penmount.c

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/*
 * Penmount serial touchscreen driver
 *
 * Copyright (c) 2006 Rick Koch <[email protected]>
 * Copyright (c) 2011 John Sung <[email protected]>
 *
 * Based on ELO driver (drivers/input/touchscreen/elo.c)
 * 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.
 */

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

#define DRIVER_DESC "PenMount serial touchscreen driver"

MODULE_AUTHOR("Rick Koch <[email protected]>");
MODULE_AUTHOR("John Sung <[email protected]>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/*
 * Definitions & global arrays.
 */

#define PM_MAX_LENGTH   6
#define PM_MAX_MTSLOT   16
#define PM_3000_MTSLOT  2
#define PM_6250_MTSLOT  12

/*
 * Multi-touch slot
 */

struct mt_slot {
    unsigned short x, y;
    bool active; /* is the touch valid? */
};

/*
 * Per-touchscreen data.
 */

struct pm {
    struct input_dev *dev;
    struct serio *serio;
    int idx;
    unsigned char data[PM_MAX_LENGTH];
    char phys[32];
    unsigned char packetsize;
    unsigned char maxcontacts;
    struct mt_slot slots[PM_MAX_MTSLOT];
    void (*parse_packet)(struct pm *);
};

/*
 * pm_mtevent() sends mt events and also emulates pointer movement
 */

static void pm_mtevent(struct pm *pm, struct input_dev *input)
{
    int i;

    for (i = 0; i < pm->maxcontacts; ++i) {
        input_mt_slot(input, i);
        input_mt_report_slot_state(input, MT_TOOL_FINGER,
                pm->slots[i].active);
        if (pm->slots[i].active) {
            input_event(input, EV_ABS, ABS_MT_POSITION_X, pm->slots[i].x);
            input_event(input, EV_ABS, ABS_MT_POSITION_Y, pm->slots[i].y);
        }
    }

    input_mt_report_pointer_emulation(input, true);
    input_sync(input);
}

/*
 * pm_checkpacket() checks if data packet is valid
 */

static bool pm_checkpacket(unsigned char *packet)
{
    int total = 0;
    int i;

    for (i = 0; i < 5; i++)
        total += packet[i];

    return packet[5] == (unsigned char)~(total & 0xff);
}

static void pm_parse_9000(struct pm *pm)
{
    struct input_dev *dev = pm->dev;

    if ((pm->data[0] & 0x80) && pm->packetsize == ++pm->idx) {
        input_report_abs(dev, ABS_X, pm->data[1] * 128 + pm->data[2]);
        input_report_abs(dev, ABS_Y, pm->data[3] * 128 + pm->data[4]);
        input_report_key(dev, BTN_TOUCH, !!(pm->data[0] & 0x40));
        input_sync(dev);
        pm->idx = 0;
    }
}

static void pm_parse_6000(struct pm *pm)
{
    struct input_dev *dev = pm->dev;

    if ((pm->data[0] & 0xbf) == 0x30 && pm->packetsize == ++pm->idx) {
        if (pm_checkpacket(pm->data)) {
            input_report_abs(dev, ABS_X,
                    pm->data[2] * 256 + pm->data[1]);
            input_report_abs(dev, ABS_Y,
                    pm->data[4] * 256 + pm->data[3]);
            input_report_key(dev, BTN_TOUCH, pm->data[0] & 0x40);
            input_sync(dev);
        }
        pm->idx = 0;
    }
}

static void pm_parse_3000(struct pm *pm)
{
    struct input_dev *dev = pm->dev;

    if ((pm->data[0] & 0xce) == 0x40 && pm->packetsize == ++pm->idx) {
        if (pm_checkpacket(pm->data)) {
            int slotnum = pm->data[0] & 0x0f;
            pm->slots[slotnum].active = pm->data[0] & 0x30;
            pm->slots[slotnum].x = pm->data[2] * 256 + pm->data[1];
            pm->slots[slotnum].y = pm->data[4] * 256 + pm->data[3];
            pm_mtevent(pm, dev);
        }
        pm->idx = 0;
    }
}

