1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (c) Vaisala Oyj. All rights reserved.
4 */
5
6#include <linux/init.h>
7#include <linux/module.h>
8#include <linux/kernel.h>
9#include <linux/of.h>
10#include <linux/nvmem-consumer.h>
11#include <linux/platform_device.h>
12#include <linux/reboot-mode.h>
13
14struct nvmem_reboot_mode {
15	struct reboot_mode_driver reboot;
16	struct nvmem_cell *cell;
17};
18
19static int nvmem_reboot_mode_write(struct reboot_mode_driver *reboot,
20				    unsigned int magic)
21{
22	int ret;
23	struct nvmem_reboot_mode *nvmem_rbm;
24
25	nvmem_rbm = container_of(reboot, struct nvmem_reboot_mode, reboot);
26
27	ret = nvmem_cell_write(nvmem_rbm->cell, &magic, sizeof(magic));
28	if (ret < 0)
29		dev_err(reboot->dev, "update reboot mode bits failed\n");
30
31	return ret;
32}
33
34static int nvmem_reboot_mode_probe(struct platform_device *pdev)
35{
36	int ret;
37	struct nvmem_reboot_mode *nvmem_rbm;
38
39	nvmem_rbm = devm_kzalloc(&pdev->dev, sizeof(*nvmem_rbm), GFP_KERNEL);
40	if (!nvmem_rbm)
41		return -ENOMEM;
42
43	nvmem_rbm->reboot.dev = &pdev->dev;
44	nvmem_rbm->reboot.write = nvmem_reboot_mode_write;
45
46	nvmem_rbm->cell = devm_nvmem_cell_get(&pdev->dev, "reboot-mode");
47	if (IS_ERR(nvmem_rbm->cell)) {
48		return dev_err_probe(&pdev->dev, PTR_ERR(nvmem_rbm->cell),
49				     "failed to get the nvmem cell reboot-mode\n");
50	}
51
52	ret = devm_reboot_mode_register(&pdev->dev, &nvmem_rbm->reboot);
53	if (ret)
54		dev_err(&pdev->dev, "can't register reboot mode\n");
55
56	return ret;
57}
58
59static const struct of_device_id nvmem_reboot_mode_of_match[] = {
60	{ .compatible = "nvmem-reboot-mode" },
61	{}
62};
63MODULE_DEVICE_TABLE(of, nvmem_reboot_mode_of_match);
64
65static struct platform_driver nvmem_reboot_mode_driver = {
66	.probe = nvmem_reboot_mode_probe,
67	.driver = {
68		.name = "nvmem-reboot-mode",
69		.of_match_table = nvmem_reboot_mode_of_match,
70	},
71};
72module_platform_driver(nvmem_reboot_mode_driver);
73
74MODULE_AUTHOR("Nandor Han <nandor.han@vaisala.com>");
75MODULE_DESCRIPTION("NVMEM reboot mode driver");
76MODULE_LICENSE("GPL");
77