Input: atmel_mxt_ts - add support for dynamic message size

The T5 object may have various sizes depending on the objects used on the
particular maXTouch chip and firmware version, therefore it can't be
hardcoded in the driver. Allocate a buffer on probe instead.

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Acked-by: Benson Leung <bleung@chromium.org>
Acked-by: Yufeng Shen <miletus@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/atmel_mxt_ts.c

@@ -80,6 +80,9 @@
 #define MXT_SPT_MESSAGECOUNT_T44	44
 #define MXT_SPT_CTECONFIG_T46		46
 
+/* MXT_GEN_MESSAGE_T5 object */
+#define MXT_RPTID_NOMSG		0xff
+
 /* MXT_GEN_COMMAND_T6 field */
 #define MXT_COMMAND_RESET	0
 #define MXT_COMMAND_BACKUPNV	1
@@ -223,11 +226,6 @@ struct mxt_object {
 	u8 num_report_ids;
 } __packed;
 
-struct mxt_message {
-	u8 reportid;
-	u8 message[7];
-};
-
 /* Each client has this additional data */
 struct mxt_data {
 	struct i2c_client *client;
@@ -244,8 +242,10 @@ struct mxt_data {
 	u32 config_crc;
 	u32 info_crc;
 	u8 bootloader_addr;
+	u8 *msg_buf;
 
 	/* Cached parameters from object table */
+	u8 T5_msg_size;
 	u8 T6_reportid;
 	u16 T6_address;
 	u16 T7_address;
@@ -306,11 +306,10 @@ static bool mxt_object_readable(unsigned int type)
 	}
 }
 
-static void mxt_dump_message(struct device *dev,
-			     struct mxt_message *message)
+static void mxt_dump_message(struct mxt_data *data, u8 *message)
 {
-	dev_dbg(dev, "reportid: %u\tmessage: %*ph\n",
-		message->reportid, 7, message->message);
+	dev_dbg(&data->client->dev, "message: %*ph\n",
+		data->T5_msg_size, message);
 }
 
 static int mxt_wait_for_completion(struct mxt_data *data,
@@ -624,8 +623,7 @@ mxt_get_object(struct mxt_data *data, u8 type)
 	return NULL;
 }
 
-static int mxt_read_message(struct mxt_data *data,
-				 struct mxt_message *message)
+static int mxt_read_message(struct mxt_data *data, u8 *message)
 {
 	struct mxt_object *object;
 	u16 reg;
@@ -636,7 +634,7 @@ static int mxt_read_message(struct mxt_data *data,
 
 	reg = object->start_address;
 	return __mxt_read_reg(data->client, reg,
-			sizeof(struct mxt_message), message);
+			data->T5_msg_size, message);
 }
 
 static int mxt_write_object(struct mxt_data *data,
@@ -653,7 +651,7 @@ static int mxt_write_object(struct mxt_data *data,
 	return mxt_write_reg(data->client, reg + offset, val);
 }
 
-static void mxt_input_button(struct mxt_data *data, struct mxt_message *message)
+static void mxt_input_button(struct mxt_data *data, u8 *message)
 {
 	struct input_dev *input = data->input_dev;
 	const struct mxt_platform_data *pdata = data->pdata;
@@ -664,7 +662,7 @@ static void mxt_input_button(struct mxt_data *data, struct mxt_message *message)
 	for (i = 0; i < pdata->t19_num_keys; i++) {
 		if (pdata->t19_keymap[i] == KEY_RESERVED)
 			continue;
-		button = !(message->message[0] & (1 << i));
+		button = !(message[1] & (1 << i));
 		input_report_key(input, pdata->t19_keymap[i], button);
 	}
 }
@@ -676,19 +674,21 @@ static void mxt_input_sync(struct mxt_data *data)
 	input_sync(data->input_dev);
 }
 
-static void mxt_input_touchevent(struct mxt_data *data,
-				      struct mxt_message *message, int id)
+static void mxt_input_touchevent(struct mxt_data *data, u8 *message)
 {
 	struct device *dev = &data->client->dev;
-	u8 status = message->message[0];
 	struct input_dev *input_dev = data->input_dev;
+	int id;
+	u8 status;
 	int x;
 	int y;
 	int area;
 	int amplitude;
 
-	x = (message->message[1] << 4) | ((message->message[3] >> 4) & 0xf);
-	y = (message->message[2] << 4) | ((message->message[3] & 0xf));
+	id = message[0] - data->T9_reportid_min;
+	status = message[1];
+	x = (message[2] << 4) | ((message[4] >> 4) & 0xf);
+	y = (message[3] << 4) | ((message[4] & 0xf));
 
 	/* Handle 10/12 bit switching */
 	if (data->max_x < 1024)
@@ -696,8 +696,8 @@ static void mxt_input_touchevent(struct mxt_data *data,
 	if (data->max_y < 1024)
 		y >>= 2;
 
-	area = message->message[4];
-	amplitude = message->message[5];
+	area = message[5];
+	amplitude = message[6];
 
 	dev_dbg(dev,
 		"[%u] %c%c%c%c%c%c%c%c x: %5u y: %5u area: %3u amp: %3u\n",
@@ -743,28 +743,28 @@ static u16 mxt_extract_T6_csum(const u8 *csum)
 	return csum[0] | (csum[1] << 8) | (csum[2] << 16);
 }
 
