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- // 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);
- }
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