| .. 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. |
