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>
diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 869065c..215ffe1 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/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 @@
 	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 @@
 	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 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 @@
 	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 @@
 
 	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 @@
 	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 @@
 	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 @@
 	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 @@
 	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 @@
 	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 @@
 			 * 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 @@
 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 @@
 	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 @@
 			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 @@
 			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 @@
 	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 @@
 	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;