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