Linux Cross Reference
Linux/drivers/net/irda/actisys.c

   /*********************************************************************
    *                
    * Filename:      actisys.c
    * Version:       1.0
    * Description:   Implementation for the ACTiSYS IR-220L and IR-220L+ 
    *                dongles
    * Status:        Beta.
    * Authors:       Dag Brattli <dagb@cs.uit.no> (initially)
    *                Jean Tourrilhes <jt@hpl.hp.com> (new version)
   * Created at:    Wed Oct 21 20:02:35 1998
   * Modified at:   Fri Dec 17 09:10:43 1999
   * Modified by:   Dag Brattli <dagb@cs.uit.no>
   * 
   *     Copyright (c) 1998-1999 Dag Brattli, All Rights Reserved.
   *     Copyright (c) 1999 Jean Tourrilhes
   *      
   *     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.
   *  
   *     Neither Dag Brattli nor University of Tromsų admit liability nor
   *     provide warranty for any of this software. This material is 
   *     provided "AS-IS" and at no charge.
   *     
   ********************************************************************/
  
  /*
   * Changelog
   *
   * 0.8 -> 0.9999 - Jean
   *      o New initialisation procedure : much safer and correct
   *      o New procedure the change speed : much faster and simpler
   *      o Other cleanups & comments
   *      Thanks to Lichen Wang @ Actisys for his excellent help...
   */
  
  #include <linux/module.h>
  #include <linux/delay.h>
  #include <linux/tty.h>
  #include <linux/sched.h>
  #include <linux/init.h>
  
  #include <net/irda/irda.h>
  #include <net/irda/irmod.h>
  #include <net/irda/irda_device.h>
  
  /* 
   * Define the timing of the pulses we send to the dongle (to reset it, and
   * to toggle speeds). Basically, the limit here is the propagation speed of
   * the signals through the serial port, the dongle being much faster.  Any
   * serial port support 115 kb/s, so we are sure that pulses 8.5 us wide can
   * go through cleanly . If you are on the wild side, you can try to lower
   * this value (Actisys recommended me 2 us, and 0 us work for me on a P233!)
   */
  #define MIN_DELAY 10    /* 10 us to be on the conservative side */
  
  static int  actisys_change_speed(struct irda_task *task);
  static int  actisys_reset(struct irda_task *task);
  static void actisys_open(dongle_t *self, struct qos_info *qos);
  static void actisys_close(dongle_t *self);
  
  /* These are the baudrates supported, in the order available */
  /* Note : the 220L doesn't support 38400, but we will fix that below */
  static __u32 baud_rates[] = { 9600, 19200, 57600, 115200, 38400 };
  #define MAX_SPEEDS 5
  
  static struct dongle_reg dongle = {
          Q_NULL,
          IRDA_ACTISYS_DONGLE,
          actisys_open,
          actisys_close,
          actisys_reset,
          actisys_change_speed,
  };
  
  static struct dongle_reg dongle_plus = {
          Q_NULL,
          IRDA_ACTISYS_PLUS_DONGLE,
          actisys_open,
          actisys_close,
          actisys_reset,
          actisys_change_speed,
  };
  
  /*
   * Function actisys_change_speed (task)
   *
   *      There is two model of Actisys dongle we are dealing with,
   * the 220L and 220L+. At this point, only irattach knows with
   * kind the user has requested (it was an argument on irattach
   * command line).
   *      So, we register a dongle of each sort and let irattach
   * pick the right one...
   */
  int __init actisys_init(void)
  {
          int ret;
  
         /* First, register an Actisys 220L dongle */
         ret = irda_device_register_dongle(&dongle);
         if (ret < 0)
                 return ret;
         /* Now, register an Actisys 220L+ dongle */
         ret = irda_device_register_dongle(&dongle_plus);
         if (ret < 0) {
                 irda_device_unregister_dongle(&dongle);
                 return ret;
         }       
         return 0;
 }
 
 void actisys_cleanup(void)
 {
         /* We have to remove both dongles */
         irda_device_unregister_dongle(&dongle);
         irda_device_unregister_dongle(&dongle_plus);
 }
 
 static void actisys_open(dongle_t *self, struct qos_info *qos)
 {
         /* Power on the dongle */
         self->set_dtr_rts(self->dev, TRUE, TRUE);
 
         /* Set the speeds we can accept */
         qos->baud_rate.bits &= IR_9600|IR_19200|IR_38400|IR_57600|IR_115200;
 
         /* Remove support for 38400 if this is not a 220L+ dongle */
         if (self->issue->type == IRDA_ACTISYS_DONGLE)
                 qos->baud_rate.bits &= ~IR_38400;
         
         qos->min_turn_time.bits = 0x7f; /* Needs 0.01 ms */
 
         MOD_INC_USE_COUNT;
 }
 
 static void actisys_close(dongle_t *self)
 {
         /* Power off the dongle */
         self->set_dtr_rts(self->dev, FALSE, FALSE);
 
