg("Unable to poweroff system\n");
42}
43
44static int syscon_poweroff_probe(struct platform_device *pdev)
45{
46 char symname[KSYM_NAME_LEN];
47 int mask_err, value_err;
48
49 map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "regmap");
50 if (IS_ERR(map)) {
51 dev_err(&pdev->dev, "unable to get syscon");
52 return PTR_ERR(map);
53 }
54
55 if (of_property_read_u32(pdev->dev.of_node, "offset", &offset)) {
56 dev_err(&pdev->dev, "unable to read 'offset'");
57 return -EINVAL;
58 }
59
60 value_err = of_property_read_u32(pdev->dev.of_node, "value", &value);
61 mask_err = of_property_read_u32(pdev->dev.of_node, "mask", &mask);
62 if (value_err && mask_err) {
63 dev_err(&pdev->dev, "unable to read 'value' and 'mask'");
64 return -EINVAL;
65 }
66
67 if (value_err) {
68 /* support old binding */
69 value = mask;
70 mask = 0xFFFFFFFF;
71 } else if (mask_err) {
72 /* support value without mask*/
73 mask = 0xFFFFFFFF;
74 }
75
76 if (pm_power_off) {
77 lookup_symbol_name((ulong)pm_power_off, symname);
78 dev_err(&pdev->dev,
79 "pm_power_off already claimed %p %s",
80 pm_power_off, symname);
81 return -EBUSY;
82 }
83
84 pm_power_off = syscon_poweroff;
85
86 return 0;
87}
88
89static int syscon_poweroff_remove(struct platform_device *pdev)
90{
91 if (pm_power_off == syscon_poweroff)
92 pm_power_off = NULL;
93
94 return 0;
95}
96
97static const struct of_device_id syscon_poweroff_of_match[] = {
98 { .compatible = "syscon-poweroff" },
99 {}
100};
101
102static struct platform_driver syscon_poweroff_driver = {
103 .probe = syscon_poweroff_probe,
104 .remove = syscon_poweroff_remove,
105 .driver = {
106 .name = "syscon-poweroff",
107 .of_match_table = syscon_poweroff_of_match,
108 },
109};
110
111static int __init syscon_poweroff_register(void)
112{
113 return platform_driver_register(&syscon_poweroff_driver);
114}
115device_initcall(syscon_poweroff_register);