static void brickpi_init_work(struct work_struct *work)
{
	struct brickpi_data *data = container_of(work, struct brickpi_data,
						 poll_work);
	int i, err;

	for (i = 0; i < data->num_channels; i++) {
		struct brickpi_channel_data *ch_data = &data->channel_data[i];

		ch_data->data = data;
		// TODO: add module parameter to get addresses
		ch_data->address = i + 1;
		ch_data->in_port[BRICKPI_PORT_1].ch_data = ch_data;
		ch_data->in_port[BRICKPI_PORT_1].sensor_type =
						BRICKPI_SENSOR_TYPE_FW_VERSION;
		ch_data->in_port[BRICKPI_PORT_2].ch_data = ch_data;
		ch_data->in_port[BRICKPI_PORT_2].sensor_type =
						BRICKPI_SENSOR_TYPE_FW_VERSION;
		err = brickpi_set_sensors(ch_data);
		if (err < 0) {
			dev_err(data->tty->dev,
				"Failed to init while setting sensors. (%d)\n",
				err);
			return;
		}
		ch_data->out_port[BRICKPI_PORT_1].ch_data = ch_data;
		ch_data->out_port[BRICKPI_PORT_2].ch_data = ch_data;
		err = brickpi_get_values(ch_data);
		if (err < 0) {
			dev_err(data->tty->dev,
				"Failed to init while getting values. (%d)\n",
				err);
			return;
		}
		ch_data->fw_version =
			ch_data->in_port[BRICKPI_PORT_1].sensor_values[0];
		debug_pr("address: %d, fw: %d\n", ch_data->address,
			 ch_data->fw_version);

		err = brickpi_register_in_ports(ch_data, data->tty->dev);
		if (err < 0) {
			dev_err(data->tty->dev,
				"Failed to register input ports (%d)",
				err);
			return;
		}
		err = brickpi_register_out_ports(ch_data, data->tty->dev);
		if (err < 0) {
			brickpi_unregister_in_ports(ch_data);
			dev_err(data->tty->dev,
				"Failed to register output ports (%d)",
				err);
			return;
		}
		ch_data->init_ok = true;
	}

	INIT_WORK(&data->poll_work, brickpi_poll_work);
	hrtimer_start(&data->poll_timer, ktime_set(0, 0), HRTIMER_MODE_REL);
}
static void brickpi_poll_work(struct work_struct *work)
{
	struct brickpi_data *data = container_of(work, struct brickpi_data,
						 poll_work);
	int i, err;

	if (data->closing)
		return;

	for (i = 0; i < data->num_channels; i++) {
		struct brickpi_channel_data *ch_data = &data->channel_data[i];
		if (ch_data->init_ok) {
			err = brickpi_get_values(ch_data);
			if (err < 0)
				debug_pr("failed to get values for address %d. (%d)\n",
				ch_data->address, err);
		}
	}
}
static void ev3_uart_handle_rx_data(struct work_struct *work)
{
	struct ev3_uart_port_data *port =
		container_of(work, struct ev3_uart_port_data, rx_data_work);
	struct circ_buf *cb = &port->circ_buf;
	u8 message[EV3_UART_MAX_MESSAGE_SIZE + 2];
	int count = CIRC_CNT(cb->head, cb->tail, EV3_UART_BUFFER_SIZE);
	int i, speed, size_to_end;
	u8 cmd, cmd2, type, mode, msg_type, msg_size, chksum;

#ifdef DEBUG
	printk("received: ");
	for (i = 0; i < count; i++) {
		cmd = cb->buf[(cb->tail + i) % EV3_UART_BUFFER_SIZE];
		if (cmd >= 32 && cmd < 127)
			printk("%c ", cmd);
		else
			printk("0x%02x ", cmd);
	}
	printk("(%d)\n", count);
#endif

	/*
	 * To get in sync with the data stream from the sensor, we look
	 * for a valid TYPE command.
	 */
	while (!port->synced) {
		if (count < 3)
			return;
		cmd = cb->buf[cb->tail];
		cb->tail++;
		if (cb->tail >= EV3_UART_BUFFER_SIZE)
			cb->tail = 0;
		count--;
		if (cmd != (EV3_UART_MSG_TYPE_CMD | EV3_UART_CMD_TYPE))
			continue;
		type = cb->buf[cb->tail];
		if (!type || type > EV3_UART_TYPE_MAX)
			continue;
		chksum = 0xFF ^ cmd ^ type;
		if ((u8)cb->buf[(cb->tail + 1) % EV3_UART_BUFFER_SIZE] != chksum)
			continue;
		port->sensor.num_modes = 1;
		port->sensor.num_view_modes = 1;
		for (i = 0; i <= EV3_UART_MODE_MAX; i++)
			port->mode_info[i] = ev3_uart_default_mode_info;
		port->type_id = type;
		/* look up well-known driver names */
		port->device_name[0] = 0;
		for (i = 0; i < NUM_LEGO_EV3_SENSOR_TYPES; i++) {
			if (type == ev3_uart_sensor_defs[i].type_id) {
				snprintf(port->device_name, LEGO_SENSOR_NAME_SIZE,
					 "%s", ev3_uart_sensor_defs[i].name);
				break;
			}
		}
		/* or use generic name if well-known name is not found */
		if (!port->device_name[0])
			snprintf(port->device_name, LEGO_SENSOR_NAME_SIZE,
				 EV3_UART_SENSOR_NAME("%u"), type);
		port->info_flags = EV3_UART_INFO_FLAG_CMD_TYPE;
		port->synced = 1;
		port->info_done = 0;
		port->data_rec = 0;
		port->num_data_err = 0;
		cb->tail = (cb->tail + 2) % EV3_UART_BUFFER_SIZE;
		count -= 2;
	}
	if (!port->synced)
		return;

