spi: mpc512x-psc: adapt mpc5121-psc document to reality

The drivers support MPC5125 additionally to MPC5121, and there is an spi
mode that is also supported. Additionally some minor corrections are
done.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/powerpc/fsl/mpc5121-psc.txt

@@ -6,14 +6,14 @@ PSC in UART mode
 For PSC in UART mode the needed PSC serial devices
 are specified by fsl,mpc5121-psc-uart nodes in the
 fsl,mpc5121-immr SoC node. Additionally the PSC FIFO
-Controller node fsl,mpc5121-psc-fifo is requered there:
+Controller node fsl,mpc5121-psc-fifo is required there:
 
-fsl,mpc5121-psc-uart nodes
+fsl,mpc512x-psc-uart nodes
 --------------------------
 
 Required properties :
- - compatible : Should contain "fsl,mpc5121-psc-uart" and "fsl,mpc5121-psc"
- - cell-index : Index of the PSC in hardware
+ - compatible : Should contain "fsl,<soc>-psc-uart" and "fsl,<soc>-psc"
+   Supported <soc>s: mpc5121, mpc5125
  - reg : Offset and length of the register set for the PSC device
  - interrupts : <a b> where a is the interrupt number of the
    PSC FIFO Controller and b is a field that represents an
@@ -25,12 +25,21 @@ Recommended properties :
  - fsl,rx-fifo-size : the size of the RX fifo slice (a multiple of 4)
  - fsl,tx-fifo-size : the size of the TX fifo slice (a multiple of 4)
 
+PSC in SPI mode
+---------------
 
-fsl,mpc5121-psc-fifo node
+Similar to the UART mode a PSC can be operated in SPI mode. The compatible used
+for that is fsl,mpc5121-psc-spi. It requires a fsl,mpc5121-psc-fifo as well.
+The required and recommended properties are identical to the
+fsl,mpc5121-psc-uart nodes, just use spi instead of uart in the compatible
+string.
+
+fsl,mpc512x-psc-fifo node
 -------------------------
 
 Required properties :
- - compatible : Should be "fsl,mpc5121-psc-fifo"
+ - compatible : Should be "fsl,<soc>-psc-fifo"
+   Supported <soc>s: mpc5121, mpc5125
  - reg : Offset and length of the register set for the PSC
          FIFO Controller
  - interrupts : <a b> where a is the interrupt number of the
@@ -39,6 +48,9 @@ Required properties :
  - interrupt-parent : the phandle for the interrupt controller that
    services interrupts for this device.
 
+Recommended properties :
+ - clocks : specifies the clock needed to operate the fifo controller
+ - clock-names : name(s) for the clock(s) listed in clocks
 
 Example for a board using PSC0 and PSC1 devices in serial mode: