i2c: piix4: Use usleep_range() (0e89b2fe) · Commits · 戴 / test

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>

drivers/i2c/busses/i2c-piix4.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -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) {

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