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Documentation: led drivers lp5521 and lp5523

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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>
This commit is contained in:
Samu Onkalo 2010-11-11 14:05:23 -08:00 committed by Linus Torvalds
parent f4920f673c
commit 5991e154b2
2 changed files with 171 additions and 0 deletions
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88
Documentation/leds/leds-lp5521.txt Normal file
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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.

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Documentation/leds/leds-lp5523.txt Normal file
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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,
};