[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>

/*
 * 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.parent;
	nvmem_config->owner = rtc->owner;
	rtc->nvmem = nvmem_register(nvmem_config);
	if (IS_ERR(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;
}
EXPORT_SYMBOL_GPL(rtc_nvmem_register);

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
697e5a47 AB	17	/*
	18	* Deprecated ABI compatibility, this should be removed at some point
	19	*/
	20
	21	static const char nvram_warning[] = "Deprecated ABI, please use nvmem";
	22
	23	static ssize_t
	24	rtc_nvram_read(struct file filp, struct kobject kobj,
	25	struct bin_attribute *attr,
	26	char *buf, loff_t off, size_t count)
	27	{
	28	struct rtc_device *rtc = attr->private;
	29
	30	dev_warn_once(kobj_to_dev(kobj), nvram_warning);
	31
	32	return nvmem_device_read(rtc->nvmem, off, count, buf);
	33	}
	34
	35	static ssize_t
	36	rtc_nvram_write(struct file filp, struct kobject kobj,
	37	struct bin_attribute *attr,
	38	char *buf, loff_t off, size_t count)
	39	{
	40	struct rtc_device *rtc = attr->private;
	41
	42	dev_warn_once(kobj_to_dev(kobj), nvram_warning);
	43
	44	return nvmem_device_write(rtc->nvmem, off, count, buf);
	45	}
	46
4cce9d39	47	static int rtc_nvram_register(struct rtc_device *rtc, size_t size)
697e5a47 AB	48	{
	49	int err;
	50
	51	rtc->nvram = devm_kzalloc(rtc->dev.parent,
	52	sizeof(struct bin_attribute),
	53	GFP_KERNEL);
	54	if (!rtc->nvram)
	55	return -ENOMEM;
	56
	57	rtc->nvram->attr.name = "nvram";
	58	rtc->nvram->attr.mode = 0644;
	59	rtc->nvram->private = rtc;
	60
	61	sysfs_bin_attr_init(rtc->nvram);
	62
	63	rtc->nvram->read = rtc_nvram_read;
	64	rtc->nvram->write = rtc_nvram_write;
4cce9d39	65	rtc->nvram->size = size;
697e5a47 AB	66
	67	err = sysfs_create_bin_file(&rtc->dev.parent->kobj,
	68	rtc->nvram);
	69	if (err) {
	70	devm_kfree(rtc->dev.parent, rtc->nvram);
	71	rtc->nvram = NULL;
	72	}
	73
	74	return err;
	75	}
	76
	77	static void rtc_nvram_unregister(struct rtc_device *rtc)
	78	{
	79	sysfs_remove_bin_file(&rtc->dev.parent->kobj, rtc->nvram);
	80	}
	81
	82	/*
	83	* New ABI, uses nvmem
	84	*/
2cc82121 AB	85	int rtc_nvmem_register(struct rtc_device *rtc,
2cc82121 AB	86	struct nvmem_config *nvmem_config)
697e5a47	87	{
ab3ea36e AB	88	if (!IS_ERR_OR_NULL(rtc->nvmem))
	89	return -EBUSY;
	90
4cce9d39	91	if (!nvmem_config)
2cc82121	92	return -ENODEV;
697e5a47	93
ac75779b	94	nvmem_config->dev = rtc->dev.parent;
4cce9d39 AB	95	nvmem_config->owner = rtc->owner;
4cce9d39 AB	96	rtc->nvmem = nvmem_register(nvmem_config);
046dbb24	97	if (IS_ERR(rtc->nvmem))
2cc82121	98	return PTR_ERR(rtc->nvmem);
697e5a47 AB	99
	100	/* Register the old ABI */
	101	if (rtc->nvram_old_abi)
4cce9d39	102	rtc_nvram_register(rtc, nvmem_config->size);
2cc82121 AB	103
2cc82121 AB	104	return 0;
697e5a47	105	}
fd5cd21d	106	EXPORT_SYMBOL_GPL(rtc_nvmem_register);
697e5a47 AB	107
	108	void rtc_nvmem_unregister(struct rtc_device *rtc)
	109	{
	110	if (IS_ERR_OR_NULL(rtc->nvmem))
	111	return;
	112
	113	/* unregister the old ABI */
	114	if (rtc->nvram)
	115	rtc_nvram_unregister(rtc);
	116
	117	nvmem_unregister(rtc->nvmem);
	118	}