drivers/power/reset/nvmem-reboot-mode.c

   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
  14 struct nvmem_reboot_mode {
  15         struct reboot_mode_driver reboot;
  16         struct nvmem_cell *cell;
  17 };
  18
  19 static 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
  34 static 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                 dev_err(&pdev->dev, "failed to get the nvmem cell reboot-mode\n");
  49                 return PTR_ERR(nvmem_rbm->cell);
  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
  59 static const struct of_device_id nvmem_reboot_mode_of_match[] = {
  60         { .compatible = "nvmem-reboot-mode" },
  61         {}
  62 };
  63 MODULE_DEVICE_TABLE(of, nvmem_reboot_mode_of_match);
  64
  65 static 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 };
  72 module_platform_driver(nvmem_reboot_mode_driver);
  73
  74 MODULE_AUTHOR("Nandor Han <nandor.han@vaisala.com>");
  75 MODULE_DESCRIPTION("NVMEM reboot mode driver");
  76 MODULE_LICENSE("GPL");