	while (count > 0)
	{
		/*
		 * Sometimes we get 0xFF after switching baud rates, so just
		 * ignore it.
		 */
		if ((u8)cb->buf[cb->tail] == 0xFF) {

			cb->tail++;
			if (cb->tail >= EV3_UART_BUFFER_SIZE)
				cb->tail = 0;
			count--;
			continue;
		}
		msg_size = ev3_uart_msg_size((u8)cb->buf[cb->tail]);
		if (msg_size > count)
			break;
		size_to_end = CIRC_CNT_TO_END(cb->head, cb->tail, EV3_UART_BUFFER_SIZE);
		if (msg_size > size_to_end) {
			memcpy(message, cb->buf + cb->tail, size_to_end);
			memcpy(message + size_to_end, cb->buf, msg_size - size_to_end);
			cb->tail = msg_size - size_to_end;
		} else {
			memcpy(message, cb->buf + cb->tail, msg_size);
			cb->tail += msg_size;
			if (cb->tail >= EV3_UART_BUFFER_SIZE)
				cb->tail = 0;
		}
		count -= msg_size;
#ifdef DEBUG
		printk("processing: ");
		for (i = 0; i < msg_size; i++)
			printk("0x%02x ", message[i]);
		printk(" (%d)\n", msg_size);
#endif
		if (msg_size > EV3_UART_MAX_MESSAGE_SIZE) {
			port->last_err = "Bad message size.";
			goto err_invalid_state;
		}
		msg_type = message[0] & EV3_UART_MSG_TYPE_MASK;
		cmd = message[0] & EV3_UART_MSG_CMD_MASK;
		mode = cmd;
		cmd2 = message[1];
		if (msg_size > 1) {
			chksum = 0xFF;
			for (i = 0; i < msg_size - 1; i++)
				chksum ^= message[i];
			debug_pr("chksum:%d, actual:%d\n",
			         chksum, message[msg_size - 1]);
			/*
			 * The LEGO EV3 color sensor sends bad checksums
			 * for RGB-RAW data (mode 4). The check here could be
			 * improved if someone can find a pattern.
			 */
			if (chksum != message[msg_size - 1]
			    && port->type_id != EV3_UART_TYPE_ID_COLOR
			    && message[0] != 0xDC)
			{
				port->last_err = "Bad checksum.";
				if (port->info_done) {
					port->num_data_err++;
					goto err_bad_data_msg_checksum;
				} else
					goto err_invalid_state;
			}
		}
		switch (msg_type) {
		case EV3_UART_MSG_TYPE_SYS:
			debug_pr("SYS:%d\n", message[0] & EV3_UART_MSG_CMD_MASK);
			switch(cmd) {
			case EV3_UART_SYS_SYNC:
				/* IR sensor (type 33) sends checksum after SYNC */
				if (msg_size > 1 && (cmd ^ cmd2) == 0xFF)
					msg_size++;
				break;
			case EV3_UART_SYS_ACK:
				if (!port->sensor.num_modes) {
					port->last_err = "Received ACK before all mode INFO.";
					goto err_invalid_state;
				}
				if ((port->info_flags & EV3_UART_INFO_FLAG_REQUIRED)
				    != EV3_UART_INFO_FLAG_REQUIRED)
				{
					port->last_err = "Did not receive all required INFO.";
					goto err_invalid_state;
				}
				schedule_delayed_work(&port->send_ack_work,
						      msecs_to_jiffies(EV3_UART_SEND_ACK_DELAY));
				port->info_done = 1;
				return;
			}
			break;
		case EV3_UART_MSG_TYPE_CMD:
			debug_pr("CMD:%d\n", cmd);
			switch (cmd) {
			case EV3_UART_CMD_MODES:
				if (test_and_set_bit(EV3_UART_INFO_BIT_CMD_MODES,
						     &port->info_flags))
				{
					port->last_err = "Received duplicate modes INFO.";
					goto err_invalid_state;
				}
				if (!cmd2 || cmd2 > EV3_UART_MODE_MAX) {
					port->last_err = "Number of modes is out of range.";
					goto err_invalid_state;
				}
				port->sensor.num_modes = cmd2 + 1;
				if (msg_size > 3)
					port->sensor.num_view_modes = message[2] + 1;
				else
					port->sensor.num_view_modes = port->sensor.num_modes;
				debug_pr("num_modes:%d, num_view_modes:%d\n",
					 port->sensor.num_modes, port->sensor.num_view_modes);
				break;
			case EV3_UART_CMD_SPEED:
				if (test_and_set_bit(EV3_UART_INFO_BIT_CMD_SPEED,
						     &port->info_flags))
				{
					port->last_err = "Received duplicate speed INFO.";
					goto err_invalid_state;
				}
				speed = *(int*)(message + 1);
				if (speed < EV3_UART_SPEED_MIN
				    || speed > EV3_UART_SPEED_MAX)
				{
					port->last_err = "Speed is out of range.";
					goto err_invalid_state;
				}
				port->new_baud_rate = speed;
				debug_pr("speed:%d\n", speed);
				break;
			default:
				port->last_err = "Unknown command.";
				goto err_invalid_state;
			}
			break;
		case EV3_UART_MSG_TYPE_INFO:
			debug_pr("INFO:%d, mode:%d\n", cmd2, mode);
			switch (cmd2) {
			case EV3_UART_INFO_NAME:
				port->info_flags &= ~EV3_UART_INFO_FLAG_ALL_INFO;
				if (message[2] < 'A' || message[2] > 'z') {
					port->last_err = "Invalid name INFO.";
					goto err_invalid_state;
				}
				/*
				 * Name may not have null terminator and we
				 * are done with the checksum at this point
				 * so we are writing 0 over the checksum to
				 * ensure a null terminator for the string
				 * functions.
				 */
				message[msg_size - 1] = 0;
				if (strlen(message + 2) > EV3_UART_MODE_NAME_SIZE) {
					port->last_err = "Name is too long.";
					goto err_invalid_state;
				}
				snprintf(port->mode_info[mode].name,
				         EV3_UART_MODE_NAME_SIZE + 1, "%s",
				         message + 2);
				if (port->sensor.mode != mode) {
					port->sensor.mode = mode;
					kobject_uevent(&port->sensor.dev.kobj,
						       KOBJ_CHANGE);
				}
				port->info_flags |= EV3_UART_INFO_FLAG_INFO_NAME;
				debug_pr("mode %d name:%s\n",
				       mode, port->sensor.address);
				break;
			case EV3_UART_INFO_RAW:
				if (port->sensor.mode != mode) {
					port->last_err = "Received INFO for incorrect mode.";
					goto err_invalid_state;
				}
				if (test_and_set_bit(EV3_UART_INFO_BIT_INFO_RAW,
						     &port->info_flags))
				{
					port->last_err = "Received duplicate raw scaling INFO.";
					goto err_invalid_state;
				}
				port->raw_min = *(u32 *)(message + 2);
				port->raw_max = *(u32 *)(message + 6);
				debug_pr("mode %d raw_min:%08x, raw_max:%08x\n",
				       mode, port->mode_info[mode].raw_min,
				       port->mode_info[mode].raw_max);
				break;
			case EV3_UART_INFO_PCT:
				if (port->sensor.mode != mode) {
					port->last_err = "Received INFO for incorrect mode.";
