| Mauro Carvalho Chehab | 8dab919 | 2019-06-28 09:20:20 -0300 | [diff] [blame] | 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. |