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Commit 84c1af4c authored by Jean Delvare's avatar Jean Delvare Committed by Jean Delvare
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i2c-i801: Use usleep_range to wait for command completion 



Use usleep_range instead of msleep when waiting for command
completion. Most SMBus commands complete in less than 2 jiffies so
this brings a pleasant performance boost.

Strongly inspired from a similar change by Olivier Sobrie to the
i2c-isch driver.

Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
Cc: Olivier Sobrie <olivier@sobrie.be>
parent 062737fb

drivers/i2c/busses/i2c-i801.c

+12 −12
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
    Copyright (c) 1998 - 2002  Frodo Looijaard <frodol@dds.nl>,

    Philip Edelbrock <phil@netroedge.com>, and Mark D. Studebaker

    <mdsxyz123@yahoo.com>

    Copyright (C) 2007, 2008   Jean Delvare <khali@linux-fr.org>

    Copyright (C) 2007 - 2012  Jean Delvare <khali@linux-fr.org>

    Copyright (C) 2010         Intel Corporation,

                               David Woodhouse <dwmw2@infradead.org>
@@ -106,7 +106,7 @@ 
#define SMBHSTCNT_KILL		2



/* Other settings */

#define MAX_TIMEOUT		100

#define MAX_RETRIES		400

#define ENABLE_INT9		0	/* set to 0x01 to enable - untested */



/* I801 command constants */
@@ -217,7 +217,7 @@ static int i801_check_post(struct i801_priv *priv, int status, int timeout) 
		dev_dbg(&priv->pci_dev->dev, "Terminating the current operation\n");

		outb_p(inb_p(SMBHSTCNT(priv)) | SMBHSTCNT_KILL,

		       SMBHSTCNT(priv));

		msleep(1);

		usleep_range(1000, 2000);

		outb_p(inb_p(SMBHSTCNT(priv)) & (~SMBHSTCNT_KILL),

		       SMBHSTCNT(priv));
@@ -274,11 +274,11 @@ static int i801_transaction(struct i801_priv *priv, int xact) 


	/* We will always wait for a fraction of a second! */

	do {

		msleep(1);

		usleep_range(250, 500);

		status = inb_p(SMBHSTSTS(priv));

	} while ((status & SMBHSTSTS_HOST_BUSY) && (timeout++ < MAX_TIMEOUT));

	} while ((status & SMBHSTSTS_HOST_BUSY) && (timeout++ < MAX_RETRIES));



	result = i801_check_post(priv, status, timeout > MAX_TIMEOUT);

	result = i801_check_post(priv, status, timeout > MAX_RETRIES);

	if (result < 0)

		return result;
@@ -293,12 +293,12 @@ static void i801_wait_hwpec(struct i801_priv *priv) 
	int status;



	do {

		msleep(1);

		usleep_range(250, 500);

		status = inb_p(SMBHSTSTS(priv));

	} while ((!(status & SMBHSTSTS_INTR))

		 && (timeout++ < MAX_TIMEOUT));

		 && (timeout++ < MAX_RETRIES));



	if (timeout > MAX_TIMEOUT)

	if (timeout > MAX_RETRIES)

		dev_dbg(&priv->pci_dev->dev, "PEC Timeout!\n");



	outb_p(status, SMBHSTSTS(priv));
@@ -382,12 +382,12 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, 
		/* We will always wait for a fraction of a second! */

		timeout = 0;

		do {

			msleep(1);

			usleep_range(250, 500);

			status = inb_p(SMBHSTSTS(priv));

		} while ((!(status & SMBHSTSTS_BYTE_DONE))

			 && (timeout++ < MAX_TIMEOUT));

			 && (timeout++ < MAX_RETRIES));



		result = i801_check_post(priv, status, timeout > MAX_TIMEOUT);

		result = i801_check_post(priv, status, timeout > MAX_RETRIES);

		if (result < 0)

			return result;