rmobile-reset.c

 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 int rmobile_reset_handler(struct sys_off_data *data)
23{
24	void __iomem *sysc_base2 = (void __iomem *)data->cb_data;
25
26	/* Let's assume we have acquired the HPB semaphore */
27	writel(RESCNT2_PRES, sysc_base2 + RESCNT2);
28
29	return NOTIFY_DONE;
30}
31
32static int rmobile_reset_probe(struct platform_device *pdev)
33{
34	void __iomem *sysc_base2;
35	int error;
36
37	sysc_base2 = devm_platform_ioremap_resource(pdev, 1);
38	if (IS_ERR(sysc_base2))
39		return PTR_ERR(sysc_base2);
40
41	error = devm_register_sys_off_handler(&pdev->dev,
42					      SYS_OFF_MODE_RESTART,
43					      SYS_OFF_PRIO_HIGH,
44					      rmobile_reset_handler,
45					      (__force void *)sysc_base2);
46	if (error) {
47		dev_err(&pdev->dev,
48			"cannot register restart handler (err=%d)\n", error);
49		return error;
50	}
51
52	return 0;
53}
54
55static const struct of_device_id rmobile_reset_of_match[] = {
56	{ .compatible = "renesas,sysc-rmobile", },
57	{ /* sentinel */ }
58};
59MODULE_DEVICE_TABLE(of, rmobile_reset_of_match);
60
61static struct platform_driver rmobile_reset_driver = {
62	.probe = rmobile_reset_probe,
63	.driver = {
64		.name = "rmobile_reset",
65		.of_match_table = rmobile_reset_of_match,
66	},
67};
68
69module_platform_driver(rmobile_reset_driver);
70
71MODULE_DESCRIPTION("Renesas R-Mobile Reset Driver");
72MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
73MODULE_LICENSE("GPL v2");