On Tue, Feb 26, 2019 at 8:06 PM Jacek Anaszewski <jacek.anaszewski@xxxxxxxxx> wrote: > > Hi Sakari, > > Thank you for the update. > > Patch set looks good to me as far as LEDs are concerned. > > I can take 1/2 as well, but need an ack from ACPI maintainer. Go for it! Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > Cc Rafael and Len. > > Best regards, > Jacek Anaszewski > > On 2/26/19 11:42 AM, Sakari Ailus wrote: > > Document referring to LEDs from remote device nodes, such as from camera > > sensors. > > > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > > Acked-by: Jacek Anaszewski <jacek.anaszewski@xxxxxxxxx> > > --- > > Documentation/acpi/dsd/leds.txt | 99 +++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 99 insertions(+) > > create mode 100644 Documentation/acpi/dsd/leds.txt > > > > diff --git a/Documentation/acpi/dsd/leds.txt b/Documentation/acpi/dsd/leds.txt > > new file mode 100644 > > index 000000000000..81a63af42ed2 > > --- /dev/null > > +++ b/Documentation/acpi/dsd/leds.txt > > @@ -0,0 +1,99 @@ > > +Describing and referring to LEDs in ACPI > > + > > +Individual LEDs are described by hierarchical data extension [6] nodes under the > > +device node, the LED driver chip. The "reg" property in the LED specific nodes > > +tells the numerical ID of each individual LED output to which the LEDs are > > +connected. [3] The hierarchical data nodes are named "led@X", where X is the > > +number of the LED output. > > + > > +Referring to LEDs in Device tree is documented in [4], in "flash-leds" property > > +documentation. In short, LEDs are directly referred to by using phandles. > > + > > +While Device tree allows referring to any node in the tree[1], in ACPI > > +references are limited to device nodes only [2]. For this reason using the same > > +mechanism on ACPI is not possible. A mechanism to refer to non-device ACPI nodes > > +is documented in [7]. > > + > > +ACPI allows (as does DT) using integer arguments after the reference. A > > +combination of the LED driver device reference and an integer argument, > > +referring to the "reg" property of the relevant LED, is used to identify > > +individual LEDs. The value of the "reg" property is a contract between the > > +firmware and software, it uniquely identifies the LED driver outputs. > > + > > +Under the LED driver device, The first hierarchical data extension package list > > +entry shall contain the string "led@" followed by the number of the LED, > > +followed by the referred object name. That object shall be named "LED" followed > > +by the number of the LED. > > + > > +An ASL example of a camera sensor device and a LED driver device for two LEDs. > > +Objects not relevant for LEDs or the references to them have been omitted. > > + > > + Device (LED) > > + { > > + Name (_DSD, Package () { > > + ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"), > > + Package () { > > + Package () { "led@0", LED0 }, > > + Package () { "led@1", LED1 }, > > + } > > + }) > > + Name (LED0, Package () { > > + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), > > + Package () { > > + Package () { "reg", 0 }, > > + Package () { "flash-max-microamp", 1000000 }, > > + Package () { "flash-timeout-us", 200000 }, > > + Package () { "led-max-microamp", 100000 }, > > + Package () { "label", "white:flash" }, > > + } > > + }) > > + Name (LED1, Package () { > > + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), > > + Package () { > > + Package () { "reg", 1 }, > > + Package () { "led-max-microamp", 10000 }, > > + Package () { "label", "red:indicator" }, > > + } > > + }) > > + } > > + > > + Device (SEN) > > + { > > + Name (_DSD, Package () { > > + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), > > + Package () { > > + Package () { > > + "flash-leds", > > + Package () { ^LED, "led@0", ^LED, "led@1" }, > > + } > > + } > > + }) > > + } > > + > > +where > > + > > + LED LED driver device > > + LED0 First LED > > + LED1 Second LED > > + SEN Camera sensor device (or another device the LED is > > + related to) > > + > > +[1] Device tree. <URL:http://www.devicetree.org>, referenced 2019-02-21. > > + > > +[2] Advanced Configuration and Power Interface Specification. > > + <URL:https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf>, > > + referenced 2019-02-21. > > + > > +[3] Documentation/devicetree/bindings/leds/common.txt > > + > > +[4] Documentation/devicetree/bindings/media/video-interfaces.txt > > + > > +[5] Device Properties UUID For _DSD. > > + <URL:http://www.uefi.org/sites/default/files/resources/_DSD-device-properties-UUID.pdf>, > > + referenced 2019-02-21. > > + > > +[6] Hierarchical Data Extension UUID For _DSD. > > + <URL:http://www.uefi.org/sites/default/files/resources/_DSD-hierarchical-data-extension-UUID-v1.1.pdf>, > > + referenced 2019-02-21. > > + > > +[7] Documentation/acpi/dsd/data-node-reference.txt > >