         MOD_DEC_USE_COUNT;
 }
 
 /*
  * Function actisys_change_speed (task)
  *
  *    Change speed of the ACTiSYS IR-220L and IR-220L+ type IrDA dongles.
  *    To cycle through the available baud rates, pulse RTS low for a few us.
  *
  *      First, we reset the dongle to always start from a known state.
  *      Then, we cycle through the speeds by pulsing RTS low and then up.
  *      The dongle allow us to pulse quite fast, se we can set speed in one go,
  * which is must faster ( < 100 us) and less complex than what is found
  * in some other dongle drivers...
  *      Note that even if the new speed is the same as the current speed,
  * we reassert the speed. This make sure that things are all right,
  * and it's fast anyway...
  *      By the way, this function will work for both type of dongles,
  * because the additional speed is at the end of the sequence...
  */
 static int actisys_change_speed(struct irda_task *task)
 {
         dongle_t *self = (dongle_t *) task->instance;
         __u32 speed = (__u32) task->param;      /* Target speed */
         int ret = 0;
         int i = 0;
 
         IRDA_DEBUG(4, __FUNCTION__ "(), speed=%d (was %d)\n", speed, 
                    self->speed);
 
         /* Go to a known state by reseting the dongle */
 
         /* Reset the dongle : set DTR low for 10 us */
         self->set_dtr_rts(self->dev, FALSE, TRUE);
         udelay(MIN_DELAY);
 
         /* Go back to normal mode (we are now at 9600 b/s) */
         self->set_dtr_rts(self->dev, TRUE, TRUE);
  
         /* 
          * Now, we can set the speed requested. Send RTS pulses until we
          * reach the target speed 
          */
         for (i=0; i<MAX_SPEEDS; i++) {
                 if (speed == baud_rates[i]) {
                         self->speed = baud_rates[i];
                         break;
                 }
                 /* Make sure previous pulse is finished */
                 udelay(MIN_DELAY);
 
                 /* Set RTS low for 10 us */
                 self->set_dtr_rts(self->dev, TRUE, FALSE);
                 udelay(MIN_DELAY);
 
                 /* Set RTS high for 10 us */
                 self->set_dtr_rts(self->dev, TRUE, TRUE);
         }
 
         /* Check if life is sweet... */
         if (i >= MAX_SPEEDS)
                 ret = -1;  /* This should not happen */
 
         /* Basta lavoro, on se casse d'ici... */
         irda_task_next_state(task, IRDA_TASK_DONE);
 
         return ret;
 }
 
 /*
  * Function actisys_reset (task)
  *
  *      Reset the Actisys type dongle. Warning, this function must only be
  *      called with a process context!
  *
  * We need to do two things in this function :
  *      o first make sure that the dongle is in a state where it can operate
  *      o second put the dongle in a know state
  *
  *      The dongle is powered of the RTS and DTR lines. In the dongle, there
  * is a big capacitor to accomodate the current spikes. This capacitor
  * takes a least 50 ms to be charged. In theory, the Bios set those lines
  * up, so by the time we arrive here we should be set. It doesn't hurt
  * to be on the conservative side, so we will wait...
  *      Then, we set the speed to 9600 b/s to get in a known state (see in
  * change_speed for details). It is needed because the IrDA stack
  * has tried to set the speed immediately after our first return,
  * so before we can be sure the dongle is up and running.
  */
 static int actisys_reset(struct irda_task *task)
 {
         dongle_t *self = (dongle_t *) task->instance;
         int ret = 0;
 
         ASSERT(task != NULL, return -1;);
 
         self->reset_task = task;
 
         switch (task->state) {
         case IRDA_TASK_INIT:
                 /* Set both DTR & RTS to power up the dongle */
                 /* In theory redundant with power up in actisys_open() */
                 self->set_dtr_rts(self->dev, TRUE, TRUE);
                 
                 /* Sleep 50 ms to make sure capacitor is charged */
                 ret = MSECS_TO_JIFFIES(50);
                 irda_task_next_state(task, IRDA_TASK_WAIT);
                 break;
         case IRDA_TASK_WAIT:                    
                 /* Reset the dongle : set DTR low for 10 us */
                 self->set_dtr_rts(self->dev, FALSE, TRUE);
                 udelay(MIN_DELAY);
 
                 /* Go back to normal mode */
                 self->set_dtr_rts(self->dev, TRUE, TRUE);
         
                 irda_task_next_state(task, IRDA_TASK_DONE);
                 self->reset_task = NULL;
                 self->speed = 9600;     /* That's the default */
                 break;
         default:
                 ERROR(__FUNCTION__ "(), unknown state %d\n", task->state);
                 irda_task_next_state(task, IRDA_TASK_DONE);
                 self->reset_task = NULL;
                 ret = -1;
                 break;
         }
         return ret;
 }
 
 #ifdef MODULE
 MODULE_AUTHOR("Dag Brattli <dagb@cs.uit.no> - Jean Tourrilhes <jt@hpl.hp.com>");
 MODULE_DESCRIPTION("ACTiSYS IR-220L and IR-220L+ dongle driver");       
                 
 /*
  * Function init_module (void)
  *
  *    Initialize Actisys module
  *
  */
 int init_module(void)
 {
         return actisys_init();
 }
 
 /*
  * Function cleanup_module (void)
  *
  *    Cleanup Actisys module
  *
  */
 void cleanup_module(void)
 {
         actisys_cleanup();
 }
 #endif /* MODULE */