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LP8501 can drive up to 9 channels like LP5523. LEDs can be controlled directly via the I2C and programmable engines are supported. LP55xx common driver LP8501 is one of LP55xx family device, so LP55xx common code are used. Chip specific data is defined in the structure, 'lp55xx_device_config'. Differences between LP8501 and LP5523 Different register layout for LED output control and others. LP8501 specific feature for separate output power selection. LP8501 doesn't support external clock detection. Different programming engine data. LP8501 specific feature - output power selection Output channels are selected by power selection - Vout or Vdd. Separate power for VDD1-6 and VDD7-9 are available. It is configurable in the platform data. To support this feature, LP55xx DT structure and header are changed. Device tree binding is updated as well. LED pattern data Example pattern data is updated in the driver documentation. Signed-off-by: Milo Kim <milo.kim@ti.com> Signed-off-by: Bryan Wu <cooloney@gmail.com>
187 lines
6.3 KiB
Plaintext
187 lines
6.3 KiB
Plaintext
LP5521/LP5523/LP55231/LP5562/LP8501 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, LP5562 and LP8501 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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The pattern sqeuence of LP8501 is same as LP5523.
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However pattern data is specific.
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Ex 1) Engine 1 is used
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echo 1 > /sys/bus/i2c/devices/xxxx/select_engine
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echo 1 > /sys/class/firmware/lp8501/loading
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echo "9d0140ff7e0040007e00a001c000" > /sys/class/firmware/lp8501/data
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echo 0 > /sys/class/firmware/lp8501/loading
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echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
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Ex 2) Engine 2 and 3 are used at the same time
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echo 2 > /sys/bus/i2c/devices/xxxx/select_engine
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sleep 1
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echo 1 > /sys/class/firmware/lp8501/loading
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echo "9d0140ff7e0040007e00a001c000" > /sys/class/firmware/lp8501/data
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echo 0 > /sys/class/firmware/lp8501/loading
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sleep 1
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echo 3 > /sys/bus/i2c/devices/xxxx/select_engine
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sleep 1
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echo 1 > /sys/class/firmware/lp8501/loading
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echo "9d0340ff7e0040007e00a001c000" > /sys/class/firmware/lp8501/data
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echo 0 > /sys/class/firmware/lp8501/loading
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sleep 1
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echo 1 > /sys/class/leds/d1/device/run_engine
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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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