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- .. SPDX-License-Identifier: GPL-2.0
- =========================================
- The device for Mediatek MT6370 RGB LED
- =========================================
- Description
- -----------
- The MT6370 integrates a four-channel RGB LED driver, designed to provide a
- variety of lighting effect for mobile device applications. The RGB LED devices
- includes a smart LED string controller and it can drive 3 channels of LEDs with
- a sink current up to 24mA and a CHG_VIN power good indicator LED with sink
- current up to 6mA. It provides three operation modes for RGB LEDs:
- PWM Dimming mode, breath pattern mode, and constant current mode. The device
- can increase or decrease the brightness of the RGB LED via an I2C interface.
- The breath pattern for a channel can be programmed using the "pattern" trigger,
- using the hw_pattern attribute.
- /sys/class/leds/<led>/hw_pattern
- --------------------------------
- Specify a hardware breath pattern for a MT6370 RGB LED.
- The breath pattern is a series of timing pairs, with the hold-time expressed in
- milliseconds. And the brightness is controlled by
- '/sys/class/leds/<led>/brightness'. The pattern doesn't include the brightness
- setting. Hardware pattern only controls the timing for each pattern stage
- depending on the current brightness setting.
- Pattern diagram::
- "0 Tr1 0 Tr2 0 Tf1 0 Tf2 0 Ton 0 Toff" --> '0' for dummy brightness code
- ^
- | ============
- | / \ /
- Icurr | / \ /
- | / \ /
- | / \ / .....repeat
- | / \ /
- | --- --- ---
- |--- --- ---
- +----------------------------------============------------> Time
- < Tr1><Tr2>< Ton ><Tf1><Tf2 >< Toff >< Tr1><Tr2>
- Timing description:
- * Tr1: First rising time for 0% - 30% load.
- * Tr2: Second rising time for 31% - 100% load.
- * Ton: On time for 100% load.
- * Tf1: First falling time for 100% - 31% load.
- * Tf2: Second falling time for 30% to 0% load.
- * Toff: Off time for 0% load.
- * Tr1/Tr2/Tf1/Tf2/Ton: 125ms to 3125ms, 200ms per step.
- * Toff: 250ms to 6250ms, 400ms per step.
- Pattern example::
- "0 125 0 125 0 125 0 125 0 625 0 1050"
- This Will configure Tr1/Tr2/Tf1/Tf2 to 125m, Ton to 625ms, and Toff to 1050ms.
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