elo.c

Go to the documentation of this file.

/*
 * Elo serial touchscreen driver
 *
 * Copyright (c) 2004 Vojtech Pavlik
 */

/*
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

/*
 * This driver can handle serial Elo touchscreens using either the Elo standard
 * 'E271-2210' 10-byte protocol, Elo legacy 'E281A-4002' 6-byte protocol, Elo
 * legacy 'E271-140' 4-byte protocol and Elo legacy 'E261-280' 3-byte protocol.
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/serio.h>
#include <linux/init.h>
#include <linux/ctype.h>

#define DRIVER_DESC "Elo serial touchscreen driver"

MODULE_AUTHOR("Vojtech Pavlik <[email protected]>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/*
 * Definitions & global arrays.
 */

#define ELO_MAX_LENGTH      10

#define ELO10_PACKET_LEN    8
#define ELO10_TOUCH     0x03
#define ELO10_PRESSURE      0x80

#define ELO10_LEAD_BYTE     'U'

#define ELO10_ID_CMD        'i'

#define ELO10_TOUCH_PACKET  'T'
#define ELO10_ACK_PACKET    'A'
#define ELI10_ID_PACKET     'I'

/*
 * Per-touchscreen data.
 */

struct elo {
    struct input_dev *dev;
    struct serio *serio;
    struct mutex cmd_mutex;
    struct completion cmd_done;
    int id;
    int idx;
    unsigned char expected_packet;
    unsigned char csum;
    unsigned char data[ELO_MAX_LENGTH];
    unsigned char response[ELO10_PACKET_LEN];
    char phys[32];
};

static void elo_process_data_10(struct elo *elo, unsigned char data)
{
    struct input_dev *dev = elo->dev;

    elo->data[elo->idx] = data;

    switch (elo->idx++) {
    case 0:
        elo->csum = 0xaa;
        if (data != ELO10_LEAD_BYTE) {
            dev_dbg(&elo->serio->dev,
                "unsynchronized data: 0x%02x\n", data);
            elo->idx = 0;
        }
        break;

    case 9:
        elo->idx = 0;
        if (data != elo->csum) {
            dev_dbg(&elo->serio->dev,
                "bad checksum: 0x%02x, expected 0x%02x\n",
                 data, elo->csum);
            break;
        }
        if (elo->data[1] != elo->expected_packet) {
            if (elo->data[1] != ELO10_TOUCH_PACKET)
                dev_dbg(&elo->serio->dev,
                    "unexpected packet: 0x%02x\n",
                     elo->data[1]);
            break;
        }
        if (likely(elo->data[1] == ELO10_TOUCH_PACKET)) {
            input_report_abs(dev, ABS_X, (elo->data[4] << 8) | elo->data[3]);
            input_report_abs(dev, ABS_Y, (elo->data[6] << 8) | elo->data[5]);
            if (elo->data[2] & ELO10_PRESSURE)
                input_report_abs(dev, ABS_PRESSURE,
                        (elo->data[8] << 8) | elo->data[7]);
            input_report_key(dev, BTN_TOUCH, elo->data[2] & ELO10_TOUCH);
            input_sync(dev);
        } else if (elo->data[1] == ELO10_ACK_PACKET) {
            if (elo->data[2] == '0')
                elo->expected_packet = ELO10_TOUCH_PACKET;
            complete(&elo->cmd_done);
        } else {
            memcpy(elo->response, &elo->data[1], ELO10_PACKET_LEN);
            elo->expected_packet = ELO10_ACK_PACKET;
        }
        break;
    }
    elo->csum += data;
}

static void elo_process_data_6(struct elo *elo, unsigned char data)
{
    struct input_dev *dev = elo->dev;

    elo->data[elo->idx] = data;

    switch (elo->idx++) {

    case 0:
        if ((data & 0xc0) != 0xc0)
            elo->idx = 0;
        break;

