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: Jean Delvare <[email protected]> Cc: Olivier Sobrie <[email protected]> --- drivers/i2c/busses/i2c-i801.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) --- linux-3.3-rc1.orig/drivers/i2c/busses/i2c-i801.c 2012-01-24 16:55:37.734394612 +0100 +++ linux-3.3-rc1/drivers/i2c/busses/i2c-i801.c 2012-01-24 17:51:00.921443870 +0100 @@ -2,7 +2,7 @@ Copyright (c) 1998 - 2002 Frodo Looijaard <[email protected]>, Philip Edelbrock <[email protected]>, and Mark D. Studebaker <[email protected]> - Copyright (C) 2007, 2008 Jean Delvare <[email protected]> + Copyright (C) 2007 - 2012 Jean Delvare <[email protected]> Copyright (C) 2010 Intel Corporation, David Woodhouse <[email protected]> @@ -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_p 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_ /* 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_ 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_b /* 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; -- Jean Delvare -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
