drivers/power/ds2780_battery.c: add a nolock function to w1 interface

Adds a nolock function to the w1 interface to avoid locking the
mutex if needed.

Signed-off-by: Clifton Barnes <cabarnes@indesign-llc.com>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: <stable@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 37 insertions, 13 deletions

diff --git a/drivers/w1/slaves/w1_ds2780.c b/drivers/w1/slaves/w1_ds2780.c
index a134b38e34b2..39f78c0b143c 100644
--- a/drivers/w1/slaves/w1_ds2780.c
+++ b/drivers/w1/slaves/w1_ds2780.c
@@ -26,20 +26,14 @@
 #include "../w1_family.h"
 #include "w1_ds2780.h"
 
-int w1_ds2780_io(struct device *dev, char *buf, int addr, size_t count,
-                        int io)
+static int w1_ds2780_do_io(struct device *dev, char *buf, int addr,
+                        size_t count, int io)
 {
         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
 
-        if (!dev)
-                return -ENODEV;
+        if (addr > DS2780_DATA_SIZE || addr < 0)
+                return 0;
 
-        mutex_lock(&sl->master->mutex);
-
-        if (addr > DS2780_DATA_SIZE || addr < 0) {
-                count = 0;
-                goto out;
-        }
         count = min_t(int, count, DS2780_DATA_SIZE - addr);
 
         if (w1_reset_select_slave(sl) == 0) {
@@ -47,7 +41,6 @@ int w1_ds2780_io(struct device *dev, char *buf, int addr, size_t count,
                         w1_write_8(sl->master, W1_DS2780_WRITE_DATA);
                         w1_write_8(sl->master, addr);
                         w1_write_block(sl->master, buf, count);
-                        /* XXX w1_write_block returns void, not n_written */
                 } else {
                         w1_write_8(sl->master, W1_DS2780_READ_DATA);
                         w1_write_8(sl->master, addr);
@@ -55,13 +48,42 @@ int w1_ds2780_io(struct device *dev, char *buf, int addr, size_t count,
                 }
         }
 
-out:
+        return count;
+}
+
+int w1_ds2780_io(struct device *dev, char *buf, int addr, size_t count,
+                        int io)
+{
+        struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
+        int ret;
+
+        if (!dev)
+                return -ENODEV;
+
+        mutex_lock(&sl->master->mutex);
+
+        ret = w1_ds2780_do_io(dev, buf, addr, count, io);
+
         mutex_unlock(&sl->master->mutex);
 
-        return count;
+        return ret;
 }
 EXPORT_SYMBOL(w1_ds2780_io);
 
+int w1_ds2780_io_nolock(struct device *dev, char *buf, int addr, size_t count,
+                        int io)
+{
+        int ret;
+
+        if (!dev)
+                return -ENODEV;
+
+        ret = w1_ds2780_do_io(dev, buf, addr, count, io);
+
+        return ret;
+}
+EXPORT_SYMBOL(w1_ds2780_io_nolock);
+
 int w1_ds2780_eeprom_cmd(struct device *dev, int addr, int cmd)
 {
         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
diff --git a/drivers/w1/slaves/w1_ds2780.h b/drivers/w1/slaves/w1_ds2780.h
index a1fba79eb1b5..737379365021 100644
--- a/drivers/w1/slaves/w1_ds2780.h
+++ b/drivers/w1/slaves/w1_ds2780.h
@@ -124,6 +124,8 @@
 
 extern int w1_ds2780_io(struct device *dev, char *buf, int addr, size_t count,
                         int io);
+extern int w1_ds2780_io_nolock(struct device *dev, char *buf, int addr,
+                        size_t count, int io);
 extern int w1_ds2780_eeprom_cmd(struct device *dev, int addr, int cmd);
 
 #endif /* !_W1_DS2780_H */