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From: Samu Onkalo on 26 May 2010 07:40
Short documentation for National Semicondutor LP5521 and LP5523
LED driver chip kernel drivers.

Signed-off-by: Samu Onkalo <samu.p.onkalo(a)nokia.com>
---
Documentation/leds-lp5521.txt | 77 +++++++++++++++++++++++++++++++++++++++++
Documentation/leds-lp5523.txt | 73 ++++++++++++++++++++++++++++++++++++++
2 files changed, 150 insertions(+), 0 deletions(-)
create mode 100644 Documentation/leds-lp5521.txt
create mode 100644 Documentation/leds-lp5523.txt

diff --git a/Documentation/leds-lp5521.txt b/Documentation/leds-lp5521.txt
new file mode 100644
index 0000000..0fe2eef
--- /dev/null
+++ b/Documentation/leds-lp5521.txt
@@ -0,0 +1,77 @@
+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
+led class control interface. Channels have a generic names:
+lp5521:channelx, where x is 0 .. 2
+
+All three channels can be also controlled using engine micro programs.
+More details of the instructions can be found from public data sheet.
+
+Control interface for 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 also selftest entry.
+It communicates with the chip and checks that
+clock mode is automatically set to requested one.
+
+example platform data:
+static struct lp5521_led_config lp5521_led_config[] = {
+ {
+ .chan_nr = 0,
+ .led_current = 50,
+ }, {
+ .chan_nr = 1,
+ .led_current = 0,
+ }, {
+ .chan_nr = 2,
+ .led_current = 0,
+ }
+};
+
+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.
diff --git a/Documentation/leds-lp5523.txt b/Documentation/leds-lp5523.txt
new file mode 100644
index 0000000..eac7241
--- /dev/null
+++ b/Documentation/leds-lp5523.txt
@@ -0,0 +1,73 @@
+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
+led class control interface. Channels have a generic names:
+lp5523:channelx where x is 0...8
+
+Chip provides 3 engines which can be control channels wihtout main CPU
+interaction. Details of the micro engine code can be found from the
+public data sheet. Leds can be muxed to different channels.
+
+Control interface for 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 also selftest entry. It measures each channel
+voltage level and checks if it looks reasonable. Too high
+level means missing led and to low value means short circuit.
+
+Example platform data:
+
+static struct lp5523_led_config lp5523_led_config[] = {
+ {
+ .chan_nr = 0,
+ .led_current = 50,
+ },
+...
+ }, {
+ .chan_nr = 8,
+ .led_current = 50,
+ }
+};
+
+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,
+};
+
--
1.6.3.3

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Prev: led-class: set permissions on max_brightness file to 0444
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