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 #include <linux/slab.h> 14 15 struct nvmem_reboot_mode { 16 struct reboot_mode_driver reboot; 17 struct nvmem_cell *cell; 18 }; 19 20 static int nvmem_reboot_mode_write(struct reboot_mode_driver *reboot, 21 unsigned int magic) 22 { 23 struct nvmem_reboot_mode *nvmem_rbm; 24 size_t buf_len; 25 void *buf; 26 int ret; 27 28 nvmem_rbm = container_of(reboot, struct nvmem_reboot_mode, reboot); 29 30 buf = nvmem_cell_read(nvmem_rbm->cell, &buf_len); 31 if (IS_ERR(buf)) 32 return PTR_ERR(buf); 33 kfree(buf); 34 35 if (buf_len > sizeof(magic)) 36 return -EINVAL; 37 38 ret = nvmem_cell_write(nvmem_rbm->cell, &magic, buf_len); 39 if (ret < 0) 40 dev_err(reboot->dev, "update reboot mode bits failed\n"); 41 42 return ret; 43 } 44 45 static int nvmem_reboot_mode_probe(struct platform_device *pdev) 46 { 47 int ret; 48 struct nvmem_reboot_mode *nvmem_rbm; 49 50 nvmem_rbm = devm_kzalloc(&pdev->dev, sizeof(*nvmem_rbm), GFP_KERNEL); 51 if (!nvmem_rbm) 52 return -ENOMEM; 53 54 nvmem_rbm->reboot.dev = &pdev->dev; 55 nvmem_rbm->reboot.write = nvmem_reboot_mode_write; 56 57 nvmem_rbm->cell = devm_nvmem_cell_get(&pdev->dev, "reboot-mode"); 58 if (IS_ERR(nvmem_rbm->cell)) { 59 return dev_err_probe(&pdev->dev, PTR_ERR(nvmem_rbm->cell), 60 "failed to get the nvmem cell reboot-mode\n"); 61 } 62 63 ret = devm_reboot_mode_register(&pdev->dev, &nvmem_rbm->reboot); 64 if (ret) 65 dev_err(&pdev->dev, "can't register reboot mode\n"); 66 67 return ret; 68 } 69 70 static const struct of_device_id nvmem_reboot_mode_of_match[] = { 71 { .compatible = "nvmem-reboot-mode" }, 72 {} 73 }; 74 MODULE_DEVICE_TABLE(of, nvmem_reboot_mode_of_match); 75 76 static struct platform_driver nvmem_reboot_mode_driver = { 77 .probe = nvmem_reboot_mode_probe, 78 .driver = { 79 .name = "nvmem-reboot-mode", 80 .of_match_table = nvmem_reboot_mode_of_match, 81 }, 82 }; 83 module_platform_driver(nvmem_reboot_mode_driver); 84 85 MODULE_AUTHOR("Nandor Han <nandor.han@vaisala.com>"); 86 MODULE_DESCRIPTION("NVMEM reboot mode driver"); 87 MODULE_LICENSE("GPL"); 88