1==================== 2Kernel driver lp3944 3==================== 4 5 * National Semiconductor LP3944 Fun-light Chip 6 7 Prefix: 'lp3944' 8 9 Addresses scanned: None (see the Notes section below) 10 11 Datasheet: 12 13 Publicly available at the National Semiconductor website 14 http://www.national.com/pf/LP/LP3944.html 15 16Authors: 17 Antonio Ospite <ospite@studenti.unina.it> 18 19 20Description 21----------- 22The LP3944 is a helper chip that can drive up to 8 leds, with two programmable 23DIM modes; it could even be used as a gpio expander but this driver assumes it 24is used as a led controller. 25 26The DIM modes are used to set _blink_ patterns for leds, the pattern is 27specified supplying two parameters: 28 29 - period: 30 from 0s to 1.6s 31 - duty cycle: 32 percentage of the period the led is on, from 0 to 100 33 34Setting a led in DIM0 or DIM1 mode makes it blink according to the pattern. 35See the datasheet for details. 36 37LP3944 can be found on Motorola A910 smartphone, where it drives the rgb 38leds, the camera flash light and the lcds power. 39 40 41Notes 42----- 43The chip is used mainly in embedded contexts, so this driver expects it is 44registered using the i2c_board_info mechanism. 45 46To register the chip at address 0x60 on adapter 0, set the platform data 47according to include/linux/leds-lp3944.h, set the i2c board info:: 48 49 static struct i2c_board_info a910_i2c_board_info[] __initdata = { 50 { 51 I2C_BOARD_INFO("lp3944", 0x60), 52 .platform_data = &a910_lp3944_leds, 53 }, 54 }; 55 56and register it in the platform init function:: 57 58 i2c_register_board_info(0, a910_i2c_board_info, 59 ARRAY_SIZE(a910_i2c_board_info)); 60