patch-2.3.35 linux/drivers/net/irda/actisys.c

• Lines: 335
• Date: Tue Dec 21 10:17:31 1999
• Orig file: v2.3.34/linux/drivers/net/irda/actisys.c
• Orig date: Wed Oct 27 16:34:12 1999

diff -u --recursive --new-file v2.3.34/linux/drivers/net/irda/actisys.c linux/drivers/net/irda/actisys.c
@@ -1,16 +1,18 @@
 /*********************************************************************
  *                
  * Filename:      actisys.c
- * Version:       0.8
+ * Version:       1.0
  * Description:   Implementation for the ACTiSYS IR-220L and IR-220L+ 
  *                dongles
- * Status:        Experimental.
- * Author:        Dag Brattli <dagb@cs.uit.no>
+ * 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:   Mon Oct 18 23:37:06 1999
+ * Modified at:   Fri Dec 17 09:16:09 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 
@@ -23,6 +25,16 @@
  *     
  ********************************************************************/
 
+/*
+ * 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>
@@ -33,13 +45,25 @@
 #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 */
+/* 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,
@@ -59,13 +83,25 @@
 	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);
@@ -76,125 +112,121 @@
 
 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 &= 0x40; /* Needs 0.01 ms */
+	qos->min_turn_time.bits = 0x7f; /* Needs 0.01 ms */
 
 	MOD_INC_USE_COUNT;
 }
 
 static void actisys_close(dongle_t *self)
 {
-	/* Power off dongle */
+	/* Power off the dongle */
 	self->set_dtr_rts(self->dev, FALSE, FALSE);
 
 	MOD_DEC_USE_COUNT;
 }
 
 /*
- * Function actisys_change_speed (tty, baud)
+ * 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
- *    ms.  
+ *    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;
-        __u32 current_speed;
-        int index = 0;
+	__u32 speed = (__u32) task->param;	/* Target speed */
 	int ret = 0;
-	
-	IRDA_DEBUG(4, __FUNCTION__ "()\n");
-
-	current_speed = self->speed;
+	int i = 0;
 
-	/* Find the correct baudrate index for the currently used baudrate */
-	while (current_speed != baud_rates[index])
-		index++;
+        IRDA_DEBUG(4, __FUNCTION__ "(), speed=%d (was %d)\n", speed, 
+		   self->speed);
 
-        IRDA_DEBUG(4, __FUNCTION__ "(), index=%d\n", index);
+	/* Go to a known state by reseting the dongle */
 
-	switch (task->state) {
-	case IRDA_TASK_INIT:
-		/* Lock dongle */
-		if (irda_lock((void *) &self->busy) == FALSE) {
-			IRDA_DEBUG(0, __FUNCTION__ "(), busy!\n");
-			ret = MSECS_TO_JIFFIES(100);
+	/* 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;
 		}
-	
-                IRDA_DEBUG(4, __FUNCTION__ "(), current baudrate = %d\n",
-		      baud_rates[index]);
-		
-		/* Set DTR, clear RTS */
+		/* Make sure previous pulse is finished */
+		udelay(MIN_DELAY);
+
+		/* Set RTS low for 10 us */
 		self->set_dtr_rts(self->dev, TRUE, FALSE);
-		
-		irda_task_next_state(task, IRDA_TASK_WAIT1);
+		udelay(MIN_DELAY);
 
-		/* Wait at a few ms */
-		ret = MSECS_TO_JIFFIES(20);
-		break;
-	case IRDA_TASK_WAIT1:
-		/* Set DTR, Set RTS */
+		/* Set RTS high for 10 us */
 		self->set_dtr_rts(self->dev, TRUE, TRUE);
-		
-		irda_task_next_state(task, IRDA_TASK_WAIT2);
-
-		/* Wait at a few ms again */
-		ret = MSECS_TO_JIFFIES(20);
-		break;
-	case IRDA_TASK_WAIT2:
-                /* Go to next baudrate */
-		if (self->issue->type == IRDA_ACTISYS_DONGLE)
-                        index = (index+1) % 4; /* IR-220L */
-		else
-                        index = (index+1) % 5; /* IR-220L+ */
-
-                current_speed = baud_rates[index];
-
-		/* Check if we need to go some more rounds */
-		if (current_speed != speed)
-			irda_task_next_state(task, IRDA_TASK_INIT);
-		else {
-			irda_task_next_state(task, IRDA_TASK_DONE);
-			self->busy = 0;
-		}
-		break;
-	default:
-		ERROR(__FUNCTION__ "(), unknown state %d\n", task->state);
-		irda_task_next_state(task, IRDA_TASK_DONE);
-		self->busy = 0;
-		ret = -1;
-		break;
-        }
+	}
 
-	self->speed = speed;
+	/* Check if life is sweet... */
+	if (i >= MAX_SPEEDS)
+		ret = -1;  /* This should not happen */
 
-	IRDA_DEBUG(4, __FUNCTION__ "(), current baudrate = %d\n", 
-	      baud_rates[index]);
+	/* Basta lavoro, on se casse d'ici... */
+	irda_task_next_state(task, IRDA_TASK_DONE);
 
 	return ret;
 }
 
 /*
- * Function actisys_reset (dev)
+ * Function actisys_reset (task)
  *
  *      Reset the Actisys type dongle. Warning, this function must only be
  *      called with a process context!
  *
- *    	1. Clear DTR for a few ms.
+ * 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)
 {
@@ -203,27 +235,34 @@
 
 	ASSERT(task != NULL, return -1;);
 
+	self->reset_task = task;
+
 	switch (task->state) {
 	case IRDA_TASK_INIT:
-		/* Clear DTR */
-		self->set_dtr_rts(self->dev, FALSE, TRUE);
+		/* 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);
-
-		/* Sleep 10-20 ms*/
-		ret = MSECS_TO_JIFFIES(20);
 		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->speed = 9600;
+		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;
 	}
@@ -231,7 +270,7 @@
 }
 
 #ifdef MODULE
-MODULE_AUTHOR("Dag Brattli <dagb@cs.uit.no>");
+MODULE_AUTHOR("Dag Brattli <dagb@cs.uit.no> - Jean Tourrilhes <jt@hpl.hp.com>");
 MODULE_DESCRIPTION("ACTiSYS IR-220L and IR-220L+ dongle driver");	
 		
 /*