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 | |
18 | static struct regmap *map; |
19 | static u32 offset; |
20 | static u32 value; |
21 | static u32 mask; |
22 | |
23 | static void syscon_poweroff(void) |
24 | { |
25 | /* Issue the poweroff */ |
26 | regmap_update_bits(map, reg: offset, mask, val: value); |
27 | |
28 | mdelay(1000); |
29 | |
30 | pr_emerg("Unable to poweroff system\n" ); |
31 | } |
32 | |
33 | static 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(np: dev->of_node, property: "regmap" ); |
39 | if (IS_ERR(ptr: map)) { |
40 | map = syscon_node_to_regmap(np: dev->parent->of_node); |
41 | if (IS_ERR(ptr: map)) { |
42 | dev_err(dev, "unable to get syscon" ); |
43 | return PTR_ERR(ptr: map); |
44 | } |
45 | } |
46 | |
47 | if (of_property_read_u32(np: dev->of_node, propname: "offset" , out_value: &offset)) { |
48 | dev_err(dev, "unable to read 'offset'" ); |
49 | return -EINVAL; |
50 | } |
51 | |
52 | value_err = of_property_read_u32(np: dev->of_node, propname: "value" , out_value: &value); |
53 | mask_err = of_property_read_u32(np: dev->of_node, propname: "mask" , out_value: &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 | |
79 | static int syscon_poweroff_remove(struct platform_device *pdev) |
80 | { |
81 | if (pm_power_off == syscon_poweroff) |
82 | pm_power_off = NULL; |
83 | |
84 | return 0; |
85 | } |
86 | |
87 | static const struct of_device_id syscon_poweroff_of_match[] = { |
88 | { .compatible = "syscon-poweroff" }, |
89 | {} |
90 | }; |
91 | |
92 | static struct platform_driver syscon_poweroff_driver = { |
93 | .probe = syscon_poweroff_probe, |
94 | .remove = syscon_poweroff_remove, |
95 | .driver = { |
96 | .name = "syscon-poweroff" , |
97 | .of_match_table = syscon_poweroff_of_match, |
98 | }, |
99 | }; |
100 | builtin_platform_driver(syscon_poweroff_driver); |
101 | |