mirror of
https://github.com/torvalds/linux.git
synced 2024-12-26 21:02:19 +00:00
51 lines
1.5 KiB
Plaintext
51 lines
1.5 KiB
Plaintext
|
Kernel driver lp3944
|
||
|
|
====================
|
||
|
|
|
||
|
|
* National Semiconductor LP3944 Fun-light Chip
|
||
|
|
Prefix: 'lp3944'
|
||
|
|
Addresses scanned: None (see the Notes section below)
|
||
|
|
Datasheet: Publicly available at the National Semiconductor website
|
||
|
|
http://www.national.com/pf/LP/LP3944.html
|
||
|
|
|
||
|
|
Authors:
|
||
|
|
Antonio Ospite <ospite@studenti.unina.it>
|
||
|
|
|
||
|
|
|
||
|
|
Description
|
||
|
|
-----------
|
||
|
|
The LP3944 is a helper chip that can drive up to 8 leds, with two programmable
|
||
|
|
DIM modes; it could even be used as a gpio expander but this driver assumes it
|
||
|
|
is used as a led controller.
|
||
|
|
|
||
|
|
The DIM modes are used to set _blink_ patterns for leds, the pattern is
|
||
|
|
specified supplying two parameters:
|
||
|
|
- period: from 0s to 1.6s
|
||
|
|
- duty cycle: percentage of the period the led is on, from 0 to 100
|
||
|
|
|
||
|
|
Setting a led in DIM0 or DIM1 mode makes it blink according to the pattern.
|
||
|
|
See the datasheet for details.
|
||
|
|
|
||
|
|
LP3944 can be found on Motorola A910 smartphone, where it drives the rgb
|
||
|
|
leds, the camera flash light and the lcds power.
|
||
|
|
|
||
|
|
|
||
|
|
Notes
|
||
|
|
-----
|
||
|
|
The chip is used mainly in embedded contexts, so this driver expects it is
|
||
|
|
registered using the i2c_board_info mechanism.
|
||
|
|
|
||
|
|
To register the chip at address 0x60 on adapter 0, set the platform data
|
||
|
|
according to include/linux/leds-lp3944.h, set the i2c board info:
|
||
|
|
|
||
|
|
static struct i2c_board_info __initdata a910_i2c_board_info[] = {
|
||
|
|
{
|
||
|
|
I2C_BOARD_INFO("lp3944", 0x60),
|
||
|
|
.platform_data = &a910_lp3944_leds,
|
||
|
|
},
|
||
|
|
};
|
||
|
|
|
||
|
|
and register it in the platform init function
|
||
|
|
|
||
|
|
i2c_register_board_info(0, a910_i2c_board_info,
|
||
|
|
ARRAY_SIZE(a910_i2c_board_info));
|