We generally don't refer to register locations with properties other than
'reg', so that approach would be worse. What I'd suggest you do is to
have the sgpio registers in a separate device node, and use the LED
binding to access it, see
It seems that none of the drivers/ata/ drivers use the leds interface
today, but that can be added to libata-*.c whenever the appropriate
properties are there.
libata-*.c implements the "Enclosure management" style led messages but also has hooks
to register a custom led control callback. Since Seattle platform does not support
the "Enclosure management" registers hence ata_port_info we are setting a ATA_FLAG_EM | ATA_FLAG_SW_ACIVITY
to indicate that we can still handle the led messages by our registered callback. I see
that sata_highbank driver is doing something similar.