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8dab9197 MCC |
1 | ======================== |
2 | Kernel driver for lp5521 | |
3 | ======================== | |
4 | ||
5 | * National Semiconductor LP5521 led driver chip | |
6 | * Datasheet: http://www.national.com/pf/LP/LP5521.html | |
7 | ||
8 | Authors: Mathias Nyman, Yuri Zaporozhets, Samu Onkalo | |
9 | ||
10 | Contact: Samu Onkalo (samu.p.onkalo-at-nokia.com) | |
11 | ||
12 | Description | |
13 | ----------- | |
14 | ||
15 | LP5521 can drive up to 3 channels. Leds can be controlled directly via | |
16 | the led class control interface. Channels have generic names: | |
17 | lp5521:channelx, where x is 0 .. 2 | |
18 | ||
19 | All three channels can be also controlled using the engine micro programs. | |
20 | More details of the instructions can be found from the public data sheet. | |
21 | ||
22 | LP5521 has the internal program memory for running various LED patterns. | |
23 | There are two ways to run LED patterns. | |
24 | ||
25 | 1) Legacy interface - enginex_mode and enginex_load | |
26 | Control interface for the engines: | |
27 | ||
28 | x is 1 .. 3 | |
29 | ||
30 | enginex_mode: | |
31 | disabled, load, run | |
32 | enginex_load: | |
33 | store program (visible only in engine load mode) | |
34 | ||
35 | Example (start to blink the channel 2 led):: | |
36 | ||
37 | cd /sys/class/leds/lp5521:channel2/device | |
38 | echo "load" > engine3_mode | |
39 | echo "037f4d0003ff6000" > engine3_load | |
40 | echo "run" > engine3_mode | |
41 | ||
42 | To stop the engine:: | |
43 | ||
44 | echo "disabled" > engine3_mode | |
45 | ||
46 | 2) Firmware interface - LP55xx common interface | |
47 | ||
48 | For the details, please refer to 'firmware' section in leds-lp55xx.txt | |
49 | ||
50 | sysfs contains a selftest entry. | |
51 | ||
52 | The test communicates with the chip and checks that | |
53 | the clock mode is automatically set to the requested one. | |
54 | ||
55 | Each channel has its own led current settings. | |
56 | ||
57 | - /sys/class/leds/lp5521:channel0/led_current - RW | |
58 | - /sys/class/leds/lp5521:channel0/max_current - RO | |
59 | ||
60 | Format: 10x mA i.e 10 means 1.0 mA | |
61 | ||
62 | example platform data:: | |
63 | ||
64 | static struct lp55xx_led_config lp5521_led_config[] = { | |
65 | { | |
66 | .name = "red", | |
67 | .chan_nr = 0, | |
68 | .led_current = 50, | |
69 | .max_current = 130, | |
70 | }, { | |
71 | .name = "green", | |
72 | .chan_nr = 1, | |
73 | .led_current = 0, | |
74 | .max_current = 130, | |
75 | }, { | |
76 | .name = "blue", | |
77 | .chan_nr = 2, | |
78 | .led_current = 0, | |
79 | .max_current = 130, | |
80 | } | |
81 | }; | |
82 | ||
83 | static int lp5521_setup(void) | |
84 | { | |
85 | /* setup HW resources */ | |
86 | } | |
87 | ||
88 | static void lp5521_release(void) | |
89 | { | |
90 | /* Release HW resources */ | |
91 | } | |
92 | ||
93 | static void lp5521_enable(bool state) | |
94 | { | |
95 | /* Control of chip enable signal */ | |
96 | } | |
97 | ||
98 | static struct lp55xx_platform_data lp5521_platform_data = { | |
99 | .led_config = lp5521_led_config, | |
100 | .num_channels = ARRAY_SIZE(lp5521_led_config), | |
101 | .clock_mode = LP55XX_CLOCK_EXT, | |
102 | .setup_resources = lp5521_setup, | |
103 | .release_resources = lp5521_release, | |
104 | .enable = lp5521_enable, | |
105 | }; | |
106 | ||
107 | Note: | |
108 | chan_nr can have values between 0 and 2. | |
109 | The name of each channel can be configurable. | |
110 | If the name field is not defined, the default name will be set to 'xxxx:channelN' | |
111 | (XXXX : pdata->label or i2c client name, N : channel number) | |
112 | ||
113 | ||
114 | If the current is set to 0 in the platform data, that channel is | |
115 | disabled and it is not visible in the sysfs. |