Expose model and fw_version via sysfs. Also query the model
in probe to make sure, that the I2C communication with the
device works before successfully probing the driver.

Signed-off-by: Sebastian Reichel <redacted>
---
 drivers/input/touchscreen/exc3000.c | 136 ++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)

diff --git a/drivers/input/touchscreen/exc3000.c b/drivers/input/touchscreen/exc3000.c
index 7d695022082c..4c9f132629b9 100644
--- a/drivers/input/touchscreen/exc3000.c
+++ b/drivers/input/touchscreen/exc3000.c

@@ -41,6 +41,11 @@ struct exc3000_data {
 	struct touchscreen_properties prop;
 	struct timer_list timer;
 	u8 buf[2 * EXC3000_LEN_FRAME];
+	char model[11];
+	char fw_version[6];
+	struct completion wait_event;
+	struct mutex query_lock;
+	int query_result;
 };
 
 static void exc3000_report_slots(struct input_dev *input,

@@ -121,6 +126,35 @@ static int exc3000_read_data(struct i2c_client *client,
 	return 0;
 }
 
+static void exc3000_query_interrupt(struct exc3000_data *data)
+{
+	u8 *buf = data->buf;
+	int err;
+
+	data->query_result = 0;
+
+	err = i2c_master_recv(data->client, buf, EXC3000_LEN_FRAME);
+	if (err < 0) {
+		data->query_result = err;
+		goto out;
+	}
+
+	if (buf[0] == 0x42 && buf[4] == 'E') {
+		memcpy(data->model, buf+5, 10);
+		data->model[10] = '\0';
+		goto out;
+	} else if (buf[0] == 0x42 && buf[4] == 'D') {
+		memcpy(data->fw_version, buf+5, 5);
+		data->fw_version[5] = '\0';
+		goto out;
+	}
+
+	data->query_result = -EPROTO;
+
+out:
+	complete(&data->wait_event);
+}
+
 static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
 {
 	struct exc3000_data *data = dev_id;

@@ -129,6 +163,11 @@ static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
 	int slots, total_slots;
 	int error;
 
+	if (mutex_is_locked(&data->query_lock)) {
+		exc3000_query_interrupt(data);
+		goto out;
+	}
+
 	error = exc3000_read_data(data->client, buf, &total_slots);
 	if (error) {
 		/* Schedule a timer to release "stuck" contacts */

@@ -156,12 +195,92 @@ static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static int exc3000_get_fw_version(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct exc3000_data *data = dev_get_drvdata(dev);
+	static const u8 request[68] =
+		{0x67, 0x00, 0x42, 0x00, 0x03, 0x01, 'D', 0x00};
+	struct i2c_client *client = data->client;
+	int err;
+
+	mutex_lock(&data->query_lock);
+
+	data->query_result = -ETIMEDOUT;
+	reinit_completion(&data->wait_event);
+
+	err = i2c_master_send(client, request, sizeof(request));
+	if (err < 0) {
+		mutex_unlock(&data->query_lock);
+		return err;
+	}
+
+	wait_for_completion_interruptible_timeout(&data->wait_event, 1*HZ);
+	mutex_unlock(&data->query_lock);
+
+	if (data->query_result < 0)
+		return data->query_result;
+
+	return sprintf(buf, "%s\n", data->fw_version);
+}
+static DEVICE_ATTR(fw_version, S_IRUGO, exc3000_get_fw_version, NULL);
+
+static ssize_t exc3000_get_model(struct exc3000_data *data)
+{
+	static const u8 request[68] =
+		{0x67, 0x00, 0x42, 0x00, 0x03, 0x01, 'E', 0x00};
+	struct i2c_client *client = data->client;
+	int err;
+
+	mutex_lock(&data->query_lock);
+	data->query_result = -ETIMEDOUT;
+	reinit_completion(&data->wait_event);
+
+	err = i2c_master_send(client, request, sizeof(request));
+	if (err < 0) {
+		mutex_unlock(&data->query_lock);
+		return err;
+	}
+
+	wait_for_completion_interruptible_timeout(&data->wait_event, 1*HZ);
+	mutex_unlock(&data->query_lock);
+
+	return data->query_result;
+}
+
+static ssize_t exc3000_get_model_sysfs(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct exc3000_data *data = dev_get_drvdata(dev);
+	int err = exc3000_get_model(data);