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Documentation: leds: update LP55xx family devices
Update changed platform data information. Add leds-lp55xx.txt which includes the firmware interface description. Signed-off-by: Milo(Woogyom) Kim <[email protected]> Signed-off-by: Bryan Wu <[email protected]>
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Original file line number | Diff line number | Diff line change |
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LP5521/LP5523/LP55231 Common Driver | ||
=================================== | ||
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Authors: Milo(Woogyom) Kim <[email protected]> | ||
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Description | ||
----------- | ||
LP5521, LP5523/55231 have common features as below. | ||
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Register access via the I2C | ||
Device initialization/deinitialization | ||
Create LED class devices for multiple output channels | ||
Device attributes for user-space interface | ||
Program memory for running LED patterns | ||
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The LP55xx common driver provides these features using exported functions. | ||
lp55xx_init_device() / lp55xx_deinit_device() | ||
lp55xx_register_leds() / lp55xx_unregister_leds() | ||
lp55xx_regsister_sysfs() / lp55xx_unregister_sysfs() | ||
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( Driver Structure Data ) | ||
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In lp55xx common driver, two different data structure is used. | ||
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o lp55xx_led | ||
control multi output LED channels such as led current, channel index. | ||
o lp55xx_chip | ||
general chip control such like the I2C and platform data. | ||
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For example, LP5521 has maximum 3 LED channels. | ||
LP5523/55231 has 9 output channels. | ||
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lp55xx_chip for LP5521 ... lp55xx_led #1 | ||
lp55xx_led #2 | ||
lp55xx_led #3 | ||
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lp55xx_chip for LP5523 ... lp55xx_led #1 | ||
lp55xx_led #2 | ||
. | ||
. | ||
lp55xx_led #9 | ||
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( Chip Dependent Code ) | ||
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To support device specific configurations, special structure | ||
'lpxx_device_config' is used. | ||
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Maximum number of channels | ||
Reset command, chip enable command | ||
Chip specific initialization | ||
Brightness control register access | ||
Setting LED output current | ||
Program memory address access for running patterns | ||
Additional device specific attributes | ||
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( Firmware Interface ) | ||
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LP55xx family devices have the internal program memory for running | ||
various LED patterns. | ||
This pattern data is saved as a file in the user-land or | ||
hex byte string is written into the memory through the I2C. | ||
LP55xx common driver supports the firmware interface. | ||
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LP55xx chips have three program engines. | ||
To load and run the pattern, the programming sequence is following. | ||
(1) Select an engine number (1/2/3) | ||
(2) Mode change to load | ||
(3) Write pattern data into selected area | ||
(4) Mode change to run | ||
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The LP55xx common driver provides simple interfaces as below. | ||
select_engine : Select which engine is used for running program | ||
run_engine : Start program which is loaded via the firmware interface | ||
firmware : Load program data | ||
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For example, run blinking pattern in engine #1 of LP5521 | ||
echo 1 > /sys/bus/i2c/devices/xxxx/select_engine | ||
echo 1 > /sys/class/firmware/lp5521/loading | ||
echo "4000600040FF6000" > /sys/class/firmware/lp5521/data | ||
echo 0 > /sys/class/firmware/lp5521/loading | ||
echo 1 > /sys/bus/i2c/devices/xxxx/run_engine | ||
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For example, run blinking pattern in engine #3 of LP55231 | ||
echo 3 > /sys/bus/i2c/devices/xxxx/select_engine | ||
echo 1 > /sys/class/firmware/lp55231/loading | ||
echo "9d0740ff7e0040007e00a0010000" > /sys/class/firmware/lp55231/data | ||
echo 0 > /sys/class/firmware/lp55231/loading | ||
echo 1 > /sys/bus/i2c/devices/xxxx/run_engine | ||
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To start blinking patterns in engine #2 and #3 simultaneously, | ||
for idx in 2 3 | ||
do | ||
echo $idx > /sys/class/leds/red/device/select_engine | ||
sleep 0.1 | ||
echo 1 > /sys/class/firmware/lp5521/loading | ||
echo "4000600040FF6000" > /sys/class/firmware/lp5521/data | ||
echo 0 > /sys/class/firmware/lp5521/loading | ||
done | ||
echo 1 > /sys/class/leds/red/device/run_engine | ||
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Here is another example for LP5523. | ||
echo 2 > /sys/bus/i2c/devices/xxxx/select_engine | ||
echo 1 > /sys/class/firmware/lp5523/loading | ||
echo "9d80400004ff05ff437f0000" > /sys/class/firmware/lp5523/data | ||
echo 0 > /sys/class/firmware/lp5523/loading | ||
echo 1 > /sys/bus/i2c/devices/xxxx/run_engine | ||
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As soon as 'loading' is set to 0, registered callback is called. | ||
Inside the callback, the selected engine is loaded and memory is updated. | ||
To run programmed pattern, 'run_engine' attribute should be enabled. | ||
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( 'run_engine' and 'firmware_cb' ) | ||
The sequence of running the program data is common. | ||
But each device has own specific register addresses for commands. | ||
To support this, 'run_engine' and 'firmware_cb' are configurable in each driver. | ||
run_engine : Control the selected engine | ||
firmware_cb : The callback function after loading the firmware is done. | ||
Chip specific commands for loading and updating program memory. |