1 .. SPDX-License-Identifier: GPL-2.0 1 .. SPDX-License-Identifier: GPL-2.0
2 2
3 ========================================= 3 =========================================
4 The device for Mediatek MT6370 RGB LED 4 The device for Mediatek MT6370 RGB LED
5 ========================================= 5 =========================================
6 6
7 Description 7 Description
8 ----------- 8 -----------
9 9
10 The MT6370 integrates a four-channel RGB LED d 10 The MT6370 integrates a four-channel RGB LED driver, designed to provide a
11 variety of lighting effect for mobile device a 11 variety of lighting effect for mobile device applications. The RGB LED devices
12 includes a smart LED string controller and it 12 includes a smart LED string controller and it can drive 3 channels of LEDs with
13 a sink current up to 24mA and a CHG_VIN power 13 a sink current up to 24mA and a CHG_VIN power good indicator LED with sink
14 current up to 6mA. It provides three operation 14 current up to 6mA. It provides three operation modes for RGB LEDs:
15 PWM Dimming mode, breath pattern mode, and con 15 PWM Dimming mode, breath pattern mode, and constant current mode. The device
16 can increase or decrease the brightness of the 16 can increase or decrease the brightness of the RGB LED via an I2C interface.
17 17
18 The breath pattern for a channel can be progra 18 The breath pattern for a channel can be programmed using the "pattern" trigger,
19 using the hw_pattern attribute. 19 using the hw_pattern attribute.
20 20
21 /sys/class/leds/<led>/hw_pattern 21 /sys/class/leds/<led>/hw_pattern
22 -------------------------------- 22 --------------------------------
23 23
24 Specify a hardware breath pattern for a MT6370 24 Specify a hardware breath pattern for a MT6370 RGB LED.
25 25
26 The breath pattern is a series of timing pairs 26 The breath pattern is a series of timing pairs, with the hold-time expressed in
27 milliseconds. And the brightness is controlled 27 milliseconds. And the brightness is controlled by
28 '/sys/class/leds/<led>/brightness'. The patter 28 '/sys/class/leds/<led>/brightness'. The pattern doesn't include the brightness
29 setting. Hardware pattern only controls the ti 29 setting. Hardware pattern only controls the timing for each pattern stage
30 depending on the current brightness setting. 30 depending on the current brightness setting.
31 31
32 Pattern diagram:: 32 Pattern diagram::
33 33
34 "0 Tr1 0 Tr2 0 Tf1 0 Tf2 0 Ton 0 Toff 34 "0 Tr1 0 Tr2 0 Tf1 0 Tf2 0 Ton 0 Toff" --> '0' for dummy brightness code
35 35
36 ^ 36 ^
37 | ============ 37 | ============
38 | / \ 38 | / \ /
39 Icurr | / \ 39 Icurr | / \ /
40 | / \ 40 | / \ /
41 | / \ 41 | / \ / .....repeat
42 | / \ 42 | / \ /
43 | --- --- 43 | --- --- ---
44 |--- --- 44 |--- --- ---
45 +----------------------------------= 45 +----------------------------------============------------> Time
46 < Tr1><Tr2>< Ton ><Tf1><Tf2 >< 46 < Tr1><Tr2>< Ton ><Tf1><Tf2 >< Toff >< Tr1><Tr2>
47 47
48 Timing description: 48 Timing description:
49 49
50 * Tr1: First rising time for 0% - 30% loa 50 * Tr1: First rising time for 0% - 30% load.
51 * Tr2: Second rising time for 31% - 100% 51 * Tr2: Second rising time for 31% - 100% load.
52 * Ton: On time for 100% load. 52 * Ton: On time for 100% load.
53 * Tf1: First falling time for 100% - 31% 53 * Tf1: First falling time for 100% - 31% load.
54 * Tf2: Second falling time for 30% to 0% 54 * Tf2: Second falling time for 30% to 0% load.
55 * Toff: Off time for 0% load. 55 * Toff: Off time for 0% load.
56 56
57 * Tr1/Tr2/Tf1/Tf2/Ton: 125ms to 3125ms, 200m 57 * Tr1/Tr2/Tf1/Tf2/Ton: 125ms to 3125ms, 200ms per step.
58 * Toff: 250ms to 6250ms, 400ms per step. 58 * Toff: 250ms to 6250ms, 400ms per step.
59 59
60 Pattern example:: 60 Pattern example::
61 61
62 "0 125 0 125 0 125 0 125 0 625 0 1050" 62 "0 125 0 125 0 125 0 125 0 625 0 1050"
63 63
64 This Will configure Tr1/Tr2/Tf1/Tf2 to 125m, T 64 This Will configure Tr1/Tr2/Tf1/Tf2 to 125m, Ton to 625ms, and Toff to 1050ms.
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