static void pm_parse_6250(struct pm *pm)
{
    struct input_dev *dev = pm->dev;

    if ((pm->data[0] & 0xb0) == 0x30 && pm->packetsize == ++pm->idx) {
        if (pm_checkpacket(pm->data)) {
            int slotnum = pm->data[0] & 0x0f;
            pm->slots[slotnum].active = pm->data[0] & 0x40;
            pm->slots[slotnum].x = pm->data[2] * 256 + pm->data[1];
            pm->slots[slotnum].y = pm->data[4] * 256 + pm->data[3];
            pm_mtevent(pm, dev);
        }
        pm->idx = 0;
    }
}

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

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

    pm->parse_packet(pm);

    return IRQ_HANDLED;
}

/*
 * pm_disconnect() is the opposite of pm_connect()
 */

static void pm_disconnect(struct serio *serio)
{
    struct pm *pm = serio_get_drvdata(serio);

    serio_close(serio);

    input_unregister_device(pm->dev);
    kfree(pm);

    serio_set_drvdata(serio, NULL);
}

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

static int pm_connect(struct serio *serio, struct serio_driver *drv)
{
    struct pm *pm;
    struct input_dev *input_dev;
    int max_x, max_y;
    int err;

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

    pm->serio = serio;
    pm->dev = input_dev;
    snprintf(pm->phys, sizeof(pm->phys), "%s/input0", serio->phys);
    pm->maxcontacts = 1;

    input_dev->name = "PenMount Serial TouchScreen";
    input_dev->phys = pm->phys;
    input_dev->id.bustype = BUS_RS232;
    input_dev->id.vendor = SERIO_PENMOUNT;
    input_dev->id.product = 0;
    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);

    switch (serio->id.id) {
    default:
    case 0:
        pm->packetsize = 5;
        pm->parse_packet = pm_parse_9000;
        input_dev->id.product = 0x9000;
        max_x = max_y = 0x3ff;
        break;

    case 1:
        pm->packetsize = 6;
        pm->parse_packet = pm_parse_6000;
        input_dev->id.product = 0x6000;
        max_x = max_y = 0x3ff;
        break;

    case 2:
        pm->packetsize = 6;
        pm->parse_packet = pm_parse_3000;
        input_dev->id.product = 0x3000;
        max_x = max_y = 0x7ff;
        pm->maxcontacts = PM_3000_MTSLOT;
        break;

    case 3:
        pm->packetsize = 6;
        pm->parse_packet = pm_parse_6250;
        input_dev->id.product = 0x6250;
        max_x = max_y = 0x3ff;
        pm->maxcontacts = PM_6250_MTSLOT;
        break;
    }

    input_set_abs_params(pm->dev, ABS_X, 0, max_x, 0, 0);
    input_set_abs_params(pm->dev, ABS_Y, 0, max_y, 0, 0);

    if (pm->maxcontacts > 1) {
        input_mt_init_slots(pm->dev, pm->maxcontacts, 0);
        input_set_abs_params(pm->dev,
                     ABS_MT_POSITION_X, 0, max_x, 0, 0);
        input_set_abs_params(pm->dev,
                     ABS_MT_POSITION_Y, 0, max_y, 0, 0);
    }

    serio_set_drvdata(serio, pm);

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

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

    return 0;

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

/*
 * The serio driver structure.
 */

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

MODULE_DEVICE_TABLE(serio, pm_serio_ids);

static struct serio_driver pm_drv = {
    .driver     = {
        .name   = "serio-penmount",
    },
    .description    = DRIVER_DESC,
    .id_table   = pm_serio_ids,
    .interrupt  = pm_interrupt,
    .connect    = pm_connect,
    .disconnect = pm_disconnect,
};

module_serio_driver(pm_drv);