    case 1:
        if ((data & 0xc0) != 0x80)
            elo->idx = 0;
        break;

    case 2:
        if ((data & 0xc0) != 0x40)
            elo->idx = 0;
        break;

    case 3:
        if (data & 0xc0) {
            elo->idx = 0;
            break;
        }

        input_report_abs(dev, ABS_X, ((elo->data[0] & 0x3f) << 6) | (elo->data[1] & 0x3f));
        input_report_abs(dev, ABS_Y, ((elo->data[2] & 0x3f) << 6) | (elo->data[3] & 0x3f));

        if (elo->id == 2) {
            input_report_key(dev, BTN_TOUCH, 1);
            input_sync(dev);
            elo->idx = 0;
        }

        break;

    case 4:
        if (data) {
            input_sync(dev);
            elo->idx = 0;
        }
        break;

    case 5:
        if ((data & 0xf0) == 0) {
            input_report_abs(dev, ABS_PRESSURE, elo->data[5]);
            input_report_key(dev, BTN_TOUCH, !!elo->data[5]);
        }
        input_sync(dev);
        elo->idx = 0;
        break;
    }
}

static void elo_process_data_3(struct elo *elo, unsigned char data)
{
    struct input_dev *dev = elo->dev;

    elo->data[elo->idx] = data;

    switch (elo->idx++) {

    case 0:
        if ((data & 0x7f) != 0x01)
            elo->idx = 0;
        break;
    case 2:
        input_report_key(dev, BTN_TOUCH, !(elo->data[1] & 0x80));
        input_report_abs(dev, ABS_X, elo->data[1]);
        input_report_abs(dev, ABS_Y, elo->data[2]);
        input_sync(dev);
        elo->idx = 0;
        break;
    }
}

static irqreturn_t elo_interrupt(struct serio *serio,
        unsigned char data, unsigned int flags)
{
    struct elo *elo = serio_get_drvdata(serio);

    switch (elo->id) {
    case 0:
        elo_process_data_10(elo, data);
        break;

    case 1:
    case 2:
        elo_process_data_6(elo, data);
        break;

    case 3:
        elo_process_data_3(elo, data);
        break;
    }

    return IRQ_HANDLED;
}

static int elo_command_10(struct elo *elo, unsigned char *packet)
{
    int rc = -1;
    int i;
    unsigned char csum = 0xaa + ELO10_LEAD_BYTE;

    mutex_lock(&elo->cmd_mutex);

    serio_pause_rx(elo->serio);
    elo->expected_packet = toupper(packet[0]);
    init_completion(&elo->cmd_done);
    serio_continue_rx(elo->serio);

    if (serio_write(elo->serio, ELO10_LEAD_BYTE))
        goto out;

    for (i = 0; i < ELO10_PACKET_LEN; i++) {
        csum += packet[i];
        if (serio_write(elo->serio, packet[i]))
            goto out;
    }

    if (serio_write(elo->serio, csum))
        goto out;

    wait_for_completion_timeout(&elo->cmd_done, HZ);

    if (elo->expected_packet == ELO10_TOUCH_PACKET) {
        /* We are back in reporting mode, the command was ACKed */
        memcpy(packet, elo->response, ELO10_PACKET_LEN);
        rc = 0;
    }

 out:
    mutex_unlock(&elo->cmd_mutex);
    return rc;
}

static int elo_setup_10(struct elo *elo)
{
    static const char *elo_types[] = { "Accu", "Dura", "Intelli", "Carroll" };
    struct input_dev *dev = elo->dev;
    unsigned char packet[ELO10_PACKET_LEN] = { ELO10_ID_CMD };

    if (elo_command_10(elo, packet))
        return -1;

    dev->id.version = (packet[5] << 8) | packet[4];

    input_set_abs_params(dev, ABS_X, 96, 4000, 0, 0);
    input_set_abs_params(dev, ABS_Y, 96, 4000, 0, 0);
    if (packet[3] & ELO10_PRESSURE)
        input_set_abs_params(dev, ABS_PRESSURE, 0, 255, 0, 0);

