led: Add Altra LED driver

Add Altra LED driver to control NVME LED.

This driver support control LED via SPCI interface on Altra system.
Currently, it is 2-LEDs system(Activity LED, Status LED). Activity
LED is completely controlled by hardware. Status LED is controlled
by this driver.
There are 4 stages of Status LED:
    - ON
    - OFF
    - Locate(blink at 1Hz)
    - Rebuild(blink at 4Hz)

Example:
To On, Off the LED on slot 9:
    1. Write the seg:bus_number corresponding to LED on slot 9 to
       altra:led
         echo 000b:03 > /sys/class/leds/altra:led/address
    2. Write 1 to brightness attr to ON, 0 to brightness attr to OFF
         echo 1 > /sys/class/leds/altra:led/brightness
         echo 0 > /sys/class/leds/altra:led/brightness
To blink the LED on slot 9:
    1. Write the seg:bus_number corresponding to LED on slot 9 to
       altra:led
         echo 000b:03 > /sys/class/leds/altra:led/address
    2. Write 1 to blink attr to select Locate(blink 1Hz), or 4 to
       blink attr to select Rebuild(blink 4Hz)
         echo 1 > /sys/class/leds/altra:led/blink
         echo 4 > /sys/class/leds/altra:led/blink
    3. Write 1 to shot attr to execute blink
         echo 1 > /sys/class/leds/altra:led/shot

cherry-pick from: AmpereComputing/ampere-centos-kernel---DEPRECATED@28c026a

Signed-off-by: Dung Cao <[email protected]>

arch/arm64/configs/altra_5.4_defconfig

@@ -1081,6 +1081,7 @@ CONFIG_LEDS_PCA955X=m
 CONFIG_LEDS_PCA963X=m
 CONFIG_LEDS_LT3593=m
 CONFIG_LEDS_BLINKM=m
+CONFIG_LEDS_ALTRA_SPCI=y
 CONFIG_LEDS_TRIGGER_TIMER=m
 CONFIG_LEDS_TRIGGER_ONESHOT=m
 CONFIG_LEDS_TRIGGER_DISK=y

drivers/leds/Kconfig

@@ -823,6 +823,13 @@ config LEDS_LM36274
 	  Say Y to enable the LM36274 LED driver for TI LMU devices.
 	  This supports the LED device LM36274.
 
+config LEDS_ALTRA_SPCI
+	bool "Altra LED support via SPCI"
+	depends on ARM64 && ACPI
+	help
+	  If you say yes here, you get support for Altra SPCI LED
+	  When in doubt, say N.
+
 comment "LED Triggers"
 source "drivers/leds/trigger/Kconfig"
 

drivers/leds/Makefile

@@ -85,6 +85,7 @@ obj-$(CONFIG_LEDS_LM3601X)		+= leds-lm3601x.o
 obj-$(CONFIG_LEDS_TI_LMU_COMMON)	+= leds-ti-lmu-common.o
 obj-$(CONFIG_LEDS_LM3697)		+= leds-lm3697.o
 obj-$(CONFIG_LEDS_LM36274)		+= leds-lm36274.o
+obj-$(CONFIG_LEDS_ALTRA_SPCI)		+= leds-altra-spci.o
 
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_CR0014114)		+= leds-cr0014114.o