On Wed, Dec 12, 2012 at 11:08:23AM +0100, Lars-Peter Clausen wrote: > Added Guenter Roeck to Cc, since he merged the hwmon patch. > > On 12/12/2012 09:59 AM, Jonathan Cameron wrote: > > On 11/12/12 20:10, Lars-Peter Clausen wrote: > >> On 12/11/2012 08:57 PM, Hartmut Knaack wrote: > >>> Jonathan Cameron schrieb: > >>>> On 7/16/2012 9:34 AM, Sascha Hauer wrote: > >>>>> On Sun, Jul 15, 2012 at 11:11:52PM +0200, Lars-Peter Clausen wrote: > >>>>>> On 07/15/2012 10:40 PM, Hartmut Knaack wrote: > >>>>>>> This patchset makes the ADT7410 usable. Main reason was the following > >>>>>>> error when trying to register one of these devices: > >>>>>>> [ 180.945561] BUG: unable to handle kernel NULL pointer dereference > >>>>>>> at (null) > >>>>>>> [ 180.945592] IP: [<f84b1e80>] > >>>>>>> iio_device_register_eventset+0x380/0x3a0 [industrialio] > >>>>>>> This happens, since in industrialio-events.c > >>>>>>> __iio_add_event_config_attrs (which does a INIT_LIST_HEAD) is not > >>>>>>> called, if the channels attribute of the device is not set. As a > >>>>>>> result, list_for_each_entry causes those NULL pointer dereference > >>>>>>> problems. So, before trying to access those list elements, we check > >>>>>>> for their existence (also in unregister functions). > >>>>>>> Now the adt7410.c ended in some complex changes - my apologies for this: > >>>>>>> > >>>>>>> * check for exact values provided through sysfs, otherwise output > >>>>>>> a verbose error/usage message for: sample mode, resolution, event mode > >>>>>>> * adt7410_show_id: I don't see a point in masking out some LSBs, > >>>>>>> if they get shifted to oblivion, anyway -> no more need for > >>>>>>> ADT7410_MANUFACTORY_ID_MASK > >>>>>>> * adt7410_convert_temperature: in 13 bit mode, the driver assumed > >>>>>>> the data to be stored in bits 0-12, but according to the data sheet, > >>>>>>> it is stored in bits 3-15. Temperature readings were always around > >>>>>>> 200(°C), while real temperature was something around 20(°C). Simple > >>>>>>> fix: mask out bits 0-2 in 13 bit mode and use the 16 bit routines > >>>>>>> from that point on. > >>>>>>> * adt7410_set_t_bound: handle float values provided through sysfs > >>>>>>> properly. Also, simplify treatment of 13 bit values by masking out > >>>>>>> bits 0-2. > >>>>>>> * adt7410_probe, adt7410_remove: fix another possible NULL > >>>>>>> pointer dereference issue, in case no platform data is provided. Sync > >>>>>>> chip->config with the config register > >>>>>> Hi, > >>>>>> > >>>>>> Sascha Hauer posted a couple of patches a while ago which seem to fix a > >>>>>> similar set of issues. > >>>>>> > >>>>>> See: http://www.spinics.net/lists/linux-iio/msg05947.html and > >>>>>> http://www.spinics.net/lists/linux-iio/msg05955.html > >>>>> Indeed, most if not all of the mentioned issues should be fixed already > >>>>> with these patches. > >>>>> > >>>> Just to reiterate what I said to Sascha at the time... This driver does > >>>> not belong in IIO. It is very much a hardware monitoring part and so > >>>> wants to move to hwmon. We aren't going to take it out of staging into > >>>> drivers/iio and I'm rather unwilling to take any 'new' features into the > >>>> staging version. Someone with hardware who is interesting needs to bite > >>>> the bullet and convert / rewrite this driver as a hwmon device. > >>>> > >>> FYI, I created a basic hwmon driver for ADT7410, which now made it into > >>> linux 3.7. > >>> Take care > >> > >> Ah, great, now we have two drivers which bind to the same device... > >> > > Yup, can one of you take a look at the two drivers and see where they > > differ in functionality. We obviously don't want this messy situation > > to go on for long! Then again, we don't want to end up with missing > > functionality in one of them either... > > The IIO driver supports more. It has support for the similar adt7310 and it > also has support for reporting over- or undertemperature, something which > can't really be implemented that nicely in the hwmon framework. We did think hwmon supports configuring over- and undertemperature and supports attributes for reporting it. > about moving this driver to hwmon, but since it does not really support > threshold events and also is more meant for PC-style hardware monitoring and There is nothing preventing you from creating such events. See gpio-fan for an example. That it isn't implemented for most drivers doesn't mean it is not possible or supported. > the adt7410 has primarily other applications I did decide against it. > Another reason was that we do have the IIO-to-hwmon bridge which would allow > to instantiate a hwmon userspace interface for the driver if necessary. > > Hartmut you knew of the existence of the IIO driver it would have really > been nice if you had included us on Cc when you submitted the hwmon driver > that would have allowed us to avoid this messy situation. > > One solution could be to just sent a patch to revert the hwmon driver patch, > but I guess that would be kind of counterproductive. > I see two contradicting comments above: "very much a hardware monitoring part" and "needs to ... rewrite the driver as hwmon device" vs. "the adt7410 has primarily other applications". Which one is it ? > Hartmut any suggestions from your side how to solve this? > Sorry, I had assumed the discussion was closed and the decision was made to move the driver to hwmon. Let me know if you want me to revert the hwmon driver; no problem. Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
