liftmon_snowcon.c.txt

这是《嵌入式linux－硬件、软件与接口》一书对应的所有linux方面实例的源代码

{
  struct liftmon_snowcon_data_t *liftmon_snowcon_data = 
                                (struct liftmon_snowcon_data_t *)data;


/* mask the snowcondata value based on the mask. Each mask is different 
 * depending which /proc/trailblazer file was read. */
  if ( snowcondata & liftmon_snowcon_data->mask )
    page[0] = '1';
  else
    page[0] = '0';

/* return the length */
  return 1;
}

/* init - init_liftmon_snowcon
 * init_liftmon_snowcon creates the /proc entry files and obtains
 * their pointers. For each file, the fields, data, read_proc, 
 * write_proc and owner, are filled.  init_liftmon_snowcon 
 * initializes the output modules in the off state then
 * completes by writing an entry to the system log using printk.
 */
static int __init init_liftmon_snowcon(void)
{
  int rv = 0;

/* Create the trailblazer /proc entry */
  tb_dir = proc_mkdir("trailblazer", NULL);
  if(tb_dir == NULL) {
    rv = -ENOMEM;
    goto out;
  }
  tb_dir->owner = THIS_MODULE;

/* Create liftacmains and make it readable by all - 0444 */
  liftacmains_file = create_proc_entry("liftacmains", 0444, tb_dir);
  if(liftacmains_file == NULL) {
    rv = -ENOMEM;
    goto no_liftacmains;
  }
  liftacmains_data.mask = LIFTACMAINS;
  liftacmains_file->data = &liftacmains_data;
  liftacmains_file->read_proc = &proc_read_liftmon;
  liftacmains_file->write_proc = NULL;
  liftacmains_file->owner = THIS_MODULE;


/* Create liftmotorcontroller and make it readable by all - 0444 */
  liftmotorcontroller_file = create_proc_entry("liftmotorcontroller", 
                                                0444, tb_dir);
  if(liftmotorcontroller_file == NULL) {
    rv = -ENOMEM;
    goto no_liftmotorcontroller;
  }
  liftmotorcontroller_data.mask = LIFTMOTORCONTROLLER;
  liftmotorcontroller_file->data = &liftmotorcontroller_data;
  liftmotorcontroller_file->read_proc = &proc_read_liftmon;
  liftmotorcontroller_file->write_proc = NULL;
  liftmotorcontroller_file->owner = THIS_MODULE;

/* Create liftslowspeed and make it readable by all - 0444 */
  liftslowspeed_file = create_proc_entry("liftslowspeed", 0444, tb_dir);
  if(liftslowspeed_file == NULL) {
    rv = -ENOMEM;
    goto no_liftslowspeed;
  }
  liftslowspeed_data.mask = LIFTSLOWSPEED;
  liftslowspeed_file->data = &liftslowspeed_data;
  liftslowspeed_file->read_proc = &proc_read_liftmon;
  liftslowspeed_file->write_proc = NULL;
  liftslowspeed_file->owner = THIS_MODULE;

/* Create lifthighspeed and make it readable by all - 0444 */
  lifthighspeed_file = create_proc_entry("lifthighspeed", 0444, tb_dir);
  if(lifthighspeed_file == NULL) {
    rv = -ENOMEM;
    goto no_lifthighspeed;
  }
  lifthighspeed_data.mask = LIFTHIGHSPEED;
  lifthighspeed_file->data = &lifthighspeed_data;
  lifthighspeed_file->read_proc = &proc_read_liftmon;
  lifthighspeed_file->write_proc = NULL;
  lifthighspeed_file->owner = THIS_MODULE;

/* Create liftoperatorswitchbase and make it readable by all - 0444 */
  liftoperatorswitchbase_file = create_proc_entry("liftoperatorswitchbase",
                                                   0444, tb_dir);
  if(liftoperatorswitchbase_file == NULL) {
    rv = -ENOMEM;
    goto no_liftoperatorswitchbase;
  }
  liftoperatorswitchbase_data.mask = LIFTOPERATORSWITCHBASE;
  liftoperatorswitchbase_file->data = &liftoperatorswitchbase_data;
  liftoperatorswitchbase_file->read_proc = &proc_read_liftmon;
  liftoperatorswitchbase_file->write_proc = NULL;
  liftoperatorswitchbase_file->owner = THIS_MODULE;

/* Create liftoperatorswitchtop and make it readable by all - 0444 */
  liftoperatorswitchtop_file = create_proc_entry("liftoperatorswitchtop",
                                                  0444, tb_dir);
  if(liftoperatorswitchtop_file == NULL) {
    rv = -ENOMEM;
    goto no_liftoperatorswitchtop;
  }
  liftoperatorswitchtop_data.mask = LIFTOPERATORSWITCHTOP;
  liftoperatorswitchtop_file->data = &liftoperatorswitchtop_data;
  liftoperatorswitchtop_file->read_proc = &proc_read_liftmon;
  liftoperatorswitchtop_file->write_proc = NULL;
  liftoperatorswitchtop_file->owner = THIS_MODULE;

/* Create snowwatervalve1 and make it root writeable, readable by all-0644 */
  snowwatervalve1_file = create_proc_entry("snowwatervalve1", 0644, tb_dir);
  if(snowwatervalve1_file == NULL) {
    rv = -ENOMEM;
    goto no_snowwatervalve1;
  }
  snowwatervalve1_data.mask = SNOWWATERVALVE1;
  snowwatervalve1_file->data = &snowwatervalve1_data;
  snowwatervalve1_file->read_proc = &proc_read_snowcondata;
  snowwatervalve1_file->write_proc = &proc_write_snowcondata;
  snowwatervalve1_file->owner = THIS_MODULE;

