3 files changed, 70 insertions, 12 deletions

diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
index ce24e3b3fc2a..280f140ae698 100644
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -121,6 +121,14 @@ int w1_add_master_device(struct w1_bus_master *master)
         int retval = 0;
         struct w1_netlink_msg msg;
 
+        /* validate minimum functionality */
+        if (!(master->touch_bit && master->reset_bus) &&
+            !(master->write_bit && master->read_bit))
+        {
+           printk(KERN_ERR "w1_add_master_device: invalid function set\n");
+           return(-EINVAL);
+        }
+
         dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_driver, &w1_device);
         if (!dev)
                 return -ENOMEM;
diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c
index 298ee8b72541..2173336b60a7 100644
--- a/drivers/w1/w1_io.c
+++ b/drivers/w1/w1_io.c
@@ -55,15 +55,29 @@ void w1_delay(unsigned long tm)
         udelay(tm * w1_delay_parm);
 }
 
+static void w1_write_bit(struct w1_master *dev, int bit);
+static u8 w1_read_bit(struct w1_master *dev);
+
+/**
+ * Generates a write-0 or write-1 cycle and samples the level.
+ */
 u8 w1_touch_bit(struct w1_master *dev, int bit)
 {
         if (dev->bus_master->touch_bit)
                 return dev->bus_master->touch_bit(dev->bus_master->data, bit);
-        else
+        else if (bit)
                 return w1_read_bit(dev);
+        else {
+                w1_write_bit(dev, 0);
+                return(0);
+        }
 }
 
-void w1_write_bit(struct w1_master *dev, int bit)
+/**
+ * Generates a write-0 or write-1 cycle.
+ * Only call if dev->bus_master->touch_bit is NULL
+ */
+static void w1_write_bit(struct w1_master *dev, int bit)
 {
         if (bit) {
                 dev->bus_master->write_bit(dev->bus_master->data, 0);
@@ -78,6 +92,12 @@ void w1_write_bit(struct w1_master *dev, int bit)
         }
 }
 
+/**
+ * Writes 8 bits.
+ *
+ * @param dev     the master device
+ * @param byte    the byte to write
+ */
 void w1_write_8(struct w1_master *dev, u8 byte)
 {
         int i;
@@ -86,10 +106,15 @@ void w1_write_8(struct w1_master *dev, u8 byte)
                 dev->bus_master->write_byte(dev->bus_master->data, byte);
         else
                 for (i = 0; i < 8; ++i)
-                        w1_write_bit(dev, (byte >> i) & 0x1);
+                        w1_touch_bit(dev, (byte >> i) & 0x1);
 }
 
-u8 w1_read_bit(struct w1_master *dev)
+
+/**
+ * Generates a write-1 cycle and samples the level.
+ * Only call if dev->bus_master->touch_bit is NULL
+ */
+static u8 w1_read_bit(struct w1_master *dev)
 {
         int result;
 
@@ -104,6 +129,12 @@ u8 w1_read_bit(struct w1_master *dev)
         return result & 0x1;
 }
 
+/**
+ * Reads 8 bits.
+ *
+ * @param dev     the master device
+ * @return        the byte read
+ */
 u8 w1_read_8(struct w1_master * dev)
 {
         int i;
@@ -113,12 +144,20 @@ u8 w1_read_8(struct w1_master * dev)
                 res = dev->bus_master->read_byte(dev->bus_master->data);
         else
                 for (i = 0; i < 8; ++i)
-                        res |= (w1_read_bit(dev) << i);
+                        res |= (w1_touch_bit(dev,1) << i);
 
         return res;
 }
 
-void w1_write_block(struct w1_master *dev, u8 *buf, int len)
+/**
+ * Writes a series of bytes.
+ *
+ * @param dev     the master device
+ * @param buf     pointer to the data to write
+ * @param len     the number of bytes to write
+ * @return        the byte read
+ */
+void w1_write_block(struct w1_master *dev, const u8 *buf, int len)
 {
         int i;
 
@@ -129,6 +168,14 @@ void w1_write_block(struct w1_master *dev, u8 *buf, int len)
                         w1_write_8(dev, buf[i]);
 }
 
+/**
+ * Reads a series of bytes.
+ *
+ * @param dev     the master device
+ * @param buf     pointer to the buffer to fill
+ * @param len     the number of bytes to read
+ * @return        the number of bytes read
+ */
 u8 w1_read_block(struct w1_master *dev, u8 *buf, int len)
 {
         int i;
@@ -145,9 +192,15 @@ u8 w1_read_block(struct w1_master *dev, u8 *buf, int len)
         return ret;
 }
 
+/**
+ * Issues a reset bus sequence.
+ *
+ * @param  dev The bus master pointer
+ * @return     0=Device present, 1=No device present or error
+ */
 int w1_reset_bus(struct w1_master *dev)
 {
-        int result = 0;
+        int result;
 
         if (dev->bus_master->reset_bus)
                 result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1;
@@ -183,9 +236,8 @@ void w1_search_devices(struct w1_master *dev, w1_slave_found_callback cb)
                 w1_search(dev);
 }
 
-EXPORT_SYMBOL(w1_write_bit);
+EXPORT_SYMBOL(w1_touch_bit);
 EXPORT_SYMBOL(w1_write_8);
-EXPORT_SYMBOL(w1_read_bit);
 EXPORT_SYMBOL(w1_read_8);
 EXPORT_SYMBOL(w1_reset_bus);
 EXPORT_SYMBOL(w1_calc_crc8);
diff --git a/drivers/w1/w1_io.h b/drivers/w1/w1_io.h
index 327c22ba50d5..d6daa3189c61 100644
--- a/drivers/w1/w1_io.h
+++ b/drivers/w1/w1_io.h
@@ -26,13 +26,11 @@
 
 void w1_delay(unsigned long);
 u8 w1_touch_bit(struct w1_master *, int);
-void w1_write_bit(struct w1_master *, int);
 void w1_write_8(struct w1_master *, u8);
-u8 w1_read_bit(struct w1_master *);
 u8 w1_read_8(struct w1_master *);
 int w1_reset_bus(struct w1_master *);
 u8 w1_calc_crc8(u8 *, int);
-void w1_write_block(struct w1_master *, 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);