5991e154b2
Create sub directory Documentation/leds and add short documentation for LP5521 and LP5523 drivers. Signed-off-by: Samu Onkalo <samu.p.onkalo@nokia.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Jean Delvare <khali@linux-fr.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
83 lines
2.4 KiB
Text
83 lines
2.4 KiB
Text
Kernel driver for lp5523
|
|
========================
|
|
|
|
* National Semiconductor LP5523 led driver chip
|
|
* Datasheet: http://www.national.com/pf/LP/LP5523.html
|
|
|
|
Authors: Mathias Nyman, Yuri Zaporozhets, Samu Onkalo
|
|
Contact: Samu Onkalo (samu.p.onkalo-at-nokia.com)
|
|
|
|
Description
|
|
-----------
|
|
LP5523 can drive up to 9 channels. Leds can be controlled directly via
|
|
the led class control interface. Channels have generic names:
|
|
lp5523:channelx where x is 0...8
|
|
|
|
The chip provides 3 engines. Each engine can control channels without
|
|
interaction from the main CPU. Details of the micro engine code can be found
|
|
from the public data sheet. Leds can be muxed to different channels.
|
|
|
|
Control interface for the engines:
|
|
x is 1 .. 3
|
|
enginex_mode : disabled, load, run
|
|
enginex_load : microcode load (visible only in load mode)
|
|
enginex_leds : led mux control (visible only in load mode)
|
|
|
|
cd /sys/class/leds/lp5523:channel2/device
|
|
echo "load" > engine3_mode
|
|
echo "9d80400004ff05ff437f0000" > engine3_load
|
|
echo "111111111" > engine3_leds
|
|
echo "run" > engine3_mode
|
|
|
|
sysfs contains a selftest entry. It measures each channel
|
|
voltage level and checks if it looks reasonable. If the level is too high,
|
|
the led is missing; if the level is too low, there is a short circuit.
|
|
|
|
Selftest uses always the current from the platform data.
|
|
|
|
Each channel contains led current settings.
|
|
/sys/class/leds/lp5523:channel2/led_current - RW
|
|
/sys/class/leds/lp5523:channel2/max_current - RO
|
|
Format: 10x mA i.e 10 means 1.0 mA
|
|
|
|
Example platform data:
|
|
|
|
Note - chan_nr can have values between 0 and 8.
|
|
|
|
static struct lp5523_led_config lp5523_led_config[] = {
|
|
{
|
|
.chan_nr = 0,
|
|
.led_current = 50,
|
|
.max_current = 130,
|
|
},
|
|
...
|
|
}, {
|
|
.chan_nr = 8,
|
|
.led_current = 50,
|
|
.max_current = 130,
|
|
}
|
|
};
|
|
|
|
static int lp5523_setup(void)
|
|
{
|
|
/* Setup HW resources */
|
|
}
|
|
|
|
static void lp5523_release(void)
|
|
{
|
|
/* Release HW resources */
|
|
}
|
|
|
|
static void lp5523_enable(bool state)
|
|
{
|
|
/* Control chip enable signal */
|
|
}
|
|
|
|
static struct lp5523_platform_data lp5523_platform_data = {
|
|
.led_config = lp5523_led_config,
|
|
.num_channels = ARRAY_SIZE(lp5523_led_config),
|
|
.clock_mode = LP5523_CLOCK_EXT,
|
|
.setup_resources = lp5523_setup,
|
|
.release_resources = lp5523_release,
|
|
.enable = lp5523_enable,
|
|
};
|