Kernel-4.18.0-80.el8_leds-lp5523

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.
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:

Note - chan_nr can have values between 0 and 8.

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,
};