mfd: cros_ec: spi: Calculate delay between transfers correctly

To avoid spamming the EC we calculate the time between the previous
transfer and the current transfer and force a delay if the time delta
is too small.

However, a small miscalculation causes the delay period to be
far too short. Most noticably this impacts commands with a long
turnaround time such as EC firmware reads and writes.

Signed-off-by: David Hendricks <[email protected]>
Signed-off-by: Doug Anderson <[email protected]>
Reviewed-by: Simon Glass <[email protected]>
Tested-by: Andrew Bresticker <[email protected]>
Tested-by: Stephen Warren <[email protected]>
Signed-off-by: Lee Jones <[email protected]>
This commit is contained in:
David Hendricks 2014-04-30 10:44:04 -07:00 • committed by Lee Jones
commit 1fe368665b

View file

@ -219,7 +219,7 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev,
ktime_get_ts(&ts);
delay = timespec_to_ns(&ts) - ec_spi->last_transfer_ns;
if (delay < EC_SPI_RECOVERY_TIME_NS)
ndelay(delay);
ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
}
/* Transmit phase - send our message */