linux-kernel - [PATCH 11/16 v2] Input: atmel_mxt_ts

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Message-Id: <1333039766-8617-12-git-send-email-djkurtz@chromium.org>
Date:	Fri, 30 Mar 2012 00:49:21 +0800
From:	Daniel Kurtz <djkurtz@...omium.org>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Henrik Rydberg <rydberg@...omail.se>,
	Joonyoung Shim <jy0922.shim@...sung.com>,
	Nick Dyer <nick.dyer@...ev.co.uk>, linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org, Benson Leung <bleung@...omium.org>,
	Yufeng Shen <miletus@...omium.org>
Cc:	Daniel Kurtz <djkurtz@...omium.org>
Subject: [PATCH 11/16 v2] Input: atmel_mxt_ts - refactor reading object table

Instead of reading each object separately, fetch the whole table in one
large i2c transaction.  A 6 byte table object requires 10 bytes to read,
so doing this dramatically reduces overhead.

Also, as a cleanup, move object_table allocation (and post-fw-update
reallocation) into mxt_get_object_table().

Signed-off-by: Daniel Kurtz <djkurtz@...omium.org>
---
 drivers/input/touchscreen/atmel_mxt_ts.c |   66 +++++++++++++++---------------
 1 files changed, 33 insertions(+), 33 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 9d88faf..0d0dab6 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -437,14 +437,7 @@ static int mxt_write_reg(struct i2c_client *client, u16 reg, u16 len,
 	return 0;
 }
 
-static int mxt_read_object_table(struct i2c_client *client,
-				      u16 reg, u8 *object_buf)
-{
-	return mxt_read_reg(client, reg, MXT_OBJECT_SIZE, object_buf);
-}
-
-static struct mxt_object *
-mxt_get_object(struct mxt_data *data, u8 type)
+static struct mxt_object *mxt_get_object(struct mxt_data *data, u8 type)
 {
 	struct mxt_object *object;
 	int i;
@@ -733,25 +726,41 @@ static void mxt_handle_pdata(struct mxt_data *data)
 
 static int mxt_get_object_table(struct mxt_data *data)
 {
+	struct i2c_client *client = data->client;
+	struct device *dev = &client->dev;
 	int error;
 	int i;
-	u16 reg;
 	u8 reportid = 0;
-	u8 buf[MXT_OBJECT_SIZE];
+	u8 *buf;
+	size_t buf_size;
 
-	for (i = 0; i < data->info.object_num; i++) {
-		struct mxt_object *object = data->object_table + i;
+	/* Free old object table, if there was one. */
+	kfree(data->object_table);
+	data->object_table = kcalloc(data->info.object_num,
+				     sizeof(struct mxt_object), GFP_KERNEL);
+	if (!data->object_table) {
+		dev_err(dev, "Failed to allocate object table\n");
+		return -ENOMEM;
+	}
 
-		reg = MXT_OBJECT_START + MXT_OBJECT_SIZE * i;
-		error = mxt_read_object_table(data->client, reg, buf);
-		if (error)
-			return error;
+	buf_size = MXT_OBJECT_SIZE * data->info.object_num;
+	buf = kmalloc(buf_size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
 
-		object->type = buf[0];
-		object->start_address = (buf[2] << 8) | buf[1];
-		object->size = buf[3] + 1;
-		object->instances = buf[4] + 1;
-		object->num_report_ids = buf[5];
+	error = mxt_read_reg(client, MXT_OBJECT_START, buf_size, buf);
+	if (error)
+		goto done;
+
+	for (i = 0; i < data->info.object_num; i++) {
+		struct mxt_object *object = &data->object_table[i];
+		u8 *obj_buf = &buf[i * MXT_OBJECT_SIZE];
+
+		object->type = obj_buf[0];
+		object->start_address = (obj_buf[2] << 8) | obj_buf[1];
+		object->size = obj_buf[3] + 1;
+		object->instances = obj_buf[4] + 1;
+		object->num_report_ids = obj_buf[5];
 
 		if (object->num_report_ids) {
 			reportid += object->num_report_ids * object->instances;
@@ -759,7 +768,9 @@ static int mxt_get_object_table(struct mxt_data *data)
 		}
 	}
 
-	return 0;
+done:
+	kfree(buf);
+	return error;
 }
 
 static int mxt_initialize(struct mxt_data *data)
@@ -774,14 +785,6 @@ static int mxt_initialize(struct mxt_data *data)
 	if (error)
 		return error;
 
-	data->object_table = kcalloc(info->object_num,
-				     sizeof(struct mxt_object),
-				     GFP_KERNEL);
-	if (!data->object_table) {
-		dev_err(&client->dev, "Failed to allocate memory\n");
-		return -ENOMEM;
-	}
-
 	/* Get object table information */
 	error = mxt_get_object_table(data);
 	if (error)
@@ -971,9 +974,6 @@ static ssize_t mxt_update_fw_store(struct device *dev,
 		/* Wait for reset */
 		msleep(MXT_FWRESET_TIME);
 
-		kfree(data->object_table);
-		data->object_table = NULL;
-
 		mxt_initialize(data);
 	}
 
-- 
1.7.7.3

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