On Sat, Mar 23, 2013 at 01:57:42PM +0100, Wim Van Sebroeck wrote: > Hi Guenter, > > > > In 2011 I started something similar but then with the MFD approach in mind. > > > Goal was also to clean-up the w836* watchdog drivers and get a clean driver that > > > supports all Winbond super-I/O based watchdog drivers. > > > > > > I dug op the development code again. I'll post it in a next e-mail so that we can > > > see what the best way forward is. Note: I took the MFD approach because: > > > 1) all superio shares the similar functions for using the Super-I/O registers. > > > 2) Goal is to have low-level driver that support the specific super-I/O chipsets > > > and that does the platform stuff for hwmon, watchdog, gpio, ... > > > > > Hi Wim, > > > > I started with a similar approach, only I used mfd cells to pass on platform > > specific information such as the device type and the superio base address. > > I still have the patchset for the mfd driver, in case you are interested. > > My code is based on the patches submitted by Rodolfo Giometti a couple > > of years ago. Want me to post it ? > > If it's not v1 then I am interested. > I think it depends on the super-I/O chipset of what info you can pass. I would > not use mfd cells for the winbond driver but use platform data (similar to > drivers/mfd/adp5520.c) because you don't need more then just pass some data. > Actually one can pass platform data through mfd cells, which is what I do. I pass the SIO address, the chip type (as enum), and the chip name to the platform driver. > > What I noticed in my testing is that the superio address range (2e or 4e), > > which the drivers currently take as granted, is at least on my systems > > (all three of them) reserved by ACPI. Unfortunately that means one can not > > use the mfd infrastructure to pass on the superio memory region, > > since it checks for acpi conflicts. With that I gave up on the idea and > > reverted to using request_muxed_region. That seemed simpler and accomplish > > the same as long as all drivers actually use it. > > Noticed the same. That's why passing the platform data together with the > superio-address and type seems the best way to go. I also kept the superio_enter > and superio_exit a function in the low level driver because I used a lock to > make sure that the hwmon code doesn't start doing things when the watchdog is > doing things. But I think that the request_muxed_region is doing something similar > also. > Yes, it does the same. Only difference is that using a function in the mfd driver increases the use count on it when a client module is loaded. Patch follows. Thanks, Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
