[PATCH] w1: Added w1_reset_select_slave() - Resets the bus and then selects the slave by
sending either a skip rom or a rom match.
Patch from Ben Gardner <bgardner@wabtec.com>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c
index 00f0322..e2a0433 100644
--- a/drivers/w1/w1_io.c
+++ b/drivers/w1/w1_io.c
@@ -277,6 +277,29 @@
w1_search(dev, cb);
}
+/**
+ * Resets the bus and then selects the slave by sending either a skip rom
+ * or a rom match.
+ * The w1 master lock must be held.
+ *
+ * @param sl the slave to select
+ * @return 0=success, anything else=error
+ */
+int w1_reset_select_slave(struct w1_slave *sl)
+{
+ if (w1_reset_bus(sl->master))
+ return -1;
+
+ if (sl->master->slave_count == 1)
+ w1_write_8(sl->master, W1_SKIP_ROM);
+ else {
+ u8 match[9] = {W1_MATCH_ROM, };
+ memcpy(&match[1], (u8 *)&sl->reg_num, 8);
+ w1_write_block(sl->master, match, 9);
+ }
+ return 0;
+}
+
EXPORT_SYMBOL(w1_touch_bit);
EXPORT_SYMBOL(w1_write_8);
EXPORT_SYMBOL(w1_read_8);
@@ -286,3 +309,4 @@
EXPORT_SYMBOL(w1_read_block);
EXPORT_SYMBOL(w1_write_block);
EXPORT_SYMBOL(w1_search_devices);
+EXPORT_SYMBOL(w1_reset_select_slave);
diff --git a/drivers/w1/w1_io.h b/drivers/w1/w1_io.h
index af58297..2328601 100644
--- a/drivers/w1/w1_io.h
+++ b/drivers/w1/w1_io.h
@@ -34,5 +34,6 @@
void w1_write_block(struct w1_master *, const u8 *, int);
u8 w1_read_block(struct w1_master *, u8 *, int);
void w1_search_devices(struct w1_master *dev, w1_slave_found_callback cb);
+int w1_reset_select_slave(struct w1_slave *sl);
#endif /* __W1_IO_H */
diff --git a/drivers/w1/w1_therm.c b/drivers/w1/w1_therm.c
index 2259f3d..2ed0e0f4 100644
--- a/drivers/w1/w1_therm.c
+++ b/drivers/w1/w1_therm.c
@@ -176,15 +176,10 @@
crc = 0;
while (max_trying--) {
- if (!w1_reset_bus (dev)) {
+ if (!w1_reset_select_slave(sl)) {
int count = 0;
- u8 match[9] = {W1_MATCH_ROM, };
unsigned int tm = 750;
- memcpy(&match[1], (u64 *) & sl->reg_num, 8);
-
- w1_write_block(dev, match, 9);
-
w1_write_8(dev, W1_CONVERT_TEMP);
while (tm) {
@@ -193,8 +188,7 @@
flush_signals(current);
}
- if (!w1_reset_bus (dev)) {
- w1_write_block(dev, match, 9);
+ if (!w1_reset_select_slave(sl)) {
w1_write_8(dev, W1_READ_SCRATCHPAD);
if ((count = w1_read_block(dev, rom, 9)) != 9) {
@@ -205,7 +199,6 @@
if (rom[8] == crc && rom[0])
verdict = 1;
-
}
}