-static bool mxt_is_T9_message(struct mxt_data *data, struct mxt_message *msg)
+static bool mxt_is_T9_message(struct mxt_data *data, u8 *msg)
 {
-	u8 id = msg->reportid;
+	u8 id = msg[0];
 	return (id >= data->T9_reportid_min && id <= data->T9_reportid_max);
 }
 
 static irqreturn_t mxt_process_messages_until_invalid(struct mxt_data *data)
 {
-	struct mxt_message message;
-	const u8 *payload = &message.message[0];
+	u8 *message = &data->msg_buf[0];
+	const u8 *payload = &data->msg_buf[1];
 	struct device *dev = &data->client->dev;
 	u8 reportid;
 	bool update_input = false;
 	u32 crc;
 
 	do {
-		if (mxt_read_message(data, &message)) {
+		if (mxt_read_message(data, message)) {
 			dev_err(dev, "Failed to read message\n");
 			return IRQ_NONE;
 		}
 
-		reportid = message.reportid;
+		reportid = message[0];
 
 		if (reportid == data->T6_reportid) {
 			u8 status = payload[0];
@@ -785,18 +785,17 @@ static irqreturn_t mxt_process_messages_until_invalid(struct mxt_data *data)
 			 * do not report events if input device
 			 * is not yet registered
 			 */
-			mxt_dump_message(dev, &message);
-		} else if (mxt_is_T9_message(data, &message)) {
-			int id = reportid - data->T9_reportid_min;
-			mxt_input_touchevent(data, &message, id);
+			mxt_dump_message(data, message);
+		} else if (mxt_is_T9_message(data, message)) {
+			mxt_input_touchevent(data, message);
 			update_input = true;
-		} else if (message.reportid == data->T19_reportid) {
-			mxt_input_button(data, &message);
+		} else if (reportid == data->T19_reportid) {
+			mxt_input_button(data, message);
 			update_input = true;
 		} else {
-			mxt_dump_message(dev, &message);
+			mxt_dump_message(data, message);
 		}
-	} while (reportid != 0xff);
+	} while (reportid != MXT_RPTID_NOMSG);
 
 	if (update_input)
 		mxt_input_sync(data);
@@ -1193,16 +1192,15 @@ release:
 static int mxt_make_highchg(struct mxt_data *data)
 {
 	struct device *dev = &data->client->dev;
-	struct mxt_message message;
 	int count = 10;
 	int error;
 
 	/* Read dummy message to make high CHG pin */
 	do {
-		error = mxt_read_message(data, &message);
+		error = mxt_read_message(data, data->msg_buf);
 		if (error)
 			return error;
-	} while (message.reportid != 0xff && --count);
+	} while (data->msg_buf[0] != MXT_RPTID_NOMSG && --count);
 
 	if (!count) {
 		dev_err(dev, "CHG pin isn't cleared\n");
@@ -1239,6 +1237,23 @@ static int mxt_get_info(struct mxt_data *data)
 	return 0;
 }
 
+static void mxt_free_object_table(struct mxt_data *data)
+{
+	input_unregister_device(data->input_dev);
+	data->input_dev = NULL;
+
+	kfree(data->object_table);
+	data->object_table = NULL;
+	kfree(data->msg_buf);
+	data->msg_buf = NULL;
+	data->T5_msg_size = 0;
+	data->T6_reportid = 0;
+	data->T7_address = 0;
+	data->T9_reportid_min = 0;
+	data->T9_reportid_max = 0;
+	data->T19_reportid = 0;
+}
+
 static int mxt_get_object_table(struct mxt_data *data)
 {
 	struct i2c_client *client = data->client;
@@ -1289,6 +1304,9 @@ static int mxt_get_object_table(struct mxt_data *data)
 			min_id, max_id);
 
 		switch (object->type) {
+		case MXT_GEN_MESSAGE_T5:
+			/* CRC not enabled, therefore don't read last byte */
+			data->T5_msg_size = mxt_obj_size(object) - 1;
 		case MXT_GEN_COMMAND_T6:
 			data->T6_reportid = min_id;
 			data->T6_address = object->start_address;
@@ -1312,22 +1330,20 @@ static int mxt_get_object_table(struct mxt_data *data)
 			data->mem_size = end_address + 1;
 	}
 
+	data->msg_buf = kzalloc(data->T5_msg_size, GFP_KERNEL);
+	if (!data->msg_buf) {
+		dev_err(&client->dev, "Failed to allocate message buffer\n");
+		error = -ENOMEM;
+		goto free_object_table;
+	}
+
 	data->object_table = object_table;
 
 	return 0;
-}
 
-static void mxt_free_object_table(struct mxt_data *data)
-{
-	input_unregister_device(data->input_dev);
-	data->input_dev = NULL;
-
-	kfree(data->object_table);
-	data->object_table = NULL;
-	data->T6_reportid = 0;
-	data->T9_reportid_min = 0;
-	data->T9_reportid_max = 0;
-	data->T19_reportid = 0;
+free_object_table:
+	mxt_free_object_table(data);
+	return error;
 }
 
 static int mxt_read_t9_resolution(struct mxt_data *data)
@@ -1963,7 +1979,7 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	return 0;
 
 err_free_object:
-	kfree(data->object_table);
+	mxt_free_object_table(data);
 err_free_irq:
 	free_irq(client->irq, data);
 err_free_mem:
@@ -1978,7 +1994,7 @@ static int mxt_remove(struct i2c_client *client)
 	sysfs_remove_group(&client->dev.kobj, &mxt_attr_group);
 	free_irq(data->irq, data);
 	input_unregister_device(data->input_dev);
-	kfree(data->object_table);
+	mxt_free_object_table(data);
 	kfree(data);
 
 	return 0;