541 lines
18 KiB
XML
541 lines
18 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
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<book id="LinuxDriversAPI">
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<bookinfo>
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<title>Linux Device Drivers</title>
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<legalnotice>
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<para>
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This documentation is free software; you can redistribute
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it and/or modify it under the terms of the GNU General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later
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version.
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</para>
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<para>
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This program is distributed in the hope that it will be
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useful, but WITHOUT ANY WARRANTY; without even the implied
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warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the GNU General Public License for more details.
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</para>
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<para>
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You should have received a copy of the GNU General Public
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License along with this program; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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MA 02111-1307 USA
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</para>
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<para>
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For more details see the file COPYING in the source
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distribution of Linux.
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</para>
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</legalnotice>
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</bookinfo>
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<toc></toc>
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<chapter id="Basics">
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<title>Driver Basics</title>
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<sect1><title>Driver Entry and Exit points</title>
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!Iinclude/linux/init.h
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</sect1>
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<sect1><title>Atomic and pointer manipulation</title>
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!Iarch/x86/include/asm/atomic.h
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</sect1>
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<sect1><title>Delaying, scheduling, and timer routines</title>
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!Iinclude/linux/sched.h
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!Ekernel/sched/core.c
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!Ikernel/sched/cpupri.c
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!Ikernel/sched/fair.c
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!Iinclude/linux/completion.h
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!Ekernel/time/timer.c
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</sect1>
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<sect1><title>Wait queues and Wake events</title>
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!Iinclude/linux/wait.h
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!Ekernel/sched/wait.c
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</sect1>
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<sect1><title>High-resolution timers</title>
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!Iinclude/linux/ktime.h
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!Iinclude/linux/hrtimer.h
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!Ekernel/time/hrtimer.c
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</sect1>
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<sect1><title>Workqueues and Kevents</title>
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!Iinclude/linux/workqueue.h
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!Ekernel/workqueue.c
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</sect1>
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<sect1><title>Internal Functions</title>
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!Ikernel/exit.c
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!Ikernel/signal.c
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!Iinclude/linux/kthread.h
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!Ekernel/kthread.c
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</sect1>
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|
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<sect1><title>Kernel objects manipulation</title>
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<!--
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X!Iinclude/linux/kobject.h
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-->
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!Elib/kobject.c
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</sect1>
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|
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<sect1><title>Kernel utility functions</title>
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!Iinclude/linux/kernel.h
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!Ekernel/printk/printk.c
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!Ekernel/panic.c
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!Ekernel/sys.c
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!Ekernel/rcu/srcu.c
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!Ekernel/rcu/tree.c
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!Ekernel/rcu/tree_plugin.h
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!Ekernel/rcu/update.c
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</sect1>
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|
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<sect1><title>Device Resource Management</title>
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!Edrivers/base/devres.c
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</sect1>
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</chapter>
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<chapter id="devdrivers">
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<title>Device drivers infrastructure</title>
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<sect1><title>The Basic Device Driver-Model Structures </title>
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!Iinclude/linux/device.h
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</sect1>
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<sect1><title>Device Drivers Base</title>
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!Idrivers/base/init.c
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!Edrivers/base/driver.c
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!Edrivers/base/core.c
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!Edrivers/base/syscore.c
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!Edrivers/base/class.c
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!Idrivers/base/node.c
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!Edrivers/base/firmware_class.c
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!Edrivers/base/transport_class.c
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|
<!-- Cannot be included, because
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attribute_container_add_class_device_adapter
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and attribute_container_classdev_to_container
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exceed allowed 44 characters maximum
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X!Edrivers/base/attribute_container.c
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-->
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!Edrivers/base/dd.c
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<!--
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X!Edrivers/base/interface.c
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-->
