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1.. SPDX-License-Identifier: GPL-2.02 3=========================================4The device for Mediatek MT6370 RGB LED5=========================================6 7Description8-----------9 10The MT6370 integrates a four-channel RGB LED driver, designed to provide a11variety of lighting effect for mobile device applications. The RGB LED devices12includes a smart LED string controller and it can drive 3 channels of LEDs with13a sink current up to 24mA and a CHG_VIN power good indicator LED with sink14current up to 6mA. It provides three operation modes for RGB LEDs:15PWM Dimming mode, breath pattern mode, and constant current mode. The device16can increase or decrease the brightness of the RGB LED via an I2C interface.17 18The breath pattern for a channel can be programmed using the "pattern" trigger,19using the hw_pattern attribute.20 21/sys/class/leds/<led>/hw_pattern22--------------------------------23 24Specify a hardware breath pattern for a MT6370 RGB LED.25 26The breath pattern is a series of timing pairs, with the hold-time expressed in27milliseconds. And the brightness is controlled by28'/sys/class/leds/<led>/brightness'. The pattern doesn't include the brightness29setting. Hardware pattern only controls the timing for each pattern stage30depending on the current brightness setting.31 32Pattern diagram::33 34 "0 Tr1 0 Tr2 0 Tf1 0 Tf2 0 Ton 0 Toff" --> '0' for dummy brightness code35 36 ^37 | ============38 | / \ /39 Icurr | / \ /40 | / \ /41 | / \ / .....repeat42 | / \ /43 | --- --- ---44 |--- --- ---45 +----------------------------------============------------> Time46 < Tr1><Tr2>< Ton ><Tf1><Tf2 >< Toff >< Tr1><Tr2>47 48Timing description:49 50 * Tr1: First rising time for 0% - 30% load.51 * Tr2: Second rising time for 31% - 100% load.52 * Ton: On time for 100% load.53 * Tf1: First falling time for 100% - 31% load.54 * Tf2: Second falling time for 30% to 0% load.55 * Toff: Off time for 0% load.56 57 * Tr1/Tr2/Tf1/Tf2/Ton: 125ms to 3125ms, 200ms per step.58 * Toff: 250ms to 6250ms, 400ms per step.59 60Pattern example::61 62 "0 125 0 125 0 125 0 125 0 625 0 1050"63 64This Will configure Tr1/Tr2/Tf1/Tf2 to 125m, Ton to 625ms, and Toff to 1050ms.65