power/reset/nvmem-reboot-mode.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  * Copyright (c) Vaisala Oyj. All rights reserved.
0004  */
0005
0006 #include <linux/init.h>
0007 #include <linux/module.h>
0008 #include <linux/kernel.h>
0009 #include <linux/of.h>
0010 #include <linux/nvmem-consumer.h>
0011 #include <linux/platform_device.h>
0012 #include <linux/reboot-mode.h>
0013
0014 struct nvmem_reboot_mode {
0015     struct reboot_mode_driver reboot;
0016     struct nvmem_cell *cell;
0017 };
0018
0019 static int nvmem_reboot_mode_write(struct reboot_mode_driver *reboot,
0020                     unsigned int magic)
0021 {
0022     int ret;
0023     struct nvmem_reboot_mode *nvmem_rbm;
0024
0025     nvmem_rbm = container_of(reboot, struct nvmem_reboot_mode, reboot);
0026
0027     ret = nvmem_cell_write(nvmem_rbm->cell, &magic, sizeof(magic));
0028     if (ret < 0)
0029         dev_err(reboot->dev, "update reboot mode bits failed\n");
0030
0031     return ret;
0032 }
0033
0034 static int nvmem_reboot_mode_probe(struct platform_device *pdev)
0035 {
0036     int ret;
0037     struct nvmem_reboot_mode *nvmem_rbm;
0038
0039     nvmem_rbm = devm_kzalloc(&pdev->dev, sizeof(*nvmem_rbm), GFP_KERNEL);
0040     if (!nvmem_rbm)
0041         return -ENOMEM;
0042
0043     nvmem_rbm->reboot.dev = &pdev->dev;
0044     nvmem_rbm->reboot.write = nvmem_reboot_mode_write;
0045
0046     nvmem_rbm->cell = devm_nvmem_cell_get(&pdev->dev, "reboot-mode");
0047     if (IS_ERR(nvmem_rbm->cell)) {
0048         dev_err(&pdev->dev, "failed to get the nvmem cell reboot-mode\n");
0049         return PTR_ERR(nvmem_rbm->cell);
0050     }
0051
0052     ret = devm_reboot_mode_register(&pdev->dev, &nvmem_rbm->reboot);
0053     if (ret)
0054         dev_err(&pdev->dev, "can't register reboot mode\n");
0055
0056     return ret;
0057 }
0058
0059 static const struct of_device_id nvmem_reboot_mode_of_match[] = {
0060     { .compatible = "nvmem-reboot-mode" },
0061     {}
0062 };
0063 MODULE_DEVICE_TABLE(of, nvmem_reboot_mode_of_match);
0064
0065 static struct platform_driver nvmem_reboot_mode_driver = {
0066     .probe = nvmem_reboot_mode_probe,
0067     .driver = {
0068         .name = "nvmem-reboot-mode",
0069         .of_match_table = nvmem_reboot_mode_of_match,
0070     },
0071 };
0072 module_platform_driver(nvmem_reboot_mode_driver);
0073
0074 MODULE_AUTHOR("Nandor Han <nandor.han@vaisala.com>");
0075 MODULE_DESCRIPTION("NVMEM reboot mode driver");
0076 MODULE_LICENSE("GPL");