Change in coreboot[master]: mb/purism/librem_mini: Rework front status LED to show all disk activity

[Matt DeVillier (Code Review)]

Attention is currently required from: Tim Wawrzynczak, Paul Menzel, Angel Pons.
Matt DeVillier has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/63749 )

Change subject: mb/purism/librem_mini: Rework front status LED to show all disk activity
......................................................................

Patch Set 2:

(3 comments)

Patchset:

PS1:
> Interesting, do other OSes work with this?

As in Windows? Untested, but assume not based on the ASL and how closely coupled it is to the Linux gpio-leds driver

File src/mainboard/purism/librem_cnl/variants/librem_mini/include/variant/acpi/variant.asl:

PS1:
> If you're bored, a drivers/generic/gpio_leds chip driver to generate the AML might be nice to have ? […]

that sounds like a great idea for a GSOC project ;-)

https://review.coreboot.org/c/coreboot/+/63749/comment/221aa178_95ee32cd 
PS1, Line 18: Scope (_SB)
            : {
            :     Device (LEDS)
            :     {
            :         Name (_HID, "PRP0001")
            :         Name (_DDN, "GPIO LEDs device")
            : 
            :         Name (_CRS, ResourceTemplate () {
            :             GpioIo (
            :                 Exclusive,                  // Not shared
            :                 PullNone,                   // No need for pulls
            :                 0,                          // Debounce timeout
            :                 0,                          // Drive strength
            :                 IoRestrictionOutputOnly,    // Only used as output
            :                 "\_SB.PCI0.GPIO",          // GPIO controller
            :                 0)                          // Must be 0
            :             {
            :                 296,                         // GPP_E8 - STATUSLED#
            :             }
            :         })
            : 
            :         Name (_DSD, Package () {
            :             ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
            :             Package () {
            :                 Package () { "compatible", Package() { "gpio-leds" } },
            :             },
            :             ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
            :             Package () {
            :                 Package () {"led-0", "LED0"},
            :             }
            :         })
            : 
            :         /*
            :          * For more information about these bindings see:
            :          * Documentation/devicetree/bindings/leds/common.yaml,
            :          * Documentation/devicetree/bindings/leds/leds-gpio.yaml and
            :          * Documentation/firmware-guide/acpi/gpio-properties.rst.
            :          */
            :         Name (LED0, Package () {
            :             ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
            :             Package () {
            :                 Package () {"label", "blue:status"},
            :                 Package () {"default-state", "keep"},
            :                 Package () {"linux,default-trigger", "disk-activity"},
            :                 Package () {"gpios", Package () {^LEDS, 0, 0, 1}},
            :                 Package () {"retain-state-suspended", 1},
            :             }
            :         })
            :     }
            : }
> Please use tabs.

Done