					goto err_invalid_state;
				}
				if (test_and_set_bit(EV3_UART_INFO_BIT_INFO_PCT,
						     &port->info_flags))
				{
					port->last_err = "Received duplicate percent scaling INFO.";
					goto err_invalid_state;
				}
				port->pct_min = *(u32 *)(message + 2);
				port->pct_max = *(u32 *)(message + 6);
				debug_pr("mode %d pct_min:%08x, pct_max:%08x\n",
				       mode, port->mode_info[mode].pct_min,
				       port->mode_info[mode].pct_max);
				break;
			case EV3_UART_INFO_SI:
				if (port->sensor.mode != mode) {
					port->last_err = "Received INFO for incorrect mode.";
					goto err_invalid_state;
				}
				if (test_and_set_bit(EV3_UART_INFO_BIT_INFO_SI,
						     &port->info_flags))
				{
					port->last_err = "Received duplicate SI scaling INFO.";
					goto err_invalid_state;
				}
				port->si_min = *(u32 *)(message + 2);
				port->si_max = *(u32 *)(message + 6);
				debug_pr("mode %d si_min:%08x, si_max:%08x\n",
				       mode, port->mode_info[mode].si_min,
				       port->mode_info[mode].si_max);
				break;
			case EV3_UART_INFO_UNITS:
				if (port->sensor.mode != mode) {
					port->last_err = "Received INFO for incorrect mode.";
					goto err_invalid_state;
				}
				if (test_and_set_bit(EV3_UART_INFO_BIT_INFO_UNITS,
						     &port->info_flags))
				{
					port->last_err = "Received duplicate SI units INFO.";
					goto err_invalid_state;
				}
				/*
				 * Units may not have null terminator and we
				 * are done with the checksum at this point
				 * so we are writing 0 over the checksum to
				 * ensure a null terminator for the string
				 * functions.
				 */
				message[msg_size - 1] = 0;
				snprintf(port->mode_info[mode].units,
					 EV3_UART_UNITS_SIZE + 1, "%s",
					 message + 2);
				debug_pr("mode %d units:%s\n",
				       mode, port->mode_info[mode].units);
				break;
			case EV3_UART_INFO_FORMAT:
				if (port->sensor.mode != mode) {
					port->last_err = "Received INFO for incorrect mode.";
					goto err_invalid_state;
				}
				if (test_and_set_bit(EV3_UART_INFO_BIT_INFO_FORMAT,
						     &port->info_flags))
				{
					port->last_err = "Received duplicate format INFO.";
					goto err_invalid_state;
				}
				port->mode_info[mode].data_sets = message[2];
				if (!port->mode_info[mode].data_sets) {
					port->last_err = "Invalid number of data sets.";
					goto err_invalid_state;
				}
				if (msg_size < 7) {
					port->last_err = "Invalid format message size.";
					goto err_invalid_state;
				}
				if ((port->info_flags & EV3_UART_INFO_FLAG_REQUIRED)
						!= EV3_UART_INFO_FLAG_REQUIRED) {
					port->last_err = "Did not receive all required INFO.";
					goto err_invalid_state;
				}
				switch (message[3]) {
				case EV3_UART_DATA_8:
					port->mode_info[mode].data_type = LEGO_SENSOR_DATA_S8;
					break;
				case EV3_UART_DATA_16:
					port->mode_info[mode].data_type = LEGO_SENSOR_DATA_S16;
					break;
				case EV3_UART_DATA_32:
					port->mode_info[mode].data_type = LEGO_SENSOR_DATA_S32;
					break;
				case EV3_UART_DATA_FLOAT:
					port->mode_info[mode].data_type = LEGO_SENSOR_DATA_FLOAT;
					break;
				default:
					port->last_err = "Invalid data type.";
					goto err_invalid_state;
				}
				port->mode_info[mode].figures = message[4];
				port->mode_info[mode].decimals = message[5];
				if (port->info_flags & EV3_UART_INFO_FLAG_INFO_RAW) {
					port->mode_info[mode].raw_min =
						lego_sensor_ftoi(port->raw_min, 0);
					port->mode_info[mode].raw_max =
						lego_sensor_ftoi(port->raw_max, 0);
				}
				if (port->info_flags & EV3_UART_INFO_FLAG_INFO_PCT) {
					port->mode_info[mode].pct_min =
						lego_sensor_ftoi(port->pct_min, 0);
					port->mode_info[mode].pct_max =
						lego_sensor_ftoi(port->pct_max, 0);
				}
				if (port->info_flags & EV3_UART_INFO_FLAG_INFO_SI) {
					port->mode_info[mode].si_min =
						lego_sensor_ftoi(port->si_min,
							port->mode_info[mode].decimals);
					port->mode_info[mode].si_max =
						lego_sensor_ftoi(port->si_max,
							port->mode_info[mode].decimals);
				}
				if (port->sensor.mode)
					port->sensor.mode--;
				debug_pr("mode %d - data_sets:%d, data_type:%d, figures:%d, decimals:%d\n",
					 mode, port->mode_info[mode].data_sets,
					 port->mode_info[mode].data_type,
					 port->mode_info[mode].figures,
					 port->mode_info[mode].decimals);
				debug_pr("raw_min: %d, raw_max: %d\n",
					 port->mode_info[mode].raw_min,
					 port->mode_info[mode].raw_max);
				debug_pr("pct_min: %d, pct_max: %d\n",
					 port->mode_info[mode].pct_min,
					 port->mode_info[mode].pct_max);
				debug_pr("si_min: %d, si_max: %d\n",
					 port->mode_info[mode].si_min,
					 port->mode_info[mode].si_max);
				break;
			}
			break;
		case EV3_UART_MSG_TYPE_DATA:
			debug_pr("DATA:%d\n", message[0] & EV3_UART_MSG_CMD_MASK);
			if (!port->info_done) {
				port->last_err = "Received DATA before INFO was complete.";
				goto err_invalid_state;
			}
			if (mode > EV3_UART_MODE_MAX) {
				port->last_err = "Invalid mode received.";
				goto err_invalid_state;
			}
			if (mode != port->sensor.mode) {
				if (mode == port->new_mode) {
					port->sensor.mode = mode;
					kobject_uevent(&port->sensor.dev.kobj,
						       KOBJ_CHANGE);
				} else {
					port->last_err = "Unexpected mode.";
					goto err_invalid_state;
				}
			}
			if (!completion_done(&port->set_mode_completion)
			    && mode == port->new_mode)
				complete(&port->set_mode_completion);
			memcpy(port->mode_info[mode].raw_data, message + 1, msg_size - 2);
			port->data_rec = 1;
			if (port->num_data_err)
				port->num_data_err--;
			break;
		}
err_bad_data_msg_checksum:
		count = CIRC_CNT(cb->head, cb->tail, EV3_UART_BUFFER_SIZE);
	}
	return;

