![Kim, Milo](/assets/img/avatar_default.png)
LP5562 can drive up to 4 channels, RGB and White. LEDs can be controlled directly via the led class control interface. LP55xx common driver LP5562 is one of LP55xx family device, so LP55xx common code are used. On the other hand, chip specific configuration is defined in the structure 'lp55xx_device_config' LED pattern data LP5562 has also internal program memory which is used for running various LED patterns. LP5562 driver supports the firmware interface and the predefined pattern data as well. LP5562 device attributes: 'led_pattern' and 'engine_mux' A 'led_pattern' is an index code which runs the predefined pattern data. And 'engine_mux' is updated with the firmware interface is activated. Detailed description has been updated in the documentation files, 'leds-lp55xx.txt' and 'leds-lp5562.txt'. Changes on the header file LP5562 configurable definitions are added. Pattern RGB data is fixed as constant value. (No side effect on other devices, LP5521 or LP5523.) (cooloney@gmail.com: remove redundant mutex_unlock(). Reported by Dan Carpenter <dan.carpenter@oracle.com>) Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com> Signed-off-by: Bryan Wu <cooloney@gmail.com>
163 lines
5.4 KiB
Plaintext
163 lines
5.4 KiB
Plaintext
LP5521/LP5523/LP55231 Common Driver
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===================================
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Authors: Milo(Woogyom) Kim <milo.kim@ti.com>
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Description
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-----------
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LP5521, LP5523/55231 and LP5562 have common features as below.
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Register access via the I2C
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Device initialization/deinitialization
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Create LED class devices for multiple output channels
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Device attributes for user-space interface
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Program memory for running LED patterns
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The LP55xx common driver provides these features using exported functions.
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lp55xx_init_device() / lp55xx_deinit_device()
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lp55xx_register_leds() / lp55xx_unregister_leds()
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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
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control multi output LED channels such as led current, channel index.
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o lp55xx_chip
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general chip control such like the I2C and platform data.
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For example, LP5521 has maximum 3 LED channels.
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LP5523/55231 has 9 output channels.
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lp55xx_chip for LP5521 ... lp55xx_led #1
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lp55xx_led #2
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lp55xx_led #3
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lp55xx_chip for LP5523 ... lp55xx_led #1
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lp55xx_led #2
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.
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.
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lp55xx_led #9
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( Chip Dependent Code )
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To support device specific configurations, special structure
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'lpxx_device_config' is used.
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Maximum number of channels
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Reset command, chip enable command
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Chip specific initialization
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Brightness control register access
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Setting LED output current
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Program memory address access for running patterns
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Additional device specific attributes
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( Firmware Interface )
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LP55xx family devices have the internal program memory for running
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various LED patterns.
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This pattern data is saved as a file in the user-land or
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hex byte string is written into the memory through the I2C.
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LP55xx common driver supports the firmware interface.
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LP55xx chips have three program engines.
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To load and run the pattern, the programming sequence is following.
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(1) Select an engine number (1/2/3)
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(2) Mode change to load
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(3) Write pattern data into selected area
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(4) Mode change to run
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The LP55xx common driver provides simple interfaces as below.
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select_engine : Select which engine is used for running program
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run_engine : Start program which is loaded via the firmware interface
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firmware : Load program data
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For example, run blinking pattern in engine #1 of LP5521
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echo 1 > /sys/bus/i2c/devices/xxxx/select_engine
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echo 1 > /sys/class/firmware/lp5521/loading
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echo "4000600040FF6000" > /sys/class/firmware/lp5521/data
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echo 0 > /sys/class/firmware/lp5521/loading
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echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
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For example, run blinking pattern in engine #3 of LP55231
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echo 3 > /sys/bus/i2c/devices/xxxx/select_engine
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echo 1 > /sys/class/firmware/lp55231/loading
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echo "9d0740ff7e0040007e00a0010000" > /sys/class/firmware/lp55231/data
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echo 0 > /sys/class/firmware/lp55231/loading
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echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
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To start blinking patterns in engine #2 and #3 simultaneously,
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for idx in 2 3
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do
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echo $idx > /sys/class/leds/red/device/select_engine
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sleep 0.1
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echo 1 > /sys/class/firmware/lp5521/loading
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echo "4000600040FF6000" > /sys/class/firmware/lp5521/data
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echo 0 > /sys/class/firmware/lp5521/loading
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done
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echo 1 > /sys/class/leds/red/device/run_engine
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Here is another example for LP5523.
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echo 2 > /sys/bus/i2c/devices/xxxx/select_engine
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echo 1 > /sys/class/firmware/lp5523/loading
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echo "9d80400004ff05ff437f0000" > /sys/class/firmware/lp5523/data
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echo 0 > /sys/class/firmware/lp5523/loading
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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.
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Inside the callback, the selected engine is loaded and memory is updated.
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To run programmed pattern, 'run_engine' attribute should be enabled.
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( 'run_engine' and 'firmware_cb' )
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The sequence of running the program data is common.
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But each device has own specific register addresses for commands.
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To support this, 'run_engine' and 'firmware_cb' are configurable in each driver.
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run_engine : Control the selected engine
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firmware_cb : The callback function after loading the firmware is done.
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Chip specific commands for loading and updating program memory.
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( Predefined pattern data )
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Without the firmware interface, LP55xx driver provides another method for
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loading a LED pattern. That is 'predefined' pattern.
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A predefined pattern is defined in the platform data and load it(or them)
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via the sysfs if needed.
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To use the predefined pattern concept, 'patterns' and 'num_patterns' should be
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configured.
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Example of predefined pattern data:
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/* mode_1: blinking data */
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static const u8 mode_1[] = {
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0x40, 0x00, 0x60, 0x00, 0x40, 0xFF, 0x60, 0x00,
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};
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/* mode_2: always on */
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static const u8 mode_2[] = { 0x40, 0xFF, };
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struct lp55xx_predef_pattern board_led_patterns[] = {
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{
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.r = mode_1,
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.size_r = ARRAY_SIZE(mode_1),
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},
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{
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.b = mode_2,
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.size_b = ARRAY_SIZE(mode_2),
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},
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}
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struct lp55xx_platform_data lp5562_pdata = {
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...
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.patterns = board_led_patterns,
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.num_patterns = ARRAY_SIZE(board_led_patterns),
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};
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Then, mode_1 and mode_2 can be run via through the sysfs.
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echo 1 > /sys/bus/i2c/devices/xxxx/led_pattern # red blinking LED pattern
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echo 2 > /sys/bus/i2c/devices/xxxx/led_pattern # blue LED always on
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To stop running pattern,
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echo 0 > /sys/bus/i2c/devices/xxxx/led_pattern
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