From: "G.Shark Jeong" <gshark.jeong@xxxxxxxxx> LM3556 : The LM3556 is a 4 MHz fixed-frequency synchronous boost converter plus 1.5A constant current driver for a high-current white LED. Datasheet: www.national.com/ds/LM/LM3556.pdf Signed-off-by: G.Shark Jeong <gshark.jeong@xxxxxxxxx> --- Documentation/leds/00-INDEX | 2 + Documentation/leds/leds-lm3556.txt | 86 ++++++++++++++++++++++++++++++++++++ 2 files changed, 88 insertions(+), 0 deletions(-) create mode 100644 Documentation/leds/leds-lm3556.txt diff --git a/Documentation/leds/00-INDEX b/Documentation/leds/00-INDEX index 29f481d..5fefe37 100644 --- a/Documentation/leds/00-INDEX +++ b/Documentation/leds/00-INDEX @@ -6,3 +6,5 @@ leds-lp5521.txt - notes on how to use the leds-lp5521 driver. leds-lp5523.txt - notes on how to use the leds-lp5523 driver. +leds-lm3556.txt + - notes on how to use the leds-lm3556 driver. diff --git a/Documentation/leds/leds-lm3556.txt b/Documentation/leds/leds-lm3556.txt new file mode 100644 index 0000000..debdf87 --- /dev/null +++ b/Documentation/leds/leds-lm3556.txt @@ -0,0 +1,86 @@ +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 +Indicater 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 + +Indicater 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. +Toregister 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 __initdata board_i2c_ch4[] = { + { + 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)); + -- 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html