1Submitting Drivers For The Linux Kernel 2--------------------------------------- 3 4This document is intended to explain how to submit device drivers to the 5Linux 2.2 and 2.4 kernel trees. Note that if you are interested in video 6card drivers you should probably talk to XFree86 (http://wwww.xfree86.org) 7instead. 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 This kernel tree is under active development. The same rules apply 39 as 2.2 but you may wish to submit your driver via linux-kernel (see 40 resources) and follow that list to track changes in API's. These 41 should no longer be occuring as we are now in a code freeze. 42 The final contact point for Linux 2.4 submissions is 43 <torvalds@transmeta.com>. 44 45What Criteria Determine Acceptance 46---------------------------------- 47 48Licensing: The code must be released to us under the GNU General Public License. 49 We don't insist on any kind of exclusively GPL licensing, 50 and if you wish the driver to be useful to other communities 51 such as BSD you may well wish to release under multiple 52 licenses. 53 54Interfaces: If your driver uses existing interfaces and behaves like 55 other drivers in the same class it will be much more likely 56 to be accepted than if it invents gratuitous new ones. 57 If you need to implement a common API over Linux and NT 58 drivers do it in userspace. 59 60Code: Please use the Linux style of code formatting as documented 61 in Documentation/CodingStyle. If you have sections of code 62 that need to be in other formats, for example because they 63 are shared with a windows driver kit and you want to 64 maintain them just once seperate them out nicely and note 65 this fact. 66 67Portability: Pointers are not always 32bits, people do not all have 68 floating point and you shouldn't use inline x86 assembler in 69 your driver without careful thought. Pure x86 drivers 70 generally are not popular. If you only have x86 hardware it 71 is hard to test portability but it is easy to make sure the 72 code can easily be made portable. 73 74Clarity: It helps if anyone can see how to fix the driver. It helps 75 you because you get patches not bug reports. If you submit a 76 driver that intentionally obfuscates how the hardware works 77 it will go in the bitbucket. 78 79Control: In general if there is active maintainance of a driver by 80 the author then patches will be redirected to them unless 81 they are totally obvious and without need of checking. 82 If you want to be the contact and update point for the 83 driver it is a good idea to state this in the comments, 84 and include an entry in MAINTAINERS for your driver. 85 86What Criteria Do Not Determine Acceptance 87----------------------------------------- 88 89Vendor: Being the hardware vendor and maintaining the driver is 90 often a good thing. If there is a stable working driver from 91 other people already in the tree don't expect 'we are the 92 vendor' to get your driver chosen. Ideally work with the 93 existing driver author to build a single perfect driver. 94 95Author: It doesn't matter if a large Linux company wrote the driver, 96 or you did. Nobody has any special access to the kernel 97 tree. Anyone who tells you otherwise isn't telling the 98 whole story. 99 100 101Resources 102--------- 103 104Linux kernel master tree: 105 ftp.??.kernel.org:/pub/linux/kernel/... 106 ?? == your country code, such as "us", "uk", "fr", etc. 107 108Linux kernel mailing list: 109 linux-kernel@vger.kernel.org 110 [mail majordomo@vger.kernel.org to subscribe] 111 112Kernel traffic: 113 Weekly summary of kernel list activity (much easier to read) 114 [http://kt.zork.net/kernel-traffic] 115 116Linux USB project: 117 http://sourceforge.net/projects/linux-usb/ 118 119