summaryrefslogtreecommitdiffstats
path: root/Documentation/leds/leds-lp5523.txt
diff options
context:
space:
mode:
authorRussell King <rmk+kernel@arm.linux.org.uk>2011-01-06 22:31:35 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-01-06 22:32:03 +0000
commit4ec3eb13634529c0bc7466658d84d0bbe3244aea (patch)
treeb491daac2ccfc7b8ca88e171a43f66888463568a /Documentation/leds/leds-lp5523.txt
parent24056f525051a9e186af28904b396320e18bf9a0 (diff)
parent15095bb0fe779c0403091bda7adce5fb3bb9ca35 (diff)
downloadlinux-4ec3eb13634529c0bc7466658d84d0bbe3244aea.tar.gz
linux-4ec3eb13634529c0bc7466658d84d0bbe3244aea.tar.bz2
linux-4ec3eb13634529c0bc7466658d84d0bbe3244aea.zip
Merge branch 'smp' into misc
Conflicts: arch/arm/kernel/entry-armv.S arch/arm/mm/ioremap.c
Diffstat (limited to 'Documentation/leds/leds-lp5523.txt')
-rw-r--r--Documentation/leds/leds-lp5523.txt83
1 files changed, 83 insertions, 0 deletions
diff --git a/Documentation/leds/leds-lp5523.txt b/Documentation/leds/leds-lp5523.txt
new file mode 100644
index 000000000000..fad2feb8b7ce
--- /dev/null
+++ b/Documentation/leds/leds-lp5523.txt
@@ -0,0 +1,83 @@
+Kernel driver for lp5523
+========================
+
+* National Semiconductor LP5523 led driver chip
+* Datasheet: http://www.national.com/pf/LP/LP5523.html
+
+Authors: Mathias Nyman, Yuri Zaporozhets, Samu Onkalo
+Contact: Samu Onkalo (samu.p.onkalo-at-nokia.com)
+
+Description
+-----------
+LP5523 can drive up to 9 channels. Leds can be controlled directly via
+the led class control interface. Channels have generic names:
+lp5523:channelx where x is 0...8
+
+The chip provides 3 engines. Each engine can control channels without
+interaction from the main CPU. Details of the micro engine code can be found
+from the public data sheet. Leds can be muxed to different channels.
+
+Control interface for the engines:
+x is 1 .. 3
+enginex_mode : disabled, load, run
+enginex_load : microcode load (visible only in load mode)
+enginex_leds : led mux control (visible only in load mode)
+
+cd /sys/class/leds/lp5523:channel2/device
+echo "load" > engine3_mode
+echo "9d80400004ff05ff437f0000" > engine3_load
+echo "111111111" > engine3_leds
+echo "run" > engine3_mode
+
+sysfs contains a selftest entry. It measures each channel
+voltage level and checks if it looks reasonable. If the level is too high,
+the led is missing; if the level is too low, there is a short circuit.
+
+Selftest uses always the current from the platform data.
+
+Each channel contains led current settings.
+/sys/class/leds/lp5523:channel2/led_current - RW
+/sys/class/leds/lp5523:channel2/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 8.
+
+static struct lp5523_led_config lp5523_led_config[] = {
+ {
+ .chan_nr = 0,
+ .led_current = 50,
+ .max_current = 130,
+ },
+...
+ }, {
+ .chan_nr = 8,
+ .led_current = 50,
+ .max_current = 130,
+ }
+};
+
+static int lp5523_setup(void)
+{
+ /* Setup HW resources */
+}
+
+static void lp5523_release(void)
+{
+ /* Release HW resources */
+}
+
+static void lp5523_enable(bool state)
+{
+ /* Control chip enable signal */
+}
+
+static struct lp5523_platform_data lp5523_platform_data = {
+ .led_config = lp5523_led_config,
+ .num_channels = ARRAY_SIZE(lp5523_led_config),
+ .clock_mode = LP5523_CLOCK_EXT,
+ .setup_resources = lp5523_setup,
+ .release_resources = lp5523_release,
+ .enable = lp5523_enable,
+};