/*
    eeprom.c - Part of lm_sensors, Linux kernel modules for hardware
               monitoring
    Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.nl> and
    Philip Edelbrock <phil@netroedge.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; 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/malloc.h>
#include "smbus.h"
#include "sensors.h"
#include "i2c.h"
#include "i2c-isa.h"
#include "version.h"

/* Addresses to scan */
static unsigned short normal_i2c[] = {SENSORS_I2C_END};
static unsigned short normal_i2c_range[] = {0x50,0x57,SENSORS_I2C_END};
static unsigned int normal_isa[] = {SENSORS_ISA_END};
static unsigned int normal_isa_range[] = {SENSORS_ISA_END};

/* Insmod parameters */
SENSORS_INSMOD_1(eeprom);

static int checksum = 0;
MODULE_PARM(checksum,"i");
MODULE_PARM_DESC(checksum,"Only accept eeproms whose checksum is correct");


/* Many constants specified below */

/* EEPROM registers */
#define EEPROM_REG_CHECKSUM 0x3f

/* EEPROM memory types: */
#define ONE_K		1
#define TWO_K		2
#define FOUR_K		3
#define EIGHT_K		4
#define SIXTEEN_K	5

/* Conversions */
/* Size of EEPROM in bytes */
#define EEPROM_SIZE 128

/* Each client has this additional data */
struct eeprom_data {
         int sysctl_id;

         struct semaphore update_lock;
         char valid;                 /* !=0 if following fields are valid */
         unsigned long last_updated; /* In jiffies */

         u8 data[EEPROM_SIZE]; /* Register values */
	 int memtype;
};

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

static int eeprom_init(void);
static int eeprom_cleanup(void);

static int eeprom_attach_adapter(struct i2c_adapter *adapter);
static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind);
static int eeprom_detach_client(struct i2c_client *client);
static int eeprom_command(struct i2c_client *client, unsigned int cmd,
                        void *arg);
			
static void eeprom_inc_use (struct i2c_client *client);
static void eeprom_dec_use (struct i2c_client *client);

#if 0
static int eeprom_write_value(struct i2c_client *client, u8 reg, u16 value);
#endif

static void eeprom_contents(struct i2c_client *client, int operation, int ctl_name,
                      int *nrels_mag, long *results);
static void eeprom_update_client(struct i2c_client *client);


/* This is the driver that will be inserted */
static struct i2c_driver eeprom_driver = {
  /* name */            "EEPROM READER",
  /* id */              I2C_DRIVERID_EEPROM,
  /* flags */           DF_NOTIFY,
  /* attach_adapter */  &eeprom_attach_adapter,
  /* detach_client */   &eeprom_detach_client,
  /* command */         &eeprom_command,
  /* inc_use */         &eeprom_inc_use,
  /* dec_use */         &eeprom_dec_use
};

/* These files are created for each detected EEPROM. This is just a template;
   though at first sight, you might think we could use a statically
   allocated list, we need some way to get back to the parent - which
   is done through one of the 'extra' fields which are initialized
   when a new copy is allocated. */
static ctl_table eeprom_dir_table_template[] = {
  { EEPROM_SYSCTL1, "data0-15", NULL, 0, 0444, NULL, &sensors_proc_real,
    &sensors_sysctl_real, NULL, &eeprom_contents },
  { EEPROM_SYSCTL2, "data16-31", NULL, 0, 0444, NULL, &sensors_proc_real,
    &sensors_sysctl_real, NULL, &eeprom_contents },
  { EEPROM_SYSCTL3, "data32-47", NULL, 0, 0444, NULL, &sensors_proc_real,
    &sensors_sysctl_real, NULL, &eeprom_contents },
  { EEPROM_SYSCTL4, "data48-63", NULL, 0, 0444, NULL, &sensors_proc_real,
    &sensors_sysctl_real, NULL, &eeprom_contents },
  { EEPROM_SYSCTL5, "data64-79", NULL, 0, 0444, NULL, &sensors_proc_real,
    &sensors_sysctl_real, NULL, &eeprom_contents },
  { EEPROM_SYSCTL6, "data80-95", NULL, 0, 0444, NULL, &sensors_proc_real,
    &sensors_sysctl_real, NULL, &eeprom_contents },
  { EEPROM_SYSCTL7, "data96-111", NULL, 0, 0444, NULL, &sensors_proc_real,
    &sensors_sysctl_real, NULL, &eeprom_contents },
  { EEPROM_SYSCTL8, "data112-127", NULL, 0, 0444, NULL, &sensors_proc_real,
    &sensors_sysctl_real, NULL, &eeprom_contents },
  { 0 }
};

