linux/drivers/misc/eeprom/max6875.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * max6875.c - driver for MAX6874/MAX6875
 *
 * Copyright (C) 2005 Ben Gardner <[email protected]>
 *
 * Based on eeprom.c
 *
 * The MAX6875 has a bank of registers and two banks of EEPROM.
 * Address ranges are defined as follows:
 *  * 0x0000 - 0x0046 = configuration registers
 *  * 0x8000 - 0x8046 = configuration EEPROM
 *  * 0x8100 - 0x82FF = user EEPROM
 *
 * This driver makes the user EEPROM available for read.
 *
 * The registers & config EEPROM should be accessed via i2c-dev.
 *
 * The MAX6875 ignores the lowest address bit, so each chip responds to
 * two addresses - 0x50/0x51 and 0x52/0x53.
 *
 * Note that the MAX6875 uses i2c_smbus_write_byte_data() to set the read
 * address, so this driver is destructive if loaded for the wrong EEPROM chip.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/mutex.h>

/* The MAX6875 can only read/write 16 bytes at a time */
#define SLICE_SIZE …
#define SLICE_BITS …

/* USER EEPROM is at addresses 0x8100 - 0x82FF */
#define USER_EEPROM_BASE …
#define USER_EEPROM_SIZE …
#define USER_EEPROM_SLICES …

/* MAX6875 commands */
#define MAX6875_CMD_BLK_READ …

/* Each client has this additional data */
struct max6875_data { … };

static void max6875_update_slice(struct i2c_client *client, int slice)
{ … }

static ssize_t max6875_read(struct file *filp, struct kobject *kobj,
			    struct bin_attribute *bin_attr,
			    char *buf, loff_t off, size_t count)
{ … }

static const struct bin_attribute user_eeprom_attr = …;

static int max6875_probe(struct i2c_client *client)
{ … }

static void max6875_remove(struct i2c_client *client)
{ … }

static const struct i2c_device_id max6875_id[] = …;
MODULE_DEVICE_TABLE(i2c, max6875_id);

static struct i2c_driver max6875_driver = …;

module_i2c_driver(…) …;

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;