drivers/1wire: Adds some improvents

The following changes where added.
- Removes dependency to slave structure. Selecting a device on the bus only
  requires the unique romcode.

- Make search operation mutual exclusive on the bus. This is necessary to
  prevent another driver instance from making a transition on the bus at
  the same time.

- Skip also rom when only 1 slave is expected on the bus. Physical
  connected devuce should be indicated by the maxslave paramter during
  initializing, not the reigstered slaves.

- Fixes some compiler warnings in existing ds28e17 driver.

Signed-off-by: Marco Krahl <ocram.lhark@gmail.com>

drivers/1wire/1wire.c

@@ -330,9 +330,9 @@ int onewire_reset_resume(FAR struct onewire_master_s *master)
  *
  ****************************************************************************/
 
-int onewire_reset_select(FAR struct onewire_slave_s *slave)
+int onewire_reset_select(FAR struct onewire_master_s *master,
+                         uint64_t romcode)
 {
-  FAR struct onewire_master_s *master = slave->master;
   uint64_t tmp;
   uint8_t skip_rom[1] =
   {
@@ -354,13 +354,13 @@ int onewire_reset_select(FAR struct onewire_slave_s *slave)
 
   /* Issue skip-ROM if single slave, match-ROM otherwise. */
 
-  if (master->nslaves == 1)
+  if (master->nslaves == 1 || master->maxslaves == 1)
     {
       ret = ONEWIRE_WRITE(master->dev, skip_rom, sizeof(skip_rom));
     }
   else
     {
-      tmp = onewire_leuint64(slave->romcode);
+      tmp = onewire_leuint64(romcode);
       memcpy(&match_rom[1], &tmp, 8);
       ret = ONEWIRE_WRITE(master->dev, match_rom, sizeof(match_rom));
     }
@@ -541,6 +541,14 @@ int onewire_search(FAR struct onewire_master_s *master,
 
   DEBUGASSERT(master->insearch == false);
 
+  /* Make complete search on the bus mutal exlusive */
+
+  ret = onewire_sem_wait(master);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
   /* Skip costly search if bus supports only a single slave. */
 
   if (master->maxslaves == 1)
@@ -554,7 +562,7 @@ int onewire_search(FAR struct onewire_master_s *master,
           nslaves_match++;
         }
 
-      return (ret < 0) ? ret : nslaves_match;
+      goto unlock;
     }
 
   /* Select search type. */
@@ -570,7 +578,7 @@ int onewire_search(FAR struct onewire_master_s *master,
       ret = ONEWIRE_RESET(dev);
       if (ret < 0)
         {
-          return ret;
+          goto unlock;
         }
 
       /* Send the Search-ROM command. */
@@ -578,7 +586,7 @@ int onewire_search(FAR struct onewire_master_s *master,
       ret = ONEWIRE_WRITE(dev, cmd, sizeof(cmd));
       if (ret < 0)
         {
-          return ret;
+          goto unlock;
         }
 
       last_rom = rom;
@@ -611,7 +619,7 @@ int onewire_search(FAR struct onewire_master_s *master,
             {
               /* Error or zero valid directions. */
 
-              return ret;
+              goto unlock;
             }
 
           if (ret == 2 && taken_bit == 0)
@@ -668,7 +676,9 @@ int onewire_search(FAR struct onewire_master_s *master,
        */
     }
 
-  return nslaves_match;
+unlock:
+  onewire_sem_post(master);
+  return (ret < 0) ? ret : nslaves_match;
 }
 
 /****************************************************************************

drivers/1wire/1wire_internal.h

@@ -111,7 +111,8 @@ int onewire_reset_resume(FAR struct onewire_master_s *master);
  *
  ****************************************************************************/
 
-int onewire_reset_select(FAR struct onewire_slave_s *slave);
+int onewire_reset_select(FAR struct onewire_master_s *master,
+                         uint64_t romcode);
 
 /****************************************************************************
  * Name: onewire_triplet

drivers/1wire/ds28e17.c

@@ -132,7 +132,9 @@ struct ds_i2c_inst_s                   /* Must be cast-compatible with i2c_maste
  * Private Function Prototypes
  ****************************************************************************/
 
+#ifdef CONFIG_I2C_RESET
 static int ds_i2c_reset(FAR struct i2c_master_s *i2cdev);
+#endif
 static int ds_i2c_transfer(FAR struct i2c_master_s *i2cdev,
                            FAR struct i2c_msg_s *msgs, int count);
 
@@ -581,15 +583,15 @@ static int ds_i2c_setfrequency(FAR struct ds_i2c_inst_s *inst,
         break;
 
       default:
-        i2cerr("ERROR: bad I2C freq %u\n", frequency);
+        i2cerr("ERROR: bad I2C freq %lu\n", frequency);
         return -EINVAL;
     }
 
-  i2cinfo("Changing I2C freq %u -> %u\n", inst->frequency, frequency);
+  i2cinfo("Changing I2C freq %lu -> %lu\n", inst->frequency, frequency);
 
   /* Select DS28E17 */
 
-  ret = onewire_reset_select(&inst->slave);
+  ret = onewire_reset_select(master, inst->slave.romcode);
   if (ret < 0)
     {
       i2cerr("ERROR: cannot change I2C freq\n");
@@ -640,7 +642,7 @@ static int ds_i2c_process(FAR struct i2c_master_s *i2cdev,
 
   /* Select DS28E17 */
 
-  i = onewire_reset_select(&inst->slave);
+  i = onewire_reset_select(master, inst->slave.romcode);
   if (i < 0)
     {
       goto errout;
@@ -714,7 +716,7 @@ static int ds_i2c_process(FAR struct i2c_master_s *i2cdev,
             }
           else
             {
-              ret = onewire_reset_select(&inst->slave);
+              ret = onewire_reset_select(master, inst->slave.romcode);
             }
 
           if (ret < 0)
@@ -877,20 +879,10 @@ int ds28e17_search(FAR struct ds28e17_dev_s *priv,
                    void *arg)
 {
   FAR struct onewire_master_s *master = (FAR struct onewire_master_s *)priv;
-  int ret;
 
   DEBUGASSERT(master != NULL && cb_search != NULL);
 
-  ret = onewire_sem_wait(master);
-  if (ret < 0)
-    {
-      return ret;
-    }
-
-  ret = onewire_search(master, DS_FAMILY, false, cb_search, arg);
-  onewire_sem_post(master);
-
-  return ret;
+  return onewire_search(master, DS_FAMILY, false, cb_search, arg);
 }
 
 /****************************************************************************