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author | Samu Onkalo <samu.p.onkalo@nokia.com> | 2010-11-11 14:05:23 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-11-12 07:55:32 -0800 |
commit | 5991e154b2d09ad28af9dc7d3226b35dbbc052c3 (patch) | |
tree | ad716cded512e81c2b0a3beacff5dfb2a1f64e0e /Documentation/leds/leds-lp5521.txt | |
parent | f4920f673c4260de966b5f72c5524de0dabb7ffe (diff) | |
download | lwn-5991e154b2d09ad28af9dc7d3226b35dbbc052c3.tar.gz lwn-5991e154b2d09ad28af9dc7d3226b35dbbc052c3.zip |
Documentation: led drivers lp5521 and lp5523
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>
Diffstat (limited to 'Documentation/leds/leds-lp5521.txt')
-rw-r--r-- | Documentation/leds/leds-lp5521.txt | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/Documentation/leds/leds-lp5521.txt b/Documentation/leds/leds-lp5521.txt new file mode 100644 index 000000000000..c4d8d151e0fe --- /dev/null +++ b/Documentation/leds/leds-lp5521.txt @@ -0,0 +1,88 @@ +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. |