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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/Documentation/leds/leds-lp5521.txt
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
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+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.
+
+LP5521 has the internal program memory for running various LED patterns.
+There are two ways to run LED patterns.
+
+1) Legacy interface - enginex_mode and enginex_load
+ 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
+
+ To stop the engine:
+ echo "disabled" > engine3_mode
+
+2) Firmware interface - LP55xx common interface
+ For the details, please refer to 'firmware' section in leds-lp55xx.txt
+
+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 lp55xx_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 lp55xx_platform_data lp5521_platform_data = {
+ .led_config = lp5521_led_config,
+ .num_channels = ARRAY_SIZE(lp5521_led_config),
+ .clock_mode = LP55XX_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.