[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>

3 files changed, 27 insertions, 9 deletions

diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c
index 00f032220173..e2a043354ddf 100644
--- a/drivers/w1/w1_io.c
+++ b/drivers/w1/w1_io.c
@@ -277,6 +277,29 @@ void w1_search_devices(struct w1_master *dev, w1_slave_found_callback cb)
                 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_delay);
 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 af5829778aaa..232860184a29 100644
--- a/drivers/w1/w1_io.h
+++ b/drivers/w1/w1_io.h
@@ -34,5 +34,6 @@ u8 w1_calc_crc8(u8 *, int);
 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 2259f3d851ff..2ed0e0f48268 100644
--- a/drivers/w1/w1_therm.c
+++ b/drivers/w1/w1_therm.c
@@ -176,15 +176,10 @@ static ssize_t w1_therm_read_bin(struct kobject *kobj, char *buf, loff_t off, si
         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 @@ static ssize_t w1_therm_read_bin(struct kobject *kobj, char *buf, loff_t off, si
                                         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 @@ static ssize_t w1_therm_read_bin(struct kobject *kobj, char *buf, loff_t off, si
 
                                 if (rom[8] == crc && rom[0])
                                         verdict = 1;
-
                         }
                 }