* Qualcomm QCA7000

The QCA7000 is a serial-to-powerline bridge with a host interface which could
be configured either as SPI or UART slave. This configuration is done by
the QCA7000 firmware.

(a) Ethernet over SPI

In order to use the QCA7000 as SPI device it must be defined as a child of a
SPI master in the device tree.

Required properties:
- compatible	    : Should be "qca,qca7000"
- reg		    : Should specify the SPI chip select
- interrupts	    : The first cell should specify the index of the source
		      interrupt and the second cell should specify the trigger
		      type as rising edge
- spi-cpha	    : Must be set
- spi-cpol	    : Must be set

Optional properties:
- spi-max-frequency : Maximum frequency of the SPI bus the chip can operate at.
		      Numbers smaller than 1000000 or greater than 16000000
		      are invalid. Missing the property will set the SPI
		      frequency to 8000000 Hertz.
- qca,legacy-mode   : Set the SPI data transfer of the QCA7000 to legacy mode.
		      In this mode the SPI master must toggle the chip select
		      between each data word. In burst mode these gaps aren't
		      necessary, which is faster. This setting depends on how
		      the QCA7000 is setup via GPIO pin strapping. If the
		      property is missing the driver defaults to burst mode.

The MAC address will be determined using the optional properties
defined in ethernet.txt.

SPI Example:

/* Freescale i.MX28 SPI master*/
ssp2: spi@80014000 {
	#address-cells = <1>;
	#size-cells = <0>;
	compatible = "fsl,imx28-spi";
	pinctrl-names = "default";
	pinctrl-0 = <&spi2_pins_a>;

	qca7000: ethernet@0 {
		compatible = "qca,qca7000";
		reg = <0x0>;
		interrupt-parent = <&gpio3>;      /* GPIO Bank 3 */
		interrupts = <25 0x1>;            /* Index: 25, rising edge */
		spi-cpha;                         /* SPI mode: CPHA=1 */
		spi-cpol;                         /* SPI mode: CPOL=1 */
		spi-max-frequency = <8000000>;    /* freq: 8 MHz */
		local-mac-address = [ A0 B0 C0 D0 E0 F0 ];
	};
};

(b) Ethernet over UART

In order to use the QCA7000 as UART slave it must be defined as a child of a
UART master in the device tree. It is possible to preconfigure the UART
settings of the QCA7000 firmware, but it's not possible to change them during
runtime.

Required properties:
- compatible        : Should be "qca,qca7000"

Optional properties:
- local-mac-address : see ./ethernet.txt
- current-speed     : current baud rate of QCA7000 which defaults to 115200
		      if absent, see also ../serial/serial.yaml

UART Example:

/* Freescale i.MX28 UART */
auart0: serial@8006a000 {
	compatible = "fsl,imx28-auart", "fsl,imx23-auart";
	reg = <0x8006a000 0x2000>;
	pinctrl-names = "default";
	pinctrl-0 = <&auart0_2pins_a>;

	qca7000: ethernet {
		compatible = "qca,qca7000";
		local-mac-address = [ A0 B0 C0 D0 E0 F0 ];
		current-speed = <38400>;
	};
};
