leds: add driver for Mellanox systems LEDs

This makes it possible to create a set of LEDs for Mellanox systems:
"msx6710", "msx6720", "msb7700", "msn2700", "msx1410", "msn2410",
"msb7800", "msn2740", "msn2100".

Driver obtains LED devices according to system configuration, provided
through system DMI data, like mlxcpld:fan1:green, mlxcpld:fan1:red and
creates devices in form: "devicename:colour:function".

LED setting is controlled through on board CPLD Lattice device.
For setting particular LED off, solid, blink:
echo 0 > /sys/class/leds/mlxcpld\:status\:green/brightness
echo 1 > /sys/class/leds/mlxcpld\:status\:green/brightness
echo timer > /sys/class/leds/mlxcpld\:status\:green/trigger

On module probing all LEDs are set green, on removing - off.

Last setting overwrites previous, f.e. sequence for
changing LED from green - red - green:
echo 1 > /sys/class/leds/mlxcpld\:psu\:green/brightness
echo 1 > /sys/class/leds/mlxcpld\:psu\:red/brightness
echo 1 > /sys/class/leds/mlxcpld\:psu\:green/brightness
Note: LEDs cannot be turned on/off simultaneously.

The Kconfig currently controlling compilation of this code is:
drivers/leds/Kconfig:config LEDS_MLXCPLD
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>

Documentation/leds/leds-mlxcpld.txt

+Kernel driver for Mellanox systems LEDs
+=======================================
+
+Provide system LED support for the nex Mellanox systems:
+"msx6710", "msx6720", "msb7700", "msn2700", "msx1410",
+"msn2410", "msb7800", "msn2740", "msn2100".
+
+Description
+-----------
+Driver provides the following LEDs for the systems "msx6710", "msx6720",
+"msb7700", "msn2700", "msx1410", "msn2410", "msb7800", "msn2740":
+  mlxcpld:fan1:green
+  mlxcpld:fan1:red
+  mlxcpld:fan2:green
+  mlxcpld:fan2:red
+  mlxcpld:fan3:green
+  mlxcpld:fan3:red
+  mlxcpld:fan4:green
+  mlxcpld:fan4:red
+  mlxcpld:psu:green
+  mlxcpld:psu:red
+  mlxcpld:status:green
+  mlxcpld:status:red
+
+ "status"
+  CPLD reg offset: 0x20
+  Bits [3:0]
+
+ "psu"
+  CPLD reg offset: 0x20
+  Bits [7:4]
+
+ "fan1"
+  CPLD reg offset: 0x21
+  Bits [3:0]
+
+ "fan2"
+  CPLD reg offset: 0x21
+  Bits [7:4]
+
+ "fan3"
+  CPLD reg offset: 0x22
+  Bits [3:0]
+
+ "fan4"
+  CPLD reg offset: 0x22
+  Bits [7:4]
+
+ Color mask for all the above LEDs:
+  [bit3,bit2,bit1,bit0] or
+  [bit7,bit6,bit5,bit4]:
+	[0,0,0,0] = LED OFF
+	[0,1,0,1] = Red static ON
+	[1,1,0,1] = Green static ON
+	[0,1,1,0] = Red blink 3Hz
+	[1,1,1,0] = Green blink 3Hz
+	[0,1,1,1] = Red blink 6Hz
+	[1,1,1,1] = Green blink 6Hz
+
+Driver provides the following LEDs for the system "msn2100":
+  mlxcpld:fan:green
+  mlxcpld:fan:red
+  mlxcpld:psu1:green
+  mlxcpld:psu1:red
+  mlxcpld:psu2:green
+  mlxcpld:psu2:red
+  mlxcpld:status:green
+  mlxcpld:status:red
+  mlxcpld:uid:blue
+
+ "status"
+  CPLD reg offset: 0x20
+  Bits [3:0]
+
+ "fan"
+  CPLD reg offset: 0x21
+  Bits [3:0]
+
+ "psu1"
+  CPLD reg offset: 0x23
+  Bits [3:0]
+
+ "psu2"
+  CPLD reg offset: 0x23
+  Bits [7:4]
+
+ "uid"
+  CPLD reg offset: 0x24
+  Bits [3:0]
+
+ Color mask for all the above LEDs, excepted uid:
+  [bit3,bit2,bit1,bit0] or
+  [bit7,bit6,bit5,bit4]:
+	[0,0,0,0] = LED OFF
+	[0,1,0,1] = Red static ON
+	[1,1,0,1] = Green static ON
+	[0,1,1,0] = Red blink 3Hz
+	[1,1,1,0] = Green blink 3Hz
+	[0,1,1,1] = Red blink 6Hz
+	[1,1,1,1] = Green blink 6Hz
+
+ Color mask for uid LED:
+  [bit3,bit2,bit1,bit0]:
+	[0,0,0,0] = LED OFF
+	[1,1,0,1] = Blue static ON
+	[1,1,1,0] = Blue blink 3Hz
+	[1,1,1,1] = Blue blink 6Hz
+
+Driver supports HW blinking at 3Hz and 6Hz frequency (50% duty cycle).
+For 3Hz duty cylce is about 167 msec, for 6Hz is about 83 msec.

MAINTAINERS

@@ -7649,6 +7649,13 @@ W:	http://www.mellanox.com
 Q:	http://patchwork.ozlabs.org/project/netdev/list/
 F:	drivers/net/ethernet/mellanox/mlxsw/
 
+MELLANOX MLXCPLD LED DRIVER
+M:	Vadim Pasternak <vadimp@mellanox.com>
+L:	linux-leds@vger.kernel.org
+S:	Supported
+F:	drivers/leds/leds-mlxcpld.c
+F:	Documentation/leds/leds-mlxcpld.txt
+
 SOFT-ROCE DRIVER (rxe)
 M:	Moni Shoua <monis@mellanox.com>
 L:	linux-rdma@vger.kernel.org

drivers/leds/Kconfig

@@ -651,6 +651,14 @@ config LEDS_PM8058
 	  Choose this option if you want to use the LED drivers in
 	  the Qualcomm PM8058 PMIC.
 
+config LEDS_MLXCPLD
+	tristate "LED support for the Mellanox boards"
+	depends on X86_64 && DMI
+	depends on LEDS_CLASS
+	help
+	  This option enabled support for the LEDs on the Mellanox
+	  boards. Say Y to enabled these.
+
 comment "LED Triggers"
 source "drivers/leds/trigger/Kconfig"
 

drivers/leds/Makefile

@@ -70,6 +70,7 @@ obj-$(CONFIG_LEDS_SEAD3)		+= leds-sead3.o
 obj-$(CONFIG_LEDS_IS31FL319X)		+= leds-is31fl319x.o
 obj-$(CONFIG_LEDS_IS31FL32XX)		+= leds-is31fl32xx.o
 obj-$(CONFIG_LEDS_PM8058)		+= leds-pm8058.o
+obj-$(CONFIG_LEDS_MLXCPLD)		+= leds-mlxcpld.o
 
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o