drivers/input/touchscreen/elo.c

/*
 * 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 <vojtech@ucw.cz>");
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) {
				pr_debug("elo: unsynchronized data: 0x%02x\n", data);
				elo->idx = 0;
			}
			break;

		case 9:
			elo->idx = 0;
			if (data != elo->csum) {
				pr_debug("elo: 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)
					pr_debug("elo: 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[] = {