powerpc: clean up ssi.txt, add definition for fsl,ssi-asynchronous

Add the definition of the fsl,ssi-asynchronous property to ssi.txt
(documentation of the device tree bindings for the Freescale SSI device).

Also tidy up the layout of ssi.txt.
Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

Documentation/powerpc/dts-bindings/fsl/ssi.txt

@@ -4,18 +4,18 @@ The SSI is a serial device that communicates with audio codecs.  It can
 be programmed in AC97, I2S, left-justified, or right-justified modes.
 
 Required properties:
-- compatible	  : compatible list, containing "fsl,ssi"
-- cell-index	  : the SSI, <0> = SSI1, <1> = SSI2, and so on
-- reg		  : offset and length of the register set for the device
-- interrupts	  : <a b> where a is the interrupt number and b is a
+- compatible:       Compatible list, contains "fsl,ssi".
+- cell-index:       The SSI, <0> = SSI1, <1> = SSI2, and so on.
+- reg:              Offset and length of the register set for the device.
+- interrupts:       <a b> where a is the interrupt number and b is a
                     field that represents an encoding of the sense and
                     level information for the interrupt.  This should be
                     encoded based on the information in section 2)
                     depending on the type of interrupt controller you
                     have.
-- interrupt-parent : the phandle for the interrupt controller that
+- interrupt-parent: The phandle for the interrupt controller that
                     services interrupts for this device.
-- fsl,mode	  : the operating mode for the SSI interface
+- fsl,mode:         The operating mode for the SSI interface.
                     "i2s-slave" - I2S mode, SSI is clock slave
                     "i2s-master" - I2S mode, SSI is clock master
                     "lj-slave" - left-justified mode, SSI is clock slave
@@ -24,26 +24,36 @@ Required properties:
                     "rj-master" - r.j., SSI is clock master
                     "ac97-slave" - AC97 mode, SSI is clock slave
                     "ac97-master" - AC97 mode, SSI is clock master
-- fsl,playback-dma: phandle to a node for the DMA channel to use for
+- fsl,playback-dma: Phandle to a node for the DMA channel to use for
                     playback of audio.  This is typically dictated by SOC
                     design.  See the notes below.
-- fsl,capture-dma:  phandle to a node for the DMA channel to use for
+- fsl,capture-dma:  Phandle to a node for the DMA channel to use for
                     capture (recording) of audio.  This is typically dictated
                     by SOC design.  See the notes below.
-- fsl,fifo-depth:   the number of elements in the transmit and receive FIFOs.
+- fsl,fifo-depth:   The number of elements in the transmit and receive FIFOs.
                     This number is the maximum allowed value for SFCSR[TFWM0].
+- fsl,ssi-asynchronous:
+                    If specified, the SSI is to be programmed in asynchronous
+                    mode.  In this mode, pins SRCK, STCK, SRFS, and STFS must
+                    all be connected to valid signals.  In synchronous mode,
+                    SRCK and SRFS are ignored.  Asynchronous mode allows
+                    playback and capture to use different sample sizes and
+                    sample rates.  Some drivers may require that SRCK and STCK
+                    be connected together, and SRFS and STFS be connected
+                    together.  This would still allow different sample sizes,
+                    but not different sample rates.
 
 Optional properties:
-- codec-handle	  : phandle to a 'codec' node that defines an audio
+- codec-handle:     Phandle to a 'codec' node that defines an audio
                     codec connected to this SSI.  This node is typically
                     a child of an I2C or other control node.
 
 Child 'codec' node required properties:
-- compatible	  : compatible list, contains the name of the codec
+- compatible:       Compatible list, contains the name of the codec
 
 Child 'codec' node optional properties:
-- clock-frequency  : The frequency of the input clock, which typically
-                     comes from an on-board dedicated oscillator.
+- clock-frequency:  The frequency of the input clock, which typically comes
+                    from an on-board dedicated oscillator.
 
 Notes on fsl,playback-dma and fsl,capture-dma: