summaryrefslogtreecommitdiffstats
path: root/kernel/Documentation/leds/leds-lm3556.txt
diff options
context:
space:
mode:
authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/Documentation/leds/leds-lm3556.txt
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/Documentation/leds/leds-lm3556.txt')
-rw-r--r--kernel/Documentation/leds/leds-lm3556.txt85
1 files changed, 85 insertions, 0 deletions
diff --git a/kernel/Documentation/leds/leds-lm3556.txt b/kernel/Documentation/leds/leds-lm3556.txt
new file mode 100644
index 000000000..62278e871
--- /dev/null
+++ b/kernel/Documentation/leds/leds-lm3556.txt
@@ -0,0 +1,85 @@
+Kernel driver for lm3556
+========================
+
+*Texas Instrument:
+ 1.5 A Synchronous Boost LED Flash Driver w/ High-Side Current Source
+* Datasheet: http://www.national.com/ds/LM/LM3556.pdf
+
+Authors:
+ Daniel Jeong
+ Contact:Daniel Jeong(daniel.jeong-at-ti.com, gshark.jeong-at-gmail.com)
+
+Description
+-----------
+There are 3 functions in LM3556, Flash, Torch and Indicator.
+
+FLASH MODE
+In Flash Mode, the LED current source(LED) provides 16 target current levels
+from 93.75 mA to 1500 mA.The Flash currents are adjusted via the CURRENT
+CONTROL REGISTER(0x09).Flash mode is activated by the ENABLE REGISTER(0x0A),
+or by pulling the STROBE pin HIGH.
+LM3556 Flash can be controlled through sys/class/leds/flash/brightness file
+* if STROBE pin is enabled, below example control brightness only, and
+ON / OFF will be controlled by STROBE pin.
+
+Flash Example:
+OFF : #echo 0 > sys/class/leds/flash/brightness
+93.75 mA: #echo 1 > sys/class/leds/flash/brightness
+... .....
+1500 mA: #echo 16 > sys/class/leds/flash/brightness
+
+TORCH MODE
+In Torch Mode, the current source(LED) is programmed via the CURRENT CONTROL
+REGISTER(0x09).Torch Mode is activated by the ENABLE REGISTER(0x0A) or by the
+hardware TORCH input.
+LM3556 torch can be controlled through sys/class/leds/torch/brightness file.
+* if TORCH pin is enabled, below example control brightness only,
+and ON / OFF will be controlled by TORCH pin.
+
+Torch Example:
+OFF : #echo 0 > sys/class/leds/torch/brightness
+46.88 mA: #echo 1 > sys/class/leds/torch/brightness
+... .....
+375 mA : #echo 8 > sys/class/leds/torch/brightness
+
+INDICATOR MODE
+Indicator pattern can be set through sys/class/leds/indicator/pattern file,
+and 4 patterns are pre-defined in indicator_pattern array.
+According to N-lank, Pulse time and N Period values, different pattern wiill
+be generated.If you want new patterns for your own device, change
+indicator_pattern array with your own values and INDIC_PATTERN_SIZE.
+Please refer datasheet for more detail about N-Blank, Pulse time and N Period.
+
+Indicator pattern example:
+pattern 0: #echo 0 > sys/class/leds/indicator/pattern
+....
+pattern 3: #echo 3 > sys/class/leds/indicator/pattern
+
+Indicator brightness can be controlled through
+sys/class/leds/indicator/brightness file.
+
+Example:
+OFF : #echo 0 > sys/class/leds/indicator/brightness
+5.86 mA : #echo 1 > sys/class/leds/indicator/brightness
+........
+46.875mA : #echo 8 > sys/class/leds/indicator/brightness
+
+Notes
+-----
+Driver expects it is registered using the i2c_board_info mechanism.
+To register the chip at address 0x63 on specific adapter, set the platform data
+according to include/linux/platform_data/leds-lm3556.h, set the i2c board info
+
+Example:
+ static struct i2c_board_info board_i2c_ch4[] __initdata = {
+ {
+ I2C_BOARD_INFO(LM3556_NAME, 0x63),
+ .platform_data = &lm3556_pdata,
+ },
+ };
+
+and register it in the platform init function
+
+Example:
+ board_register_i2c_bus(4, 400,
+ board_i2c_ch4, ARRAY_SIZE(board_i2c_ch4));