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authorMauro Carvalho Chehab <mchehab+samsung@kernel.org>2019-06-28 09:20:20 -0300
committerJacek Anaszewski <jacek.anaszewski@gmail.com>2019-06-28 20:57:31 +0200
commit8dab91970a8c01ffc7816bf8a4c4cd587b481f34 (patch)
treebadc731b9da46037457092b360ed83baaa4351b9 /Documentation/leds/leds-lp3944.rst
parent25529edef561ca51dadcbb6e97b1c40d2dbc5bae (diff)
docs: leds: convert to ReST
Rename the leds documentation files to ReST, add an index for them and adjust in order to produce a nice html output via the Sphinx build system. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
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+====================
+Kernel driver lp3944
+====================
+
+ * National Semiconductor LP3944 Fun-light Chip
+
+ Prefix: 'lp3944'
+
+ Addresses scanned: None (see the Notes section below)
+
+ Datasheet:
+
+ Publicly available at the National Semiconductor website
+ http://www.national.com/pf/LP/LP3944.html
+
+Authors:
+ Antonio Ospite <ospite@studenti.unina.it>
+
+
+Description
+-----------
+The LP3944 is a helper chip that can drive up to 8 leds, with two programmable
+DIM modes; it could even be used as a gpio expander but this driver assumes it
+is used as a led controller.
+
+The DIM modes are used to set _blink_ patterns for leds, the pattern is
+specified supplying two parameters:
+
+ - period:
+ from 0s to 1.6s
+ - duty cycle:
+ percentage of the period the led is on, from 0 to 100
+
+Setting a led in DIM0 or DIM1 mode makes it blink according to the pattern.
+See the datasheet for details.
+
+LP3944 can be found on Motorola A910 smartphone, where it drives the rgb
+leds, the camera flash light and the lcds power.
+
+
+Notes
+-----
+The chip is used mainly in embedded contexts, so this driver expects it is
+registered using the i2c_board_info mechanism.
+
+To register the chip at address 0x60 on adapter 0, set the platform data
+according to include/linux/leds-lp3944.h, set the i2c board info::
+
+ static struct i2c_board_info a910_i2c_board_info[] __initdata = {
+ {
+ I2C_BOARD_INFO("lp3944", 0x60),
+ .platform_data = &a910_lp3944_leds,
+ },
+ };
+
+and register it in the platform init function::
+
+ i2c_register_board_info(0, a910_i2c_board_info,
+ ARRAY_SIZE(a910_i2c_board_info));