1Kernel driver for lp5521
2========================
3
4* National Semiconductor LP5521 led driver chip
5* Datasheet: http://www.national.com/pf/LP/LP5521.html
6
7Authors: Mathias Nyman, Yuri Zaporozhets, Samu Onkalo
8Contact: Samu Onkalo (samu.p.onkalo-at-nokia.com)
9
10Description
11-----------
12
13LP5521 can drive up to 3 channels. Leds can be controlled directly via
14the led class control interface. Channels have generic names:
15lp5521:channelx, where x is 0 .. 2
16
17All three channels can be also controlled using the engine micro programs.
18More details of the instructions can be found from the public data sheet.
19
20LP5521 has the internal program memory for running various LED patterns.
21There are two ways to run LED patterns.
22
231) 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
382) Firmware interface - LP55xx common interface
39  For the details, please refer to 'firmware' section in leds-lp55xx.txt
40
41sysfs contains a selftest entry.
42The test communicates with the chip and checks that
43the clock mode is automatically set to the requested one.
44
45Each 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
48Format: 10x mA i.e 10 means 1.0 mA
49
50example platform data:
51
52Note: chan_nr can have values between 0 and 2.
53The name of each channel can be configurable.
54If 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
57static 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
76static int lp5521_setup(void)
77{
78	/* setup HW resources */
79}
80
81static void lp5521_release(void)
82{
83	/* Release HW resources */
84}
85
86static void lp5521_enable(bool state)
87{
88	/* Control of chip enable signal */
89}
90
91static 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
100If the current is set to 0 in the platform data, that channel is
101disabled and it is not visible in the sysfs.
102