LAN969x SGPIO

1. SoC Resources

The Serial GPIO Controller for LAN969x supports as many Serial GPIOs as configured in the device tree.

The EVB-LAN9696-24port EVB has 128 input and 128 output.

2. Kernel configurations

Following kernel config options should be enabled to use LAN969x GPIO Controller:

CONFIG_PINCTRL_MICROCHIP_SGPIO - Serial GPIO controller config option.

3. Devicetree Configuration

To use SGPIO pins of a specific peripheral, configure following properties in the device tree:

compatible must be set to "microchip,sparx5-sgpio".
reg must be set to <0xe2010230 0x118>.
clocks must refer to the 320MHz core clock <&fx100_clk>.
reset-names must be set to "switch".
resets must refer to the switch reset controllers reset signal, e.g. <&reset 0>.
#address-cells must be 1.
#size-cells must be 0.

For each direction there must be a child node.

For the IN direction the following properties must be provided:

compatible must be set to "microchip,sparx5-sgpio-bank".
reg must be set to <0>.
gpio-controller must be set.
#gpio-cells must be set to 3.
interrupts must be set to <GIC_SPI 16 IRQ_TYPE_LEVEL_HIGH>.

Peripheral

Shared Peripheral Interrupt

CPU INTR

sgpio

Note

Shared peripheral interrupt lines start at index ID32. So, CPU INTR must be calculated as [Shared peripheral interrupt number - 32].

interrupt-controller must be set.
#interrupt-cells must be set to 3.
#address-cells must be set to 0.

For the OUT direction the following properties must be provided:

compatible must be set to "microchip,sparx5-sgpio-bank".
reg must be set to 1.
gpio-controller must be set.
#gpio-cells must be set to 3.

3.1. References

SGPIO DT Documentation

3.2. Example

Following example shows how an SGPIO controller should be defined in the DT to enable SGPIO pins for a mux controller and an SFP.

The clients refer to the IN and OUT directions to get the appropriate SGPIOs.

dtsi file:

sgpio: gpio@e2010230 {
	compatible = "microchip,sparx5-sgpio";
	reg = <0xe2010230 0x118>;
	clocks = <&fx100_clk>;
	resets = <&reset 0>;
	reset-names = "switch";
	#address-cells = <1>;
	#size-cells = <0>;
	status = "disabled";

	sgpio_in: gpio@0 {
		compatible = "microchip,sparx5-sgpio-bank";
		reg = <0>;
		gpio-controller;
		#gpio-cells = <3>;
		interrupts = <GIC_SPI 16 IRQ_TYPE_LEVEL_HIGH>;
		interrupt-controller;
		#interrupt-cells = <3>;
		#address-cells = <0>;
	};

	sgpio_out: gpio@1 {
		compatible = "microchip,sparx5-sgpio-bank";
		reg = <1>;
		gpio-controller;
		#gpio-cells = <3>;
	};
};

dts file changes to use the SGPIO:

&gpio {
	sgpio_pins: sgpio-pins {
		/* SCK, D0, D1, LD */
		pins = "GPIO_5", "GPIO_6", "GPIO_7", "GPIO_8";
		function = "sgpio_a";
	};
};


&sgpio {
	pinctrl-0 = <&sgpio_pins>;
	pinctrl-names = "default";

	microchip,sgpio-port-ranges = <0 1>, <6 9>;
	status = "okay";

	gpio@0 {
		ngpios = <128>;
	};
	gpio@1 {
		ngpios = <128>;
	};
};

/ {
	mux-controller {
		compatible = "gpio-mux";
		#mux-control-cells = <0>;

		mux-gpios = <&sgpio_out 1 2 GPIO_ACTIVE_LOW>,
			    <&sgpio_out 1 3 GPIO_ACTIVE_LOW>;
	};

	sfp0: sfp0 {
		compatible = "sff,sfp";
		i2c-bus = <&i2c_sfp0>;
		tx-disable-gpios = <&sgpio_out 6 2 GPIO_ACTIVE_HIGH>;
		los-gpios = <&sgpio_in 6 0 GPIO_ACTIVE_HIGH>;
		mod-def0-gpios = <&sgpio_in 6 1 GPIO_ACTIVE_LOW>;
		tx-fault-gpios = <&sgpio_in 6 2 GPIO_ACTIVE_HIGH>;
	};
};

4. UserSpace

4.1. Confirm instances are created

Checking if the SGPIO driver is registered:

# cat /sys/kernel/debug/pinctrl/pinctrl-devices
name [pinmux] [pinconf]
lan969x-pinctrl yes yes
e2010230.gpio-input yes yes
e2010230.gpio-output yes yes

Here the lan969x-pinctrl is the device described on this page, and the e2010230.gpio-input and e2010230.gpio-output are the Serial GPIO Controllers two direction nodes - each of them being its own pin controller device.

4.2. Setting the SFP LEDs

The LEDs for the SFP cages are available via SGPIOs:

leds {
	compatible = "gpio-leds";

	led-s6-green {
		label = "s6:green";
		gpios = <&sgpio_out 6 0 GPIO_ACTIVE_LOW>;
		default-state = "off";
	};

	led-s6-yellow {
		label = "s6:yellow";
		gpios = <&sgpio_out 6 1 GPIO_ACTIVE_LOW>;
		default-state = "off";
	};

... more LED nodes follows...
};

You can locate the LEDs in sysfs with:

# find /sys/class/leds/
/sys/class/leds/
/sys/class/leds/s7:green
/sys/class/leds/s6:yellow
/sys/class/leds/s7:yellow
/sys/class/leds/s8:yellow
/sys/class/leds/s8:green
/sys/class/leds/s9:yellow
/sys/class/leds/s9:green
/sys/class/leds/s6:green
/sys/class/leds/mmc0::

Now you can turn on the green LED of the Serdes 6 SFP using:

# echo 1 > /sys/class/leds/s6:green/brightness

And you can turn it off again using;

# echo 0 > /sys/class/leds/s6:green/brightness