linux-imx

/*

    i2c-stub.c - I2C/SMBus chip emulator

​

    Copyright (c) 2004 Mark M. Hoffman <mhoffman@lightlink.com>

    Copyright (C) 2007-2014 Jean Delvare <jdelvare@suse.de>

​

    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; either version 2 of the License, or

    (at your option) any later version.

​

    This program is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    GNU General Public License for more details.

*/

​

#define DEBUG 1

#define pr_fmt(fmt) "i2c-stub: " fmt

​

#include <linux/errno.h>

#include <linux/i2c.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/list.h>

#include <linux/module.h>

#include <linux/slab.h>

​

#define MAX_CHIPS 10

​

/*

 * Support for I2C_FUNC_SMBUS_BLOCK_DATA is disabled by default and must

 * be enabled explicitly by setting the I2C_FUNC_SMBUS_BLOCK_DATA bits

 * in the 'functionality' module parameter.

 */

#define STUB_FUNC_DEFAULT \

        (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | \

         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | \

         I2C_FUNC_SMBUS_I2C_BLOCK)

​

#define STUB_FUNC_ALL \

        (STUB_FUNC_DEFAULT | I2C_FUNC_SMBUS_BLOCK_DATA)

​

static unsigned short chip_addr[MAX_CHIPS];

module_param_array(chip_addr, ushort, NULL, S_IRUGO);

MODULE_PARM_DESC(chip_addr,

         "Chip addresses (up to 10, between 0x03 and 0x77)");

​

static unsigned long functionality = STUB_FUNC_DEFAULT;

module_param(functionality, ulong, S_IRUGO | S_IWUSR);

MODULE_PARM_DESC(functionality, "Override functionality bitfield");

​

/* Some chips have banked register ranges */

​

static u8 bank_reg[MAX_CHIPS];

module_param_array(bank_reg, byte, NULL, S_IRUGO);

MODULE_PARM_DESC(bank_reg, "Bank register");

​

static u8 bank_mask[MAX_CHIPS];

module_param_array(bank_mask, byte, NULL, S_IRUGO);

MODULE_PARM_DESC(bank_mask, "Bank value mask");

​

static u8 bank_start[MAX_CHIPS];

module_param_array(bank_start, byte, NULL, S_IRUGO);

MODULE_PARM_DESC(bank_start, "First banked register");

​

static u8 bank_end[MAX_CHIPS];

module_param_array(bank_end, byte, NULL, S_IRUGO);

MODULE_PARM_DESC(bank_end, "Last banked register");

​

struct smbus_block_data {

    struct list_head node;

    u8 command;

    u8 len;

    u8 block[I2C_SMBUS_BLOCK_MAX];

};

​

struct stub_chip {

    u8 pointer;

    u16 words[256];     /* Byte operations use the LSB as per SMBus

                   specification */

    struct list_head smbus_blocks;

​

    /* For chips with banks, extra registers are allocated dynamically */

    u8 bank_reg;

    u8 bank_shift;

    u8 bank_mask;

    u8 bank_sel;        /* Currently selected bank */

    u8 bank_start;

    u8 bank_end;

    u16 bank_size;

    u16 *bank_words;    /* Room for bank_mask * bank_size registers */