mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-25 20:14:25 +08:00
f7f84f38cd
The kernel-api docbook was much larger than any of the others, so processing it took longer and needed some docbook extras in some cases, so split it into kernel-api (infrastructure etc.) and device drivers/device subsystems. This allows these docbooks to be generated in parallel. (This reduced the docbook processing time on my 4-proc system with make -j4 from about 5min:16sec to about 2min:01sec.) The chapters that were moved from kernel-api to device-drivers are: Driver Basics Device drivers infrastructure Parallel Port Devices Message-based devices Sound Devices 16x50 UART Driver Frame Buffer Library Input Subsystem Serial Peripheral Interface (SPI) I2C and SMBus Subsystem Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Acked-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
419 lines
14 KiB
XML
419 lines
14 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
|
|
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
|
|
|
|
<book id="LinuxDriversAPI">
|
|
<bookinfo>
|
|
<title>Linux Device Drivers</title>
|
|
|
|
<legalnotice>
|
|
<para>
|
|
This documentation is free software; you can redistribute
|
|
it and/or modify it under the terms of the GNU General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2 of the License, or (at your option) any later
|
|
version.
|
|
</para>
|
|
|
|
<para>
|
|
This program is distributed in the hope that it will be
|
|
useful, but WITHOUT ANY WARRANTY; without even the implied
|
|
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
|
|
See the GNU General Public License for more details.
|
|
</para>
|
|
|
|
<para>
|
|
You should have received a copy of the GNU General Public
|
|
License along with this program; if not, write to the Free
|
|
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
|
|
MA 02111-1307 USA
|
|
</para>
|
|
|
|
<para>
|
|
For more details see the file COPYING in the source
|
|
distribution of Linux.
|
|
</para>
|
|
</legalnotice>
|
|
</bookinfo>
|
|
|
|
<toc></toc>
|
|
|
|
<chapter id="Basics">
|
|
<title>Driver Basics</title>
|
|
<sect1><title>Driver Entry and Exit points</title>
|
|
!Iinclude/linux/init.h
|
|
</sect1>
|
|
|
|
<sect1><title>Atomic and pointer manipulation</title>
|
|
!Iarch/x86/include/asm/atomic_32.h
|
|
!Iarch/x86/include/asm/unaligned.h
|
|
</sect1>
|
|
|
|
<sect1><title>Delaying, scheduling, and timer routines</title>
|
|
!Iinclude/linux/sched.h
|
|
!Ekernel/sched.c
|
|
!Ekernel/timer.c
|
|
</sect1>
|
|
<sect1><title>High-resolution timers</title>
|
|
!Iinclude/linux/ktime.h
|
|
!Iinclude/linux/hrtimer.h
|
|
!Ekernel/hrtimer.c
|
|
</sect1>
|
|
<sect1><title>Workqueues and Kevents</title>
|
|
!Ekernel/workqueue.c
|
|
</sect1>
|
|
<sect1><title>Internal Functions</title>
|
|
!Ikernel/exit.c
|
|
!Ikernel/signal.c
|
|
!Iinclude/linux/kthread.h
|
|
!Ekernel/kthread.c
|
|
</sect1>
|
|
|
|
<sect1><title>Kernel objects manipulation</title>
|
|
<!--
|
|
X!Iinclude/linux/kobject.h
|
|
-->
|
|
!Elib/kobject.c
|
|
</sect1>
|
|
|
|
<sect1><title>Kernel utility functions</title>
|
|
!Iinclude/linux/kernel.h
|
|
!Ekernel/printk.c
|
|
!Ekernel/panic.c
|
|
!Ekernel/sys.c
|
|
!Ekernel/rcupdate.c
|
|
</sect1>
|
|
|
|
<sect1><title>Device Resource Management</title>
|
|
!Edrivers/base/devres.c
|
|
</sect1>
|
|
|
|
</chapter>
|
|
|
|
<chapter id="devdrivers">
|
|
<title>Device drivers infrastructure</title>
|
|
<sect1><title>Device Drivers Base</title>
|
|
<!--
|
|
X!Iinclude/linux/device.h
|
|
-->
|
|
!Edrivers/base/driver.c
|
|
!Edrivers/base/core.c
