1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Renesas R-Mobile Reset Driver
4 *
5 * Copyright (C) 2014 Glider bvba
6 */
7
8#include <linux/io.h>
9#include <linux/module.h>
10#include <linux/notifier.h>
11#include <linux/of_address.h>
12#include <linux/platform_device.h>
13#include <linux/printk.h>
14#include <linux/reboot.h>
15
16/* SYSC Register Bank 2 */
17#define RESCNT2 0x20 /* Reset Control Register 2 */
18
19/* Reset Control Register 2 */
20#define RESCNT2_PRES 0x80000000 /* Soft power-on reset */
21
22static void __iomem *sysc_base2;
23
24static int rmobile_reset_handler(struct notifier_block *this,
25 unsigned long mode, void *cmd)
26{
27 pr_debug("%s %lu\n", __func__, mode);
28
29 /* Let's assume we have acquired the HPB semaphore */
30 writel(RESCNT2_PRES, addr: sysc_base2 + RESCNT2);
31
32 return NOTIFY_DONE;
33}
34
35static struct notifier_block rmobile_reset_nb = {
36 .notifier_call = rmobile_reset_handler,
37 .priority = 192,
38};
39
40static int rmobile_reset_probe(struct platform_device *pdev)
41{
42 int error;
43
44 sysc_base2 = of_iomap(node: pdev->dev.of_node, index: 1);
45 if (!sysc_base2)
46 return -ENODEV;
47
48 error = register_restart_handler(&rmobile_reset_nb);
49 if (error) {
50 dev_err(&pdev->dev,
51 "cannot register restart handler (err=%d)\n", error);
52 goto fail_unmap;
53 }
54
55 return 0;
56
57fail_unmap:
58 iounmap(addr: sysc_base2);
59 return error;
60}
61
62static int rmobile_reset_remove(struct platform_device *pdev)
63{
64 unregister_restart_handler(&rmobile_reset_nb);
65 iounmap(addr: sysc_base2);
66 return 0;
67}
68
69static const struct of_device_id rmobile_reset_of_match[] = {
70 { .compatible = "renesas,sysc-rmobile", },
71 { /* sentinel */ }
72};
73MODULE_DEVICE_TABLE(of, rmobile_reset_of_match);
74
75static struct platform_driver rmobile_reset_driver = {
76 .probe = rmobile_reset_probe,
77 .remove = rmobile_reset_remove,
78 .driver = {
79 .name = "rmobile_reset",
80 .of_match_table = rmobile_reset_of_match,
81 },
82};
83
84module_platform_driver(rmobile_reset_driver);
85
86MODULE_DESCRIPTION("Renesas R-Mobile Reset Driver");
87MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
88MODULE_LICENSE("GPL v2");
89

source code of linux/drivers/power/reset/rmobile-reset.c