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author | Srikant Patnaik | 2015-01-13 15:08:24 +0530 |
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committer | Srikant Patnaik | 2015-01-13 15:08:24 +0530 |
commit | 97327692361306d1e6259021bc425e32832fdb50 (patch) | |
tree | fe9088f3248ec61e24f404f21b9793cb644b7f01 /Documentation/leds/leds-lp5521.txt | |
parent | 2d05a8f663478a44e088d122e0d62109bbc801d0 (diff) | |
parent | a3a8b90b61e21be3dde9101c4e86c881e0f06210 (diff) | |
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dirty fix to merging
Diffstat (limited to 'Documentation/leds/leds-lp5521.txt')
-rw-r--r-- | Documentation/leds/leds-lp5521.txt | 151 |
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diff --git a/Documentation/leds/leds-lp5521.txt b/Documentation/leds/leds-lp5521.txt new file mode 100644 index 00000000..0e542ab3 --- /dev/null +++ b/Documentation/leds/leds-lp5521.txt @@ -0,0 +1,151 @@ +Kernel driver for lp5521 +======================== + +* National Semiconductor LP5521 led driver chip +* Datasheet: http://www.national.com/pf/LP/LP5521.html + +Authors: Mathias Nyman, Yuri Zaporozhets, Samu Onkalo +Contact: Samu Onkalo (samu.p.onkalo-at-nokia.com) + +Description +----------- + +LP5521 can drive up to 3 channels. Leds can be controlled directly via +the led class control interface. Channels have generic names: +lp5521:channelx, where x is 0 .. 2 + +All three channels can be also controlled using the engine micro programs. +More details of the instructions can be found from the public data sheet. + +Control interface for the engines: +x is 1 .. 3 +enginex_mode : disabled, load, run +enginex_load : store program (visible only in engine load mode) + +Example (start to blink the channel 2 led): +cd /sys/class/leds/lp5521:channel2/device +echo "load" > engine3_mode +echo "037f4d0003ff6000" > engine3_load +echo "run" > engine3_mode + +stop the engine: +echo "disabled" > engine3_mode + +sysfs contains a selftest entry. +The test communicates with the chip and checks that +the clock mode is automatically set to the requested one. + +Each channel has its own led current settings. +/sys/class/leds/lp5521:channel0/led_current - RW +/sys/class/leds/lp5521:channel0/max_current - RO +Format: 10x mA i.e 10 means 1.0 mA + +example platform data: + +Note: chan_nr can have values between 0 and 2. +The name of each channel can be configurable. +If the name field is not defined, the default name will be set to 'xxxx:channelN' +(XXXX : pdata->label or i2c client name, N : channel number) + +static struct lp5521_led_config lp5521_led_config[] = { + { + .name = "red", + .chan_nr = 0, + .led_current = 50, + .max_current = 130, + }, { + .name = "green", + .chan_nr = 1, + .led_current = 0, + .max_current = 130, + }, { + .name = "blue", + .chan_nr = 2, + .led_current = 0, + .max_current = 130, + } +}; + +static int lp5521_setup(void) +{ + /* setup HW resources */ +} + +static void lp5521_release(void) +{ + /* Release HW resources */ +} + +static void lp5521_enable(bool state) +{ + /* Control of chip enable signal */ +} + +static struct lp5521_platform_data lp5521_platform_data = { + .led_config = lp5521_led_config, + .num_channels = ARRAY_SIZE(lp5521_led_config), + .clock_mode = LP5521_CLOCK_EXT, + .setup_resources = lp5521_setup, + .release_resources = lp5521_release, + .enable = lp5521_enable, +}; + +If the current is set to 0 in the platform data, that channel is +disabled and it is not visible in the sysfs. + +The 'update_config' : CONFIG register (ADDR 08h) +This value is platform-specific data. +If update_config is not defined, the CONFIG register is set with +'LP5521_PWRSAVE_EN | LP5521_CP_MODE_AUTO | LP5521_R_TO_BATT'. +(Enable auto-powersave, set charge pump to auto, red to battery) + +example of update_config : + +#define LP5521_CONFIGS (LP5521_PWM_HF | LP5521_PWRSAVE_EN | \ + LP5521_CP_MODE_AUTO | LP5521_R_TO_BATT | \ + LP5521_CLK_INT) + +static struct lp5521_platform_data lp5521_pdata = { + .led_config = lp5521_led_config, + .num_channels = ARRAY_SIZE(lp5521_led_config), + .clock_mode = LP5521_CLOCK_INT, + .update_config = LP5521_CONFIGS, +}; + +LED patterns : LP5521 has autonomous operation without external control. +Pattern data can be defined in the platform data. + +example of led pattern data : + +/* RGB(50,5,0) 500ms on, 500ms off, infinite loop */ +static u8 pattern_red[] = { + 0x40, 0x32, 0x60, 0x00, 0x40, 0x00, 0x60, 0x00, + }; + +static u8 pattern_green[] = { + 0x40, 0x05, 0x60, 0x00, 0x40, 0x00, 0x60, 0x00, + }; + +static struct lp5521_led_pattern board_led_patterns[] = { + { + .r = pattern_red, + .g = pattern_green, + .size_r = ARRAY_SIZE(pattern_red), + .size_g = ARRAY_SIZE(pattern_green), + }, +}; + +static struct lp5521_platform_data lp5521_platform_data = { + .led_config = lp5521_led_config, + .num_channels = ARRAY_SIZE(lp5521_led_config), + .clock_mode = LP5521_CLOCK_EXT, + .patterns = board_led_patterns, + .num_patterns = ARRAY_SIZE(board_led_patterns), +}; + +Then predefined led pattern(s) can be executed via the sysfs. +To start the pattern #1, +# echo 1 > /sys/bus/i2c/devices/xxxx/led_pattern +(xxxx : i2c bus & slave address) +To end the pattern, +# echo 0 > /sys/bus/i2c/devices/xxxx/led_pattern |