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authorJonathan Corbet <corbet@lwn.net>2016-08-20 15:02:50 -0400
committerJonathan Corbet <corbet@lwn.net>2016-08-22 16:11:22 -0400
commit47cb398dd75a9faa89d0617b55d4cf537935b731 (patch)
tree12ff5f67133219fcf86b6e1166a14e25838346da
parent5512128f027aec63a9a2ca792858801554a57baf (diff)
Docs: sphinxify device-drivers.tmpl
Perform a basic sphinx conversion of the device-drivers docbook and move it to its own directory. Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat
-rw-r--r--Documentation/DocBook/Makefile2
-rw-r--r--Documentation/DocBook/device-drivers.tmpl521
-rw-r--r--Documentation/driver-api/drivers.rst654
-rw-r--r--Documentation/index.rst1
4 files changed, 656 insertions, 522 deletions
diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile
index a91c96522379..5fbfb7273f38 100644
--- a/Documentation/DocBook/Makefile
+++ b/Documentation/DocBook/Makefile
@@ -6,7 +6,7 @@
6# To add a new book the only step required is to add the book to the 6# To add a new book the only step required is to add the book to the
7# list of DOCBOOKS. 7# list of DOCBOOKS.
8 8
9DOCBOOKS := z8530book.xml device-drivers.xml \ 9DOCBOOKS := z8530book.xml \
10 kernel-hacking.xml kernel-locking.xml deviceiobook.xml \ 10 kernel-hacking.xml kernel-locking.xml deviceiobook.xml \
11 writing_usb_driver.xml networking.xml \ 11 writing_usb_driver.xml networking.xml \
12 kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \ 12 kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \
diff --git a/Documentation/DocBook/device-drivers.tmpl b/Documentation/DocBook/device-drivers.tmpl
deleted file mode 100644
index 9c10030eb2be..000000000000
--- a/Documentation/DocBook/device-drivers.tmpl
+++ /dev/null
@@ -1,521 +0,0 @@
1<?xml version="1.0" encoding="UTF-8"?>
2<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
3 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
4
5<book id="LinuxDriversAPI">
6 <bookinfo>
7 <title>Linux Device Drivers</title>
8
9 <legalnotice>
10 <para>
11 This documentation is free software; you can redistribute
12 it and/or modify it under the terms of the GNU General Public
13 License as published by the Free Software Foundation; either
14 version 2 of the License, or (at your option) any later
15 version.
16 </para>
17
18 <para>
19 This program is distributed in the hope that it will be
20 useful, but WITHOUT ANY WARRANTY; without even the implied
21 warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22 See the GNU General Public License for more details.
23 </para>
24
25 <para>
26 You should have received a copy of the GNU General Public
27 License along with this program; if not, write to the Free
28 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
29 MA 02111-1307 USA
30 </para>
31
32 <para>
33 For more details see the file COPYING in the source
34 distribution of Linux.
35 </para>
36 </legalnotice>
37 </bookinfo>
38
39<toc></toc>
40
41 <chapter id="Basics">
42 <title>Driver Basics</title>
43 <sect1><title>Driver Entry and Exit points</title>
44!Iinclude/linux/init.h
45 </sect1>
46
47 <sect1><title>Atomic and pointer manipulation</title>
48!Iarch/x86/include/asm/atomic.h
49 </sect1>
50
51 <sect1><title>Delaying, scheduling, and timer routines</title>
52!Iinclude/linux/sched.h
53!Ekernel/sched/core.c
54!Ikernel/sched/cpupri.c
55!Ikernel/sched/fair.c
56!Iinclude/linux/completion.h
57!Ekernel/time/timer.c
58 </sect1>
59 <sect1><title>Wait queues and Wake events</title>
60!Iinclude/linux/wait.h
61!Ekernel/sched/wait.c
62 </sect1>
63 <sect1><title>High-resolution timers</title>
64!Iinclude/linux/ktime.h
65!Iinclude/linux/hrtimer.h
66!Ekernel/time/hrtimer.c
67 </sect1>
68 <sect1><title>Workqueues and Kevents</title>
69!Iinclude/linux/workqueue.h
70!Ekernel/workqueue.c
71 </sect1>
72 <sect1><title>Internal Functions</title>
73!Ikernel/exit.c
74!Ikernel/signal.c
75!Iinclude/linux/kthread.h
76!Ekernel/kthread.c
77 </sect1>
78
79 <sect1><title>Kernel objects manipulation</title>
80<!--
81X!Iinclude/linux/kobject.h
82-->
83!Elib/kobject.c
84 </sect1>
85
86 <sect1><title>Kernel utility functions</title>
87!Iinclude/linux/kernel.h
88!Ekernel/printk/printk.c
89!Ekernel/panic.c
90!Ekernel/sys.c
91!Ekernel/rcu/srcu.c
92!Ekernel/rcu/tree.c
93!Ekernel/rcu/tree_plugin.h
94!Ekernel/rcu/update.c
95 </sect1>
96
97 <sect1><title>Device Resource Management</title>
98!Edrivers/base/devres.c
99 </sect1>
100
101 </chapter>
102
103 <chapter id="devdrivers">
104 <title>Device drivers infrastructure</title>
105 <sect1><title>The Basic Device Driver-Model Structures </title>
106!Iinclude/linux/device.h
107 </sect1>
108 <sect1><title>Device Drivers Base</title>
109!Idrivers/base/init.c
110!Edrivers/base/driver.c
111!Edrivers/base/core.c
112!Edrivers/base/syscore.c
113!Edrivers/base/class.c
114!Idrivers/base/node.c
115!Edrivers/base/firmware_class.c
116!Edrivers/base/transport_class.c
117<!-- Cannot be included, because
118 attribute_container_add_class_device_adapter
119 and attribute_container_classdev_to_container
120 exceed allowed 44 characters maximum
121X!Edrivers/base/attribute_container.c
122-->
123!Edrivers/base/dd.c
124<!--
125X!Edrivers/base/interface.c
126-->
127!Iinclude/linux/platform_device.h
128!Edrivers/base/platform.c
129!Edrivers/base/bus.c
130 </sect1>
131 <sect1>
132 <title>Buffer Sharing and Synchronization</title>
133 <para>
134 The dma-buf subsystem provides the framework for sharing buffers
135 for hardware (DMA) access across multiple device drivers and
136 subsystems, and for synchronizing asynchronous hardware access.
