mcp2120-sir.c

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/*********************************************************************
 *            
 *    
 * Filename:      mcp2120.c
 * Version:       1.0
 * Description:   Implementation for the MCP2120 (Microchip)
 * Status:        Experimental.
 * Author:        Felix Tang ([email protected])
 * Created at:    Sun Mar 31 19:32:12 EST 2002
 * Based on code by:   Dag Brattli <[email protected]>
 * 
 *     Copyright (c) 2002 Felix Tang, 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.
 *  
 ********************************************************************/

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/init.h>

#include <net/irda/irda.h>

#include "sir-dev.h"

static int mcp2120_reset(struct sir_dev *dev);
static int mcp2120_open(struct sir_dev *dev);
static int mcp2120_close(struct sir_dev *dev);
static int mcp2120_change_speed(struct sir_dev *dev, unsigned speed);

#define MCP2120_9600    0x87
#define MCP2120_19200   0x8B
#define MCP2120_38400   0x85
#define MCP2120_57600   0x83
#define MCP2120_115200  0x81

#define MCP2120_COMMIT  0x11

static struct dongle_driver mcp2120 = {
    .owner      = THIS_MODULE,
    .driver_name    = "Microchip MCP2120",
    .type       = IRDA_MCP2120_DONGLE,
    .open       = mcp2120_open,
    .close      = mcp2120_close,
    .reset      = mcp2120_reset,
    .set_speed  = mcp2120_change_speed,
};

static int __init mcp2120_sir_init(void)
{
    return irda_register_dongle(&mcp2120);
}

static void __exit mcp2120_sir_cleanup(void)
{
    irda_unregister_dongle(&mcp2120);
}

static int mcp2120_open(struct sir_dev *dev)
{
    struct qos_info *qos = &dev->qos;

    IRDA_DEBUG(2, "%s()\n", __func__);

    /* seems no explicit power-on required here and reset switching it on anyway */

    qos->baud_rate.bits &= IR_9600|IR_19200|IR_38400|IR_57600|IR_115200;
    qos->min_turn_time.bits = 0x01;
    irda_qos_bits_to_value(qos);

    return 0;
}

static int mcp2120_close(struct sir_dev *dev)
{
    IRDA_DEBUG(2, "%s()\n", __func__);

    /* Power off dongle */
        /* reset and inhibit mcp2120 */
    sirdev_set_dtr_rts(dev, TRUE, TRUE);
    // sirdev_set_dtr_rts(dev, FALSE, FALSE);

    return 0;
}

/*
 * Function mcp2120_change_speed (dev, speed)
 *
 *    Set the speed for the MCP2120.
 *
 */

#define MCP2120_STATE_WAIT_SPEED    (SIRDEV_STATE_DONGLE_SPEED+1)

static int mcp2120_change_speed(struct sir_dev *dev, unsigned speed)
{
    unsigned state = dev->fsm.substate;
    unsigned delay = 0;
    u8 control[2];
    static int ret = 0;

    IRDA_DEBUG(2, "%s()\n", __func__);

    switch (state) {
    case SIRDEV_STATE_DONGLE_SPEED:
        /* Set DTR to enter command mode */
        sirdev_set_dtr_rts(dev, TRUE, FALSE);
                udelay(500);

        ret = 0;
        switch (speed) {
        default:
            speed = 9600;
            ret = -EINVAL;
            /* fall through */
        case 9600:
            control[0] = MCP2120_9600;
                        //printk("mcp2120 9600\n");
            break;
        case 19200:
            control[0] = MCP2120_19200;
                        //printk("mcp2120 19200\n");
            break;
        case 34800:
            control[0] = MCP2120_38400;
                        //printk("mcp2120 38400\n");
            break;
        case 57600:
            control[0] = MCP2120_57600;
                        //printk("mcp2120 57600\n");
            break;
        case 115200:
                        control[0] = MCP2120_115200;
                        //printk("mcp2120 115200\n");
            break;
        }
        control[1] = MCP2120_COMMIT;
    
        /* Write control bytes */
        sirdev_raw_write(dev, control, 2);
        dev->speed = speed;

        state = MCP2120_STATE_WAIT_SPEED;
        delay = 100;
                //printk("mcp2120_change_speed: dongle_speed\n");
        break;

    case MCP2120_STATE_WAIT_SPEED:
        /* Go back to normal mode */
        sirdev_set_dtr_rts(dev, FALSE, FALSE);
                //printk("mcp2120_change_speed: mcp_wait\n");
        break;

    default:
        IRDA_ERROR("%s(), undefine state %d\n", __func__, state);
        ret = -EINVAL;
        break;
    }
    dev->fsm.substate = state;
    return (delay > 0) ? delay : ret;
}

/*
 * Function mcp2120_reset (driver)
 *
 *      This function resets the mcp2120 dongle.
 *      
 *      Info: -set RTS to reset mcp2120
 *            -set DTR to set mcp2120 software command mode
 *            -mcp2120 defaults to 9600 baud after reset
 *
 *      Algorithm:
 *      0. Set RTS to reset mcp2120.
 *      1. Clear RTS and wait for device reset timer of 30 ms (max).
 *      
 */

#define MCP2120_STATE_WAIT1_RESET   (SIRDEV_STATE_DONGLE_RESET+1)
#define MCP2120_STATE_WAIT2_RESET   (SIRDEV_STATE_DONGLE_RESET+2)

static int mcp2120_reset(struct sir_dev *dev)
{
    unsigned state = dev->fsm.substate;
    unsigned delay = 0;
    int ret = 0;

    IRDA_DEBUG(2, "%s()\n", __func__);

    switch (state) {
    case SIRDEV_STATE_DONGLE_RESET:
                //printk("mcp2120_reset: dongle_reset\n");
        /* Reset dongle by setting RTS*/
        sirdev_set_dtr_rts(dev, TRUE, TRUE);
        state = MCP2120_STATE_WAIT1_RESET;
        delay = 50;
        break;

    case MCP2120_STATE_WAIT1_RESET:
                //printk("mcp2120_reset: mcp2120_wait1\n");
                /* clear RTS and wait for at least 30 ms. */
        sirdev_set_dtr_rts(dev, FALSE, FALSE);
        state = MCP2120_STATE_WAIT2_RESET;
        delay = 50;
        break;

    case MCP2120_STATE_WAIT2_RESET:
                //printk("mcp2120_reset mcp2120_wait2\n");
        /* Go back to normal mode */
        sirdev_set_dtr_rts(dev, FALSE, FALSE);
        break;

    default:
        IRDA_ERROR("%s(), undefined state %d\n", __func__, state);
        ret = -EINVAL;
        break;
    }
    dev->fsm.substate = state;
    return (delay > 0) ? delay : ret;
}

MODULE_AUTHOR("Felix Tang <[email protected]>");
MODULE_DESCRIPTION("Microchip MCP2120");
MODULE_LICENSE("GPL");
MODULE_ALIAS("irda-dongle-9"); /* IRDA_MCP2120_DONGLE */

module_init(mcp2120_sir_init);
module_exit(mcp2120_sir_cleanup);