|
|
!Edrivers/base/class.c
|
|
!Edrivers/base/firmware_class.c
|
|
!Edrivers/base/transport_class.c
|
|
<!-- Cannot be included, because
|
|
attribute_container_add_class_device_adapter
|
|
and attribute_container_classdev_to_container
|
|
exceed allowed 44 characters maximum
|
|
X!Edrivers/base/attribute_container.c
|
|
-->
|
|
!Edrivers/base/sys.c
|
|
<!--
|
|
X!Edrivers/base/interface.c
|
|
-->
|
|
!Edrivers/base/platform.c
|
|
!Edrivers/base/bus.c
|
|
</sect1>
|
|
<sect1><title>Device Drivers Power Management</title>
|
|
!Edrivers/base/power/main.c
|
|
</sect1>
|
|
<sect1><title>Device Drivers ACPI Support</title>
|
|
<!-- Internal functions only
|
|
X!Edrivers/acpi/sleep/main.c
|
|
X!Edrivers/acpi/sleep/wakeup.c
|
|
X!Edrivers/acpi/motherboard.c
|
|
X!Edrivers/acpi/bus.c
|
|
-->
|
|
!Edrivers/acpi/scan.c
|
|
!Idrivers/acpi/scan.c
|
|
<!-- No correct structured comments
|
|
X!Edrivers/acpi/pci_bind.c
|
|
-->
|
|
</sect1>
|
|
<sect1><title>Device drivers PnP support</title>
|
|
!Idrivers/pnp/core.c
|
|
<!-- No correct structured comments
|
|
X!Edrivers/pnp/system.c
|
|
-->
|
|
!Edrivers/pnp/card.c
|
|
!Idrivers/pnp/driver.c
|
|
!Edrivers/pnp/manager.c
|
|
!Edrivers/pnp/support.c
|
|
</sect1>
|
|
<sect1><title>Userspace IO devices</title>
|
|
!Edrivers/uio/uio.c
|
|
!Iinclude/linux/uio_driver.h
|
|
</sect1>
|
|
</chapter>
|
|
|
|
<chapter id="parportdev">
|
|
<title>Parallel Port Devices</title>
|
|
!Iinclude/linux/parport.h
|
|
!Edrivers/parport/ieee1284.c
|
|
!Edrivers/parport/share.c
|
|
!Idrivers/parport/daisy.c
|
|
</chapter>
|
|
|
|
<chapter id="message_devices">
|
|
<title>Message-based devices</title>
|
|
<sect1><title>Fusion message devices</title>
|
|
!Edrivers/message/fusion/mptbase.c
|
|
!Idrivers/message/fusion/mptbase.c
|
|
!Edrivers/message/fusion/mptscsih.c
|
|
!Idrivers/message/fusion/mptscsih.c
|
|
!Idrivers/message/fusion/mptctl.c
|
|
!Idrivers/message/fusion/mptspi.c
|
|
!Idrivers/message/fusion/mptfc.c
|
|
!Idrivers/message/fusion/mptlan.c
|
|
</sect1>
|
|
<sect1><title>I2O message devices</title>
|
|
!Iinclude/linux/i2o.h
|
|
!Idrivers/message/i2o/core.h
|
|
!Edrivers/message/i2o/iop.c
|
|
!Idrivers/message/i2o/iop.c
|
|
!Idrivers/message/i2o/config-osm.c
|
|
!Edrivers/message/i2o/exec-osm.c
|
|
!Idrivers/message/i2o/exec-osm.c
|
|
!Idrivers/message/i2o/bus-osm.c
|
|
!Edrivers/message/i2o/device.c
|
|
!Idrivers/message/i2o/device.c
|
|
!Idrivers/message/i2o/driver.c
|
|
!Idrivers/message/i2o/pci.c
|
|
!Idrivers/message/i2o/i2o_block.c
|
|
!Idrivers/message/i2o/i2o_scsi.c
|
|
!Idrivers/message/i2o/i2o_proc.c
|
|
</sect1>
|
|
</chapter>
|
|
|
|
<chapter id="snddev">
|
|
<title>Sound Devices</title>
|
|
!Iinclude/sound/core.h
|
|
!Esound/sound_core.c
|
|
!Iinclude/sound/pcm.h
|
|
!Esound/core/pcm.c
|
|
!Esound/core/device.c
|
|
!Esound/core/info.c
|
|
!Esound/core/rawmidi.c
|
|
!Esound/core/sound.c
|
|
!Esound/core/memory.c
|
|
!Esound/core/pcm_memory.c
|
|
!Esound/core/init.c
|
|
!Esound/core/isadma.c
|
|
!Esound/core/control.c
|
|
!Esound/core/pcm_lib.c
|
|
!Esound/core/hwdep.c
|
|
!Esound/core/pcm_native.c
|
|
!Esound/core/memalloc.c
|
|
<!-- FIXME: Removed for now since no structured comments in source
|
|
X!Isound/sound_firmware.c
|
|
-->
|
|
</chapter>
|
|
|
|
<chapter id="uart16x50">
|
|
<title>16x50 UART Driver</title>
|
|
!Iinclude/linux/serial_core.h
|
|
!Edrivers/serial/serial_core.c
|
|
!Edrivers/serial/8250.c
|
|
</chapter>
|
|
|
|
<chapter id="fbdev">
|
|
<title>Frame Buffer Library</title>
|
|
|
|
<para>
|
|
The frame buffer drivers depend heavily on four data structures.
