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| -rw-r--r-- | Documentation/hwmon/submitting-patches | 109 |
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diff --git a/Documentation/hwmon/submitting-patches b/Documentation/hwmon/submitting-patches new file mode 100644 index 00000000000..86f42e8e9e4 --- /dev/null +++ b/Documentation/hwmon/submitting-patches @@ -0,0 +1,109 @@ + How to Get Your Patch Accepted Into the Hwmon Subsystem + ------------------------------------------------------- + +This text is is a collection of suggestions for people writing patches or +drivers for the hwmon subsystem. Following these suggestions will greatly +increase the chances of your change being accepted. + + +1. General +---------- + +* It should be unnecessary to mention, but please read and follow + Documentation/SubmitChecklist + Documentation/SubmittingDrivers + Documentation/SubmittingPatches + Documentation/CodingStyle + +* If your patch generates checkpatch warnings, please refrain from explanations + such as "I don't like that coding style". Keep in mind that each unnecessary + warning helps hiding a real problem. If you don't like the kernel coding + style, don't write kernel drivers. + +* Please test your patch thoroughly. We are not your test group. + Sometimes a patch can not or not completely be tested because of missing + hardware. In such cases, you should test-build the code on at least one + architecture. If run-time testing was not achieved, it should be written + explicitly below the patch header. + +* If your patch (or the driver) is affected by configuration options such as + CONFIG_SMP or CONFIG_HOTPLUG, make sure it compiles for all configuration + variants. + + +2. Adding functionality to existing drivers +------------------------------------------- + +* Make sure the documentation in Documentation/hwmon/<driver_name> is up to + date. + +* Make sure the information in Kconfig is up to date. + +* If the added functionality requires some cleanup or structural changes, split + your patch into a cleanup part and the actual addition. This makes it easier + to review your changes, and to bisect any resulting problems. + +* Never mix bug fixes, cleanup, and functional enhancements in a single patch. + + +3. New drivers +-------------- + +* Running your patch or driver file(s) through checkpatch does not mean its + formatting is clean. If unsure about formatting in your new driver, run it + through Lindent. Lindent is not perfect, and you may have to do some minor + cleanup, but it is a good start. + +* Consider adding yourself to MAINTAINERS. + +* Document the driver in Documentation/hwmon/<driver_name>. + +* Add the driver to Kconfig and Makefile in alphabetical order. + +* Make sure that all dependencies are listed in Kconfig. For new drivers, it + is most likely prudent to add a dependency on EXPERIMENTAL. + +* Avoid forward declarations if you can. Rearrange the code if necessary. + +* Avoid calculations in macros and macro-generated functions. While such macros + may save a line or so in the source, it obfuscates the code and makes code + review more difficult. It may also result in code which is more complicated + than necessary. Use inline functions or just regular functions instead. + +* If the driver has a detect function, make sure it is silent. Debug messages + and messages printed after a successful detection are acceptable, but it + must not print messages such as "Chip XXX not found/supported". + + Keep in mind that the detect function will run for all drivers supporting an + address if a chip is detected on that address. Unnecessary messages will just + pollute the kernel log and not provide any value. + +* Provide a detect function if and only if a chip can be detected reliably. + +* Avoid writing to chip registers in the detect function. If you have to write, + only do it after you have already gathered enough data to be certain that the + detection is going to be successful. + + Keep in mind that the chip might not be what your driver believes it is, and + writing to it might cause a bad misconfiguration. + +* Make sure there are no race conditions in the probe function. Specifically, + completely initialize your chip first, then create sysfs entries and register + with the hwmon subsystem. + +* Do not provide support for deprecated sysfs attributes. + +* Do not create non-standard attributes unless really needed. If you have to use + non-standard attributes, or you believe you do, discuss it on the mailing list + first. Either case, provide a detailed explanation why you need the + non-standard attribute(s). + Standard attributes are specified in Documentation/hwmon/sysfs-interface. + +* When deciding which sysfs attributes to support, look at the chip's + capabilities. While we do not expect your driver to support everything the + chip may offer, it should at least support all limits and alarms. + +* Last but not least, please check if a driver for your chip already exists + before starting to write a new driver. Especially for temperature sensors, + new chips are often variants of previously released chips. In some cases, + a presumably new chip may simply have been relabeled. |