w1: add fast search for single slave bus
This enables a much more efficient way of device searching. It uses the
1-wire read-rom operation which allows the direct reading of the slave
address. BUT this works only with exactly one slave on the bus.
Signed-off-by: Hubert Feurstein <h.feurstein@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
index c374978..9761950 100644
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index c374978..9761950 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -892,6 +892,16 @@
break;
}
+ /* Do fast search on single slave bus */
+ if (dev->max_slave_count == 1) {
+ w1_write_8(dev, W1_READ_ROM);
+
+ if (w1_read_block(dev, (u8 *)&rn, 8) == 8 && rn)
+ cb(dev, rn);
+
+ break;
+ }
+
/* Start the search */
w1_write_8(dev, search_type);
for (i = 0; i < 64; ++i) {