linux-kernel - [PATCH 2/8 v3] i2c: i801: optimize waiting for HWPEC to finish

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Message-Id: <1340805255-8041-3-git-send-email-djkurtz@chromium.org>
Date:	Wed, 27 Jun 2012 21:54:09 +0800
From:	Daniel Kurtz <djkurtz@...omium.org>
To:	Jean Delvare <khali@...ux-fr.org>, Ben Dooks <ben-linux@...ff.org>,
	Wolfram Sang <w.sang@...gutronix.de>,
	Seth Heasley <seth.heasley@...el.com>
Cc:	Olof Johansson <olof@...om.net>,
	Benson Leung <bleung@...omium.org>, linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org, Daniel Kurtz <djkurtz@...omium.org>
Subject: [PATCH 2/8 v3] i2c: i801: optimize waiting for HWPEC to finish

When a transaction has finished (including the PEC), the SMBus controller
sets the INTR bit.
Slightly optimize the polling loop by reading status before the first
sleep.

Signed-off-by: Daniel Kurtz <djkurtz@...omium.org>
---
 drivers/i2c/busses/i2c-i801.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 51e11eb..8b74e1e 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -291,11 +291,11 @@ static void i801_wait_hwpec(struct i801_priv *priv)
 	int timeout = 0;
 	int status;
 
-	do {
+	status = inb_p(SMBHSTSTS(priv));
+	while ((!(status & SMBHSTSTS_INTR)) && (timeout++ < MAX_RETRIES)) {
 		usleep_range(250, 500);
 		status = inb_p(SMBHSTSTS(priv));
-	} while ((!(status & SMBHSTSTS_INTR))
-		 && (timeout++ < MAX_RETRIES));
+	}
 
 	if (timeout > MAX_RETRIES)
 		dev_dbg(&priv->pci_dev->dev, "PEC Timeout!\n");
-- 
1.7.7.3

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