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!Iinclude/linux/platform_device.h
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!Edrivers/base/platform.c
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!Edrivers/base/bus.c
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</sect1>
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<sect1><title>Device Drivers DMA Management</title>
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!Edrivers/dma-buf/dma-buf.c
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!Edrivers/dma-buf/fence.c
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!Edrivers/dma-buf/seqno-fence.c
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!Iinclude/linux/fence.h
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!Iinclude/linux/seqno-fence.h
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!Edrivers/dma-buf/reservation.c
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!Iinclude/linux/reservation.h
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!Edrivers/base/dma-coherent.c
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!Edrivers/base/dma-mapping.c
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</sect1>
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<sect1><title>Device Drivers Power Management</title>
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!Edrivers/base/power/main.c
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</sect1>
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<sect1><title>Device Drivers ACPI Support</title>
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<!-- Internal functions only
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X!Edrivers/acpi/sleep/main.c
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X!Edrivers/acpi/sleep/wakeup.c
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X!Edrivers/acpi/motherboard.c
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X!Edrivers/acpi/bus.c
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-->
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!Edrivers/acpi/scan.c
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!Idrivers/acpi/scan.c
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<!-- No correct structured comments
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X!Edrivers/acpi/pci_bind.c
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-->
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</sect1>
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<sect1><title>Device drivers PnP support</title>
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!Idrivers/pnp/core.c
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<!-- No correct structured comments
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X!Edrivers/pnp/system.c
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-->
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!Edrivers/pnp/card.c
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!Idrivers/pnp/driver.c
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!Edrivers/pnp/manager.c
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!Edrivers/pnp/support.c
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</sect1>
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<sect1><title>Userspace IO devices</title>
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!Edrivers/uio/uio.c
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!Iinclude/linux/uio_driver.h
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</sect1>
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</chapter>
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<chapter id="parportdev">
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<title>Parallel Port Devices</title>
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!Iinclude/linux/parport.h
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!Edrivers/parport/ieee1284.c
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!Edrivers/parport/share.c
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!Idrivers/parport/daisy.c
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</chapter>
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<chapter id="message_devices">
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<title>Message-based devices</title>
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<sect1><title>Fusion message devices</title>
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!Edrivers/message/fusion/mptbase.c
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!Idrivers/message/fusion/mptbase.c
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!Edrivers/message/fusion/mptscsih.c
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!Idrivers/message/fusion/mptscsih.c
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!Idrivers/message/fusion/mptctl.c
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!Idrivers/message/fusion/mptspi.c
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!Idrivers/message/fusion/mptfc.c
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!Idrivers/message/fusion/mptlan.c
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</sect1>
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</chapter>
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<chapter id="snddev">
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<title>Sound Devices</title>
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!Iinclude/sound/core.h
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!Esound/sound_core.c
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!Iinclude/sound/pcm.h
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!Esound/core/pcm.c
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!Esound/core/device.c
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!Esound/core/info.c
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!Esound/core/rawmidi.c
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!Esound/core/sound.c
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!Esound/core/memory.c
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!Esound/core/pcm_memory.c
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!Esound/core/init.c
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!Esound/core/isadma.c
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!Esound/core/control.c
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!Esound/core/pcm_lib.c
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!Esound/core/hwdep.c
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!Esound/core/pcm_native.c
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!Esound/core/memalloc.c
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<!-- FIXME: Removed for now since no structured comments in source
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X!Isound/sound_firmware.c
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-->
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</chapter>
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<chapter id="mediadev">
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<title>Media Devices</title>
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<sect1><title>Video2Linux devices</title>
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!Iinclude/media/tuner.h
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!Iinclude/media/tuner-types.h
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!Iinclude/media/tveeprom.h
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!Iinclude/media/v4l2-async.h
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!Iinclude/media/v4l2-ctrls.h
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!Iinclude/media/v4l2-dv-timings.h
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!Iinclude/media/v4l2-event.h
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!Iinclude/media/v4l2-flash-led-class.h
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!Iinclude/media/v4l2-mediabus.h
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!Iinclude/media/v4l2-mem2mem.h
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!Iinclude/media/v4l2-of.h
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!Iinclude/media/v4l2-subdev.h
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!Iinclude/media/videobuf2-core.h
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!Iinclude/media/videobuf2-v4l2.h
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!Iinclude/media/videobuf2-memops.h
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</sect1>