137 </para>
138 <para>
139 This is used, for example, by drm "prime" multi-GPU support, but
140 is of course not limited to GPU use cases.
141 </para>
142 <para>
143 The three main components of this are: (1) dma-buf, representing
144 a sg_table and exposed to userspace as a file descriptor to allow
145 passing between devices, (2) fence, which provides a mechanism
146 to signal when one device as finished access, and (3) reservation,
147 which manages the shared or exclusive fence(s) associated with
148 the buffer.
149 </para>
150 <sect2><title>dma-buf</title>
151!Edrivers/dma-buf/dma-buf.c
152!Iinclude/linux/dma-buf.h
153 </sect2>
154 <sect2><title>reservation</title>
155!Pdrivers/dma-buf/reservation.c Reservation Object Overview
156!Edrivers/dma-buf/reservation.c
157!Iinclude/linux/reservation.h
158 </sect2>
159 <sect2><title>fence</title>
160!Edrivers/dma-buf/fence.c
161!Iinclude/linux/fence.h
162!Edrivers/dma-buf/seqno-fence.c
163!Iinclude/linux/seqno-fence.h
164!Edrivers/dma-buf/fence-array.c
165!Iinclude/linux/fence-array.h
166!Edrivers/dma-buf/reservation.c
167!Iinclude/linux/reservation.h
168!Edrivers/dma-buf/sync_file.c
169!Iinclude/linux/sync_file.h
170 </sect2>
171 </sect1>
172 <sect1><title>Device Drivers DMA Management</title>
173!Edrivers/base/dma-coherent.c
174!Edrivers/base/dma-mapping.c
175 </sect1>
176 <sect1><title>Device Drivers Power Management</title>
177!Edrivers/base/power/main.c
178 </sect1>
179 <sect1><title>Device Drivers ACPI Support</title>
180<!-- Internal functions only
181X!Edrivers/acpi/sleep/main.c
182X!Edrivers/acpi/sleep/wakeup.c
183X!Edrivers/acpi/motherboard.c
184X!Edrivers/acpi/bus.c
185-->
186!Edrivers/acpi/scan.c
187!Idrivers/acpi/scan.c
188<!-- No correct structured comments
189X!Edrivers/acpi/pci_bind.c
190-->
191 </sect1>
192 <sect1><title>Device drivers PnP support</title>
193!Idrivers/pnp/core.c
194<!-- No correct structured comments
195X!Edrivers/pnp/system.c
196 -->
197!Edrivers/pnp/card.c
198!Idrivers/pnp/driver.c
199!Edrivers/pnp/manager.c
200!Edrivers/pnp/support.c
201 </sect1>
202 <sect1><title>Userspace IO devices</title>
203!Edrivers/uio/uio.c
204!Iinclude/linux/uio_driver.h
205 </sect1>
206 </chapter>
207
208 <chapter id="parportdev">
209 <title>Parallel Port Devices</title>
210!Iinclude/linux/parport.h
211!Edrivers/parport/ieee1284.c
212!Edrivers/parport/share.c
213!Idrivers/parport/daisy.c
214 </chapter>
215
216 <chapter id="message_devices">
217 <title>Message-based devices</title>
218 <sect1><title>Fusion message devices</title>
219!Edrivers/message/fusion/mptbase.c
220!Idrivers/message/fusion/mptbase.c
221!Edrivers/message/fusion/mptscsih.c
222!Idrivers/message/fusion/mptscsih.c
223!Idrivers/message/fusion/mptctl.c
224!Idrivers/message/fusion/mptspi.c
225!Idrivers/message/fusion/mptfc.c
226!Idrivers/message/fusion/mptlan.c
227 </sect1>
228 </chapter>
229
230 <chapter id="snddev">
231 <title>Sound Devices</title>
232!Iinclude/sound/core.h
233!Esound/sound_core.c
234!Iinclude/sound/pcm.h
235!Esound/core/pcm.c
236!Esound/core/device.c
237!Esound/core/info.c
238!Esound/core/rawmidi.c
239!Esound/core/sound.c
240!Esound/core/memory.c
241!Esound/core/pcm_memory.c
242!Esound/core/init.c
243!Esound/core/isadma.c
244!Esound/core/control.c
245!Esound/core/pcm_lib.c
246!Esound/core/hwdep.c
247!Esound/core/pcm_native.c
248!Esound/core/memalloc.c
249<!-- FIXME: Removed for now since no structured comments in source
250X!Isound/sound_firmware.c
251-->
252 </chapter>
253
254
255 <chapter id="uart16x50">
256 <title>16x50 UART Driver</title>
257!Edrivers/tty/serial/serial_core.c
258!Edrivers/tty/serial/8250/8250_core.c
259 </chapter>
260
261 <chapter id="fbdev">
262 <title>Frame Buffer Library</title>
263
264 <para>
265 The frame buffer drivers depend heavily on four data structures.
266 These structures are declared in include/linux/fb.h. They are
267 fb_info, fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs.
