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i2c: piix4: Use usleep_range() 

The piix4 i2c driver is extremely slow. Replacing msleep()
with usleep_range() increases its speed substantially.
Use sleep ranges similar to those used in the i2c-801 driver
to keep things simple.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Guenter Roeck 2018-02-26 12:46:52 -08:00 committed by Wolfram Sang
parent be5b928038
commit 0e89b2fec7
1 changed files with 3 additions and 3 deletions
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6
drivers/i2c/busses/i2c-piix4.c
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@ -462,13 +462,13 @@ static int piix4_transaction(struct i2c_adapter *piix4_adapter)
/* We will always wait for a fraction of a second! (See PIIX4 docs errata) */
if (srvrworks_csb5_delay) /* Extra delay for SERVERWORKS_CSB5 */
msleep(2);
usleep_range(2000, 2100);
else
msleep(1);
usleep_range(250, 500);
while ((++timeout < MAX_TIMEOUT) &&
((temp = inb_p(SMBHSTSTS)) & 0x01))
msleep(1);
usleep_range(250, 500);
/* If the SMBus is still busy, we give up */
if (timeout == MAX_TIMEOUT) {