powerpc: doc/dts-bindings: document mpc5121 psc uart dts-bindings

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 requered there:

fsl,mpc5121-psc-uart nodes

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

Required properties :

 - compatible : Should contain "fsl,mpc5121-psc-uart" and "fsl,mpc5121-psc"

 - cell-index : Index of the PSC in hardware

 - 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)

fsl,mpc5121-psc-fifo node

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

Required properties :

 - compatible : Should be "fsl,mpc5121-psc-fifo"

 - 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.

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 >;

};