From 3fd306c85adcde7209281cb663dd8ea247e97cc3 Mon Sep 17 00:00:00 2001 From: Jan Weitzel Date: Wed, 2 Nov 2011 13:40:02 -0700 Subject: w1: disable irqs in critical section Interrupting w1_delay() in w1_read_bit() results in missing the low level on the w1 line and receiving "1" instead of "0". Add local_irq_save()/local_irq_restore() around the critical section Signed-off-by: Jan Weitzel Acked-by: Evgeniy Polyakov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/w1/w1_io.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'drivers/w1/w1_io.c') diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c index 765b37b62a4f..3135b2c63998 100644 --- a/drivers/w1/w1_io.c +++ b/drivers/w1/w1_io.c @@ -158,13 +158,18 @@ EXPORT_SYMBOL_GPL(w1_write_8); static u8 w1_read_bit(struct w1_master *dev) { int result; + unsigned long flags; + /* sample timing is critical here */ + local_irq_save(flags); dev->bus_master->write_bit(dev->bus_master->data, 0); w1_delay(6); dev->bus_master->write_bit(dev->bus_master->data, 1); w1_delay(9); result = dev->bus_master->read_bit(dev->bus_master->data); + local_irq_restore(flags); + w1_delay(55); return result & 0x1; -- cgit v1.2.3