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<sect1><title>Digital TV (DVB) devices</title>
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<sect1><title>Digital TV Common functions</title>
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!Idrivers/media/dvb-core/dvb_math.h
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!Idrivers/media/dvb-core/dvb_ringbuffer.h
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!Idrivers/media/dvb-core/dvbdev.h
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</sect1>
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<sect1><title>Digital TV Frontend kABI</title>
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!Pdrivers/media/dvb-core/dvb_frontend.h Digital TV Frontend
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!Idrivers/media/dvb-core/dvb_frontend.h
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</sect1>
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<sect1><title>Digital TV Demux kABI</title>
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!Pdrivers/media/dvb-core/demux.h Digital TV Demux
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<sect1><title>Demux Callback API</title>
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!Pdrivers/media/dvb-core/demux.h Demux Callback
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</sect1>
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!Idrivers/media/dvb-core/demux.h
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</sect1>
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<sect1><title>Digital TV Conditional Access kABI</title>
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!Idrivers/media/dvb-core/dvb_ca_en50221.h
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</sect1>
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</sect1>
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<sect1><title>Remote Controller devices</title>
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!Iinclude/media/rc-core.h
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!Iinclude/media/lirc_dev.h
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</sect1>
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<sect1><title>Media Controller devices</title>
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!Pinclude/media/media-device.h Media Controller
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!Iinclude/media/media-device.h
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!Iinclude/media/media-devnode.h
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!Iinclude/media/media-entity.h
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</sect1>
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</chapter>
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<chapter id="uart16x50">
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<title>16x50 UART Driver</title>
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!Edrivers/tty/serial/serial_core.c
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!Edrivers/tty/serial/8250/8250_core.c
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</chapter>
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<chapter id="fbdev">
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<title>Frame Buffer Library</title>
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<para>
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The frame buffer drivers depend heavily on four data structures.
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These structures are declared in include/linux/fb.h. They are
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fb_info, fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs.
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The last three can be made available to and from userland.
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</para>
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<para>
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fb_info defines the current state of a particular video card.
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Inside fb_info, there exists a fb_ops structure which is a
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collection of needed functions to make fbdev and fbcon work.
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fb_info is only visible to the kernel.
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</para>
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<para>
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fb_var_screeninfo is used to describe the features of a video card
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that are user defined. With fb_var_screeninfo, things such as
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depth and the resolution may be defined.
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</para>
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<para>
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The next structure is fb_fix_screeninfo. This defines the
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properties of a card that are created when a mode is set and can't
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be changed otherwise. A good example of this is the start of the
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frame buffer memory. This "locks" the address of the frame buffer
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memory, so that it cannot be changed or moved.
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</para>
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<para>
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The last structure is fb_monospecs. In the old API, there was
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little importance for fb_monospecs. This allowed for forbidden things
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such as setting a mode of 800x600 on a fix frequency monitor. With
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the new API, fb_monospecs prevents such things, and if used
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correctly, can prevent a monitor from being cooked. fb_monospecs
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will not be useful until kernels 2.5.x.
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</para>
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<sect1><title>Frame Buffer Memory</title>
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!Edrivers/video/fbdev/core/fbmem.c
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</sect1>
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<!--
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<sect1><title>Frame Buffer Console</title>
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X!Edrivers/video/console/fbcon.c
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</sect1>
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-->
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<sect1><title>Frame Buffer Colormap</title>
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!Edrivers/video/fbdev/core/fbcmap.c
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</sect1>
|
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<!-- FIXME:
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drivers/video/fbgen.c has no docs, which stuffs up the sgml. Comment
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out until somebody adds docs. KAO
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<sect1><title>Frame Buffer Generic Functions</title>
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X!Idrivers/video/fbgen.c
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</sect1>
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KAO -->
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<sect1><title>Frame Buffer Video Mode Database</title>
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!Idrivers/video/fbdev/core/modedb.c
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!Edrivers/video/fbdev/core/modedb.c
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</sect1>
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<sect1><title>Frame Buffer Macintosh Video Mode Database</title>
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!Edrivers/video/fbdev/macmodes.c
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</sect1>
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<sect1><title>Frame Buffer Fonts</title>
|
|
<para>
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Refer to the file lib/fonts/fonts.c for more information.
