From cadd486cfc838ead0ad899db129cff9f61ef4267 Mon Sep 17 00:00:00 2001 From: David Fries Date: Wed, 15 Oct 2008 22:05:01 -0700 Subject: W1: ds1wm.c msleep for reset Like the previous w1_io.c reset coments and msleep patch, I don't have the hardware to verify the change, but I think it is safe. It also helps to see a comment like this in the code. "We'll wait a bit longer just to be sure." If they are going to calculate delaying 324.9us, but actually delay 500us, why not just give up the CPU and sleep? This is designed for a battery powered ARM system, avoiding busywaiting has to be good for battery life. I sent a request for testers March 7, 2008 to the Linux kernel mailing list and two developers who have patches for ds1wm.c, but I didn't get any respons. Signed-off-by: David Fries Signed-off-by: Evgeniy Polyakov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/w1/masters/ds1wm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/w1') diff --git a/drivers/w1/masters/ds1wm.c b/drivers/w1/masters/ds1wm.c index ea894bf18113..29e144f81cbe 100644 --- a/drivers/w1/masters/ds1wm.c +++ b/drivers/w1/masters/ds1wm.c @@ -160,8 +160,10 @@ static int ds1wm_reset(struct ds1wm_data *ds1wm_data) * 625 us - 60 us - 240 us - 100 ns = 324.9 us * * We'll wait a bit longer just to be sure. + * Was udelay(500), but if it is going to busywait the cpu that long, + * might as well come back later. */ - udelay(500); + msleep(1); ds1wm_write_register(ds1wm_data, DS1WM_INT_EN, DS1WM_INTEN_ERBF | DS1WM_INTEN_ETMT | DS1WM_INTEN_EPD | -- cgit v1.2.3