mirror of
https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
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>
88 lines
2.4 KiB
Text
88 lines
2.4 KiB
Text
Kernel driver for lp5521
|
|
========================
|
|
|
|
* National Semiconductor LP5521 led driver chip
|
|
* Datasheet: http://www.national.com/pf/LP/LP5521.html
|
|
|
|
Authors: Mathias Nyman, Yuri Zaporozhets, Samu Onkalo
|
|
Contact: Samu Onkalo (samu.p.onkalo-at-nokia.com)
|
|
|
|
Description
|
|
-----------
|
|
|
|
LP5521 can drive up to 3 channels. Leds can be controlled directly via
|
|
the led class control interface. Channels have generic names:
|
|
lp5521:channelx, where x is 0 .. 2
|
|
|
|
All three channels can be also controlled using the engine micro programs.
|
|
More details of the instructions can be found from the public data sheet.
|
|
|
|
Control interface for the engines:
|
|
x is 1 .. 3
|
|
enginex_mode : disabled, load, run
|
|
enginex_load : store program (visible only in engine load mode)
|
|
|
|
Example (start to blink the channel 2 led):
|
|
cd /sys/class/leds/lp5521:channel2/device
|
|
echo "load" > engine3_mode
|
|
echo "037f4d0003ff6000" > engine3_load
|
|
echo "run" > engine3_mode
|
|
|
|
stop the engine:
|
|
echo "disabled" > engine3_mode
|
|
|
|
sysfs contains a selftest entry.
|
|
The test communicates with the chip and checks that
|
|
the clock mode is automatically set to the requested one.
|
|
|
|
Each channel has its own led current settings.
|
|
/sys/class/leds/lp5521:channel0/led_current - RW
|
|
/sys/class/leds/lp5521:channel0/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 2.
|
|
|
|
static struct lp5521_led_config lp5521_led_config[] = {
|
|
{
|
|
.chan_nr = 0,
|
|
.led_current = 50,
|
|
.max_current = 130,
|
|
}, {
|
|
.chan_nr = 1,
|
|
.led_current = 0,
|
|
.max_current = 130,
|
|
}, {
|
|
.chan_nr = 2,
|
|
.led_current = 0,
|
|
.max_current = 130,
|
|
}
|
|
};
|
|
|
|
static int lp5521_setup(void)
|
|
{
|
|
/* setup HW resources */
|
|
}
|
|
|
|
static void lp5521_release(void)
|
|
{
|
|
/* Release HW resources */
|
|
}
|
|
|
|
static void lp5521_enable(bool state)
|
|
{
|
|
/* Control of chip enable signal */
|
|
}
|
|
|
|
static struct lp5521_platform_data lp5521_platform_data = {
|
|
.led_config = lp5521_led_config,
|
|
.num_channels = ARRAY_SIZE(lp5521_led_config),
|
|
.clock_mode = LP5521_CLOCK_EXT,
|
|
.setup_resources = lp5521_setup,
|
|
.release_resources = lp5521_release,
|
|
.enable = lp5521_enable,
|
|
};
|
|
|
|
If the current is set to 0 in the platform data, that channel is
|
|
disabled and it is not visible in the sysfs.
|