268 The last three can be made available to and from userland.
269 </para>
270
271 <para>
272 fb_info defines the current state of a particular video card.
273 Inside fb_info, there exists a fb_ops structure which is a
274 collection of needed functions to make fbdev and fbcon work.
275 fb_info is only visible to the kernel.
276 </para>
277
278 <para>
279 fb_var_screeninfo is used to describe the features of a video card
280 that are user defined. With fb_var_screeninfo, things such as
281 depth and the resolution may be defined.
282 </para>
283
284 <para>
285 The next structure is fb_fix_screeninfo. This defines the
286 properties of a card that are created when a mode is set and can't
287 be changed otherwise. A good example of this is the start of the
288 frame buffer memory. This "locks" the address of the frame buffer
289 memory, so that it cannot be changed or moved.
290 </para>
291
292 <para>
293 The last structure is fb_monospecs. In the old API, there was
294 little importance for fb_monospecs. This allowed for forbidden things
295 such as setting a mode of 800x600 on a fix frequency monitor. With
296 the new API, fb_monospecs prevents such things, and if used
297 correctly, can prevent a monitor from being cooked. fb_monospecs
298 will not be useful until kernels 2.5.x.
299 </para>
300
301 <sect1><title>Frame Buffer Memory</title>
302!Edrivers/video/fbdev/core/fbmem.c
303 </sect1>
304<!--
305 <sect1><title>Frame Buffer Console</title>
306X!Edrivers/video/console/fbcon.c
307 </sect1>
308-->
309 <sect1><title>Frame Buffer Colormap</title>
310!Edrivers/video/fbdev/core/fbcmap.c
311 </sect1>
312<!-- FIXME:
313 drivers/video/fbgen.c has no docs, which stuffs up the sgml. Comment
314 out until somebody adds docs. KAO
315 <sect1><title>Frame Buffer Generic Functions</title>
316X!Idrivers/video/fbgen.c
317 </sect1>
318KAO -->
319 <sect1><title>Frame Buffer Video Mode Database</title>
320!Idrivers/video/fbdev/core/modedb.c
321!Edrivers/video/fbdev/core/modedb.c
322 </sect1>
323 <sect1><title>Frame Buffer Macintosh Video Mode Database</title>
324!Edrivers/video/fbdev/macmodes.c
325 </sect1>
326 <sect1><title>Frame Buffer Fonts</title>
327 <para>
328 Refer to the file lib/fonts/fonts.c for more information.
329 </para>
330<!-- FIXME: Removed for now since no structured comments in source
331X!Ilib/fonts/fonts.c
332-->
333 </sect1>
334 </chapter>
335
336 <chapter id="input_subsystem">
337 <title>Input Subsystem</title>
338 <sect1><title>Input core</title>
339!Iinclude/linux/input.h
340!Edrivers/input/input.c
341!Edrivers/input/ff-core.c
342!Edrivers/input/ff-memless.c
343 </sect1>
344 <sect1><title>Multitouch Library</title>
345!Iinclude/linux/input/mt.h
346!Edrivers/input/input-mt.c
347 </sect1>
348 <sect1><title>Polled input devices</title>
349!Iinclude/linux/input-polldev.h
350!Edrivers/input/input-polldev.c
351 </sect1>
352 <sect1><title>Matrix keyboards/keypads</title>
353!Iinclude/linux/input/matrix_keypad.h
354 </sect1>
355 <sect1><title>Sparse keymap support</title>
356!Iinclude/linux/input/sparse-keymap.h
357!Edrivers/input/sparse-keymap.c
358 </sect1>
359 </chapter>
360
361 <chapter id="spi">
362 <title>Serial Peripheral Interface (SPI)</title>
363 <para>
364 SPI is the "Serial Peripheral Interface", widely used with
365 embedded systems because it is a simple and efficient
366 interface: basically a multiplexed shift register.
367 Its three signal wires hold a clock (SCK, often in the range
368 of 1-20 MHz), a "Master Out, Slave In" (MOSI) data line, and
369 a "Master In, Slave Out" (MISO) data line.
370 SPI is a full duplex protocol; for each bit shifted out the
371 MOSI line (one per clock) another is shifted in on the MISO line.
372 Those bits are assembled into words of various sizes on the
373 way to and from system memory.
374 An additional chipselect line is usually active-low (nCS);
375 four signals are normally used for each peripheral, plus
376 sometimes an interrupt.
377 </para>
378 <para>
379 The SPI bus facilities listed here provide a generalized
380 interface to declare SPI busses and devices, manage them
381 according to the standard Linux driver model, and perform
382 input/output operations.
383 At this time, only "master" side interfaces are supported,
384 where Linux talks to SPI peripherals and does not implement
385 such a peripheral itself.
386 (Interfaces to support implementing SPI slaves would
387 necessarily look different.)
388 </para>
389 <para>
390 The programming interface is structured around two kinds of driver,
391 and two kinds of device.
392 A "Controller Driver" abstracts the controller hardware, which may
393 be as simple as a set of GPIO pins or as complex as a pair of FIFOs
394 connected to dual DMA engines on the other side of the SPI shift
395 register (maximizing throughput). Such drivers bridge between
396 whatever bus they sit on (often the platform bus) and SPI, and
397 expose the SPI side of their device as a
398 <structname>struct spi_master</structname>.
399 SPI devices are children of that master, represented as a
400 <structname>struct spi_device</structname> and manufactured from
401 <structname>struct spi_board_info</structname> descriptors which
402 are usually provided by board-specific initialization code.
403 A <structname>struct spi_driver</structname> is called a
404 "Protocol Driver", and is bound to a spi_device using normal
405 driver model calls.
406 </para>
407 <para>
408 The I/O model is a set of queued messages. Protocol drivers
409 submit one or more <structname>struct spi_message</structname>
410 objects, which are processed and completed asynchronously.
411 (There are synchronous wrappers, however.) Messages are
412 built from one or more <structname>struct spi_transfer</structname>
413 objects, each of which wraps a full duplex SPI transfer.
414 A variety of protocol tweaking options are needed, because
415 different chips adopt very different policies for how they
416 use the bits transferred with SPI.
417 </para>
418!Iinclude/linux/spi/spi.h
419!Fdrivers/spi/spi.c spi_register_board_info
420!Edrivers/spi/spi.c
421 </chapter>
422
423 <chapter id="i2c">
424 <title>I<superscript>2</superscript>C and SMBus Subsystem</title>
425
426 <para>
427 I<superscript>2</superscript>C (or without fancy typography, "I2C")
428 is an acronym for the "Inter-IC" bus, a simple bus protocol which is
429 widely used where low data rate communications suffice.
430 Since it's also a licensed trademark, some vendors use another
431 name (such as "Two-Wire Interface", TWI) for the same bus.
432 I2C only needs two signals (SCL for clock, SDA for data), conserving
433 board real estate and minimizing signal quality issues.
434 Most I2C devices use seven bit addresses, and bus speeds of up
435 to 400 kHz; there's a high speed extension (3.4 MHz) that's not yet
436 found wide use.
437 I2C is a multi-master bus; open drain signaling is used to
438 arbitrate between masters, as well as to handshake and to
439 synchronize clocks from slower clients.
440 </para>
441
442 <para>
443 The Linux I2C programming interfaces support only the master
444 side of bus interactions, not the slave side.
445 The programming interface is structured around two kinds of driver,
446 and two kinds of device.
447 An I2C "Adapter Driver" abstracts the controller hardware; it binds
448 to a physical device (perhaps a PCI device or platform_device) and
449 exposes a <structname>struct i2c_adapter</structname> representing
450 each I2C bus segment it manages.
451 On each I2C bus segment will be I2C devices represented by a
452 <structname>struct i2c_client</structname>. Those devices will
453 be bound to a <structname>struct i2c_driver</structname>,
454 which should follow the standard Linux driver model.
455 (At this writing, a legacy model is more widely used.)
456 There are functions to perform various I2C protocol operations; at
457 this writing all such functions are usable only from task context.
458 </para>
459
460 <para>
461 The System Management Bus (SMBus) is a sibling protocol. Most SMBus
462 systems are also I2C conformant. The electrical constraints are
463 tighter for SMBus, and it standardizes particular protocol messages
464 and idioms. Controllers that support I2C can also support most
465 SMBus operations, but SMBus controllers don't support all the protocol
466 options that an I2C controller will.
467 There are functions to perform various SMBus protocol operations,
468 either using I2C primitives or by issuing SMBus commands to
469 i2c_adapter devices which don't support those I2C operations.
470 </para>
471
472!Iinclude/linux/i2c.h
473!Fdrivers/i2c/i2c-boardinfo.c i2c_register_board_info
474!Edrivers/i2c/i2c-core.c
475 </chapter>
476
477 <chapter id="hsi">
478 <title>High Speed Synchronous Serial Interface (HSI)</title>
479
480 <para>
481 High Speed Synchronous Serial Interface (HSI) is a
482 serial interface mainly used for connecting application
483 engines (APE) with cellular modem engines (CMT) in cellular
484 handsets.
485
486 HSI provides multiplexing for up to 16 logical channels,
487 low-latency and full duplex communication.
488 </para>
489
490!Iinclude/linux/hsi/hsi.h
491!Edrivers/hsi/hsi_core.c
492 </chapter>
493
494 <chapter id="pwm">
495 <title>Pulse-Width Modulation (PWM)</title>
496 <para>
497 Pulse-width modulation is a modulation technique primarily used to
498 control power supplied to electrical devices.
499 </para>
500 <para>
501 The PWM framework provides an abstraction for providers and consumers
502 of PWM signals. A controller that provides one or more PWM signals is
503 registered as <structname>struct pwm_chip</structname>. Providers are
504 expected to embed this structure in a driver-specific structure. This
505 structure contains fields that describe a particular chip.