err_invalid_state:
	port->synced = 0;
	port->new_baud_rate = EV3_UART_SPEED_MIN;
	schedule_work(&port->change_bitrate_work);
}
static void ev3_uart_write_wakeup(struct tty_struct *tty)
{
	debug_pr("%s\n", __func__);
}
int brickpi_get_values(struct brickpi_channel_data *ch_data)
{
	struct brickpi_data *data = ch_data->data;
	int i, j, err;
	u8 port_size[NUM_BRICKPI_PORT];

	if (data->closing)
		return 0;
	mutex_lock(&data->tx_mutex);
	data->tx_buffer_tail = BRICKPI_TX_BUFFER_TAIL_INIT;
	for (i = 0; i < NUM_BRICKPI_PORT; i++) {
		brickpi_append_tx(data, 1, ch_data->out_port[i].motor_use_offset);
		/* TODO: handle use_offset */
	}
	for (i = 0; i < NUM_BRICKPI_PORT; i++) {
		brickpi_append_tx(data, 1, ch_data->out_port[i].motor_enabled);
		brickpi_append_tx(data, 1, ch_data->out_port[i].motor_reversed);
		brickpi_append_tx(data, 8, ch_data->out_port[i].motor_speed);
	}
	for (i = 0; i < NUM_BRICKPI_PORT; i++) {
		struct brickpi_in_port_data *port = &ch_data->in_port[i];
		int num_msg = port->num_i2c_msg;

		if (port->sensor_type == BRICKPI_SENSOR_TYPE_NXT_I2C
			|| port->sensor_type == BRICKPI_SENSOR_TYPE_NXT_I2C_9V)
		{
			for (j = 0; j < num_msg; j++) {
				struct brickpi_i2c_msg_data *msg = &port->i2c_msg[j];

				if (!(msg->settings & BRICKPI_I2C_SAME)) {
					int k;

					brickpi_append_tx(data, 4, msg->write_size);
					brickpi_append_tx(data, 4, msg->read_size);
					for (k = 0; k < msg->write_size; k++) {
						brickpi_append_tx(data, 8, msg->write_data[k]);
					}
				}
			}
		}
	}
	err = brickpi_send_message(data, ch_data->address,
				   BRICK_PI_MESSAGE_GET_VALUES, 100);
	if (err < 0) {
		/* TODO: Set encoder offsets to 0 */
		mutex_unlock(&data->tx_mutex);
		return err;
	}

	data->rx_buffer_head = BRICKPI_RX_BUFFER_HEAD_INIT;
	port_size[BRICKPI_PORT_1] = brickpi_read_rx(data, 5);
	debug_pr("port_size[BRICKPI_PORT_1]: %u\n", port_size[BRICKPI_PORT_1]);
	port_size[BRICKPI_PORT_2] = brickpi_read_rx(data, 5);
	debug_pr("port_size[BRICKPI_PORT_2]: %u\n", port_size[BRICKPI_PORT_2]);
	for (i = 0; i < NUM_BRICKPI_PORT; i++) {
		u64 bits = brickpi_read_rx(data, port_size[i]);
		s64 position = bits >> 1;
		if (bits & 1)
			position *= -1;
		ch_data->out_port[i].motor_position = position;
		debug_pr("motor_position[%d]: %d\n", i, (int)position);
		if (ch_data->out_port[i].stop_at_target_position) {
			if (((ch_data->out_port[i].motor_reversed)
			     && position < (ch_data->out_port[i].target_position))
			    || (!(ch_data->out_port[i].motor_reversed)
			     && position > (ch_data->out_port[i].target_position)))
			{
				ch_data->out_port[i].motor_enabled = false;
			}
		}
	}
	for (i = 0; i < NUM_BRICKPI_PORT; i++) {
		s32 *sensor_values = ch_data->in_port[i].sensor_values;
		u8 *raw_data = ch_data->in_port[i].port.raw_data;