|
|
These structures are declared in include/linux/fb.h. They are
|
|
fb_info, fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs.
|
|
The last three can be made available to and from userland.
|
|
</para>
|
|
|
|
<para>
|
|
fb_info defines the current state of a particular video card.
|
|
Inside fb_info, there exists a fb_ops structure which is a
|
|
collection of needed functions to make fbdev and fbcon work.
|
|
fb_info is only visible to the kernel.
|
|
</para>
|
|
|
|
<para>
|
|
fb_var_screeninfo is used to describe the features of a video card
|
|
that are user defined. With fb_var_screeninfo, things such as
|
|
depth and the resolution may be defined.
|
|
</para>
|
|
|
|
<para>
|
|
The next structure is fb_fix_screeninfo. This defines the
|
|
properties of a card that are created when a mode is set and can't
|
|
be changed otherwise. A good example of this is the start of the
|
|
frame buffer memory. This "locks" the address of the frame buffer
|
|
memory, so that it cannot be changed or moved.
|
|
</para>
|
|
|
|
<para>
|
|
The last structure is fb_monospecs. In the old API, there was
|
|
little importance for fb_monospecs. This allowed for forbidden things
|
|
such as setting a mode of 800x600 on a fix frequency monitor. With
|
|
the new API, fb_monospecs prevents such things, and if used
|
|
correctly, can prevent a monitor from being cooked. fb_monospecs
|
|
will not be useful until kernels 2.5.x.
|
|
</para>
|
|
|
|
<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>
|
|
|
|
<para>
|
|
I<superscript>2</superscript>C (or without fancy typography, "I2C")
|
|
is an acronym for the "Inter-IC" bus, a simple bus protocol which is
|
|
widely used where low data rate communications suffice.
|
|
Since it's also a licensed trademark, some vendors use another
|
|
name (such as "Two-Wire Interface", TWI) for the same bus.
|
|
I2C only needs two signals (SCL for clock, SDA for data), conserving
|
|
board real estate and minimizing signal quality issues.
|
|
Most I2C devices use seven bit addresses, and bus speeds of up
|
|
to 400 kHz; there's a high speed extension (3.4 MHz) that's not yet
|
|
found wide use.
|
|
I2C is a multi-master bus; open drain signaling is used to
|
|
arbitrate between masters, as well as to handshake and to
|
|
synchronize clocks from slower clients.
|
|
</para>
|
|
|
|
<para>
|
|
The Linux I2C programming interfaces support only the master
|
|
side of bus interactions, not the slave side.
|
|
The programming interface is structured around two kinds of driver,
|
|
and two kinds of device.
|
|
An I2C "Adapter Driver" abstracts the controller hardware; it binds
|
|
to a physical device (perhaps a PCI device or platform_device) and
|
|
exposes a <structname>struct i2c_adapter</structname> representing
|
|
each I2C bus segment it manages.
|
|
On each I2C bus segment will be I2C devices represented by a
|
|
<structname>struct i2c_client</structname>. Those devices will
|
|
be bound to a <structname>struct i2c_driver</structname>,
|
|
which should follow the standard Linux driver model.
|
|
(At this writing, a legacy model is more widely used.)
|
|
There are functions to perform various I2C protocol operations; at
|
|
this writing all such functions are usable only from task context.
|
|
</para>
|
|
|
|
<para>
|
|
The System Management Bus (SMBus) is a sibling protocol. Most SMBus
|
|
systems are also I2C conformant. The electrical constraints are
|
|
tighter for SMBus, and it standardizes particular protocol messages
|
|
and idioms. Controllers that support I2C can also support most
|
|
SMBus operations, but SMBus controllers don't support all the protocol
|
|
options that an I2C controller will.
|
|
There are functions to perform various SMBus protocol operations,
|
|
either using I2C primitives or by issuing SMBus commands to
|
|
i2c_adapter devices which don't support those I2C operations.
|
|
</para>
|
|
|
|
!Iinclude/linux/i2c.h
|
|
!Fdrivers/i2c/i2c-boardinfo.c i2c_register_board_info
|
|
!Edrivers/i2c/i2c-core.c
|
|
</chapter>
|
|
|
|
</book>
|