MPC5121 PSC Device Tree Bindings

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 required there:

fsl,mpc512x-psc-uart nodes
--------------------------

Required properties :
 - 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
   encoding of the sense and level information for the interrupt.
 - interrupt-parent : the phandle for the interrupt controller that
   services interrupts for this device.

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
---------------

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,<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
   PSC FIFO Controller and b is a field that represents an
   encoding of the sense and level information for the interrupt.
 - 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:

serial@11000 {
	compatible = "fsl,mpc5121-psc-uart", "fsl,mpc5121-psc";
	cell-index = <0>;
	reg = <0x11000 0x100>;
	interrupts = <40 0x8>;
	interrupt-parent = < &ipic >;
	fsl,rx-fifo-size = <16>;
	fsl,tx-fifo-size = <16>;
};

serial@11100 {
	compatible = "fsl,mpc5121-psc-uart", "fsl,mpc5121-psc";
	cell-index = <1>;
	reg = <0x11100 0x100>;
	interrupts = <40 0x8>;
	interrupt-parent = < &ipic >;
	fsl,rx-fifo-size = <16>;
	fsl,tx-fifo-size = <16>;
};

pscfifo@11f00 {
	compatible = "fsl,mpc5121-psc-fifo";
	reg = <0x11f00 0x100>;
	interrupts = <40 0x8>;
	interrupt-parent = < &ipic >;
};