		switch (ch_data->in_port[i].sensor_type) {
		case BRICKPI_SENSOR_TYPE_NXT_TOUCH:
		case BRICKPI_SENSOR_TYPE_NXT_TOUCH_DEBOUNCED:
			sensor_values[0] = brickpi_read_rx(data, 1);
			break;
		case BRICKPI_SENSOR_TYPE_NXT_ULTRASONIC_CONT:
		case BRICKPI_SENSOR_TYPE_NXT_ULTRASONIC_SS:
			sensor_values[0] = brickpi_read_rx(data, 8);
			break;
		case BRICKPI_SENSOR_TYPE_NXT_COLOR_FULL:
			sensor_values[0] = brickpi_read_rx(data, 3);
			sensor_values[1] = brickpi_read_rx(data, 10);
			sensor_values[2] = brickpi_read_rx(data, 10);
			sensor_values[3] = brickpi_read_rx(data, 10);
			sensor_values[4] = brickpi_read_rx(data, 10);
			break;
		case BRICKPI_SENSOR_TYPE_NXT_I2C:
		case BRICKPI_SENSOR_TYPE_NXT_I2C_9V:
			sensor_values[0] = brickpi_read_rx(data,
					ch_data->in_port[i].num_i2c_msg);
			for (j = 0; j < ch_data->in_port[i].num_i2c_msg; j++) {
				if (sensor_values[0] & (1 << j)) {
					int k;
					struct brickpi_i2c_msg_data *msg =
						&ch_data->in_port[i].i2c_msg[j];
					for (k = 0; k < msg->read_size; k++) {
						msg->read_data[k] =
							brickpi_read_rx(data, 8);
					}
				}
			}
			break;
		case BRICKPI_SENSOR_TYPE_EV3_US_M0:
		case BRICKPI_SENSOR_TYPE_EV3_US_M1:
		case BRICKPI_SENSOR_TYPE_EV3_US_M2:
		case BRICKPI_SENSOR_TYPE_EV3_US_M3:
		case BRICKPI_SENSOR_TYPE_EV3_US_M4:
		case BRICKPI_SENSOR_TYPE_EV3_US_M5:
		case BRICKPI_SENSOR_TYPE_EV3_US_M6:
		case BRICKPI_SENSOR_TYPE_EV3_COLOR_M0:
		case BRICKPI_SENSOR_TYPE_EV3_COLOR_M1:
		case BRICKPI_SENSOR_TYPE_EV3_COLOR_M2:
		case BRICKPI_SENSOR_TYPE_EV3_COLOR_M4:
		case BRICKPI_SENSOR_TYPE_EV3_COLOR_M5:
		case BRICKPI_SENSOR_TYPE_EV3_GYRO_M0:
		case BRICKPI_SENSOR_TYPE_EV3_GYRO_M1:
		case BRICKPI_SENSOR_TYPE_EV3_GYRO_M2:
		case BRICKPI_SENSOR_TYPE_EV3_GYRO_M4:
		case BRICKPI_SENSOR_TYPE_EV3_INFRARED_M0:
		case BRICKPI_SENSOR_TYPE_EV3_INFRARED_M1:
		case BRICKPI_SENSOR_TYPE_EV3_INFRARED_M3:
		case BRICKPI_SENSOR_TYPE_EV3_INFRARED_M4:
		case BRICKPI_SENSOR_TYPE_EV3_INFRARED_M5:
			sensor_values[0] = brickpi_read_rx(data, 16);
			/*
			 * There is a race condition in the BrickPi firmware v2 that
			 * causes these errors to be returned quite frequently. This
			 * is unfortunate because these may actually be legitimate
			 * values. Hopefully this can be fixed in future versions
			 * of the frimware, in which case we can add a version check
			 * here. But for now, we just ignore these values.
			 */
			if (sensor_values[0] == (s16)(-2))
				continue;
			if (sensor_values[0] == (s16)(-4))
				continue;
			break;
		case BRICKPI_SENSOR_TYPE_EV3_COLOR_M3:
		case BRICKPI_SENSOR_TYPE_EV3_GYRO_M3:
		case BRICKPI_SENSOR_TYPE_EV3_INFRARED_M2:
			sensor_values[0] = brickpi_read_rx(data, 32);
			/* see comment above */
			if (sensor_values[0] == (s32)(-2))
				continue;
			if (sensor_values[0] == (s32)(-4))
				continue;
			break;
		case BRICKPI_SENSOR_TYPE_EV3_TOUCH:
		case BRICKPI_SENSOR_TYPE_EV3_TOUCH_DEBOUNCED:
			/*
			 * The EV3 Touch sensor returns a value of 0x07 or 0x10
			 * when pressed, so this converts it to an approx. mV
			 * value that is close enough for the ev3-analog-sensor
			 * driver to interpret correctly.
			 */
			sensor_values[0] = brickpi_read_rx(data, 16) << 8;
			break;
		default:
			/* NXT Analog expects value in mV */
			if (ch_data->in_port[i].sensor_type <= BRICKPI_SENSOR_TYPE_NXT_ANALOG_MAX)
				sensor_values[0] = brickpi_read_rx(data, 10) * 5000 / 1024;
			else
				sensor_values[0] = brickpi_read_rx(data, 10);
			break;
		}
		debug_pr("ch_data->sensor_values[%d][0]: %ld\n", i,
			 sensor_values[0]);

		if (!raw_data)
			continue;
		if (ch_data->in_port[i].sensor_type == BRICKPI_SENSOR_TYPE_NXT_I2C
			|| ch_data->in_port[i].sensor_type == BRICKPI_SENSOR_TYPE_NXT_I2C_9V)
		{
			memcpy(raw_data, ch_data->in_port[i].i2c_msg[0].read_data,
				ch_data->in_port[i].i2c_msg[0].read_size);
		} else {
			memcpy(raw_data, sensor_values,
			       sizeof(s32) * NUM_BRICKPI_SENSOR_VALUES);
		}
		lego_port_call_raw_data_func(&ch_data->in_port[i].port);
	}
	mutex_unlock(&data->tx_mutex);

	return 0;
}
static void legoev3_uart_receive_buf(struct tty_struct *tty,
                                     const unsigned char *cp, char *fp,
                                     int count)
{
	struct legoev3_uart_port_data *port = tty->disc_data;
	int i = 0;
	int j, speed;
	u8 cmd, cmd2, type, mode, msg_type, msg_size, chksum;

#ifdef DEBUG
	printk("received: ");
	for (i = 0; i < count; i++)
		printk("0x%02x ", cp[i]);
	printk(" (%d)\n", count);
	i=0;
#endif

	/*
	 * To get in sync with the data stream from the sensor, we look
	 * for a valid TYPE command.
	 */
	while (!port->synced) {
		if (i + 2 >= count)
			return;
		cmd = cp[i++];
		if (cmd != (LEGOEV3_UART_MSG_TYPE_CMD | LEGOEV3_UART_CMD_TYPE))
			continue;
		type = cp[i];
		if (!type || type > LEGOEV3_UART_TYPE_MAX)
			continue;
		chksum = 0xFF ^ cmd ^ type;
		if (cp[i + 1] != chksum)
			continue;
		port->ms.num_modes = 1;
		port->ms.num_view_modes = 1;
		for (j = 0; j <= MSENSOR_MODE_MAX; j++)
			port->mode_info[j] = legoev3_uart_default_mode_info;
		port->ms.type_id = type;
		port->info_flags = LEGOEV3_UART_INFO_FLAG_CMD_TYPE;
		port->synced = 1;
		port->info_done = 0;
		port->write_ptr = 0;
		port->data_rec = 0;
		port->num_data_err = 0;
		i += 2;
	}
	if (!port->synced)
		return;

	/*
	 * Once we are synced, we keep reading data until we have read
	 * a complete command.
	 */
	while (i < count) {
		if (port->write_ptr >= LEGOEV3_UART_BUFFER_SIZE) {
			port->last_err = "Receive buffer overrun.";
			goto err_invalid_state;
		}
		port->buffer[port->write_ptr++] = cp[i++];
	}

	/*
	 * Process all complete messages that have been received.
	 */
	while ((msg_size = legoev3_uart_msg_size(port->buffer[0]))
	        <= port->write_ptr)
	{
#ifdef DEBUG
		printk("processing: ");
		for (i = 0; i < port->write_ptr; i++)
			printk("0x%02x ", port->buffer[i]);
		printk(" (%d)\n", port->write_ptr);
		printk("msg_size:%d\n", msg_size);
#endif
		/*
		 * The IR sensor sends 0xFF after SYNC (0x00). If these two
		 * bytes get split between two interrupts, then it will throw
		 * us off and prevent the sensor from being recognized. So,
		 * if the first byte is 0xFF, we just ignore it and continue
		 * with our loop.
		 */
		if (port->buffer[0] == 0xFF) {
			msg_size = 1;
			goto err_split_sync_checksum;
		}
		if (msg_size > MSENSOR_RAW_DATA_SIZE + 2) {
			port->last_err = "Bad message size.";
			goto err_invalid_state;
		}
		msg_type = port->buffer[0] & LEGOEV3_UART_MSG_TYPE_MASK;
		cmd = port->buffer[0] & LEGOEV3_UART_MSG_CMD_MASK;
		mode = cmd;
		cmd2 = port->buffer[1];
		if (msg_size > 1) {
			chksum = 0xFF;
			for (i = 0; i < msg_size - 1; i++)
				chksum ^= port->buffer[i];
			debug_pr("chksum:%d, actual:%d\n",
			         chksum, port->buffer[msg_size - 1]);
			/*
			 * The LEGO EV3 color sensor (type 29) sends bad checksums
			 * for RGB-RAW data (mode 4). The check here could be
			 * improved if someone can find a pattern.
			 */
			if (chksum != port->buffer[msg_size - 1]
			    && port->ms.type_id != 29 && port->buffer[0] != 0xDC)
			{
				port->last_err = "Bad checksum.";
				if (port->info_done) {
					port->num_data_err++;
					goto err_bad_data_msg_checksum;
				} else
					goto err_invalid_state;
			}
		}
		switch (msg_type) {
		case LEGOEV3_UART_MSG_TYPE_SYS:
			debug_pr("SYS:%d\n", port->buffer[0] & LEGOEV3_UART_MSG_CMD_MASK);
			switch(cmd) {
			case LEGOEV3_UART_SYS_SYNC:
				/* IR sensor (type 33) sends checksum after SYNC */
				if (msg_size > 1 && (cmd ^ cmd2) == 0xFF)
					msg_size++;
				break;
			case LEGOEV3_UART_SYS_ACK:
				if (!port->ms.num_modes) {
					port->last_err = "Received ACK before all mode INFO.";
					goto err_invalid_state;
				}
				if ((port->info_flags & LEGOEV3_UART_INFO_FLAG_REQUIRED)
				    != LEGOEV3_UART_INFO_FLAG_REQUIRED)
				{
					port->last_err = "Did not receive all required INFO.";
					goto err_invalid_state;
				}
				schedule_delayed_work(&port->send_ack_work,
				                      msecs_to_jiffies(LEGOEV3_UART_SEND_ACK_DELAY));
				port->info_done = 1;
				break;
			}
			break;
		case LEGOEV3_UART_MSG_TYPE_CMD:
			debug_pr("CMD:%d\n", cmd);
			switch (cmd) {
			case LEGOEV3_UART_CMD_MODES:
				if (test_and_set_bit(LEGOEV3_UART_INFO_BIT_CMD_MODES,
						     &port->info_flags))
				{
					port->last_err = "Received duplicate modes INFO.";
					goto err_invalid_state;
				}
				if (!cmd2 || cmd2 > MSENSOR_MODE_MAX) {
					port->last_err = "Number of modes is out of range.";
					goto err_invalid_state;
				}
				port->ms.num_modes = cmd2 + 1;
				if (msg_size > 3)
					port->ms.num_view_modes = port->buffer[2] + 1;
				else
					port->ms.num_view_modes = port->ms.num_modes;
				debug_pr("num_modes:%d, num_view_modes:%d\n",
					 port->ms.num_modes, port->ms.num_view_modes);
				break;
			case LEGOEV3_UART_CMD_SPEED:
				if (test_and_set_bit(LEGOEV3_UART_INFO_BIT_CMD_SPEED,
						     &port->info_flags))
				{
					port->last_err = "Received duplicate speed INFO.";
					goto err_invalid_state;
				}
				speed = *(int*)(port->buffer + 1);
				if (speed < LEGOEV3_UART_SPEED_MIN
				    || speed > LEGOEV3_UART_SPEED_MAX)
				{
					port->last_err = "Speed is out of range.";
					goto err_invalid_state;
				}
				port->new_baud_rate = speed;
				debug_pr("speed:%d\n", speed);
				break;
			default:
				port->last_err = "Unknown command.";
				goto err_invalid_state;
			}
			break;
		case LEGOEV3_UART_MSG_TYPE_INFO:
			debug_pr("INFO:%d, mode:%d\n", cmd2, mode);
			switch (cmd2) {
			case LEGOEV3_UART_INFO_NAME:
				port->info_flags &= ~LEGOEV3_UART_INFO_FLAG_ALL_INFO;
				if (port->buffer[2] < 'A' || port->buffer[2] > 'z') {
					port->last_err = "Invalid name INFO.";
					goto err_invalid_state;
				}
				/*
				 * Name may not have null terminator and we
				 * are done with the checksum at this point
				 * so we are writing 0 over the checksum to
				 * ensure a null terminator for the string
				 * functions.
				 */
				port->buffer[msg_size - 1] = 0;
				if (strlen(port->buffer + 2) > LEGOEV3_UART_MODE_NAME_SIZE) {
					port->last_err = "Name is too long.";
					goto err_invalid_state;
				}
				snprintf(port->mode_info[mode].name,
				         LEGOEV3_UART_MODE_NAME_SIZE + 1, "%s",
				         port->buffer + 2);
				port->mode = mode;
				port->info_flags |= LEGOEV3_UART_INFO_FLAG_INFO_NAME;
				debug_pr("mode %d name:%s\n",
				       mode, port->mode_info[mode].port_name);
				break;
			case LEGOEV3_UART_INFO_RAW:
				if (port->mode != mode) {
					port->last_err = "Received INFO for incorrect mode.";
					goto err_invalid_state;
				}
				if (test_and_set_bit(LEGOEV3_UART_INFO_BIT_INFO_RAW,
						     &port->info_flags))
				{
					port->last_err = "Received duplicate raw scaling INFO.";
					goto err_invalid_state;
				}
				port->raw_min = *(u32 *)(port->buffer + 2);
				port->raw_max = *(u32 *)(port->buffer + 6);
				debug_pr("mode %d raw_min:%08x, raw_max:%08x\n",
				       mode, port->mode_info[mode].raw_min,
				       port->mode_info[mode].raw_max);
				break;
			case LEGOEV3_UART_INFO_PCT:
				if (port->mode != mode) {
					port->last_err = "Received INFO for incorrect mode.";
					goto err_invalid_state;
				}
				if (test_and_set_bit(LEGOEV3_UART_INFO_BIT_INFO_PCT,
						     &port->info_flags))
				{
