atmel触摸屏中断改轮询

普通电容式触摸屏是中断方式的，由于v3s引脚较少，所以尝试改为轮询方式驱动，节省一个IO。

static int __devexit mxt_remove(struct i2c_client *client)
#ifndef _TS_POLL
    free_irq(data->irq, data);
#endif

static int __devinit mxt_probe(struct i2c_client *client,
        const struct i2c_device_id *id)
err_free_irq:
#ifndef _TS_POLL
    free_irq(client->irq, data);
#endif

#ifndef _TS_POLL
    error = request_threaded_irq(client->irq, NULL, mxt_interrupt,
            pdata->irqflags, client->dev.driver->name, data);
    if (error) {
        dev_err(&client->dev, "Failed to register interrupt\n");
        goto err_free_object;
    }
    error = input_register_device(input_dev);
    if (error)
        goto err_free_irq;
#else
    {
        struct input_polled_dev *polled_dev;
        polled_dev = devm_input_allocate_polled_device(dev);
        if (!polled_dev) {
            dev_err(dev,
                "Failed to allocate polled input device\n");
            return -ENOMEM;
        }
        polled_dev->private = data;
        polled_dev->poll = mxt_poll;
        polled_dev->poll_interval = POLL_INTERVAL;
        polled_dev->input = input_dev;

        error = input_register_polled_device(polled_dev);
    }
#endif

#ifdef _TS_POLL
#define POLL_INTERVAL 5

static void mxt_poll(struct input_polled_dev *dev)
{
    struct mxt_data *data = dev->private;
    struct mxt_message message;
    struct mxt_object *object;
    struct device *dev = &data->client->dev;
    int id;
    u8 reportid;
    u8 max_reportid;
    u8 min_reportid;

    do {
        if (mxt_read_message(data, &message)) {
            dev_err(dev, "Failed to read message\n");
            goto end;
        }

        reportid = message.reportid;

        /* whether reportid is thing of MXT_TOUCH_MULTI_T9 */
        object = mxt_get_object(data, MXT_TOUCH_MULTI_T9);
        if (!object)
            goto end;

        max_reportid = object->max_reportid;
        min_reportid = max_reportid - object->num_report_ids + 1;
        id = reportid - min_reportid;

        if (reportid >= min_reportid && reportid <= max_reportid)
            mxt_input_touchevent(data, &message, id);
        else
            mxt_dump_message(dev, &message);
    } while (reportid != 0xff);

end:
    return;
}
#endif

#ifndef _FLIP_X
input_report_abs(input_dev, ABS_MT_POSITION_X, finger[id].x);
#else
input_report_abs(input_dev, ABS_MT_POSITION_X, 800-finger[id].x);
#end
#ifndef _FLIP_Y     
input_report_abs(input_dev, ABS_MT_POSITION_Y, finger[id].y);
#else
input_report_abs(input_dev, ABS_MT_POSITION_Y, 480-finger[id].y);
#endif