/* * RTC subsystem, nvmem interface * * Copyright (C) 2017 Alexandre Belloni * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/err.h>#include <linux/types.h>#include <linux/nvmem-consumer.h>#include <linux/rtc.h>#include <linux/sysfs.h> #include "rtc-core.h" /* * Deprecated ABI compatibility, this should be removed at some point */ static const char nvram_warning[] = "Deprecated ABI, please use nvmem"; static ssize_trtc_nvram_read(struct file *filp, struct kobject *kobj,	       struct bin_attribute *attr,	       char *buf, loff_t off, size_t count){	struct rtc_device *rtc = attr->private; 	dev_warn_once(kobj_to_dev(kobj), nvram_warning); 	return nvmem_device_read(rtc->nvmem, off, count, buf);} static ssize_trtc_nvram_write(struct file *filp, struct kobject *kobj,		struct bin_attribute *attr,		char *buf, loff_t off, size_t count){	struct rtc_device *rtc = attr->private; 	dev_warn_once(kobj_to_dev(kobj), nvram_warning); 	return nvmem_device_write(rtc->nvmem, off, count, buf);} static int rtc_nvram_register(struct rtc_device *rtc){	int err; 	rtc->nvram = devm_kzalloc(rtc->dev.parent,				sizeof(struct bin_attribute),				GFP_KERNEL);	if (!rtc->nvram)		return -ENOMEM; 	rtc->nvram->attr.name = "nvram";	rtc->nvram->attr.mode = 0644;	rtc->nvram->private = rtc; 	sysfs_bin_attr_init(rtc->nvram); 	rtc->nvram->read = rtc_nvram_read;	rtc->nvram->write = rtc_nvram_write;	rtc->nvram->size = rtc->nvmem_config->size; 	err = sysfs_create_bin_file(&rtc->dev.parent->kobj,				    rtc->nvram);	if (err) {		devm_kfree(rtc->dev.parent, 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);} /* * New ABI, uses nvmem */void rtc_nvmem_register(struct rtc_device *rtc){	if (!rtc->nvmem_config)		return; 	rtc->nvmem_config->dev = &rtc->dev;	rtc->nvmem_config->owner = rtc->owner;	rtc->nvmem = nvmem_register(rtc->nvmem_config);	if (IS_ERR_OR_NULL(rtc->nvmem))		return; 	/* Register the old ABI */	if (rtc->nvram_old_abi)		rtc_nvram_register(rtc);} void rtc_nvmem_unregister(struct rtc_device *rtc){	if (IS_ERR_OR_NULL(rtc->nvmem))		return; 	/* unregister the old ABI */	if (rtc->nvram)		rtc_nvram_unregister(rtc); 	nvmem_unregister(rtc->nvmem);}