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Kernel driver for lp5523

Documentation/leds/leds-lp5523.rst

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======================== Kernel driver for lp5523

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. The name of each channel is configurable in the platform data - name and label. There are three options to make the channel name.

a) Define the 'name' in the platform data

To make specific channel name, then use 'name' platform data.

  • /sys/class/leds/R1 (name: 'R1')
  • /sys/class/leds/B1 (name: 'B1')

b) Use the 'label' with no 'name' field

For one device name with channel number, then use 'label'.

  • /sys/class/leds/RGB:channelN (label: 'RGB', N: 0 ~ 8)

c) Default

If both fields are NULL, 'lp5523' is used by default.

  • /sys/class/leds/lp5523:channelN (N: 0 ~ 8)

LP5523 has the internal program memory for running various LED patterns. There are two ways to run LED patterns.

  1. Legacy interface - enginex_mode, enginex_load and enginex_leds

Control interface for the engines:

x is 1 .. 3

enginex_mode: disabled, load, run enginex_load: microcode load enginex_leds: led mux control

::

cd /sys/class/leds/lp5523:channel2/device
echo "load" > engine3_mode
echo "9d80400004ff05ff437f0000" > engine3_load
echo "111111111" > engine3_leds
echo "run" > engine3_mode

To stop the engine::

echo "disabled" > engine3_mode

2) Firmware interface - LP55xx common interface

For the details, please refer to 'firmware' section in leds-lp55xx.txt

LP5523 has three master faders. If a channel is mapped to one of the master faders, its output is dimmed based on the value of the master fader.

For example::

echo "123000123" > master_fader_leds

creates the following channel-fader mappings::

channel 0,6 to master_fader1 channel 1,7 to master_fader2 channel 2,8 to master_fader3

Then, to have 25% of the original output on channel 0,6::

echo 64 > master_fader1

To have 0% of the original output (i.e. no output) channel 1,7::

echo 0 > master_fader2

To have 100% of the original output (i.e. no dimming) on channel 2,8::

echo 255 > master_fader3

To clear all master fader controls::

echo "000000000" > master_fader_leds

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::

static struct lp55xx_led_config lp5523_led_config[] = {
	{
		.name		= "D1",
		.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 lp55xx_platform_data lp5523_platform_data = {
	.led_config     = lp5523_led_config,
	.num_channels   = ARRAY_SIZE(lp5523_led_config),
	.clock_mode     = LP55XX_CLOCK_EXT,
	.setup_resources   = lp5523_setup,
	.release_resources = lp5523_release,
	.enable            = lp5523_enable,
};

Note chan_nr can have values between 0 and 8.