Documentation/SubmittingDrivers

   1 Submitting Drivers For The Linux Kernel
   2 ---------------------------------------
   3
   4 This document is intended to explain how to submit device drivers to the
   5 various kernel trees. Note that if you are interested in video card drivers
   6 you should probably talk to XFree86 (http://www.xfree86.org/) and/or X.Org
   7 (http://x.org/) instead.
   8
   9 Also read the Documentation/SubmittingPatches document.
  10
  11
  12 Allocating Device Numbers
  13 -------------------------
  14
  15 Major and minor numbers for block and character devices are allocated
  16 by the Linux assigned name and number authority (currently this is
  17 Torben Mathiasen). The site is http://www.lanana.org/. This
  18 also deals with allocating numbers for devices that are not going to
  19 be submitted to the mainstream kernel.
  20 See Documentation/devices.txt for more information on this.
  21
  22 If you don't use assigned numbers then when your device is submitted it will
  23 be given an assigned number even if that is different from values you may
  24 have shipped to customers before.
  25
  26 Who To Submit Drivers To
  27 ------------------------
  28
  29 Linux 2.0:
  30         No new drivers are accepted for this kernel tree.
  31
  32 Linux 2.2:
  33         No new drivers are accepted for this kernel tree.
  34
  35 Linux 2.4:
  36         If the code area has a general maintainer then please submit it to
  37         the maintainer listed in MAINTAINERS in the kernel file. If the
  38         maintainer does not respond or you cannot find the appropriate
  39         maintainer then please contact Marcelo Tosatti
  40         <marcelo.tosatti@cyclades.com>.
  41
  42 Linux 2.6:
  43         The same rules apply as 2.4 except that you should follow linux-kernel
  44         to track changes in API's. The final contact point for Linux 2.6
  45         submissions is Andrew Morton <akpm@osdl.org>.
  46
  47 What Criteria Determine Acceptance
  48 ----------------------------------
  49
  50 Licensing:      The code must be released to us under the
  51                 GNU General Public License. We don't insist on any kind
  52                 of exclusive GPL licensing, and if you wish the driver
  53                 to be useful to other communities such as BSD you may well
  54                 wish to release under multiple licenses.
  55                 See accepted licenses at include/linux/module.h
  56
  57 Copyright:      The copyright owner must agree to use of GPL.
  58                 It's best if the submitter and copyright owner
  59                 are the same person/entity. If not, the name of
  60                 the person/entity authorizing use of GPL should be
  61                 listed in case it's necessary to verify the will of
  62                 the copright owner.
  63
  64 Interfaces:     If your driver uses existing interfaces and behaves like
  65                 other drivers in the same class it will be much more likely
  66                 to be accepted than if it invents gratuitous new ones.
  67                 If you need to implement a common API over Linux and NT
  68                 drivers do it in userspace.
  69
  70 Code:           Please use the Linux style of code formatting as documented
  71                 in Documentation/CodingStyle. If you have sections of code
  72                 that need to be in other formats, for example because they
  73                 are shared with a windows driver kit and you want to
  74                 maintain them just once separate them out nicely and note
  75                 this fact.
  76
  77 Portability:    Pointers are not always 32bits, not all computers are little
  78                 endian, people do not all have floating point and you
  79                 shouldn't use inline x86 assembler in your driver without
  80                 careful thought. Pure x86 drivers generally are not popular.
  81                 If you only have x86 hardware it is hard to test portability
  82                 but it is easy to make sure the code can easily be made
  83                 portable.
  84
  85 Clarity:        It helps if anyone can see how to fix the driver. It helps
  86                 you because you get patches not bug reports. If you submit a
  87                 driver that intentionally obfuscates how the hardware works
  88                 it will go in the bitbucket.
  89
  90 Control:        In general if there is active maintainance of a driver by
  91                 the author then patches will be redirected to them unless
  92                 they are totally obvious and without need of checking.
  93                 If you want to be the contact and update point for the
  94                 driver it is a good idea to state this in the comments,
  95                 and include an entry in MAINTAINERS for your driver.
  96
  97 What Criteria Do Not Determine Acceptance
  98 -----------------------------------------
  99
 100 Vendor:         Being the hardware vendor and maintaining the driver is
 101                 often a good thing. If there is a stable working driver from
 102                 other people already in the tree don't expect 'we are the
 103                 vendor' to get your driver chosen. Ideally work with the
 104                 existing driver author to build a single perfect driver.
 105
 106 Author:         It doesn't matter if a large Linux company wrote the driver,
 107                 or you did. Nobody has any special access to the kernel
 108                 tree. Anyone who tells you otherwise isn't telling the
 109                 whole story.
 110
 111
 112 Resources
 113 ---------
 114
 115 Linux kernel master tree:
 116         ftp.??.kernel.org:/pub/linux/kernel/...
 117         ?? == your country code, such as "us", "uk", "fr", etc.
 118
 119 Linux kernel mailing list:
 120         linux-kernel@vger.kernel.org
 121         [mail majordomo@vger.kernel.org to subscribe]
 122
 123 Linux Device Drivers, Third Edition (covers 2.6.10):
 124         http://lwn.net/Kernel/LDD3/  (free version)
 125
 126 Kernel traffic:
 127         Weekly summary of kernel list activity (much easier to read)
 128         http://www.kerneltraffic.org/kernel-traffic/
 129
 130 LWN.net:
 131         Weekly summary of kernel development activity - http://lwn.net/
 132         2.6 API changes:
 133                 http://lwn.net/Articles/2.6-kernel-api/
 134         Porting drivers from prior kernels to 2.6:
 135                 http://lwn.net/Articles/driver-porting/
 136
 137 KernelTrap:
 138         Occasional Linux kernel articles and developer interviews
 139         http://kerneltrap.org/
 140
 141 KernelNewbies:
 142         Documentation and assistance for new kernel programmers
 143         http://kernelnewbies.org/
 144
 145 Linux USB project:
 146         http://linux-usb.sourceforge.net/
 147
 148 How to NOT write kernel driver by arjanv@redhat.com
 149         http://people.redhat.com/arjanv/olspaper.pdf
 150
 151 Kernel Janitor:
 152         http://janitor.kernelnewbies.org/
 153
 154 --
 155 Last updated on 17 Nov 2005.