/* Create snowwatervalve2 and make it root writeable, readable by all-0644 */
  snowwatervalve2_file = create_proc_entry("snowwatervalve2", 0644, tb_dir);
  if(snowwatervalve2_file == NULL) {
    rv = -ENOMEM;
    goto no_snowwatervalve2;
  }
  snowwatervalve2_data.mask = SNOWWATERVALVE2;
  snowwatervalve2_file->data = &snowwatervalve2_data;
  snowwatervalve2_file->read_proc = &proc_read_snowcondata;
  snowwatervalve2_file->write_proc = &proc_write_snowcondata;
  snowwatervalve2_file->owner = THIS_MODULE;

/* Create snowwatervalve3 and make it root writeable, readable by all-0644 */
  snowwatervalve3_file = create_proc_entry("snowwatervalve3", 0644, tb_dir);
  if(snowwatervalve3_file == NULL) {
    rv = -ENOMEM;
    goto no_snowwatervalve3;
  }
  snowwatervalve3_data.mask = SNOWWATERVALVE3;
  snowwatervalve3_file->data = &snowwatervalve3_data;
  snowwatervalve3_file->read_proc = &proc_read_snowcondata;
  snowwatervalve3_file->write_proc = &proc_write_snowcondata;
  snowwatervalve3_file->owner = THIS_MODULE;

/* Create snowheater1 and make it root writeable, readable by all-0644 */
  snowheater1_file = create_proc_entry("snowheater1", 0644, tb_dir);
  if(snowheater1_file == NULL) {
    rv = -ENOMEM;
    goto no_snowheater1;
  }
  snowheater1_data.mask = SNOWHEATER1;
  snowheater1_file->data = &snowheater1_data;
  snowheater1_file->read_proc = &proc_read_snowcondata;
  snowheater1_file->write_proc = &proc_write_snowcondata;
  snowheater1_file->owner = THIS_MODULE;


/* initialize snowcondata to 0, all output modules off */
  snowcondata = 0;

/* initialize the control port to know value 0 */ 
  outb(0, SPPCONTROLPORT);

/* put snowcondata on the data bus */ 
  outb(snowcondata, SPPDATAPORT);

/* latch it first before we turn on the output modules */
  outb(OUTPUTLATCH, SPPCONTROLPORT);

/* turn on the latch output to drive the output modules */
  outb(OUTPUTENABLE,SPPCONTROLPORT); 

/* everything initialized */
  printk(KERN_INFO "%s %s initialized\n", MODULE_NAME, MODULE_VERSION);
  return 0;

/* this removes /proc entries if we have an error along the way */
no_snowheater1:
  remove_proc_entry("snowwatervalve3", tb_dir);
no_snowwatervalve3:
  remove_proc_entry("snowwatervalve2", tb_dir);
no_snowwatervalve2:
  remove_proc_entry("snowwatervalve1", tb_dir);
no_snowwatervalve1:
  remove_proc_entry("liftoperatorswitchtop", tb_dir);
no_liftoperatorswitchtop:
  remove_proc_entry("liftoperatorswitchbase", tb_dir);
no_liftoperatorswitchbase:
  remove_proc_entry("lifthighspeed", tb_dir);
no_lifthighspeed:
  remove_proc_entry("liftslowspeed", tb_dir);
no_liftslowspeed:
  remove_proc_entry("liftmotorcontroller", tb_dir);
no_liftmotorcontroller:
  remove_proc_entry("liftacmains", tb_dir);
no_liftacmains:
  remove_proc_entry("trailblazer", NULL);
out:
  return rv;
}

/* exit - cleanup_liftmon_snowcon
 * cleanup_liftmon_snowcon turns off the output modules and
 * deasserts the OUTPUT_ENABLE signal. It removes the /proc entry files
 * prints a message to the system log.
 */

static void __exit cleanup_liftmon_snowcon(void)
{

/* this turns off all the output modules */
  outb(0, SPPCONTROLPORT);
  outb(0, SPPDATAPORT);
  outb(OUTPUTLATCH, SPPCONTROLPORT);
  outb(0,SPPCONTROLPORT);

/* removing the /proc entries */
  remove_proc_entry("liftacmains", tb_dir);
  remove_proc_entry("liftmotorcontroller", tb_dir);
  remove_proc_entry("liftslowspeed", tb_dir);
  remove_proc_entry("lifthighspeed", tb_dir);
  remove_proc_entry("liftoperatorswitchbase", tb_dir);
  remove_proc_entry("liftoperatorswitchtop", tb_dir);
  remove_proc_entry("snowwatervalve1", tb_dir);
  remove_proc_entry("snowwatervalve2", tb_dir);
  remove_proc_entry("snowwatervalve3", tb_dir);
  remove_proc_entry("snowheater1", tb_dir);
  remove_proc_entry("trailblazer", NULL);

/* we're done */
  printk(KERN_INFO "%s %s removed\n", MODULE_NAME, MODULE_VERSION);
}


module_init(init_liftmon_snowcon);
module_exit(cleanup_liftmon_snowcon);

MODULE_AUTHOR("Craig Hollabaugh");
MODULE_DESCRIPTION("Trailblazer Lift Monitor and Snow-making Control");

EXPORT_NO_SYMBOLS;