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"); 77