506 </para>
507 <para>
508 A chip exposes one or more PWM signal sources, each of which exposed
509 as a <structname>struct pwm_device</structname>. Operations can be
510 performed on PWM devices to control the period, duty cycle, polarity
511 and active state of the signal.
512 </para>
513 <para>
514 Note that PWM devices are exclusive resources: they can always only be
515 used by one consumer at a time.
516 </para>
517!Iinclude/linux/pwm.h
518!Edrivers/pwm/core.c
519 </chapter>
520
521</book>
diff --git a/Documentation/driver-api/drivers.rst b/Documentation/driver-api/drivers.rst
new file mode 100644
index 000000000000..17f99d441b52
--- /dev/null
+++ b/Documentation/driver-api/drivers.rst
@@ -0,0 +1,654 @@
1====================
2Linux Device Drivers
3====================
4
5Driver Basics
6=============
7
8Driver Entry and Exit points
9----------------------------
10
11.. kernel-doc:: include/linux/init.h
12 :internal:
13
14Atomic and pointer manipulation
15-------------------------------
16
17.. kernel-doc:: arch/x86/include/asm/atomic.h
18 :internal:
19
20Delaying, scheduling, and timer routines
21----------------------------------------
22
23.. kernel-doc:: include/linux/sched.h
24 :internal:
25
26.. kernel-doc:: kernel/sched/core.c
27 :export:
28
29.. kernel-doc:: kernel/sched/cpupri.c
30 :internal:
31
32.. kernel-doc:: kernel/sched/fair.c
33 :internal:
34
35.. kernel-doc:: include/linux/completion.h
36 :internal:
37
38.. kernel-doc:: kernel/time/timer.c
39 :export:
40
41Wait queues and Wake events
42---------------------------
43
44.. kernel-doc:: include/linux/wait.h
45 :internal:
46
47.. kernel-doc:: kernel/sched/wait.c
48 :export:
49
50High-resolution timers
51----------------------
52
53.. kernel-doc:: include/linux/ktime.h
54 :internal:
55
56.. kernel-doc:: include/linux/hrtimer.h
57 :internal:
58
59.. kernel-doc:: kernel/time/hrtimer.c
60 :export:
61
62Workqueues and Kevents
63----------------------
64
65.. kernel-doc:: include/linux/workqueue.h
66 :internal:
67
68.. kernel-doc:: kernel/workqueue.c
69 :export:
70
71Internal Functions
72------------------
73
74.. kernel-doc:: kernel/exit.c
75 :internal:
76
77.. kernel-doc:: kernel/signal.c
78 :internal:
79
80.. kernel-doc:: include/linux/kthread.h
81 :internal:
82
83.. kernel-doc:: kernel/kthread.c
84 :export:
85
86Kernel objects manipulation
87---------------------------
88
89.. kernel-doc:: lib/kobject.c
90 :export:
91
92Kernel utility functions
93------------------------
94
95.. kernel-doc:: include/linux/kernel.h
96 :internal:
97
98.. kernel-doc:: kernel/printk/printk.c
99 :export:
100
101.. kernel-doc:: kernel/panic.c
102 :export:
103
104.. kernel-doc:: kernel/sys.c
105 :export:
106
107.. kernel-doc:: kernel/rcu/srcu.c
108 :export:
109
110.. kernel-doc:: kernel/rcu/tree.c
111 :export:
112
113.. kernel-doc:: kernel/rcu/tree_plugin.h
114 :export:
115
116.. kernel-doc:: kernel/rcu/update.c
117 :export:
118
119Device Resource Management
120--------------------------
121
122.. kernel-doc:: drivers/base/devres.c
123 :export:
124
125Device drivers infrastructure
126=============================
127
128The Basic Device Driver-Model Structures
129----------------------------------------
130
131.. kernel-doc:: include/linux/device.h
132 :internal:
133
134Device Drivers Base
135-------------------
136
137.. kernel-doc:: drivers/base/init.c
138 :internal:
139
140.. kernel-doc:: drivers/base/driver.c
141 :export:
142
143.. kernel-doc:: drivers/base/core.c
144 :export:
145
146.. kernel-doc:: drivers/base/syscore.c
147 :export:
148
149.. kernel-doc:: drivers/base/class.c
150 :export:
151
152.. kernel-doc:: drivers/base/node.c
153 :internal:
154
155.. kernel-doc:: drivers/base/firmware_class.c
156 :export:
157
158.. kernel-doc:: drivers/base/transport_class.c
159 :export:
160
161.. kernel-doc:: drivers/base/dd.c
162 :export:
163
164.. kernel-doc:: include/linux/platform_device.h
165 :internal:
166
167.. kernel-doc:: drivers/base/platform.c
168 :export:
169
170.. kernel-doc:: drivers/base/bus.c
171 :export:
172
173Buffer Sharing and Synchronization
174----------------------------------
175
176The dma-buf subsystem provides the framework for sharing buffers for
177hardware (DMA) access across multiple device drivers and subsystems, and
178for synchronizing asynchronous hardware access.
179
180This is used, for example, by drm "prime" multi-GPU support, but is of
181course not limited to GPU use cases.