					port->last_err = "Received duplicate percent scaling INFO.";
					goto err_invalid_state;
				}
				port->pct_min = *(u32 *)(port->buffer + 2);
				port->pct_max = *(u32 *)(port->buffer + 6);
				debug_pr("mode %d pct_min:%08x, pct_max:%08x\n",
				       mode, port->mode_info[mode].pct_min,
				       port->mode_info[mode].pct_max);
				break;
			case LEGOEV3_UART_INFO_SI:
				if (port->mode != mode) {
					port->last_err = "Received INFO for incorrect mode.";
					goto err_invalid_state;
				}
				if (test_and_set_bit(LEGOEV3_UART_INFO_BIT_INFO_SI,
						     &port->info_flags))
				{
					port->last_err = "Received duplicate SI scaling INFO.";
					goto err_invalid_state;
				}
				port->si_min = *(u32 *)(port->buffer + 2);
				port->si_max = *(u32 *)(port->buffer + 6);
				debug_pr("mode %d si_min:%08x, si_max:%08x\n",
				       mode, port->mode_info[mode].si_min,
				       port->mode_info[mode].si_max);
				break;
			case LEGOEV3_UART_INFO_UNITS:
				if (port->mode != mode) {
					port->last_err = "Received INFO for incorrect mode.";
					goto err_invalid_state;
				}
				if (test_and_set_bit(LEGOEV3_UART_INFO_BIT_INFO_UNITS,
						     &port->info_flags))
				{
					port->last_err = "Received duplicate SI units INFO.";
					goto err_invalid_state;
				}
				/*
				 * Units may not have null terminator and we
				 * are done with the checksum at this point
				 * so we are writing 0 over the checksum to
				 * ensure a null terminator for the string
				 * functions.
				 */
				port->buffer[msg_size - 1] = 0;
				snprintf(port->mode_info[mode].units,
					 MSENSOR_UNITS_SIZE + 1, "%s",
					 port->buffer + 2);
				debug_pr("mode %d units:%s\n",
				       mode, port->mode_info[mode].units);
				break;
			case LEGOEV3_UART_INFO_FORMAT:
				if (port->mode != mode) {
					port->last_err = "Received INFO for incorrect mode.";
					goto err_invalid_state;
				}
				if (test_and_set_bit(LEGOEV3_UART_INFO_BIT_INFO_FORMAT,
						     &port->info_flags))
				{
					port->last_err = "Received duplicate format INFO.";
					goto err_invalid_state;
				}
				port->mode_info[mode].data_sets = port->buffer[2];
				if (!port->mode_info[mode].data_sets) {
					port->last_err = "Invalid number of data sets.";
					goto err_invalid_state;
				}
				if (msg_size < 7) {
					port->last_err = "Invalid format message size.";
					goto err_invalid_state;
				}
				if ((port->info_flags & LEGOEV3_UART_INFO_FLAG_REQUIRED)
						!= LEGOEV3_UART_INFO_FLAG_REQUIRED) {
					port->last_err = "Did not receive all required INFO.";
					goto err_invalid_state;
				}
				switch (port->buffer[3]) {
				case LEGOEV3_UART_DATA_8:
					port->mode_info[mode].data_type =
					(port->mode_info[mode].si_min < 0) ?
						MSENSOR_DATA_S8 : MSENSOR_DATA_U8;
					break;
				case LEGOEV3_UART_DATA_16:
					port->mode_info[mode].data_type =
					(port->mode_info[mode].si_min < 0) ?
						MSENSOR_DATA_S16 : MSENSOR_DATA_U16;
					break;
				case LEGOEV3_UART_DATA_32:
					port->mode_info[mode].data_type =
					(port->mode_info[mode].si_min < 0) ?
						MSENSOR_DATA_S32 : MSENSOR_DATA_U32;
					break;
				case LEGOEV3_UART_DATA_FLOAT:
					port->mode_info[mode].data_type =
						MSENSOR_DATA_FLOAT;
					break;
				default:
					port->last_err = "Invalid data type.";
					goto err_invalid_state;
				}
				port->mode_info[mode].figures = port->buffer[4];
				port->mode_info[mode].decimals = port->buffer[5];
				if (port->info_flags & LEGOEV3_UART_INFO_FLAG_INFO_RAW) {
					port->mode_info[mode].raw_min =
						msensor_ftoi(port->raw_min,
							port->mode_info[mode].decimals);
					port->mode_info[mode].raw_max =
						msensor_ftoi(port->raw_max,
							port->mode_info[mode].decimals);
				}
				if (port->info_flags & LEGOEV3_UART_INFO_FLAG_INFO_PCT) {
					port->mode_info[mode].pct_min =
						msensor_ftoi(port->pct_min,
							port->mode_info[mode].decimals);
					port->mode_info[mode].pct_max =
						msensor_ftoi(port->pct_max,
							port->mode_info[mode].decimals);
				}
				if (port->info_flags & LEGOEV3_UART_INFO_FLAG_INFO_SI) {
					port->mode_info[mode].si_min =
						msensor_ftoi(port->si_min,
							port->mode_info[mode].decimals);
					port->mode_info[mode].si_max =
						msensor_ftoi(port->si_max,
							port->mode_info[mode].decimals);
				}
				if (port->mode)
					port->mode--;
				debug_pr("mode %d data_sets:%d, data_type:%d, figures:%d, decimals:%d\n",
					mode, port->mode_info[mode].data_sets,
					port->mode_info[mode].data_type,
					port->mode_info[mode].figures,
					port->mode_info[mode].decimals);
				break;
			}
			break;
		case LEGOEV3_UART_MSG_TYPE_DATA:
			debug_pr("DATA:%d\n", port->buffer[0] & LEGOEV3_UART_MSG_CMD_MASK);
			if (!port->info_done) {
				port->last_err = "Received DATA before INFO was complete.";
				goto err_invalid_state;
			}
			if (mode > MSENSOR_MODE_MAX) {
				port->last_err = "Invalid mode received.";
				goto err_invalid_state;
			}
			port->mode = mode;
			memcpy(port->mode_info[mode].raw_data,
			       port->buffer + 1, msg_size - 2);
			port->data_rec = 1;
			if (port->num_data_err)
				port->num_data_err--;
			break;
		}

err_bad_data_msg_checksum:
		if (port->info_done && port->num_data_err > LEGOEV3_UART_MAX_DATA_ERR)
			goto err_invalid_state;
err_split_sync_checksum:
		/*
		 * If there is leftover data, we move it to the beginning
		 * of the buffer.
		 */
		for (i = 0; i + msg_size < port->write_ptr; i++)
			port->buffer[i] = port->buffer[i + msg_size];
		port->write_ptr = i;
	}
	return;

err_invalid_state:
	port->synced = 0;
	port->new_baud_rate = LEGOEV3_UART_SPEED_MIN;
	schedule_delayed_work(&port->change_bitrate_work,
	                      msecs_to_jiffies(LEGOEV3_UART_SET_BITRATE_DELAY));
}