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/*
* intel_fg_helper.c : Intel fuel gauging config helper
*
* (C) Copyright 2014 Intel Corporation
* Author: Gopal, Saranya <saranya.gopal@intel.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; version 2
* of the License.
*/
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/atomic.h>
#define MAX_DATA_SIZE 256
static atomic_t fopen_count;
static bool is_fg_data_avail;
static void *fg_data;
static int num_bytes;
int (*intel_restore_data)(void *data, int len);
int (*intel_store_data)(void *data, int len);
/**
* intel_fg_get_data - get FG config data
* @data - config data output pointer
* @len - length of config data
*/
int intel_fg_get_data(void *data, int len)
{
if (!is_fg_data_avail)
return -ENODATA;
if (num_bytes < len)
return -EINVAL;
memcpy(data, fg_data, len);
return 0;
}
EXPORT_SYMBOL(intel_fg_get_data);
/**
* intel_fg_set_data - set FG config data
* This function will set the config data to be stored
* when the device file content is saved.
* @data - config data input pointer
* @len - length of the config data
*/
void intel_fg_set_data(void *data, int len)
{
memcpy(fg_data, data, len);
}
EXPORT_SYMBOL(intel_fg_set_data);
/**
* intel_fg_set_restore_fn - set the pointer to restore function.
* The restore function set by this function will be called once FG
* config data is written to the device file.
* @restore_fn - pointer to restore function.
*/
void intel_fg_set_restore_fn(int (*restore_fn)(void *data, int len))
{
intel_restore_data = restore_fn;
}
EXPORT_SYMBOL(intel_fg_set_restore_fn);
static int intel_fg_dev_file_open(struct inode *inode, struct file *file)
{
if (atomic_read(&fopen_count))
return -EBUSY;
atomic_inc(&fopen_count);
return 0;
}
/**
* intel_fg_set_store_fn - set the pointer to store function
* The store function set by this function will be called when
* FG config data is read from the device file.
* @store_fn - pointer to store function.
*/
void intel_fg_set_store_fn(int (*store_fn)(void *data, int len))
{
intel_store_data = store_fn;
}
EXPORT_SYMBOL(intel_fg_set_store_fn);
static int intel_fg_dev_file_close(struct inode *inode, struct file *file)
{
atomic_dec(&fopen_count);
return 0;
}
static ssize_t intel_fg_dev_file_read(struct file *f, char __user *buf,
size_t len, loff_t *off)
{
if (!is_fg_data_avail)
return -ENODATA;
if (intel_store_data && !intel_store_data(fg_data, num_bytes))
pr_info("FG data is updated");
if (!copy_to_user(buf, fg_data, len))
return len;
return -EINVAL;
}
static ssize_t intel_fg_dev_file_write(struct file *f, const char __user *buf,
size_t len, loff_t *off)
{
if (copy_from_user(fg_data, buf, len))
return -EINVAL;
if (intel_restore_data && !intel_restore_data(fg_data, len))
pr_info("FG data restored successfully");
is_fg_data_avail = true;
num_bytes = len;
return len;
}
static const struct file_operations intel_fg_helper_fops = {
.owner = THIS_MODULE,
.open = &intel_fg_dev_file_open,
.release = &intel_fg_dev_file_close,
.read = &intel_fg_dev_file_read,
.write = &intel_fg_dev_file_write,
};
static struct miscdevice fg_helper = {
.minor = MISC_DYNAMIC_MINOR,
.name = "intel_fg",
.fops = &intel_fg_helper_fops,
};
static int __init fg_helper_init(void)
{
fg_data = kzalloc(MAX_DATA_SIZE, GFP_KERNEL);
intel_store_data = NULL;
intel_restore_data = NULL;
return misc_register(&fg_helper);
}
fs_initcall(fg_helper_init);
static void __exit fg_helper_exit(void)
{
misc_deregister(&fg_helper);
}
module_exit(fg_helper_exit);
MODULE_AUTHOR("Saranya Gopal <saranya.gopal@intel.com>");
MODULE_DESCRIPTION("Fuel gauge config helper");
MODULE_LICENSE("GPL");
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