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1 | Kernel driver for lp5521 | |
2 | ======================== | |
3 | ||
4 | * National Semiconductor LP5521 led driver chip | |
5 | * Datasheet: http://www.national.com/pf/LP/LP5521.html | |
6 | ||
7 | Authors: Mathias Nyman, Yuri Zaporozhets, Samu Onkalo | |
8 | Contact: Samu Onkalo (samu.p.onkalo-at-nokia.com) | |
9 | ||
10 | Description | |
11 | ----------- | |
12 | ||
13 | LP5521 can drive up to 3 channels. Leds can be controlled directly via | |
14 | the led class control interface. Channels have generic names: | |
15 | lp5521:channelx, where x is 0 .. 2 | |
16 | ||
17 | All three channels can be also controlled using the engine micro programs. | |
18 | More details of the instructions can be found from the public data sheet. | |
19 | ||
20 | LP5521 has the internal program memory for running various LED patterns. | |
21 | There are two ways to run LED patterns. | |
22 | ||
23 | 1) Legacy interface - enginex_mode and enginex_load | |
24 | Control interface for the engines: | |
25 | x is 1 .. 3 | |
26 | enginex_mode : disabled, load, run | |
27 | enginex_load : store program (visible only in engine load mode) | |
28 | ||
29 | Example (start to blink the channel 2 led): | |
30 | cd /sys/class/leds/lp5521:channel2/device | |
31 | echo "load" > engine3_mode | |
32 | echo "037f4d0003ff6000" > engine3_load | |
33 | echo "run" > engine3_mode | |
34 | ||
35 | To stop the engine: | |
36 | echo "disabled" > engine3_mode | |
37 | ||
38 | 2) Firmware interface - LP55xx common interface | |
39 | For the details, please refer to 'firmware' section in leds-lp55xx.txt | |
40 | ||
41 | sysfs contains a selftest entry. | |
42 | The test communicates with the chip and checks that | |
43 | the clock mode is automatically set to the requested one. | |
44 | ||
45 | Each channel has its own led current settings. | |
46 | /sys/class/leds/lp5521:channel0/led_current - RW | |
47 | /sys/class/leds/lp5521:channel0/max_current - RO | |
48 | Format: 10x mA i.e 10 means 1.0 mA | |
49 | ||
50 | example platform data: | |
51 | ||
52 | Note: chan_nr can have values between 0 and 2. | |
53 | The name of each channel can be configurable. | |
54 | If the name field is not defined, the default name will be set to 'xxxx:channelN' | |
55 | (XXXX : pdata->label or i2c client name, N : channel number) | |
56 | ||
57 | static struct lp55xx_led_config lp5521_led_config[] = { | |
58 | { | |
59 | .name = "red", | |
60 | .chan_nr = 0, | |
61 | .led_current = 50, | |
62 | .max_current = 130, | |
63 | }, { | |
64 | .name = "green", | |
65 | .chan_nr = 1, | |
66 | .led_current = 0, | |
67 | .max_current = 130, | |
68 | }, { | |
69 | .name = "blue", | |
70 | .chan_nr = 2, | |
71 | .led_current = 0, | |
72 | .max_current = 130, | |
73 | } | |
74 | }; | |
75 | ||
76 | static int lp5521_setup(void) | |
77 | { | |
78 | /* setup HW resources */ | |
79 | } | |
80 | ||
81 | static void lp5521_release(void) | |
82 | { | |
83 | /* Release HW resources */ | |
84 | } | |
85 | ||
86 | static void lp5521_enable(bool state) | |
87 | { | |
88 | /* Control of chip enable signal */ | |
89 | } | |
90 | ||
91 | static struct lp55xx_platform_data lp5521_platform_data = { | |
92 | .led_config = lp5521_led_config, | |
93 | .num_channels = ARRAY_SIZE(lp5521_led_config), | |
94 | .clock_mode = LP55XX_CLOCK_EXT, | |
95 | .setup_resources = lp5521_setup, | |
96 | .release_resources = lp5521_release, | |
97 | .enable = lp5521_enable, | |
98 | }; | |
99 | ||
100 | If the current is set to 0 in the platform data, that channel is | |
101 | disabled and it is not visible in the sysfs. |