On Tue, Dec 28, 2021 at 04:37:28PM -0800, Colin Foster wrote:

Expose a debugfs / devicetree interface for Microsemi SGPIO controllers.
By writing values of 2-5, the SGPIO pins can be configured for either
automatic blinking or activity.

The implementation is modeled after the code in
/drivers/pinctrl/pinctrl-ocelot.c.

I have only tested this with currently out-of-tree patches for the
VSC7512 that I hope to get in soon. They are not needed for VSC7513 /
VSC7514, SPARX5, or LUTON - but I don't have any hardware to test.

Of note: the 7512 chip has a discrepancy between the datasheet and the
registers. The datahseet claims 20Hz blink default frequency, the
registers claim 5 Hz default frequency for BMODE_0. I override the
OCELOT registers to correct for this. I don't know if that is needed for
LUTON or SPARX, but having two blink modes at the same frequency isn't
beneficial. As such, I make the blink modes match the 5Hz / 20Hz for the
two modes.

Tested with VSC7512 by way of:
echo SGPIO_O_p1b0 {blink0,blink1,activity0,activity1} > 
/sys/kernel/debug/pinctrl/pinctrl-sgpio-pinctrl-sgpio-output/pinmux-select

Hi Colin

Since this is an LED, you should be using the Linux LED interface in
/sys/class/leds. See Documentation/leds/leds-class.rst. It includes a
way to make an LED blink, using hardware.

Activity is another story. I assume you mean Ethernet frame Rx and Tx?
For that you should wait until the Ethernet LED offload code
eventually lands.

	   Andrew

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