lm-sensors/kernel/smbus.c

/*
    smbus.c - A Linux module for reading sensor data.
    Copyright (c) 1998  Frodo Looijaard <frodol@dds.nl> 

    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.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <linux/module.h>
#include <linux/kernel.h>
#include "smbus.h"

static s32 smbus_access_i2c (struct smbus_adapter * adapter, u8 addr,
                             char read_write, u8 command, int size,
                             union smbus_data * data);

static int smbus_master_xfer (struct smbus_adapter *adap,
                              struct i2c_msg msgs[], int num);
static int smbus_slave_send (struct smbus_adapter *adap, char *data, int len);
static int smbus_slave_recv (struct smbus_adapter *adap, char *data, int len);
static int smbus_algo_control (struct smbus_adapter *adap, unsigned int cmd, 
                               unsigned long arg);
static int smbus_client_register (struct smbus_client *client);
static int smbus_client_unregister (struct smbus_client *client);

static int smbus_init(void);
static int smbus_cleanup(void);

#ifdef MODULE
extern int init_module(void);
extern int cleanup_module(void);
#endif /* MODULE */

/* This is the actual algorithm we define */
struct smbus_algorithm smbus_algorithm = {
  /* name */		"Non-I2C SMBus adapter",
  /* id */		ALGO_SMBUS,
  /* master_xfer */	&smbus_master_xfer,
  /* slave_send */	&smbus_slave_send,
  /* slave_rcv */	&smbus_slave_recv,
  /* algo_control */	&smbus_algo_control,
  /* client_register */ &smbus_client_register,
  /* client_unregister*/&smbus_client_unregister
};


/* OK, so you want to access a bus using the SMBus protocols. Well, it either
   is registered as a SMBus-only adapter (like the PIIX4), or we need to
   simulate the SMBus commands using the i2c access routines. */
s32 smbus_access (struct smbus_adapter * adapter, u8 addr, char read_write,
                  u8 command, int size, union smbus_data * data)
{
  if (adapter->id & ALGO_SMBUS) 
    return adapter->smbus_access(addr,read_write,command,size,data);
  else
    return smbus_access_i2c(adapter,addr,read_write,command,size,data);
}
  
/* Simulate a SMBus command using the i2c protocol 
   No checking of paramters is done!
   For SMBUS_QUICK: Use addr, read_write 
   For SMBUS_BYTE: Use addr, read_write, command 
   ....  */
s32 smbus_access_i2c(struct smbus_adapter * adapter, u8 addr, char read_write,
                     u8 command, int size, union smbus_data * data)
{
  /* So we need to generate a series of msgs */
  struct i2c_msg msg[2];
  char msgbuf0[2];
  char msgbuf1[32];
  msg[0].addr = addr;
  msg[0].flags = read_write;
  msg[0].len = 0;
  msg[0].buf = msgbuf0;
  /* WHATEVER */
}

/* Algorithm master_xfer call-back implementation. Can't do that... */
int smbus_master_xfer (struct smbus_adapter *adap, struct i2c_msg msgs[], 
                       int num)
{
  printk("smbus_master_xfer called for adapter `%s' "
         "(no i2c level access possible!)\n",
         adap->name);
  return 0;
}

/* Algorithm slave_send call-back implementation. Can't do that... */
int smbus_slave_send (struct smbus_adapter *adap, char *data, int len)
{
  printk("smbus_slave_send called for adapter `%s' "
         "(no i2c level access possible!)\n",
         adap->name);
  return 0;
}

/* Algorithm slave_recv call-back implementation. Can't do that... */
int smbus_slave_recv (struct smbus_adapter *adap, char *data, int len)
{
  printk("smbus_slave_recv called for adapter `%s' "
         "(no i2c level access possible!)\n",
         adap->name);
  return 0;
}

/* Here we can put additional calls to modify the workings of the algorithm.
   But right now, there is no need for that. */
int smbus_algo_control (struct smbus_adapter *adap, unsigned int cmd, 
                         unsigned long arg)
{
  return 0;
}

/* Ehm... This is called when a client is registered to an adapter. We could
   do all kinds of neat stuff here like, ehm - returning success? */
int smbus_client_register (struct smbus_client *client)
{
  return 0;
}
  
int smbus_client_unregister (struct smbus_client *client)
{
  return 0;
}

/* Next: define SMBus variants of registering. Very boring. To make it possible
   to change these definitions in the future without recompiling all modules,
   we do not define them as inline. */
int smbus_add_algorithm(struct smbus_algorithm *algorithm)
{
  return i2c_add_algorithm( (struct i2c_algorithm *) algorithm);
}

int smbus_del_algorithm(struct smbus_algorithm *algorithm)
{
  return i2c_del_algorithm( (struct i2c_algorithm *) algorithm);
}

int smbus_add_adapter(struct smbus_adapter *adapter)
{
  return i2c_add_adapter( (struct i2c_adapter *) adapter);
}

int smbus_del_adapter(struct smbus_adapter *adapter)
{
  return i2c_del_adapter( (struct i2c_adapter *) adapter);
}

int smbus_add_driver(struct smbus_driver *driver)
{
  return i2c_add_driver( (struct i2c_driver *) driver);
}

int smbus_del_driver(struct smbus_driver *driver)
{
  return i2c_del_driver( (struct i2c_driver *) driver);
}

int smbus_attach_client(struct smbus_client *client)
{
  return i2c_attach_client( (struct i2c_client *) client);
}

int smbus_detach_client(struct smbus_client *client)
{
  return i2c_detach_client( (struct i2c_client *) client);
}

int smbus_init(void)
{
  int res;
  if ((res = smbus_add_algorithm(&smbus_algorithm)))
    printk("Module smbus.o not inserted!\n");
  else
    printk("smbus.o initialized");
  return res;
}

int smbus_cleanup(void)
{
  int res;
  if ((res = smbus_del_algorithm(&smbus_algorithm)))
    printk("Module smbus.o could not be removed cleanly!\n");
  return res;
}

/* OK, this will for now _only_ compile as a module, but this is neat for
   later, if we want to compile it straight into the kernel */
#ifdef MODULE

MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
MODULE_DESCRIPTION("System Management Bus (SMBus) access");

int init_module(void)
{
  return smbus_init();
}

int cleanup_module(void)
{
  return smbus_cleanup();
}

#endif /* MODULE */