linux-kernel - [PATCH 13/21 v5] Input: atmel_mxt_ts - read ID information block in one i2c transaction

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Message-Id: <1340693829-18665-14-git-send-email-djkurtz@chromium.org>
Date:	Tue, 26 Jun 2012 14:57:01 +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
Cc:	Iiro Valkonen <iiro.valkonen@...el.com>,
	Benson Leung <bleung@...omium.org>,
	Yufeng Shen <miletus@...omium.org>,
	Olof Johansson <olofj@...omium.org>,
	linux-kernel@...r.kernel.org, Daniel Kurtz <djkurtz@...omium.org>
Subject: [PATCH 13/21 v5] Input: atmel_mxt_ts - read ID information block in one i2c transaction

Reading the whole info block in one i2c transaction speeds up driver
probe significantly, especially on slower i2c busses.

Signed-off-by: Daniel Kurtz <djkurtz@...omium.org>
---
 drivers/input/touchscreen/atmel_mxt_ts.c |   26 +++-----------------------
 1 files changed, 3 insertions(+), 23 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index c16fd9c..07e0238 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -36,6 +36,7 @@
 #define MXT_FW_NAME		"maxtouch.fw"
 
 /* Registers */
+#define MXT_INFO		0x00
 #define MXT_FAMILY_ID		0x00
 #define MXT_VARIANT_ID		0x01
 #define MXT_VERSION		0x02
@@ -759,32 +760,11 @@ static int mxt_get_info(struct mxt_data *data)
 	struct i2c_client *client = data->client;
 	struct mxt_info *info = &data->info;
 	int error;
-	u8 val;
-
-	error = mxt_read_reg(client, MXT_FAMILY_ID, &val);
-	if (error)
-		return error;
-	info->family_id = val;
-
-	error = mxt_read_reg(client, MXT_VARIANT_ID, &val);
-	if (error)
-		return error;
-	info->variant_id = val;
-
-	error = mxt_read_reg(client, MXT_VERSION, &val);
-	if (error)
-		return error;
-	info->version = val;
-
-	error = mxt_read_reg(client, MXT_BUILD, &val);
-	if (error)
-		return error;
-	info->build = val;
 
-	error = mxt_read_reg(client, MXT_OBJECT_NUM, &val);
+	/* Read 7-byte info block starting at address 0 */
+	error = __mxt_read_reg(client, MXT_INFO, sizeof(*info), info);
 	if (error)
 		return error;
-	info->object_num = val;
 
 	return 0;
 }
-- 
1.7.7.3

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