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| author | Jan Weitzel <j.weitzel@phytec.de> | 2011-11-02 13:40:02 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-11-02 16:07:03 -0700 |
| commit | 3fd306c85adcde7209281cb663dd8ea247e97cc3 (patch) | |
| tree | 67bd829e0ef4e8e350af7fd06e4936bec616b49a /drivers/w1/w1_io.c | |
| parent | 68a436aec345c2bcd05dbdafae1f5f608ff8f61f (diff) | |
| download | lwn-3fd306c85adcde7209281cb663dd8ea247e97cc3.tar.gz lwn-3fd306c85adcde7209281cb663dd8ea247e97cc3.zip | |
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 <j.weitzel@phytec.de>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/w1/w1_io.c')
| -rw-r--r-- | drivers/w1/w1_io.c | 5 |
1 files changed, 5 insertions, 0 deletions
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; |