    dev_info(&elo->serio->dev,
         "%sTouch touchscreen, fw: %02x.%02x, features: 0x%02x, controller: 0x%02x\n",
         elo_types[(packet[1] -'0') & 0x03],
         packet[5], packet[4], packet[3], packet[7]);

    return 0;
}

/*
 * elo_disconnect() is the opposite of elo_connect()
 */

static void elo_disconnect(struct serio *serio)
{
    struct elo *elo = serio_get_drvdata(serio);

    input_get_device(elo->dev);
    input_unregister_device(elo->dev);
    serio_close(serio);
    serio_set_drvdata(serio, NULL);
    input_put_device(elo->dev);
    kfree(elo);
}

/*
 * elo_connect() is the routine that is called when someone adds a
 * new serio device that supports Gunze protocol and registers it as
 * an input device.
 */

static int elo_connect(struct serio *serio, struct serio_driver *drv)
{
    struct elo *elo;
    struct input_dev *input_dev;
    int err;

    elo = kzalloc(sizeof(struct elo), GFP_KERNEL);
    input_dev = input_allocate_device();
    if (!elo || !input_dev) {
        err = -ENOMEM;
        goto fail1;
    }

    elo->serio = serio;
    elo->id = serio->id.id;
    elo->dev = input_dev;
    elo->expected_packet = ELO10_TOUCH_PACKET;
    mutex_init(&elo->cmd_mutex);
    init_completion(&elo->cmd_done);
    snprintf(elo->phys, sizeof(elo->phys), "%s/input0", serio->phys);

    input_dev->name = "Elo Serial TouchScreen";
    input_dev->phys = elo->phys;
    input_dev->id.bustype = BUS_RS232;
    input_dev->id.vendor = SERIO_ELO;
    input_dev->id.product = elo->id;
    input_dev->id.version = 0x0100;
    input_dev->dev.parent = &serio->dev;

    input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
    input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);

    serio_set_drvdata(serio, elo);
    err = serio_open(serio, drv);
    if (err)
        goto fail2;

    switch (elo->id) {

    case 0: /* 10-byte protocol */
        if (elo_setup_10(elo))
            goto fail3;

        break;

    case 1: /* 6-byte protocol */
        input_set_abs_params(input_dev, ABS_PRESSURE, 0, 15, 0, 0);

    case 2: /* 4-byte protocol */
        input_set_abs_params(input_dev, ABS_X, 96, 4000, 0, 0);
        input_set_abs_params(input_dev, ABS_Y, 96, 4000, 0, 0);
        break;

    case 3: /* 3-byte protocol */
        input_set_abs_params(input_dev, ABS_X, 0, 255, 0, 0);
        input_set_abs_params(input_dev, ABS_Y, 0, 255, 0, 0);
        break;
    }

    err = input_register_device(elo->dev);
    if (err)
        goto fail3;

    return 0;

 fail3: serio_close(serio);
 fail2: serio_set_drvdata(serio, NULL);
 fail1: input_free_device(input_dev);
    kfree(elo);
    return err;
}

/*
 * The serio driver structure.
 */

static struct serio_device_id elo_serio_ids[] = {
    {
        .type   = SERIO_RS232,
        .proto  = SERIO_ELO,
        .id = SERIO_ANY,
        .extra  = SERIO_ANY,
    },
    { 0 }
};

MODULE_DEVICE_TABLE(serio, elo_serio_ids);

static struct serio_driver elo_drv = {
    .driver     = {
        .name   = "elo",
    },
    .description    = DRIVER_DESC,
    .id_table   = elo_serio_ids,
    .interrupt  = elo_interrupt,
    .connect    = elo_connect,
    .disconnect = elo_disconnect,
};

module_serio_driver(elo_drv);