// SPDX-License-Identifier: GPL-2.0 /* * RTC subsystem, nvmem interface * * Copyright (C) 2017 Alexandre Belloni */ #include <linux/err.h> #include <linux/types.h> #include <linux/nvmem-consumer.h> #include <linux/rtc.h> #include <linux/slab.h> #include <linux/sysfs.h> /* * Deprecated ABI compatibility, this should be removed at some point */ static const char nvram_warning[] = "Deprecated ABI, please use nvmem"; static ssize_t rtc_nvram_read(struct file *filp, struct kobject *kobj, struct bin_attribute *attr, char *buf, loff_t off, size_t count) { dev_warn_once(kobj_to_dev(kobj), nvram_warning); return nvmem_device_read(attr->private, off, count, buf); } static ssize_t rtc_nvram_write(struct file *filp, struct kobject *kobj, struct bin_attribute *attr, char *buf, loff_t off, size_t count) { dev_warn_once(kobj_to_dev(kobj), nvram_warning); return nvmem_device_write(attr->private, off, count, buf); } static int rtc_nvram_register(struct rtc_device *rtc, struct nvmem_device *nvmem, size_t size) { int err; rtc->nvram = kzalloc(sizeof(*rtc->nvram), GFP_KERNEL); if (!rtc->nvram) return -ENOMEM; rtc->nvram->attr.name = "nvram"; rtc->nvram->attr.mode = 0644; rtc->nvram->private = nvmem; sysfs_bin_attr_init(rtc->nvram); rtc->nvram->read = rtc_nvram_read; rtc->nvram->write = rtc_nvram_write; rtc->nvram->size = size; err = sysfs_create_bin_file(&rtc->dev.parent->kobj, rtc->nvram); if (err) { kfree(rtc->nvram); rtc->nvram = NULL; } return err; } static void rtc_nvram_unregister(struct rtc_device *rtc) { sysfs_remove_bin_file(&rtc->dev.parent->kobj, rtc->nvram); kfree(rtc->nvram); rtc->nvram = NULL; } /* * New ABI, uses nvmem */ int rtc_nvmem_register(struct rtc_device *rtc, struct nvmem_config *nvmem_config) { struct nvmem_device *nvmem; if (!nvmem_config) return -ENODEV; nvmem_config->dev = rtc->dev.parent; nvmem_config->owner = rtc->owner; nvmem = devm_nvmem_register(rtc->dev.parent, nvmem_config); if (IS_ERR(nvmem)) return PTR_ERR(nvmem); /* Register the old ABI */ if (rtc->nvram_old_abi) rtc_nvram_register(rtc, nvmem, nvmem_config->size); return 0; } EXPORT_SYMBOL_GPL(rtc_nvmem_register); void rtc_nvmem_unregister(struct rtc_device *rtc) { /* unregister the old ABI */ if (rtc->nvram) rtc_nvram_unregister(rtc); }