/* Used by init/cleanup */
static int eeprom_initialized = 0;

/* I choose here for semi-static LM78 allocation. Complete dynamic
   allocation could also be used; the code needed for this would probably
   take more memory than the datastructure takes now. */
#define MAX_EEPROM_NR 8
static struct i2c_client *eeprom_list[MAX_EEPROM_NR];

int eeprom_attach_adapter(struct i2c_adapter *adapter)
{
  return sensors_detect(adapter,&addr_data,eeprom_detect);
}

/* This function is called by sensors_detect */
int eeprom_detect(struct i2c_adapter *adapter, int address, int kind)
{
  int i,cs;
  struct i2c_client *new_client;
  struct eeprom_data *data;
  int err=0;
  const char *type_name,*client_name;

  /* Make sure we aren't probing the ISA bus!! This is just a safety check
     at this moment; sensors_detect really won't call us. */
#ifdef DEBUG
  if (i2c_is_isa_adapter(adapter)) {
    printk("eeprom.o: eeprom_detect called for an ISA bus adapter?!?\n");
    return 0;
  }
#endif

  /* Here, we have to do the address registration check for the I2C bus.
     But that is not yet implemented. */

  /* OK. For now, we presume we have a valid client. We now create the
     client structure, even though we cannot fill it completely yet.
     But it allows us to access eeprom_{read,write}_value. */
  if (! (new_client = kmalloc(sizeof(struct i2c_client) +
                              sizeof(struct eeprom_data),
                              GFP_KERNEL))) {
    err = -ENOMEM;
    goto ERROR0;
  }

  data = (struct eeprom_data *) (((struct i2c_client *) new_client) + 1);
  new_client->addr = address;
  new_client->data = data;
  new_client->adapter = adapter;
  new_client->driver = &eeprom_driver;

  /* Now, we do the remaining detection. It is not there, unless you force
     the checksum to work out. */
  if (checksum) {
    cs = 0;
    for (i = 0; i <= 0x3e; i++)
      cs += smbus_read_byte_data(adapter,address,i);
    cs &= 0xff;
    if (smbus_read_byte_data(adapter,address,EEPROM_REG_CHECKSUM) != cs)
      goto ERROR1;
  }
  
  /* Determine the chip type - only one kind supported! */
  if (kind <= 0)
    kind = eeprom;

  if (kind == eeprom) {
    type_name = "eeprom";
    client_name = "EEPROM chip";
  } else {
#ifdef DEBUG
    printk("eeprom.o: Internal error: unknown kind (%d)?!?",kind);
#endif
    goto ERROR1;
  }

  /* Fill in the remaining client fields and put it into the global list */
  strcpy(new_client->name,client_name);

  /* Find a place in our global list */
  for (i = 0; i < MAX_EEPROM_NR; i++)
    if (! eeprom_list[i])
       break;
  if (i == MAX_EEPROM_NR) {
    err = -ENOMEM;
    printk("eeprom.o: No empty slots left, recompile and heighten "
           "MAX_EEPROM_NR!\n");
    goto ERROR2;
  }
  eeprom_list[i] = new_client;
  new_client->id = i;
  data->valid = 0;
  data->update_lock = MUTEX;

  /* Tell the I2C layer a new client has arrived */
  if ((err = i2c_attach_client(new_client)))
    goto ERROR3;

  /* Register a new directory entry with module sensors */
  if ((i = sensors_register_entry(new_client,type_name,
                                  eeprom_dir_table_template)) < 0) {
    err = i;
    goto ERROR4;
  }
  data->sysctl_id = i;

  return 0;

/* OK, this is not exactly good programming practice, usually. But it is
   very code-efficient in this case. */

