- <sect1><title>Frame Buffer Memory</title>
-!Edrivers/video/fbmem.c
- </sect1>
-<!--
- <sect1><title>Frame Buffer Console</title>
-X!Edrivers/video/console/fbcon.c
- </sect1>
--->
- <sect1><title>Frame Buffer Colormap</title>
-!Edrivers/video/fbcmap.c
- </sect1>
-<!-- FIXME:
- drivers/video/fbgen.c has no docs, which stuffs up the sgml. Comment
- out until somebody adds docs. KAO
- <sect1><title>Frame Buffer Generic Functions</title>
-X!Idrivers/video/fbgen.c
- </sect1>
-KAO -->
- <sect1><title>Frame Buffer Video Mode Database</title>
-!Idrivers/video/modedb.c
-!Edrivers/video/modedb.c
- </sect1>
- <sect1><title>Frame Buffer Macintosh Video Mode Database</title>
-!Edrivers/video/macmodes.c
- </sect1>
- <sect1><title>Frame Buffer Fonts</title>
- <para>
- Refer to the file drivers/video/console/fonts.c for more information.
- </para>
-<!-- FIXME: Removed for now since no structured comments in source
-X!Idrivers/video/console/fonts.c
--->
- </sect1>
- </chapter>
-
- <chapter id="input_subsystem">
- <title>Input Subsystem</title>
-!Iinclude/linux/input.h
-!Edrivers/input/input.c
-!Edrivers/input/ff-core.c
-!Edrivers/input/ff-memless.c
- </chapter>
-
- <chapter id="spi">
- <title>Serial Peripheral Interface (SPI)</title>
- <para>
- SPI is the "Serial Peripheral Interface", widely used with
- embedded systems because it is a simple and efficient
- interface: basically a multiplexed shift register.
- Its three signal wires hold a clock (SCK, often in the range
- of 1-20 MHz), a "Master Out, Slave In" (MOSI) data line, and
- a "Master In, Slave Out" (MISO) data line.
- SPI is a full duplex protocol; for each bit shifted out the
- MOSI line (one per clock) another is shifted in on the MISO line.
- Those bits are assembled into words of various sizes on the
- way to and from system memory.
- An additional chipselect line is usually active-low (nCS);
- four signals are normally used for each peripheral, plus
- sometimes an interrupt.
- </para>
- <para>
- The SPI bus facilities listed here provide a generalized
- interface to declare SPI busses and devices, manage them
- according to the standard Linux driver model, and perform
- input/output operations.
- At this time, only "master" side interfaces are supported,
- where Linux talks to SPI peripherals and does not implement
- such a peripheral itself.
- (Interfaces to support implementing SPI slaves would
- necessarily look different.)
- </para>
- <para>
- The programming interface is structured around two kinds of driver,
- and two kinds of device.
- A "Controller Driver" abstracts the controller hardware, which may
- be as simple as a set of GPIO pins or as complex as a pair of FIFOs
- connected to dual DMA engines on the other side of the SPI shift
- register (maximizing throughput). Such drivers bridge between
- whatever bus they sit on (often the platform bus) and SPI, and
- expose the SPI side of their device as a
- <structname>struct spi_master</structname>.
- SPI devices are children of that master, represented as a
- <structname>struct spi_device</structname> and manufactured from
- <structname>struct spi_board_info</structname> descriptors which
- are usually provided by board-specific initialization code.
- A <structname>struct spi_driver</structname> is called a
- "Protocol Driver", and is bound to a spi_device using normal
- driver model calls.
- </para>
- <para>
- The I/O model is a set of queued messages. Protocol drivers
- submit one or more <structname>struct spi_message</structname>
- objects, which are processed and completed asynchronously.
- (There are synchronous wrappers, however.) Messages are
- built from one or more <structname>struct spi_transfer</structname>
- objects, each of which wraps a full duplex SPI transfer.
- A variety of protocol tweaking options are needed, because
- different chips adopt very different policies for how they
- use the bits transferred with SPI.
- </para>
-!Iinclude/linux/spi/spi.h
-!Fdrivers/spi/spi.c spi_register_board_info
-!Edrivers/spi/spi.c
- </chapter>
-
- <chapter id="i2c">
- <title>I<superscript>2</superscript>C and SMBus Subsystem</title>
-