Hi Iztok, Moritz, Am Freitag, den 21.10.2016, 10:04 -0700 schrieb Moritz Fischer: > Iztok, > > On Fri, Oct 21, 2016 at 03:08:47AM -0700, [email protected] wrote: > > Hi Moritz, > > > > I was looking at your reset implementation for Zynq: > > https://github.com/Xilinx/linux-xlnx/blob/629041605b93343ad2e8971ceaac3edcef0b043b/drivers/reset/reset-zynq.c > > I went through related mailing list posts (including earlier versions of > > the patch) so I kind of understand what to change in the device tree. > > Please look at the upstream kernel sources and use the mailing list > (lkml) if you want to report bugs. Xilinx' vendor tree might or might > not be up to date. > > > I would like to use this driver to reset the Zynq I2C controller, since we > > have trouble with it getting into a lock up state. > > I plan to use function device_reset_optional() from: > > https://github.com/Xilinx/linux-xlnx/blob/629041605b93343ad2e8971ceaac3edcef0b043b/include/linux/reset.h > > > > But this function is calling the reset function pointer from the > > reset_control_ops structure. > > For the zynq driver this function pointer is not defined, only assert, > > deassert and status are. > > > > Is this a missing implementation, or is there a default implementation (I > > did not find one) which which performs an assert+deassert, > > or is there another set of reset APIs I should use inside the kernel. > > You could just call reset_control_assert() and reset_control_deassert(). > You're right there is currently no implementation for the 'reset' function for > zynq (and most of the other SoCs). I'll need to see if it makes sense at > all.
The implementation of reset_control_reset in software really only makes sense if the reset provider driver knows about the necessary delays for all reset consumers. > Please note that you'd probably have to modify the i2c driver to > integrate reset functionality cleanly. > > Thanks, > > Moritz regards Philipp
