1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Generic Syscon Poweroff Driver
5 * Copyright (c) 2015, National Instruments Corp.
6 * Author: Moritz Fischer <moritz.fischer@ettus.com>
9 #include <linux/delay.h>
11 #include <linux/notifier.h>
12 #include <linux/mfd/syscon.h>
13 #include <linux/of_address.h>
14 #include <linux/of_device.h>
15 #include <linux/platform_device.h>
17 #include <linux/regmap.h>
19 static struct regmap *map;
24 static void syscon_poweroff(void)
26 /* Issue the poweroff */
27 regmap_update_bits(map, offset, mask, value);
31 pr_emerg("Unable to poweroff system\n");
34 static int syscon_poweroff_probe(struct platform_device *pdev)
36 int mask_err, value_err;
38 map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "regmap");
40 dev_err(&pdev->dev, "unable to get syscon");
44 if (of_property_read_u32(pdev->dev.of_node, "offset", &offset)) {
45 dev_err(&pdev->dev, "unable to read 'offset'");
49 value_err = of_property_read_u32(pdev->dev.of_node, "value", &value);
50 mask_err = of_property_read_u32(pdev->dev.of_node, "mask", &mask);
51 if (value_err && mask_err) {
52 dev_err(&pdev->dev, "unable to read 'value' and 'mask'");
57 /* support old binding */
60 } else if (mask_err) {
61 /* support value without mask*/
66 dev_err(&pdev->dev, "pm_power_off already claimed for %ps",
71 pm_power_off = syscon_poweroff;
76 static int syscon_poweroff_remove(struct platform_device *pdev)
78 if (pm_power_off == syscon_poweroff)
84 static const struct of_device_id syscon_poweroff_of_match[] = {
85 { .compatible = "syscon-poweroff" },
89 static struct platform_driver syscon_poweroff_driver = {
90 .probe = syscon_poweroff_probe,
91 .remove = syscon_poweroff_remove,
93 .name = "syscon-poweroff",
94 .of_match_table = syscon_poweroff_of_match,
98 static int __init syscon_poweroff_register(void)
100 return platform_driver_register(&syscon_poweroff_driver);
102 device_initcall(syscon_poweroff_register);