[media] rc: make s_tx_carrier consistent

LIRC_SET_SEND_CARRIER should return 0 on success or -errno.
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/DocBook/media/v4l/lirc_device_interface.xml

@@ -157,7 +157,7 @@ on working with the default settings initially.</para>
   <varlistentry>
     <term>LIRC_SET_{SEND,REC}_CARRIER</term>
     <listitem>
-      <para>Set send/receive carrier (in Hz).</para>
+      <para>Set send/receive carrier (in Hz). Return 0 on success.</para>
     </listitem>
   </varlistentry>
   <varlistentry>

drivers/media/rc/ene_ir.c

@@ -904,7 +904,7 @@ static int ene_set_tx_carrier(struct rc_dev *rdev, u32 carrier)
 
 		dbg("TX: out of range %d-%d kHz carrier",
 			2000 / ENE_CIRMOD_PRD_MIN, 2000 / ENE_CIRMOD_PRD_MAX);
-		return -1;
+		return -EINVAL;
 	}
 
 	dev->tx_period = period;

drivers/media/rc/iguanair.c

@@ -330,7 +330,7 @@ static int iguanair_set_tx_carrier(struct rc_dev *dev, uint32_t carrier)
 
 	mutex_unlock(&ir->lock);
 
-	return carrier;
+	return 0;
 }
 
 static int iguanair_set_tx_mask(struct rc_dev *dev, uint32_t mask)

drivers/media/rc/mceusb.c

@@ -942,7 +942,7 @@ static int mceusb_set_tx_carrier(struct rc_dev *dev, u32 carrier)
 
 	}
 
-	return carrier;
+	return 0;
 }
 
 /*

drivers/media/rc/redrat3.c

@@ -708,7 +708,7 @@ static int redrat3_set_tx_carrier(struct rc_dev *rcdev, u32 carrier)
 
 	rr3->carrier = carrier;
 
-	return carrier;
+	return 0;
 }
 
 static int redrat3_transmit_ir(struct rc_dev *rcdev, unsigned *txbuf,