182
183The three main components of this are: (1) dma-buf, representing a
184sg_table and exposed to userspace as a file descriptor to allow passing
185between devices, (2) fence, which provides a mechanism to signal when
186one device as finished access, and (3) reservation, which manages the
187shared or exclusive fence(s) associated with the buffer.
188
189dma-buf
190~~~~~~~
191
192.. kernel-doc:: drivers/dma-buf/dma-buf.c
193 :export:
194
195.. kernel-doc:: include/linux/dma-buf.h
196 :internal:
197
198reservation
199~~~~~~~~~~~
200
201.. kernel-doc:: drivers/dma-buf/reservation.c
202 :doc: Reservation Object Overview
203
204.. kernel-doc:: drivers/dma-buf/reservation.c
205 :export:
206
207.. kernel-doc:: include/linux/reservation.h
208 :internal:
209
210fence
211~~~~~
212
213.. kernel-doc:: drivers/dma-buf/fence.c
214 :export:
215
216.. kernel-doc:: include/linux/fence.h
217 :internal:
218
219.. kernel-doc:: drivers/dma-buf/seqno-fence.c
220 :export:
221
222.. kernel-doc:: include/linux/seqno-fence.h
223 :internal:
224
225.. kernel-doc:: drivers/dma-buf/fence-array.c
226 :export:
227
228.. kernel-doc:: include/linux/fence-array.h
229 :internal:
230
231.. kernel-doc:: drivers/dma-buf/reservation.c
232 :export:
233
234.. kernel-doc:: include/linux/reservation.h
235 :internal:
236
237.. kernel-doc:: drivers/dma-buf/sync_file.c
238 :export:
239
240.. kernel-doc:: include/linux/sync_file.h
241 :internal:
242
243Device Drivers DMA Management
244-----------------------------
245
246.. kernel-doc:: drivers/base/dma-coherent.c
247 :export:
248
249.. kernel-doc:: drivers/base/dma-mapping.c
250 :export:
251
252Device Drivers Power Management
253-------------------------------
254
255.. kernel-doc:: drivers/base/power/main.c
256 :export:
257
258Device Drivers ACPI Support
259---------------------------
260
261.. kernel-doc:: drivers/acpi/scan.c
262 :export:
263
264.. kernel-doc:: drivers/acpi/scan.c
265 :internal:
266
267Device drivers PnP support
268--------------------------
269
270.. kernel-doc:: drivers/pnp/core.c
271 :internal:
272
273.. kernel-doc:: drivers/pnp/card.c
274 :export:
275
276.. kernel-doc:: drivers/pnp/driver.c
277 :internal:
278
279.. kernel-doc:: drivers/pnp/manager.c
280 :export:
281
282.. kernel-doc:: drivers/pnp/support.c
283 :export:
284
285Userspace IO devices
286--------------------
287
288.. kernel-doc:: drivers/uio/uio.c
289 :export:
290
291.. kernel-doc:: include/linux/uio_driver.h
292 :internal:
293
294Parallel Port Devices
295=====================
296
297.. kernel-doc:: include/linux/parport.h
298 :internal:
299
300.. kernel-doc:: drivers/parport/ieee1284.c
301 :export:
302
303.. kernel-doc:: drivers/parport/share.c
304 :export:
305
306.. kernel-doc:: drivers/parport/daisy.c
307 :internal:
308
309Message-based devices
310=====================
311
312Fusion message devices
313----------------------
314
315.. kernel-doc:: drivers/message/fusion/mptbase.c
316 :export:
317
318.. kernel-doc:: drivers/message/fusion/mptbase.c
319 :internal:
320
321.. kernel-doc:: drivers/message/fusion/mptscsih.c
322 :export:
323
324.. kernel-doc:: drivers/message/fusion/mptscsih.c
325 :internal:
326
327.. kernel-doc:: drivers/message/fusion/mptctl.c
328 :internal:
329
330.. kernel-doc:: drivers/message/fusion/mptspi.c
331 :internal:
332
333.. kernel-doc:: drivers/message/fusion/mptfc.c
334 :internal:
335
336.. kernel-doc:: drivers/message/fusion/mptlan.c
337 :internal:
338
339Sound Devices
340=============
341
342.. kernel-doc:: include/sound/core.h
343 :internal:
344
345.. kernel-doc:: sound/sound_core.c
346 :export:
347
348.. kernel-doc:: include/sound/pcm.h
349 :internal:
350
351.. kernel-doc:: sound/core/pcm.c
352 :export:
353
354.. kernel-doc:: sound/core/device.c
355 :export:
356
357.. kernel-doc:: sound/core/info.c
358 :export:
359
360.. kernel-doc:: sound/core/rawmidi.c
361 :export:
362
363.. kernel-doc:: sound/core/sound.c
364 :export:
365
366.. kernel-doc:: sound/core/memory.c
367 :export:
368
369.. kernel-doc:: sound/core/pcm_memory.c
370 :export:
371
372.. kernel-doc:: sound/core/init.c
373 :export:
374
375.. kernel-doc:: sound/core/isadma.c
376 :export:
377
378.. kernel-doc:: sound/core/control.c
379 :export:
380
381.. kernel-doc:: sound/core/pcm_lib.c
382 :export:
383
384.. kernel-doc:: sound/core/hwdep.c
385 :export:
386
387.. kernel-doc:: sound/core/pcm_native.c
388 :export:
389
390.. kernel-doc:: sound/core/memalloc.c
391 :export:
392
39316x50 UART Driver
394=================
395
396.. kernel-doc:: drivers/tty/serial/serial_core.c
397 :export:
398
399.. kernel-doc:: drivers/tty/serial/8250/8250_core.c
400 :export:
401
402Frame Buffer Library
403====================
404
405The frame buffer drivers depend heavily on four data structures. These
406structures are declared in include/linux/fb.h. They are fb_info,
407fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs. The last
408three can be made available to and from userland.