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|
</para>
|
|
<!-- FIXME: Removed for now since no structured comments in source
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X!Ilib/fonts/fonts.c
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-->
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</sect1>
|
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</chapter>
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|
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<chapter id="input_subsystem">
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<title>Input Subsystem</title>
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<sect1><title>Input core</title>
|
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!Iinclude/linux/input.h
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!Edrivers/input/input.c
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!Edrivers/input/ff-core.c
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!Edrivers/input/ff-memless.c
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</sect1>
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<sect1><title>Multitouch Library</title>
|
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!Iinclude/linux/input/mt.h
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!Edrivers/input/input-mt.c
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</sect1>
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<sect1><title>Polled input devices</title>
|
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!Iinclude/linux/input-polldev.h
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!Edrivers/input/input-polldev.c
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|
</sect1>
|
|
<sect1><title>Matrix keyboars/keypads</title>
|
|
!Iinclude/linux/input/matrix_keypad.h
|
|
</sect1>
|
|
<sect1><title>Sparse keymap support</title>
|
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!Iinclude/linux/input/sparse-keymap.h
|
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!Edrivers/input/sparse-keymap.c
|
|
</sect1>
|
|
</chapter>
|
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|
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<chapter id="spi">
|
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<title>Serial Peripheral Interface (SPI)</title>
|
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<para>
|
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SPI is the "Serial Peripheral Interface", widely used with
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embedded systems because it is a simple and efficient
|
|
interface: basically a multiplexed shift register.
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|
Its three signal wires hold a clock (SCK, often in the range
|
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of 1-20 MHz), a "Master Out, Slave In" (MOSI) data line, and
|
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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>
|
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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>
|
|
|
|
<chapter id="hsi">
|
|
<title>High Speed Synchronous Serial Interface (HSI)</title>
|
|
|
|
<para>
|
|
High Speed Synchronous Serial Interface (HSI) is a
|
|
serial interface mainly used for connecting application
|
|
engines (APE) with cellular modem engines (CMT) in cellular
|
|
handsets.
|
|
|
|
HSI provides multiplexing for up to 16 logical channels,
|
|
low-latency and full duplex communication.
|
|
</para>
|
|
|
|
!Iinclude/linux/hsi/hsi.h
|
|
!Edrivers/hsi/hsi.c
|
|
</chapter>
|
|
|
|
<chapter id="pwm">
|
|
<title>Pulse-Width Modulation (PWM)</title>
|
|
<para>
|
|
Pulse-width modulation is a modulation technique primarily used to
|
|
control power supplied to electrical devices.
|
|
</para>
|
|
<para>
|
|
The PWM framework provides an abstraction for providers and consumers
|
|
of PWM signals. A controller that provides one or more PWM signals is
|
|
registered as <structname>struct pwm_chip</structname>. Providers are
|
|
expected to embed this structure in a driver-specific structure. This
|
|
structure contains fields that describe a particular chip.
|
|
</para>
|
|
<para>
|
|
A chip exposes one or more PWM signal sources, each of which exposed
|
|
as a <structname>struct pwm_device</structname>. Operations can be
|
|
performed on PWM devices to control the period, duty cycle, polarity
|
|
and active state of the signal.
|
|
</para>
|
|
<para>
|
|
Note that PWM devices are exclusive resources: they can always only be
|
|
used by one consumer at a time.
|
|
</para>
|
|
!Iinclude/linux/pwm.h
|
|
!Edrivers/pwm/core.c
|
|
</chapter>
|
|
|
|
</book>
|