blob: 9ae3f5fe252db28403e1e853c0722afad56e2788 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
|
.. SPDX-License-Identifier: GPL-2.0+
LED
===
.. kernel-doc:: include/led.h
:doc: Overview
.. kernel-doc:: include/led.h
:internal:
Legacy LED
==========
Please use the new LED API as defined above. This section is only for reference
for currently supported devices and to aid for migration to the new API.
Status LED
----------
This README describes the status LED API.
The API is defined by the include file include/status_led.h
The first step is to enable CONFIG_LED_STATUS in menuconfig::
> Device Drivers > LED Support.
If the LED support is only for specific board, enable
CONFIG_LED_STATUS_BOARD_SPECIFIC in the menuconfig.
Status LEDS 0 to 5 are enabled by the following configurations at menuconfig:
CONFIG_STATUS_LED0, CONFIG_STATUS_LED1, ... CONFIG_STATUS_LED5
The following should be configured for each of the enabled LEDs:
- CONFIG_STATUS_LED_BIT<n>
- CONFIG_STATUS_LED_STATE<n>
- CONFIG_STATUS_LED_FREQ<n>
Where <n> is an integer 1 through 5 (empty for 0).
CONFIG_STATUS_LED_BIT is passed into the __led_* functions to identify which LED
is being acted on. As such, the value choose must be unique with respect to
the other CONFIG_STATUS_LED_BIT's. Mapping the value to a physical LED is the
reponsiblity of the __led_* function.
CONFIG_STATUS_LED_STATE is the initial state of the LED. It should be set to one
of these values: CONFIG_LED_STATUS_OFF or CONFIG_LED_STATUS_ON.
CONFIG_STATUS_LED_FREQ determines the LED blink frequency.
Values range from 2 to 10.
Some other LED macros
~~~~~~~~~~~~~~~~~~~~~
CONFIG_STATUS_LED_BOOT is the LED to light when the board is booting.
This must be a valid LED number (0-5).
General LED functions
~~~~~~~~~~~~~~~~~~~~~
The following functions should be defined:
__led_init is called once to initialize the LED to CONFIG_STATUS_LED_STATE.
One time start up code should be placed here.
__led_set is called to change the state of the LED.
__led_toggle is called to toggle the current state of the LED.
TBD : Describe older board dependent macros similar to what is done for
TBD : Describe general support via asm/status_led.h
|
