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The [[Nokia N900|N900]] has LP5523 <ref name="lp5523-spec">http://www.national.com/pf/LP/LP5523.html</ref> <ref name="leds-lp5523-driver">http://mxr.maemo.org/fremantle/source/kernel/drivers/leds/leds-lp5523.c</ref>, which has 3 engines like LP5521 (compatible though augmented instruction set) but can drive 9 LEDs via a multiplexer which maps each LED to one of the 3 engines. A LED also can be unassigned to any engine, in which case you can control it by writing to the corresponding brightness sysnode) which handles the keyboard and notification LED. (not the [[N900 Hardware Flash Torch|flash LEDs]] and red indicator light next to those, and also not the Infrared-LED used for CIR) | The [[Nokia N900|N900]] has LP5523 <ref name="lp5523-spec">http://www.national.com/pf/LP/LP5523.html</ref> <ref name="leds-lp5523-driver">http://mxr.maemo.org/fremantle/source/kernel/drivers/leds/leds-lp5523.c</ref>, which has 3 engines like LP5521 (compatible though augmented instruction set) but can drive 9 LEDs via a multiplexer which maps each LED to one of the 3 engines. A LED also can be unassigned to any engine, in which case you can control it by writing to the corresponding brightness sysnode) which handles the keyboard and notification LED. (not the [[N900 Hardware Flash Torch|flash LEDs]] and red indicator light next to those, and also not the Infrared-LED used for CIR) | ||
| - | The controller can be programmed via "/sys/class/i2c-adapter/i2c-2/2-0032". In that directory there are three files corresponding to the three channels: <code>engine1_mode</code>, <code>engine2_mode</code> and <code>engine3_mode</code>. Each file "stores" one of <code>run</code>, <code>load</code>, <code>disabled</code> (it seems that there is another mode "direct" but it doesn't work)(direct mode requires explicit writes to PWM, current and multiplexing registers, which may not be supported in the code...): | + | The controller can be programmed via "/sys/class/i2c-adapter/i2c-2/2-0032" (FIXME: is this stable?). In that directory there are three files corresponding to the three channels: <code>engine1_mode</code>, <code>engine2_mode</code> and <code>engine3_mode</code>. Each file "stores" one of <code>run</code>, <code>load</code>, <code>disabled</code> (it seems that there is another mode "direct" but it doesn't work)(direct mode requires explicit writes to PWM, current and multiplexing registers, which may not be supported in the code...): |
* <code>run</code>: The program runs | * <code>run</code>: The program runs | ||
* <code>disabled</code>: The channel is disabled - not running | * <code>disabled</code>: The channel is disabled - not running | ||
* <code>load</code>: In that state, there are two more files in that directory: | * <code>load</code>: In that state, there are two more files in that directory: | ||
| - | ** engine1_LEDs is in the form " | + | ** engine1_LEDs is in the form "0000rgb00" (9 digits, "1" or "0"), where rgb control which LEDs should participate. The 6 "0" in the above pattern correspond to the 6 kbd white LEDs controlled by MCE via engine3, so readout of engine3_leds gives 111100011 ;-) |
** engine1_load accepts a string as specified above (e.g. 9d804000427f0d7f7f007f0042000000). LP5523 has an absolute storage of 96 steps a 16bits, which can dynamically partitioned between the three engines. (Supports 32-96 steps per engine, dynamically-assigned, alas the lp5523.ko driver is braindamaged and doesn't support more than 16 instructions per engine) | ** engine1_load accepts a string as specified above (e.g. 9d804000427f0d7f7f007f0042000000). LP5523 has an absolute storage of 96 steps a 16bits, which can dynamically partitioned between the three engines. (Supports 32-96 steps per engine, dynamically-assigned, alas the lp5523.ko driver is braindamaged and doesn't support more than 16 instructions per engine) | ||
After that, when the state is changed to "run", the program will be ran by the controller. | After that, when the state is changed to "run", the program will be ran by the controller. | ||
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</source> | </source> | ||
suggesting different, the units in there are 0.1 mA (100 µA per step is correct). So the driver init default "50" for all LEDs is 5 mA, and mce seems to set current to 0.2 mA (value 2 in the led_current sysnode) for B and G, and either to 0.2 mA or 0.8 mA for R. Probably settings as high as 100 for 10 mA are safe for the RGB LED, higher values might destroy the LED. (yes, correct, the RGB could be damaged from heat if set to more than 10 mA on all 3 LEDs) | suggesting different, the units in there are 0.1 mA (100 µA per step is correct). So the driver init default "50" for all LEDs is 5 mA, and mce seems to set current to 0.2 mA (value 2 in the led_current sysnode) for B and G, and either to 0.2 mA or 0.8 mA for R. Probably settings as high as 100 for 10 mA are safe for the RGB LED, higher values might destroy the LED. (yes, correct, the RGB could be damaged from heat if set to more than 10 mA on all 3 LEDs) | ||
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| + | NOTE: There must be a delay (how much? The specs of LP5521 mentions it) between writes to sysfs files. | ||
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==Software== | ==Software== | ||
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== References == | == References == | ||
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also see [[LED_patterns]] of which this page is a "fork" without cleaning the original page, so now there are two versions with almost identical but slightly complementary info | also see [[LED_patterns]] of which this page is a "fork" without cleaning the original page, so now there are two versions with almost identical but slightly complementary info | ||
| - | Since beginning of 2012 a datasheet for LP5523 is available from TI: http://www.ti.com/ | + | Since beginning of 2012 a datasheet for LP5523 is available from TI: http://www.ti.com/lit/ds/snvs550c/snvs550c.pdf |
<references /> | <references /> | ||
[[Category:N900 Hardware]] | [[Category:N900 Hardware]] | ||
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