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kernel/linux-imx6_3.14.28/drivers/net/irda/litelink-sir.c 5.23 KB
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  /*********************************************************************
   *                
   * Filename:      litelink.c
   * Version:       1.1
   * Description:   Driver for the Parallax LiteLink dongle
   * Status:        Stable
   * Author:        Dag Brattli <dagb@cs.uit.no>
   * Created at:    Fri May  7 12:50:33 1999
   * Modified at:   Fri Dec 17 09:14:23 1999
   * Modified by:   Dag Brattli <dagb@cs.uit.no>
   * 
   *     Copyright (c) 1999 Dag Brattli, All Rights Reserved.
   *     
   *     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, see <http://www.gnu.org/licenses/>.
   *     
   ********************************************************************/
  
  /*
   * Modified at:   Thu Jan 15 2003
   * Modified by:   Eugene Crosser <crosser@average.org>
   *
   * Convert to "new" IRDA infrastructure for kernel 2.6
   */
  
  #include <linux/module.h>
  #include <linux/delay.h>
  #include <linux/init.h>
  
  #include <net/irda/irda.h>
  
  #include "sir-dev.h"
  
  #define MIN_DELAY 25      /* 15 us, but wait a little more to be sure */
  #define MAX_DELAY 10000   /* 1 ms */
  
  static int litelink_open(struct sir_dev *dev);
  static int litelink_close(struct sir_dev *dev);
  static int litelink_change_speed(struct sir_dev *dev, unsigned speed);
  static int litelink_reset(struct sir_dev *dev);
  
  /* These are the baudrates supported - 9600 must be last one! */
  static unsigned baud_rates[] = { 115200, 57600, 38400, 19200, 9600 };
  
  static struct dongle_driver litelink = {
  	.owner		= THIS_MODULE,
  	.driver_name	= "Parallax LiteLink",
  	.type		= IRDA_LITELINK_DONGLE,
  	.open		= litelink_open,
  	.close		= litelink_close,
  	.reset		= litelink_reset,
  	.set_speed	= litelink_change_speed,
  };
  
  static int __init litelink_sir_init(void)
  {
  	return irda_register_dongle(&litelink);
  }
  
  static void __exit litelink_sir_cleanup(void)
  {
  	irda_unregister_dongle(&litelink);
  }
  
  static int litelink_open(struct sir_dev *dev)
  {
  	struct qos_info *qos = &dev->qos;
  
  	IRDA_DEBUG(2, "%s()
  ", __func__);
  
  	/* Power up dongle */
  	sirdev_set_dtr_rts(dev, TRUE, TRUE);
  
  	/* Set the speeds we can accept */
  	qos->baud_rate.bits &= IR_115200|IR_57600|IR_38400|IR_19200|IR_9600;
  	qos->min_turn_time.bits = 0x7f; /* Needs 0.01 ms */
  	irda_qos_bits_to_value(qos);
  
  	/* irda thread waits 50 msec for power settling */
  
  	return 0;
  }
  
  static int litelink_close(struct sir_dev *dev)
  {
  	IRDA_DEBUG(2, "%s()
  ", __func__);
  
  	/* Power off dongle */
  	sirdev_set_dtr_rts(dev, FALSE, FALSE);
  
  	return 0;
  }
  
  /*
   * Function litelink_change_speed (task)
   *
   *    Change speed of the Litelink dongle. To cycle through the available 
   *    baud rates, pulse RTS low for a few ms.  
   */
  static int litelink_change_speed(struct sir_dev *dev, unsigned speed)
  {
          int i;
  
  	IRDA_DEBUG(2, "%s()
  ", __func__);
  
  	/* dongle already reset by irda-thread - current speed (dongle and
  	 * port) is the default speed (115200 for litelink!)
  	 */
  
  	/* Cycle through avaiable baudrates until we reach the correct one */
  	for (i = 0; baud_rates[i] != speed; i++) {
  
  		/* end-of-list reached due to invalid speed request */
  		if (baud_rates[i] == 9600)
  			break;
  
  		/* Set DTR, clear RTS */
  		sirdev_set_dtr_rts(dev, FALSE, TRUE);
  
  		/* Sleep a minimum of 15 us */
  		udelay(MIN_DELAY);
  
  		/* Set DTR, Set RTS */
  		sirdev_set_dtr_rts(dev, TRUE, TRUE);
  
  		/* Sleep a minimum of 15 us */
  		udelay(MIN_DELAY);
          }
  
  	dev->speed = baud_rates[i];
  
  	/* invalid baudrate should not happen - but if, we return -EINVAL and
  	 * the dongle configured for 9600 so the stack has a chance to recover
  	 */
  
  	return (dev->speed == speed) ? 0 : -EINVAL;
  }
  
  /*
   * Function litelink_reset (task)
   *
   *      Reset the Litelink type dongle.
   *
   */
  static int litelink_reset(struct sir_dev *dev)
  {
  	IRDA_DEBUG(2, "%s()
  ", __func__);
  
  	/* probably the power-up can be dropped here, but with only
  	 * 15 usec delay it's not worth the risk unless somebody with
  	 * the hardware confirms it doesn't break anything...
  	 */
  
  	/* Power on dongle */
  	sirdev_set_dtr_rts(dev, TRUE, TRUE);
  
  	/* Sleep a minimum of 15 us */
  	udelay(MIN_DELAY);
  
  	/* Clear RTS to reset dongle */
  	sirdev_set_dtr_rts(dev, TRUE, FALSE);
  
  	/* Sleep a minimum of 15 us */
  	udelay(MIN_DELAY);
  
  	/* Go back to normal mode */
  	sirdev_set_dtr_rts(dev, TRUE, TRUE);
  
  	/* Sleep a minimum of 15 us */
  	udelay(MIN_DELAY);
  
  	/* This dongles speed defaults to 115200 bps */
  	dev->speed = 115200;
  
  	return 0;
  }
  
  MODULE_AUTHOR("Dag Brattli <dagb@cs.uit.no>");
  MODULE_DESCRIPTION("Parallax Litelink dongle driver");	
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("irda-dongle-5"); /* IRDA_LITELINK_DONGLE */
  
  /*
   * Function init_module (void)
   *
   *    Initialize Litelink module
   *
   */
  module_init(litelink_sir_init);
  
  /*
   * Function cleanup_module (void)
   *
   *    Cleanup Litelink module
   *
   */
  module_exit(litelink_sir_cleanup);