cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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leds-lp5523.rst (3511B)


      1========================
      2Kernel driver for lp5523
      3========================
      4
      5* National Semiconductor LP5523 led driver chip
      6* Datasheet: http://www.national.com/pf/LP/LP5523.html
      7
      8Authors: Mathias Nyman, Yuri Zaporozhets, Samu Onkalo
      9Contact: Samu Onkalo (samu.p.onkalo-at-nokia.com)
     10
     11Description
     12-----------
     13LP5523 can drive up to 9 channels. Leds can be controlled directly via
     14the led class control interface.
     15The name of each channel is configurable in the platform data - name and label.
     16There are three options to make the channel name.
     17
     18a) Define the 'name' in the platform data
     19
     20To make specific channel name, then use 'name' platform data.
     21
     22- /sys/class/leds/R1               (name: 'R1')
     23- /sys/class/leds/B1               (name: 'B1')
     24
     25b) Use the 'label' with no 'name' field
     26
     27For one device name with channel number, then use 'label'.
     28- /sys/class/leds/RGB:channelN     (label: 'RGB', N: 0 ~ 8)
     29
     30c) Default
     31
     32If both fields are NULL, 'lp5523' is used by default.
     33- /sys/class/leds/lp5523:channelN  (N: 0 ~ 8)
     34
     35LP5523 has the internal program memory for running various LED patterns.
     36There are two ways to run LED patterns.
     37
     381) Legacy interface - enginex_mode, enginex_load and enginex_leds
     39
     40  Control interface for the engines:
     41
     42  x is 1 .. 3
     43
     44  enginex_mode:
     45	disabled, load, run
     46  enginex_load:
     47	microcode load
     48  enginex_leds:
     49	led mux control
     50
     51  ::
     52
     53	cd /sys/class/leds/lp5523:channel2/device
     54	echo "load" > engine3_mode
     55	echo "9d80400004ff05ff437f0000" > engine3_load
     56	echo "111111111" > engine3_leds
     57	echo "run" > engine3_mode
     58
     59  To stop the engine::
     60
     61	echo "disabled" > engine3_mode
     62
     632) Firmware interface - LP55xx common interface
     64
     65For the details, please refer to 'firmware' section in leds-lp55xx.txt
     66
     67LP5523 has three master faders. If a channel is mapped to one of
     68the master faders, its output is dimmed based on the value of the master
     69fader.
     70
     71For example::
     72
     73  echo "123000123" > master_fader_leds
     74
     75creates the following channel-fader mappings::
     76
     77  channel 0,6 to master_fader1
     78  channel 1,7 to master_fader2
     79  channel 2,8 to master_fader3
     80
     81Then, to have 25% of the original output on channel 0,6::
     82
     83  echo 64 > master_fader1
     84
     85To have 0% of the original output (i.e. no output) channel 1,7::
     86
     87  echo 0 > master_fader2
     88
     89To have 100% of the original output (i.e. no dimming) on channel 2,8::
     90
     91  echo 255 > master_fader3
     92
     93To clear all master fader controls::
     94
     95  echo "000000000" > master_fader_leds
     96
     97Selftest uses always the current from the platform data.
     98
     99Each channel contains led current settings.
    100- /sys/class/leds/lp5523:channel2/led_current - RW
    101- /sys/class/leds/lp5523:channel2/max_current - RO
    102
    103Format: 10x mA i.e 10 means 1.0 mA
    104
    105Example platform data::
    106
    107	static struct lp55xx_led_config lp5523_led_config[] = {
    108		{
    109			.name		= "D1",
    110			.chan_nr        = 0,
    111			.led_current    = 50,
    112			.max_current    = 130,
    113		},
    114	...
    115		{
    116			.chan_nr        = 8,
    117			.led_current    = 50,
    118			.max_current    = 130,
    119		}
    120	};
    121
    122	static int lp5523_setup(void)
    123	{
    124		/* Setup HW resources */
    125	}
    126
    127	static void lp5523_release(void)
    128	{
    129		/* Release HW resources */
    130	}
    131
    132	static void lp5523_enable(bool state)
    133	{
    134		/* Control chip enable signal */
    135	}
    136
    137	static struct lp55xx_platform_data lp5523_platform_data = {
    138		.led_config     = lp5523_led_config,
    139		.num_channels   = ARRAY_SIZE(lp5523_led_config),
    140		.clock_mode     = LP55XX_CLOCK_EXT,
    141		.setup_resources   = lp5523_setup,
    142		.release_resources = lp5523_release,
    143		.enable            = lp5523_enable,
    144	};
    145
    146Note
    147  chan_nr can have values between 0 and 8.