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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(struct bin_attribute), 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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