1 // SPDX-License-Identifier: GPL-2.0
3 * RTC subsystem, nvmem interface
5 * Copyright (C) 2017 Alexandre Belloni
9 #include <linux/types.h>
10 #include <linux/nvmem-consumer.h>
11 #include <linux/rtc.h>
12 #include <linux/slab.h>
13 #include <linux/sysfs.h>
16 * Deprecated ABI compatibility, this should be removed at some point
19 static const char nvram_warning[] = "Deprecated ABI, please use nvmem";
22 rtc_nvram_read(struct file *filp, struct kobject *kobj,
23 struct bin_attribute *attr,
24 char *buf, loff_t off, size_t count)
26 dev_warn_once(kobj_to_dev(kobj), nvram_warning);
28 return nvmem_device_read(attr->private, off, count, buf);
32 rtc_nvram_write(struct file *filp, struct kobject *kobj,
33 struct bin_attribute *attr,
34 char *buf, loff_t off, size_t count)
36 dev_warn_once(kobj_to_dev(kobj), nvram_warning);
38 return nvmem_device_write(attr->private, off, count, buf);
41 static int rtc_nvram_register(struct rtc_device *rtc,
42 struct nvmem_device *nvmem, size_t size)
46 rtc->nvram = kzalloc(sizeof(*rtc->nvram), GFP_KERNEL);
50 rtc->nvram->attr.name = "nvram";
51 rtc->nvram->attr.mode = 0644;
52 rtc->nvram->private = nvmem;
54 sysfs_bin_attr_init(rtc->nvram);
56 rtc->nvram->read = rtc_nvram_read;
57 rtc->nvram->write = rtc_nvram_write;
58 rtc->nvram->size = size;
60 err = sysfs_create_bin_file(&rtc->dev.parent->kobj,
70 static void rtc_nvram_unregister(struct rtc_device *rtc)
72 sysfs_remove_bin_file(&rtc->dev.parent->kobj, rtc->nvram);
80 int rtc_nvmem_register(struct rtc_device *rtc,
81 struct nvmem_config *nvmem_config)
83 struct nvmem_device *nvmem;
88 nvmem_config->dev = rtc->dev.parent;
89 nvmem_config->owner = rtc->owner;
90 nvmem = devm_nvmem_register(rtc->dev.parent, nvmem_config);
92 return PTR_ERR(nvmem);
94 /* Register the old ABI */
95 if (rtc->nvram_old_abi)
96 rtc_nvram_register(rtc, nvmem, nvmem_config->size);
100 EXPORT_SYMBOL_GPL(rtc_nvmem_register);
102 void rtc_nvmem_unregister(struct rtc_device *rtc)
104 /* unregister the old ABI */
106 rtc_nvram_unregister(rtc);