409
410fb_info defines the current state of a particular video card. Inside
411fb_info, there exists a fb_ops structure which is a collection of
412needed functions to make fbdev and fbcon work. fb_info is only visible
413to the kernel.
414
415fb_var_screeninfo is used to describe the features of a video card
416that are user defined. With fb_var_screeninfo, things such as depth
417and the resolution may be defined.
418
419The next structure is fb_fix_screeninfo. This defines the properties
420of a card that are created when a mode is set and can't be changed
421otherwise. A good example of this is the start of the frame buffer
422memory. This "locks" the address of the frame buffer memory, so that it
423cannot be changed or moved.
424
425The last structure is fb_monospecs. In the old API, there was little
426importance for fb_monospecs. This allowed for forbidden things such as
427setting a mode of 800x600 on a fix frequency monitor. With the new API,
428fb_monospecs prevents such things, and if used correctly, can prevent a
429monitor from being cooked. fb_monospecs will not be useful until
430kernels 2.5.x.
431
432Frame Buffer Memory
433-------------------
434
435.. kernel-doc:: drivers/video/fbdev/core/fbmem.c
436 :export:
437
438Frame Buffer Colormap
439---------------------
440
441.. kernel-doc:: drivers/video/fbdev/core/fbcmap.c
442 :export:
443
444Frame Buffer Video Mode Database
445--------------------------------
446
447.. kernel-doc:: drivers/video/fbdev/core/modedb.c
448 :internal:
449
450.. kernel-doc:: drivers/video/fbdev/core/modedb.c
451 :export:
452
453Frame Buffer Macintosh Video Mode Database
454------------------------------------------
455
456.. kernel-doc:: drivers/video/fbdev/macmodes.c
457 :export:
458
459Frame Buffer Fonts
460------------------
461
462Refer to the file lib/fonts/fonts.c for more information.
463
464Input Subsystem
465===============
466
467Input core
468----------
469
470.. kernel-doc:: include/linux/input.h
471 :internal:
472
473.. kernel-doc:: drivers/input/input.c
474 :export:
475
476.. kernel-doc:: drivers/input/ff-core.c
477 :export:
478
479.. kernel-doc:: drivers/input/ff-memless.c
480 :export:
481
482Multitouch Library
483------------------
484
485.. kernel-doc:: include/linux/input/mt.h
486 :internal:
487
488.. kernel-doc:: drivers/input/input-mt.c
489 :export:
490
491Polled input devices
492--------------------
493
494.. kernel-doc:: include/linux/input-polldev.h
495 :internal:
496
497.. kernel-doc:: drivers/input/input-polldev.c
498 :export:
499
500Matrix keyboards/keypads
501------------------------
502
503.. kernel-doc:: include/linux/input/matrix_keypad.h
504 :internal:
505
506Sparse keymap support
507---------------------
508
509.. kernel-doc:: include/linux/input/sparse-keymap.h
510 :internal:
511
512.. kernel-doc:: drivers/input/sparse-keymap.c
513 :export:
514
515Serial Peripheral Interface (SPI)
516=================================
517
518SPI is the "Serial Peripheral Interface", widely used with embedded
519systems because it is a simple and efficient interface: basically a
520multiplexed shift register. Its three signal wires hold a clock (SCK,
521often in the range of 1-20 MHz), a "Master Out, Slave In" (MOSI) data
522line, and a "Master In, Slave Out" (MISO) data line. SPI is a full
523duplex protocol; for each bit shifted out the MOSI line (one per clock)
524another is shifted in on the MISO line. Those bits are assembled into
525words of various sizes on the way to and from system memory. An
526additional chipselect line is usually active-low (nCS); four signals are
527normally used for each peripheral, plus sometimes an interrupt.
528
529The SPI bus facilities listed here provide a generalized interface to
530declare SPI busses and devices, manage them according to the standard
531Linux driver model, and perform input/output operations. At this time,
532only "master" side interfaces are supported, where Linux talks to SPI
533peripherals and does not implement such a peripheral itself. (Interfaces
534to support implementing SPI slaves would necessarily look different.)
535
536The programming interface is structured around two kinds of driver, and
537two kinds of device. A "Controller Driver" abstracts the controller
538hardware, which may be as simple as a set of GPIO pins or as complex as
539a pair of FIFOs connected to dual DMA engines on the other side of the
540SPI shift register (maximizing throughput). Such drivers bridge between
541whatever bus they sit on (often the platform bus) and SPI, and expose
542the SPI side of their device as a :c:type:`struct spi_master
543<spi_master>`. SPI devices are children of that master,
544represented as a :c:type:`struct spi_device <spi_device>` and
545manufactured from :c:type:`struct spi_board_info
546<spi_board_info>` descriptors which are usually provided by
547board-specific initialization code. A :c:type:`struct spi_driver
548<spi_driver>` is called a "Protocol Driver", and is bound to a
549spi_device using normal driver model calls.
