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>

1 files changed, 110 insertions, 0 deletions

diff --git a/Documentation/leds/leds-mlxcpld.txt b/Documentation/leds/leds-mlxcpld.txt
new file mode 100644
index 0000000..a0e8fd4
--- /dev/null
+++ b/Documentation/leds/leds-mlxcpld.txt
@@ -0,0 +1,110 @@
+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.