From patchwork Mon Aug 22 20:57:42 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jonathan Corbet X-Patchwork-Id: 74468 Delivered-To: patch@linaro.org Received: by 10.140.29.52 with SMTP id a49csp1761640qga; Mon, 22 Aug 2016 13:59:38 -0700 (PDT) X-Received: by 10.98.35.145 with SMTP id q17mr46566177pfj.42.1471899578345; Mon, 22 Aug 2016 13:59:38 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id j12si27505727pat.285.2016.08.22.13.59.37; Mon, 22 Aug 2016 13:59:38 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756561AbcHVU7I (ORCPT + 27 others); Mon, 22 Aug 2016 16:59:08 -0400 Received: from tex.lwn.net ([70.33.254.29]:47227 "EHLO vena.lwn.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756161AbcHVU6v (ORCPT ); Mon, 22 Aug 2016 16:58:51 -0400 Received: from tpad.home.lan (localhost.localdomain [127.0.0.1]) by vena.lwn.net (Postfix) with ESMTP id 8B0A1154003E; Mon, 22 Aug 2016 14:58:19 -0600 (MDT) From: Jonathan Corbet To: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jonathan Corbet , Jani Nikula , Mauro Carvalho Chehab Subject: [PATCH 2/3] docs: split up the driver book Date: Mon, 22 Aug 2016 14:57:42 -0600 Message-Id: <1471899463-5774-3-git-send-email-corbet@lwn.net> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1471899463-5774-1-git-send-email-corbet@lwn.net> References: <1471899463-5774-1-git-send-email-corbet@lwn.net> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We don't need to keep it as a single large file anymore; split it up so that it is easier to manage and the individual sections can be read directly as plain files. Cc: Jani Nikula Cc: Mauro Carvalho Chehab Signed-off-by: Jonathan Corbet --- Documentation/driver-api/basics.rst | 120 +++++ Documentation/driver-api/drivers.rst | 654 ------------------------- Documentation/driver-api/frame-buffer.rst | 62 +++ Documentation/driver-api/index.rst | 24 + Documentation/driver-api/infrastructure.rst | 169 +++++++ Documentation/driver-api/input.rst | 51 ++ Documentation/driver-api/message-based.rst | 30 ++ Documentation/driver-api/miscellaneous.rst | 50 ++ Documentation/driver-api/serial-interfaces.rst | 115 +++++ Documentation/driver-api/sound.rst | 54 ++ Documentation/index.rst | 2 +- 11 files changed, 676 insertions(+), 655 deletions(-) -- 2.7.4 diff --git a/Documentation/driver-api/basics.rst b/Documentation/driver-api/basics.rst new file mode 100644 index 000000000000..935b9b8d456c --- /dev/null +++ b/Documentation/driver-api/basics.rst @@ -0,0 +1,120 @@ +Driver Basics +============= + +Driver Entry and Exit points +---------------------------- + +.. kernel-doc:: include/linux/init.h + :internal: + +Atomic and pointer manipulation +------------------------------- + +.. kernel-doc:: arch/x86/include/asm/atomic.h + :internal: + +Delaying, scheduling, and timer routines +---------------------------------------- + +.. kernel-doc:: include/linux/sched.h + :internal: + +.. kernel-doc:: kernel/sched/core.c + :export: + +.. kernel-doc:: kernel/sched/cpupri.c + :internal: + +.. kernel-doc:: kernel/sched/fair.c + :internal: + +.. kernel-doc:: include/linux/completion.h + :internal: + +.. kernel-doc:: kernel/time/timer.c + :export: + +Wait queues and Wake events +--------------------------- + +.. kernel-doc:: include/linux/wait.h + :internal: + +.. kernel-doc:: kernel/sched/wait.c + :export: + +High-resolution timers +---------------------- + +.. kernel-doc:: include/linux/ktime.h + :internal: + +.. kernel-doc:: include/linux/hrtimer.h + :internal: + +.. kernel-doc:: kernel/time/hrtimer.c + :export: + +Workqueues and Kevents +---------------------- + +.. kernel-doc:: include/linux/workqueue.h + :internal: + +.. kernel-doc:: kernel/workqueue.c + :export: + +Internal Functions +------------------ + +.. kernel-doc:: kernel/exit.c + :internal: + +.. kernel-doc:: kernel/signal.c + :internal: + +.. kernel-doc:: include/linux/kthread.h + :internal: + +.. kernel-doc:: kernel/kthread.c + :export: + +Kernel objects manipulation +--------------------------- + +.. kernel-doc:: lib/kobject.c + :export: + +Kernel utility functions +------------------------ + +.. kernel-doc:: include/linux/kernel.h + :internal: + +.. kernel-doc:: kernel/printk/printk.c + :export: + +.. kernel-doc:: kernel/panic.c + :export: + +.. kernel-doc:: kernel/sys.c + :export: + +.. kernel-doc:: kernel/rcu/srcu.c + :export: + +.. kernel-doc:: kernel/rcu/tree.c + :export: + +.. kernel-doc:: kernel/rcu/tree_plugin.h + :export: + +.. kernel-doc:: kernel/rcu/update.c + :export: + +Device Resource Management +-------------------------- + +.. kernel-doc:: drivers/base/devres.c + :export: + diff --git a/Documentation/driver-api/drivers.rst b/Documentation/driver-api/drivers.rst deleted file mode 100644 index 17f99d441b52..000000000000 --- a/Documentation/driver-api/drivers.rst +++ /dev/null @@ -1,654 +0,0 @@ -==================== -Linux Device Drivers -==================== - -Driver Basics -============= - -Driver Entry and Exit points ----------------------------- - -.. kernel-doc:: include/linux/init.h - :internal: - -Atomic and pointer manipulation -------------------------------- - -.. kernel-doc:: arch/x86/include/asm/atomic.h - :internal: - -Delaying, scheduling, and timer routines ----------------------------------------- - -.. kernel-doc:: include/linux/sched.h - :internal: - -.. kernel-doc:: kernel/sched/core.c - :export: - -.. kernel-doc:: kernel/sched/cpupri.c - :internal: - -.. kernel-doc:: kernel/sched/fair.c - :internal: - -.. kernel-doc:: include/linux/completion.h - :internal: - -.. kernel-doc:: kernel/time/timer.c - :export: - -Wait queues and Wake events ---------------------------- - -.. kernel-doc:: include/linux/wait.h - :internal: - -.. kernel-doc:: kernel/sched/wait.c - :export: - -High-resolution timers ----------------------- - -.. kernel-doc:: include/linux/ktime.h - :internal: - -.. kernel-doc:: include/linux/hrtimer.h - :internal: - -.. kernel-doc:: kernel/time/hrtimer.c - :export: - -Workqueues and Kevents ----------------------- - -.. kernel-doc:: include/linux/workqueue.h - :internal: - -.. kernel-doc:: kernel/workqueue.c - :export: - -Internal Functions ------------------- - -.. kernel-doc:: kernel/exit.c - :internal: - -.. kernel-doc:: kernel/signal.c - :internal: - -.. kernel-doc:: include/linux/kthread.h - :internal: - -.. kernel-doc:: kernel/kthread.c - :export: - -Kernel objects manipulation ---------------------------- - -.. kernel-doc:: lib/kobject.c - :export: - -Kernel utility functions ------------------------- - -.. kernel-doc:: include/linux/kernel.h - :internal: - -.. kernel-doc:: kernel/printk/printk.c - :export: - -.. kernel-doc:: kernel/panic.c - :export: - -.. kernel-doc:: kernel/sys.c - :export: - -.. kernel-doc:: kernel/rcu/srcu.c - :export: - -.. kernel-doc:: kernel/rcu/tree.c - :export: - -.. kernel-doc:: kernel/rcu/tree_plugin.h - :export: - -.. kernel-doc:: kernel/rcu/update.c - :export: - -Device Resource Management --------------------------- - -.. kernel-doc:: drivers/base/devres.c - :export: - -Device drivers infrastructure -============================= - -The Basic Device Driver-Model Structures ----------------------------------------- - -.. kernel-doc:: include/linux/device.h - :internal: - -Device Drivers Base -------------------- - -.. kernel-doc:: drivers/base/init.c - :internal: - -.. kernel-doc:: drivers/base/driver.c - :export: - -.. kernel-doc:: drivers/base/core.c - :export: - -.. kernel-doc:: drivers/base/syscore.c - :export: - -.. kernel-doc:: drivers/base/class.c - :export: - -.. kernel-doc:: drivers/base/node.c - :internal: - -.. kernel-doc:: drivers/base/firmware_class.c - :export: - -.. kernel-doc:: drivers/base/transport_class.c - :export: - -.. kernel-doc:: drivers/base/dd.c - :export: - -.. kernel-doc:: include/linux/platform_device.h - :internal: - -.. kernel-doc:: drivers/base/platform.c - :export: - -.. kernel-doc:: drivers/base/bus.c - :export: - -Buffer Sharing and Synchronization ----------------------------------- - -The dma-buf subsystem provides the framework for sharing buffers for -hardware (DMA) access across multiple device drivers and subsystems, and -for synchronizing asynchronous hardware access. - -This is used, for example, by drm "prime" multi-GPU support, but is of -course not limited to GPU use cases. - -The three main components of this are: (1) dma-buf, representing a -sg_table and exposed to userspace as a file descriptor to allow passing -between devices, (2) fence, which provides a mechanism to signal when -one device as finished access, and (3) reservation, which manages the -shared or exclusive fence(s) associated with the buffer. - -dma-buf -~~~~~~~ - -.. kernel-doc:: drivers/dma-buf/dma-buf.c - :export: - -.. kernel-doc:: include/linux/dma-buf.h - :internal: - -reservation -~~~~~~~~~~~ - -.. kernel-doc:: drivers/dma-buf/reservation.c - :doc: Reservation Object Overview - -.. kernel-doc:: drivers/dma-buf/reservation.c - :export: - -.. kernel-doc:: include/linux/reservation.h - :internal: - -fence -~~~~~ - -.. kernel-doc:: drivers/dma-buf/fence.c - :export: - -.. kernel-doc:: include/linux/fence.h - :internal: - -.. kernel-doc:: drivers/dma-buf/seqno-fence.c - :export: - -.. kernel-doc:: include/linux/seqno-fence.h - :internal: - -.. kernel-doc:: drivers/dma-buf/fence-array.c - :export: - -.. kernel-doc:: include/linux/fence-array.h - :internal: - -.. kernel-doc:: drivers/dma-buf/reservation.c - :export: - -.. kernel-doc:: include/linux/reservation.h - :internal: - -.. kernel-doc:: drivers/dma-buf/sync_file.c - :export: - -.. kernel-doc:: include/linux/sync_file.h - :internal: - -Device Drivers DMA Management ------------------------------ - -.. kernel-doc:: drivers/base/dma-coherent.c - :export: - -.. kernel-doc:: drivers/base/dma-mapping.c - :export: - -Device Drivers Power Management -------------------------------- - -.. kernel-doc:: drivers/base/power/main.c - :export: - -Device Drivers ACPI Support ---------------------------- - -.. kernel-doc:: drivers/acpi/scan.c - :export: - -.. kernel-doc:: drivers/acpi/scan.c - :internal: - -Device drivers PnP support --------------------------- - -.. kernel-doc:: drivers/pnp/core.c - :internal: - -.. kernel-doc:: drivers/pnp/card.c - :export: - -.. kernel-doc:: drivers/pnp/driver.c - :internal: - -.. kernel-doc:: drivers/pnp/manager.c - :export: - -.. kernel-doc:: drivers/pnp/support.c - :export: - -Userspace IO devices --------------------- - -.. kernel-doc:: drivers/uio/uio.c - :export: - -.. kernel-doc:: include/linux/uio_driver.h - :internal: - -Parallel Port Devices -===================== - -.. kernel-doc:: include/linux/parport.h - :internal: - -.. kernel-doc:: drivers/parport/ieee1284.c - :export: - -.. kernel-doc:: drivers/parport/share.c - :export: - -.. kernel-doc:: drivers/parport/daisy.c - :internal: - -Message-based devices -===================== - -Fusion message devices ----------------------- - -.. kernel-doc:: drivers/message/fusion/mptbase.c - :export: - -.. kernel-doc:: drivers/message/fusion/mptbase.c - :internal: - -.. kernel-doc:: drivers/message/fusion/mptscsih.c - :export: - -.. kernel-doc:: drivers/message/fusion/mptscsih.c - :internal: - -.. kernel-doc:: drivers/message/fusion/mptctl.c - :internal: - -.. kernel-doc:: drivers/message/fusion/mptspi.c - :internal: - -.. kernel-doc:: drivers/message/fusion/mptfc.c - :internal: - -.. kernel-doc:: drivers/message/fusion/mptlan.c - :internal: - -Sound Devices -============= - -.. kernel-doc:: include/sound/core.h - :internal: - -.. kernel-doc:: sound/sound_core.c - :export: - -.. kernel-doc:: include/sound/pcm.h - :internal: - -.. kernel-doc:: sound/core/pcm.c - :export: - -.. kernel-doc:: sound/core/device.c - :export: - -.. kernel-doc:: sound/core/info.c - :export: - -.. kernel-doc:: sound/core/rawmidi.c - :export: - -.. kernel-doc:: sound/core/sound.c - :export: - -.. kernel-doc:: sound/core/memory.c - :export: - -.. kernel-doc:: sound/core/pcm_memory.c - :export: - -.. kernel-doc:: sound/core/init.c - :export: - -.. kernel-doc:: sound/core/isadma.c - :export: - -.. kernel-doc:: sound/core/control.c - :export: - -.. kernel-doc:: sound/core/pcm_lib.c - :export: - -.. kernel-doc:: sound/core/hwdep.c - :export: - -.. kernel-doc:: sound/core/pcm_native.c - :export: - -.. kernel-doc:: sound/core/memalloc.c - :export: - -16x50 UART Driver -================= - -.. kernel-doc:: drivers/tty/serial/serial_core.c - :export: - -.. kernel-doc:: drivers/tty/serial/8250/8250_core.c - :export: - -Frame Buffer Library -==================== - -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. - -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. - -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. - -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. - -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. - -Frame Buffer Memory -------------------- - -.. kernel-doc:: drivers/video/fbdev/core/fbmem.c - :export: - -Frame Buffer Colormap ---------------------- - -.. kernel-doc:: drivers/video/fbdev/core/fbcmap.c - :export: - -Frame Buffer Video Mode Database --------------------------------- - -.. kernel-doc:: drivers/video/fbdev/core/modedb.c - :internal: - -.. kernel-doc:: drivers/video/fbdev/core/modedb.c - :export: - -Frame Buffer Macintosh Video Mode Database ------------------------------------------- - -.. kernel-doc:: drivers/video/fbdev/macmodes.c - :export: - -Frame Buffer Fonts ------------------- - -Refer to the file lib/fonts/fonts.c for more information. - -Input Subsystem -=============== - -Input core ----------- - -.. kernel-doc:: include/linux/input.h - :internal: - -.. kernel-doc:: drivers/input/input.c - :export: - -.. kernel-doc:: drivers/input/ff-core.c - :export: - -.. kernel-doc:: drivers/input/ff-memless.c - :export: - -Multitouch Library ------------------- - -.. kernel-doc:: include/linux/input/mt.h - :internal: - -.. kernel-doc:: drivers/input/input-mt.c - :export: - -Polled input devices --------------------- - -.. kernel-doc:: include/linux/input-polldev.h - :internal: - -.. kernel-doc:: drivers/input/input-polldev.c - :export: - -Matrix keyboards/keypads ------------------------- - -.. kernel-doc:: include/linux/input/matrix_keypad.h - :internal: - -Sparse keymap support ---------------------- - -.. kernel-doc:: include/linux/input/sparse-keymap.h - :internal: - -.. kernel-doc:: drivers/input/sparse-keymap.c - :export: - -Serial Peripheral Interface (SPI) -================================= - -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. - -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.) - -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 :c:type:`struct spi_master -`. SPI devices are children of that master, -represented as a :c:type:`struct spi_device ` and -manufactured from :c:type:`struct spi_board_info -` descriptors which are usually provided by -board-specific initialization code. A :c:type:`struct spi_driver -` is called a "Protocol Driver", and is bound to a -spi_device using normal driver model calls. - -The I/O model is a set of queued messages. Protocol drivers submit one -or more :c:type:`struct spi_message ` objects, -which are processed and completed asynchronously. (There are synchronous -wrappers, however.) Messages are built from one or more -:c:type:`struct spi_transfer ` 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. - -.. kernel-doc:: include/linux/spi/spi.h - :internal: - -.. kernel-doc:: drivers/spi/spi.c - :functions: spi_register_board_info - -.. kernel-doc:: drivers/spi/spi.c - :export: - -I\ :sup:`2`\ C and SMBus Subsystem -================================== - -I\ :sup:`2`\ 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. - -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 -:c:type:`struct i2c_adapter ` representing each -I2C bus segment it manages. On each I2C bus segment will be I2C devices -represented by a :c:type:`struct i2c_client `. -Those devices will be bound to a :c:type:`struct i2c_driver -`, 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. - -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. - -.. kernel-doc:: include/linux/i2c.h - :internal: - -.. kernel-doc:: drivers/i2c/i2c-boardinfo.c - :functions: i2c_register_board_info - -.. kernel-doc:: drivers/i2c/i2c-core.c - :export: - -High Speed Synchronous Serial Interface (HSI) -============================================= - -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. - -.. kernel-doc:: include/linux/hsi/hsi.h - :internal: - -.. kernel-doc:: drivers/hsi/hsi_core.c - :export: - -Pulse-Width Modulation (PWM) -============================ - -Pulse-width modulation is a modulation technique primarily used to -control power supplied to electrical devices. - -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 :c:type:`struct pwm_chip `. Providers -are expected to embed this structure in a driver-specific structure. -This structure contains fields that describe a particular chip. - -A chip exposes one or more PWM signal sources, each of which exposed as -a :c:type:`struct pwm_device `. Operations can be -performed on PWM devices to control the period, duty cycle, polarity and -active state of the signal. - -Note that PWM devices are exclusive resources: they can always only be -used by one consumer at a time. - -.. kernel-doc:: include/linux/pwm.h - :internal: - -.. kernel-doc:: drivers/pwm/core.c - :export: diff --git a/Documentation/driver-api/frame-buffer.rst b/Documentation/driver-api/frame-buffer.rst new file mode 100644 index 000000000000..9dd3060f027d --- /dev/null +++ b/Documentation/driver-api/frame-buffer.rst @@ -0,0 +1,62 @@ +Frame Buffer Library +==================== + +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. + +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. + +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. + +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. + +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. + +Frame Buffer Memory +------------------- + +.. kernel-doc:: drivers/video/fbdev/core/fbmem.c + :export: + +Frame Buffer Colormap +--------------------- + +.. kernel-doc:: drivers/video/fbdev/core/fbcmap.c + :export: + +Frame Buffer Video Mode Database +-------------------------------- + +.. kernel-doc:: drivers/video/fbdev/core/modedb.c + :internal: + +.. kernel-doc:: drivers/video/fbdev/core/modedb.c + :export: + +Frame Buffer Macintosh Video Mode Database +------------------------------------------ + +.. kernel-doc:: drivers/video/fbdev/macmodes.c + :export: + +Frame Buffer Fonts +------------------ + +Refer to the file lib/fonts/fonts.c for more information. + diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst new file mode 100644 index 000000000000..b50c41011e47 --- /dev/null +++ b/Documentation/driver-api/index.rst @@ -0,0 +1,24 @@ +======================================== +The Linux driver implementer's API guide +======================================== + +The kernel offers a wide variety of interfaces to support the development +of device drivers. This document is an only somewhat organized collection +of some of those interfaces — it will hopefully get better over time! The +available subsections can be seen below. + +.. class:: toc-title + + Table of contents + +.. toctree:: + :maxdepth: 2 + + basics + infrastructure + message-based + sound + frame-buffer + input + serial-interfaces + miscellaneous diff --git a/Documentation/driver-api/infrastructure.rst b/Documentation/driver-api/infrastructure.rst new file mode 100644 index 000000000000..5d50d6733db3 --- /dev/null +++ b/Documentation/driver-api/infrastructure.rst @@ -0,0 +1,169 @@ +Device drivers infrastructure +============================= + +The Basic Device Driver-Model Structures +---------------------------------------- + +.. kernel-doc:: include/linux/device.h + :internal: + +Device Drivers Base +------------------- + +.. kernel-doc:: drivers/base/init.c + :internal: + +.. kernel-doc:: drivers/base/driver.c + :export: + +.. kernel-doc:: drivers/base/core.c + :export: + +.. kernel-doc:: drivers/base/syscore.c + :export: + +.. kernel-doc:: drivers/base/class.c + :export: + +.. kernel-doc:: drivers/base/node.c + :internal: + +.. kernel-doc:: drivers/base/firmware_class.c + :export: + +.. kernel-doc:: drivers/base/transport_class.c + :export: + +.. kernel-doc:: drivers/base/dd.c + :export: + +.. kernel-doc:: include/linux/platform_device.h + :internal: + +.. kernel-doc:: drivers/base/platform.c + :export: + +.. kernel-doc:: drivers/base/bus.c + :export: + +Buffer Sharing and Synchronization +---------------------------------- + +The dma-buf subsystem provides the framework for sharing buffers for +hardware (DMA) access across multiple device drivers and subsystems, and +for synchronizing asynchronous hardware access. + +This is used, for example, by drm "prime" multi-GPU support, but is of +course not limited to GPU use cases. + +The three main components of this are: (1) dma-buf, representing a +sg_table and exposed to userspace as a file descriptor to allow passing +between devices, (2) fence, which provides a mechanism to signal when +one device as finished access, and (3) reservation, which manages the +shared or exclusive fence(s) associated with the buffer. + +dma-buf +~~~~~~~ + +.. kernel-doc:: drivers/dma-buf/dma-buf.c + :export: + +.. kernel-doc:: include/linux/dma-buf.h + :internal: + +reservation +~~~~~~~~~~~ + +.. kernel-doc:: drivers/dma-buf/reservation.c + :doc: Reservation Object Overview + +.. kernel-doc:: drivers/dma-buf/reservation.c + :export: + +.. kernel-doc:: include/linux/reservation.h + :internal: + +fence +~~~~~ + +.. kernel-doc:: drivers/dma-buf/fence.c + :export: + +.. kernel-doc:: include/linux/fence.h + :internal: + +.. kernel-doc:: drivers/dma-buf/seqno-fence.c + :export: + +.. kernel-doc:: include/linux/seqno-fence.h + :internal: + +.. kernel-doc:: drivers/dma-buf/fence-array.c + :export: + +.. kernel-doc:: include/linux/fence-array.h + :internal: + +.. kernel-doc:: drivers/dma-buf/reservation.c + :export: + +.. kernel-doc:: include/linux/reservation.h + :internal: + +.. kernel-doc:: drivers/dma-buf/sync_file.c + :export: + +.. kernel-doc:: include/linux/sync_file.h + :internal: + +Device Drivers DMA Management +----------------------------- + +.. kernel-doc:: drivers/base/dma-coherent.c + :export: + +.. kernel-doc:: drivers/base/dma-mapping.c + :export: + +Device Drivers Power Management +------------------------------- + +.. kernel-doc:: drivers/base/power/main.c + :export: + +Device Drivers ACPI Support +--------------------------- + +.. kernel-doc:: drivers/acpi/scan.c + :export: + +.. kernel-doc:: drivers/acpi/scan.c + :internal: + +Device drivers PnP support +-------------------------- + +.. kernel-doc:: drivers/pnp/core.c + :internal: + +.. kernel-doc:: drivers/pnp/card.c + :export: + +.. kernel-doc:: drivers/pnp/driver.c + :internal: + +.. kernel-doc:: drivers/pnp/manager.c + :export: + +.. kernel-doc:: drivers/pnp/support.c + :export: + +Userspace IO devices +-------------------- + +.. kernel-doc:: drivers/uio/uio.c + :export: + +.. kernel-doc:: include/linux/uio_driver.h + :internal: + diff --git a/Documentation/driver-api/input.rst b/Documentation/driver-api/input.rst new file mode 100644 index 000000000000..d05bf58fa83e --- /dev/null +++ b/Documentation/driver-api/input.rst @@ -0,0 +1,51 @@ +Input Subsystem +=============== + +Input core +---------- + +.. kernel-doc:: include/linux/input.h + :internal: + +.. kernel-doc:: drivers/input/input.c + :export: + +.. kernel-doc:: drivers/input/ff-core.c + :export: + +.. kernel-doc:: drivers/input/ff-memless.c + :export: + +Multitouch Library +------------------ + +.. kernel-doc:: include/linux/input/mt.h + :internal: + +.. kernel-doc:: drivers/input/input-mt.c + :export: + +Polled input devices +-------------------- + +.. kernel-doc:: include/linux/input-polldev.h + :internal: + +.. kernel-doc:: drivers/input/input-polldev.c + :export: + +Matrix keyboards/keypads +------------------------ + +.. kernel-doc:: include/linux/input/matrix_keypad.h + :internal: + +Sparse keymap support +--------------------- + +.. kernel-doc:: include/linux/input/sparse-keymap.h + :internal: + +.. kernel-doc:: drivers/input/sparse-keymap.c + :export: + diff --git a/Documentation/driver-api/message-based.rst b/Documentation/driver-api/message-based.rst new file mode 100644 index 000000000000..ef5867a7de20 --- /dev/null +++ b/Documentation/driver-api/message-based.rst @@ -0,0 +1,30 @@ +Message-based devices +===================== + +Fusion message devices +---------------------- + +.. kernel-doc:: drivers/message/fusion/mptbase.c + :export: + +.. kernel-doc:: drivers/message/fusion/mptbase.c + :internal: + +.. kernel-doc:: drivers/message/fusion/mptscsih.c + :export: + +.. kernel-doc:: drivers/message/fusion/mptscsih.c + :internal: + +.. kernel-doc:: drivers/message/fusion/mptctl.c + :internal: + +.. kernel-doc:: drivers/message/fusion/mptspi.c + :internal: + +.. kernel-doc:: drivers/message/fusion/mptfc.c + :internal: + +.. kernel-doc:: drivers/message/fusion/mptlan.c + :internal: + diff --git a/Documentation/driver-api/miscellaneous.rst b/Documentation/driver-api/miscellaneous.rst new file mode 100644 index 000000000000..8da7d115bafc --- /dev/null +++ b/Documentation/driver-api/miscellaneous.rst @@ -0,0 +1,50 @@ +Parallel Port Devices +===================== + +.. kernel-doc:: include/linux/parport.h + :internal: + +.. kernel-doc:: drivers/parport/ieee1284.c + :export: + +.. kernel-doc:: drivers/parport/share.c + :export: + +.. kernel-doc:: drivers/parport/daisy.c + :internal: + +16x50 UART Driver +================= + +.. kernel-doc:: drivers/tty/serial/serial_core.c + :export: + +.. kernel-doc:: drivers/tty/serial/8250/8250_core.c + :export: + +Pulse-Width Modulation (PWM) +============================ + +Pulse-width modulation is a modulation technique primarily used to +control power supplied to electrical devices. + +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 :c:type:`struct pwm_chip `. Providers +are expected to embed this structure in a driver-specific structure. +This structure contains fields that describe a particular chip. + +A chip exposes one or more PWM signal sources, each of which exposed as +a :c:type:`struct pwm_device `. Operations can be +performed on PWM devices to control the period, duty cycle, polarity and +active state of the signal. + +Note that PWM devices are exclusive resources: they can always only be +used by one consumer at a time. + +.. kernel-doc:: include/linux/pwm.h + :internal: + +.. kernel-doc:: drivers/pwm/core.c + :export: + diff --git a/Documentation/driver-api/serial-interfaces.rst b/Documentation/driver-api/serial-interfaces.rst new file mode 100644 index 000000000000..d0d65e58c14b --- /dev/null +++ b/Documentation/driver-api/serial-interfaces.rst @@ -0,0 +1,115 @@ +Serial Peripheral Interface (SPI) +================================= + +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. + +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.) + +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 :c:type:`struct spi_master +`. SPI devices are children of that master, +represented as a :c:type:`struct spi_device ` and +manufactured from :c:type:`struct spi_board_info +` descriptors which are usually provided by +board-specific initialization code. A :c:type:`struct spi_driver +` is called a "Protocol Driver", and is bound to a +spi_device using normal driver model calls. + +The I/O model is a set of queued messages. Protocol drivers submit one +or more :c:type:`struct spi_message ` objects, +which are processed and completed asynchronously. (There are synchronous +wrappers, however.) Messages are built from one or more +:c:type:`struct spi_transfer ` 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. + +.. kernel-doc:: include/linux/spi/spi.h + :internal: + +.. kernel-doc:: drivers/spi/spi.c + :functions: spi_register_board_info + +.. kernel-doc:: drivers/spi/spi.c + :export: + +I\ :sup:`2`\ C and SMBus Subsystem +================================== + +I\ :sup:`2`\ 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. + +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 +:c:type:`struct i2c_adapter ` representing each +I2C bus segment it manages. On each I2C bus segment will be I2C devices +represented by a :c:type:`struct i2c_client `. +Those devices will be bound to a :c:type:`struct i2c_driver +`, 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. + +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. + +.. kernel-doc:: include/linux/i2c.h + :internal: + +.. kernel-doc:: drivers/i2c/i2c-boardinfo.c + :functions: i2c_register_board_info + +.. kernel-doc:: drivers/i2c/i2c-core.c + :export: + +High Speed Synchronous Serial Interface (HSI) +============================================= + +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. + +.. kernel-doc:: include/linux/hsi/hsi.h + :internal: + +.. kernel-doc:: drivers/hsi/hsi_core.c + :export: + diff --git a/Documentation/driver-api/sound.rst b/Documentation/driver-api/sound.rst new file mode 100644 index 000000000000..afef6eabc073 --- /dev/null +++ b/Documentation/driver-api/sound.rst @@ -0,0 +1,54 @@ +Sound Devices +============= + +.. kernel-doc:: include/sound/core.h + :internal: + +.. kernel-doc:: sound/sound_core.c + :export: + +.. kernel-doc:: include/sound/pcm.h + :internal: + +.. kernel-doc:: sound/core/pcm.c + :export: + +.. kernel-doc:: sound/core/device.c + :export: + +.. kernel-doc:: sound/core/info.c + :export: + +.. kernel-doc:: sound/core/rawmidi.c + :export: + +.. kernel-doc:: sound/core/sound.c + :export: + +.. kernel-doc:: sound/core/memory.c + :export: + +.. kernel-doc:: sound/core/pcm_memory.c + :export: + +.. kernel-doc:: sound/core/init.c + :export: + +.. kernel-doc:: sound/core/isadma.c + :export: + +.. kernel-doc:: sound/core/control.c + :export: + +.. kernel-doc:: sound/core/pcm_lib.c + :export: + +.. kernel-doc:: sound/core/hwdep.c + :export: + +.. kernel-doc:: sound/core/pcm_native.c + :export: + +.. kernel-doc:: sound/core/memalloc.c + :export: + diff --git a/Documentation/index.rst b/Documentation/index.rst index 0d6992b897c8..9fe5e0cacdd0 100644 --- a/Documentation/index.rst +++ b/Documentation/index.rst @@ -13,7 +13,7 @@ Contents: kernel-documentation dev-tools/tools - driver-api/drivers + driver-api/index media/index gpu/index