ERROR4:
  i2c_detach_client(new_client);
ERROR3:
  for (i = 0; i < MAX_EEPROM_NR; i++)
    if (new_client == eeprom_list[i])
      eeprom_list[i] = NULL;
ERROR2:
ERROR1:
  kfree(new_client);
ERROR0:
  return err;
}

int eeprom_detach_client(struct i2c_client *client)
{
  int err,i;

  sensors_deregister_entry(((struct eeprom_data *)(client->data))->sysctl_id);

  if ((err = i2c_detach_client(client))) {
    printk("eeprom.o: Client deregistration failed, client not detached.\n");
    return err;
  }

  for (i = 0; i < MAX_EEPROM_NR; i++)
    if (client == eeprom_list[i])
      break;
  if ((i == MAX_EEPROM_NR)) {
    printk("eeprom.o: Client to detach not found.\n");
    return -ENOENT;
  }
  eeprom_list[i] = NULL;

  kfree(client);

  return 0;
}


/* No commands defined yet */
int eeprom_command(struct i2c_client *client, unsigned int cmd, void *arg)
{
  return 0;
}

void eeprom_inc_use (struct i2c_client *client)
{
#ifdef MODULE
  MOD_INC_USE_COUNT;
#endif
}

void eeprom_dec_use (struct i2c_client *client)
{
#ifdef MODULE
  MOD_DEC_USE_COUNT;
#endif
}

#if 0
/* No writes yet (PAE) */
int eeprom_write_value(struct i2c_client *client, u8 reg, u16 value)
{
  if (reg == EEPROM_REG_CONF)
    return smbus_write_byte_data(client->adapter,client->addr,reg,value);
  else
    return smbus_write_word_data(client->adapter,client->addr,reg,value); */
    
    return 0;
}
#endif

void eeprom_update_client(struct i2c_client *client)
{
  struct eeprom_data *data = client->data;
  int i;

  down(&data->update_lock);

  if ((jiffies - data->last_updated > HZ+HZ/2 ) ||
      (jiffies < data->last_updated) || ! data->valid) {

#ifdef DEBUG
    printk("Starting eeprom update\n");
#endif

   if (smbus_write_byte(client->adapter,client->addr,0)) {
#ifdef DEBUG
    printk("eeprom read start has failed!\n");
#endif   	
   }
    for (i=0;i<EEPROM_SIZE;i++) {
         data->data[i] = (u8)smbus_read_byte(client->adapter,client->addr);
    }
    
    data->last_updated = jiffies;
    data->valid = 1;
  }

  up(&data->update_lock);
}


void eeprom_contents(struct i2c_client *client, int operation, int ctl_name,
               int *nrels_mag, long *results)
{
  int i;
  int base=0;
  struct eeprom_data *data = client->data;
  
  if (ctl_name == EEPROM_SYSCTL2){ base=16; }
  if (ctl_name == EEPROM_SYSCTL3){ base=32; }
  if (ctl_name == EEPROM_SYSCTL4){ base=48; }
  if (ctl_name == EEPROM_SYSCTL5){ base=64; }
  if (ctl_name == EEPROM_SYSCTL6){ base=80; }
  if (ctl_name == EEPROM_SYSCTL7){ base=96; }
  if (ctl_name == EEPROM_SYSCTL8){ base=112; }
  
  if (operation == SENSORS_PROC_REAL_INFO)
    *nrels_mag = 0;
  else if (operation == SENSORS_PROC_REAL_READ) {
    eeprom_update_client(client);
    for (i=0; i<16; i++) {
    	results[i]=data->data[i + base];
    }
#ifdef DEBUG
    printk("eeprom.o: 0x%X EEPROM Contents (base %d): ",client->addr,base);
    for (i=0; i<16; i++) {
      printk(" 0x%X",data->data[i + base]);
    }
    printk(" .\n");
#endif
    *nrels_mag = 16;
  } else if (operation == SENSORS_PROC_REAL_WRITE) {

/* No writes to the EEPROM (yet, anyway) (PAE) */
	printk("eeprom.o: No writes to EEPROMs supported!\n");
  }
}

int eeprom_init(void)
{
  int res;

  printk("eeprom.o version %s (%s)\n",LM_VERSION,LM_DATE);
  eeprom_initialized = 0;
  if ((res = i2c_add_driver(&eeprom_driver))) {
    printk("eeprom.o: Driver registration failed, module not inserted.\n");
    eeprom_cleanup();
    return res;
  }
  eeprom_initialized ++;
  return 0;
}

int eeprom_cleanup(void)
{
  int res;

  if (eeprom_initialized >= 1) {
    if ((res = i2c_del_driver(&eeprom_driver))) {
      printk("eeprom.o: Driver deregistration failed, module not removed.\n");
      return res;
    }
  } else
    eeprom_initialized --;

  return 0;
}


#ifdef MODULE

MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and Philip Edelbrock <phil@netroedge.com>");
MODULE_DESCRIPTION("EEPROM driver");

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

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

#endif /* MODULE */