550
551The I/O model is a set of queued messages. Protocol drivers submit one
552or more :c:type:`struct spi_message <spi_message>` objects,
553which are processed and completed asynchronously. (There are synchronous
554wrappers, however.) Messages are built from one or more
555:c:type:`struct spi_transfer <spi_transfer>` objects, each of
556which wraps a full duplex SPI transfer. A variety of protocol tweaking
557options are needed, because different chips adopt very different
558policies for how they use the bits transferred with SPI.
559
560.. kernel-doc:: include/linux/spi/spi.h
561 :internal:
562
563.. kernel-doc:: drivers/spi/spi.c
564 :functions: spi_register_board_info
565
566.. kernel-doc:: drivers/spi/spi.c
567 :export:
568
569I\ :sup:`2`\ C and SMBus Subsystem
570==================================
571
572I\ :sup:`2`\ C (or without fancy typography, "I2C") is an acronym for
573the "Inter-IC" bus, a simple bus protocol which is widely used where low
574data rate communications suffice. Since it's also a licensed trademark,
575some vendors use another name (such as "Two-Wire Interface", TWI) for
576the same bus. I2C only needs two signals (SCL for clock, SDA for data),
577conserving board real estate and minimizing signal quality issues. Most
578I2C devices use seven bit addresses, and bus speeds of up to 400 kHz;
579there's a high speed extension (3.4 MHz) that's not yet found wide use.
580I2C is a multi-master bus; open drain signaling is used to arbitrate
581between masters, as well as to handshake and to synchronize clocks from
582slower clients.
583
584The Linux I2C programming interfaces support only the master side of bus
585interactions, not the slave side. The programming interface is
586structured around two kinds of driver, and two kinds of device. An I2C
587"Adapter Driver" abstracts the controller hardware; it binds to a
588physical device (perhaps a PCI device or platform_device) and exposes a
589:c:type:`struct i2c_adapter <i2c_adapter>` representing each
590I2C bus segment it manages. On each I2C bus segment will be I2C devices
591represented by a :c:type:`struct i2c_client <i2c_client>`.
592Those devices will be bound to a :c:type:`struct i2c_driver
593<i2c_driver>`, which should follow the standard Linux driver
594model. (At this writing, a legacy model is more widely used.) There are
595functions to perform various I2C protocol operations; at this writing
596all such functions are usable only from task context.
597
598The System Management Bus (SMBus) is a sibling protocol. Most SMBus
599systems are also I2C conformant. The electrical constraints are tighter
600for SMBus, and it standardizes particular protocol messages and idioms.
601Controllers that support I2C can also support most SMBus operations, but
602SMBus controllers don't support all the protocol options that an I2C
603controller will. There are functions to perform various SMBus protocol
604operations, either using I2C primitives or by issuing SMBus commands to
605i2c_adapter devices which don't support those I2C operations.
606
607.. kernel-doc:: include/linux/i2c.h
608 :internal:
609
610.. kernel-doc:: drivers/i2c/i2c-boardinfo.c
611 :functions: i2c_register_board_info
612
613.. kernel-doc:: drivers/i2c/i2c-core.c
614 :export:
615
616High Speed Synchronous Serial Interface (HSI)
617=============================================
618
619High Speed Synchronous Serial Interface (HSI) is a serial interface
620mainly used for connecting application engines (APE) with cellular modem
621engines (CMT) in cellular handsets. HSI provides multiplexing for up to
62216 logical channels, low-latency and full duplex communication.
623
624.. kernel-doc:: include/linux/hsi/hsi.h
625 :internal:
626
627.. kernel-doc:: drivers/hsi/hsi_core.c
628 :export:
629
630Pulse-Width Modulation (PWM)
631============================
632
633Pulse-width modulation is a modulation technique primarily used to
634control power supplied to electrical devices.
635
636The PWM framework provides an abstraction for providers and consumers of
637PWM signals. A controller that provides one or more PWM signals is
638registered as :c:type:`struct pwm_chip <pwm_chip>`. Providers
639are expected to embed this structure in a driver-specific structure.
640This structure contains fields that describe a particular chip.
641
642A chip exposes one or more PWM signal sources, each of which exposed as
643a :c:type:`struct pwm_device <pwm_device>`. Operations can be
644performed on PWM devices to control the period, duty cycle, polarity and
645active state of the signal.
646
647Note that PWM devices are exclusive resources: they can always only be
648used by one consumer at a time.
649
650.. kernel-doc:: include/linux/pwm.h
651 :internal:
652
653.. kernel-doc:: drivers/pwm/core.c
654 :export:
diff --git a/Documentation/index.rst b/Documentation/index.rst
index 05eded59820e..0d6992b897c8 100644
--- a/Documentation/index.rst
+++ b/Documentation/index.rst
@@ -13,6 +13,7 @@ Contents:
13 13
14 kernel-documentation 14 kernel-documentation
15 dev-tools/tools 15 dev-tools/tools
16 driver-api/drivers
16 media/index 17 media/index
17 gpu/index 18 gpu/index
18 19
generated by cgit v1.2.2 (git 2.25.0) at 2025-02-21 01:18:00 -0500