Hi Greg, thanks for your advice: * Greg KH <greg at kroah.com> [2005-04-12 14:55:55 -0700]: > On Mon, Apr 11, 2005 at 12:44:27AM -0400, Mark M. Hoffman wrote: > > Hi Khali, Greg, et. al: > > > > After a brief chat w/ Khali last week (and some reading LDDv3) I did these > > patches. The result for me looks like this: > > > > /sys/class/hwmon/1-0290/device/ -> /sys/devices/platform/i2c-1/1-0290 > > > > Notes/Questions: > > First a question from me, why? What are you trying to do here? Who > will be using the hwmon class? And what for? Will all "sensor-like" > sysfs files move to this new class, or is it just to enable userspace to > be able to find the hwmon devices easier? Khali is working on patches to get rid of the i2c-isa 'pseudo-adapter'. Since any sensor chip attached to the ISA bus will no longer appear in the /sys/bus/i2c tree, a new way is needed. Userspace tools can be taught to look in /sys/class/hwmon first, and then /sys/bus/i2c for backwards-compatibility. > > 1. I don't like "1-0290" for a class ID, but it was the easiest thing to > > use at the time. A better name might be w83627thf-0. > > As long as it's unique, that's the only requirement. I just strlcpy'd the '1-0290' ID from the /sys/bus/i2c tree because it is unique. My concern is that it's not very descriptive. > > 2. The kernel complains if I don't provide a class::release function, but > > I can't really see a need for it in this case. If I hold a file open through > > the /sys/class/hwmon/X/device/Y link and then try to rmmod the driver, the > > rmmod will sleep until I close the file just as I expect. Any hints here > > Greg? > > Ick, yes, you _must_ have a release function. _Please_ listen to the > kernel, it isn't saying those things for no reason... If you add a file > to the class device, and do not have a release function, then you can But... I didn't add any files to the class device. ;) I'm not planning to move any existing files (temp1_input, etc) - I just want the link back to the device. It didn't look like that (by itself) should require a release function, but I'll go back and read it again. > have a memory leak. The way that you use the class device owned by a > different device is not safe, nor a good idea. I recommend using the Err... what about struct i2c_adapter? > "class_device_create()" function that has been added to the -mm tree (or > the class_simple stuff that's in mainline, if you want an idea of what > it is. Hm, no that will not quite work, that's why I wrote the > class_device_create() call...use that.) OK, I'll try it again that way. > > 3. I added the struct class_device to struct i2c_client. This makes it > > slightly easier to modify the sensors drivers... but not all i2c_clients > > will need it (bloat). It could be added to each struct <driver>_data > > (e.g. w83627hf_data) instead. > > Use a pointer instead, and the class_device_create function. OK. Thanks and regards, -- Mark M. Hoffman mhoffman at lightlink.com
