tree 4b3b7aad0c8d20bea8a682162ee66f2ae2525c36
parent a8ab316ab12501908cc355fee6aff7065609f4e2
author Mariusz Bialonczyk <manio@skyboo.net> 1459269698 +0200
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1462136659 -0700

w1: enable active pullup for DS2482 by default

This commit enables the active pullup (APU bit) by default for
the DS2482 1-Wire master.

>From the DS2482 datasheet:
"The APU bit controls whether an active pullup (controlled slew-rate
transistor) or a passive pullup (Rwpu resistor) will be used to drive
a 1-Wire line from low to high. When APU = 0, active pullup is disabled
(resistor mode). Active Pullup should always be selected unless there is
only a single slave on the 1-Wire line."

According to the module author, Ben Gardner:
"It doesn't look like active pullup would cause any hurt if there
is only a single slave."
And my tests with multiple and single slaves on 1-Wire bus
confirms that.

This active pullup can be manually disabled using the introduced
module parameter:
  active_pullup = 0

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>