[linux-2.6-block.git] / drivers / rtc / nvmem.c

/*
 * 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_t
rtc_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_t
rtc_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, size_t size)
{
	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 = 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
 */
int rtc_nvmem_register(struct rtc_device *rtc,
		       struct nvmem_config *nvmem_config)
{
	if (!IS_ERR_OR_NULL(rtc->nvmem))
		return -EBUSY;

	if (!nvmem_config)
		return -ENODEV;

	nvmem_config->dev = &rtc->dev;
	nvmem_config->owner = rtc->owner;
	rtc->nvmem = nvmem_register(nvmem_config);
	if (IS_ERR_OR_NULL(rtc->nvmem))
		return PTR_ERR(rtc->nvmem);

	/* Register the old ABI */
	if (rtc->nvram_old_abi)
		rtc_nvram_register(rtc, nvmem_config->size);

	return 0;
}

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);
}
Commit	Line	Data
697e5a47 AB	1	/*
	2	* RTC subsystem, nvmem interface
	3	*
	4	* Copyright (C) 2017 Alexandre Belloni
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*/
	10
	11	#include <linux/err.h>
	12	#include <linux/types.h>
	13	#include <linux/nvmem-consumer.h>
	14	#include <linux/rtc.h>
	15	#include <linux/sysfs.h>
	16
	17	#include "rtc-core.h"
	18
	19	/*
	20	* Deprecated ABI compatibility, this should be removed at some point
	21	*/
	22
	23	static const char nvram_warning[] = "Deprecated ABI, please use nvmem";
	24
	25	static ssize_t
	26	rtc_nvram_read(struct file filp, struct kobject kobj,
	27	struct bin_attribute *attr,
	28	char *buf, loff_t off, size_t count)
	29	{
	30	struct rtc_device *rtc = attr->private;
	31
	32	dev_warn_once(kobj_to_dev(kobj), nvram_warning);
	33
	34	return nvmem_device_read(rtc->nvmem, off, count, buf);
	35	}
	36
	37	static ssize_t
	38	rtc_nvram_write(struct file filp, struct kobject kobj,
	39	struct bin_attribute *attr,
	40	char *buf, loff_t off, size_t count)
	41	{
	42	struct rtc_device *rtc = attr->private;
	43
	44	dev_warn_once(kobj_to_dev(kobj), nvram_warning);
	45
	46	return nvmem_device_write(rtc->nvmem, off, count, buf);
	47	}
	48
4cce9d39	49	static int rtc_nvram_register(struct rtc_device *rtc, size_t size)
697e5a47 AB	50	{
	51	int err;
	52
	53	rtc->nvram = devm_kzalloc(rtc->dev.parent,
	54	sizeof(struct bin_attribute),
	55	GFP_KERNEL);
	56	if (!rtc->nvram)
	57	return -ENOMEM;
	58
	59	rtc->nvram->attr.name = "nvram";
	60	rtc->nvram->attr.mode = 0644;
	61	rtc->nvram->private = rtc;
	62
	63	sysfs_bin_attr_init(rtc->nvram);
	64
	65	rtc->nvram->read = rtc_nvram_read;
	66	rtc->nvram->write = rtc_nvram_write;
4cce9d39	67	rtc->nvram->size = size;
697e5a47 AB	68
	69	err = sysfs_create_bin_file(&rtc->dev.parent->kobj,
	70	rtc->nvram);
	71	if (err) {
	72	devm_kfree(rtc->dev.parent, rtc->nvram);
	73	rtc->nvram = NULL;
	74	}
	75
	76	return err;
	77	}
	78
	79	static void rtc_nvram_unregister(struct rtc_device *rtc)
	80	{
	81	sysfs_remove_bin_file(&rtc->dev.parent->kobj, rtc->nvram);
	82	}
	83
	84	/*
	85	* New ABI, uses nvmem
	86	*/
2cc82121 AB	87	int rtc_nvmem_register(struct rtc_device *rtc,
2cc82121 AB	88	struct nvmem_config *nvmem_config)
697e5a47	89	{
ab3ea36e AB	90	if (!IS_ERR_OR_NULL(rtc->nvmem))
	91	return -EBUSY;
	92
4cce9d39	93	if (!nvmem_config)
2cc82121	94	return -ENODEV;
697e5a47	95
4cce9d39 AB	96	nvmem_config->dev = &rtc->dev;
	97	nvmem_config->owner = rtc->owner;
	98	rtc->nvmem = nvmem_register(nvmem_config);
697e5a47	99	if (IS_ERR_OR_NULL(rtc->nvmem))
2cc82121	100	return PTR_ERR(rtc->nvmem);
697e5a47 AB	101
	102	/* Register the old ABI */
	103	if (rtc->nvram_old_abi)
4cce9d39	104	rtc_nvram_register(rtc, nvmem_config->size);
2cc82121 AB	105
2cc82121 AB	106	return 0;
697e5a47 AB	107	}
	108
	109	void rtc_nvmem_unregister(struct rtc_device *rtc)
	110	{
	111	if (IS_ERR_OR_NULL(rtc->nvmem))
	112	return;
	113
	114	/* unregister the old ABI */
	115	if (rtc->nvram)
	116	rtc_nvram_unregister(rtc);
	117
	118	nvmem_unregister(rtc->nvmem);
	119	}