Hi Wolfram, On 09/06/16 21:04, Wolfram Sang wrote: > On Thu, Jun 09, 2016 at 03:45:52PM -0400, Javier Martinez Canillas wrote: >> Hello Wolfram, >> >> On 06/09/2016 03:15 PM, Wolfram Sang wrote: >>> Hi Kieran, >>> >>>> * Device Tree >>>> I tested that the device would still register by adding a node in the >>>> device >>>> tree for the board, and testing with a built-in module. >>>> >>>> - This worked fine. >>>> >>>> * Module Autoloading >>>> With the device tree node in the board dts file, it wouldn't >>>> automatically >>>> load from the external module. This was due to the rtc-ds1307 module not >>>> exporting an of_match table, and not yet having Javier's "report OF style >>>> modalias when probing using DT" [0] patch applied > > Let's call this a) > >>> >>> What I didn't get here: did your version of the RTC driver use probe() >>> or probe_new() without i2c_device_id table or did you try both? I assume >>> module autoloading only fails with probe_new(), otherwise we would be in >>> serious trouble. But I'd wonder then that userspace instantiation works. >>> >> >> I can't answer for Kieran but you trimmed this last sentence from him: >> >>> - With the module updated, and Javiers patch applied, the module autoloads
> Let's call this b) > >>> >> >> So my understanding is that by updated he meant a patched rtc-ds1307 driver >> using a .probe_new, whose i2c_device_id table was removed and of_device_id >> table added (that's not present in the mainline driver). >> >> And that's why he needed my RFC patch to report a MODALIAS=of:N*T*Cfoo,bar >> and match what's exported to the module using the of_device_id table. >> >> Because drivers that only use .probe and have an i2c_device_id table will >> continue to match and report MODALIAS=i2c:foo as before after this series. Yes, Javier's interpretation is correct here. > Yes, this is my understanding and expectation, too. However, he wrote > that module loading fails on a) where he never wrote anything about an > updated module before. That comes only later with b). So what I would > have expected: > > 1) update the module (which is "b)" above) > 2) autoloading fails (which is "a)" above) > 3) applying your patch > 4) everything works > > which implies > > 0) nothing done, everything works > > But I don't see this in the text, so I better ask. This also raises the > question open how userspace instantiation was tested. With or without > updating (ideally both). Well it's a month later, and I can't remember - so I've retested. Kernel built with this patchset - and *without* Javiers patch for 0) position test. RTC_DS1307 driver *unmodified* root@arm:~# uname -a Linux arm 4.7.0-rc2-00027-g72baec98c9f0 #27 SMP Fri Jun 10 10:42:09 BST 2016 armv7l GNU/Linux root@arm:~# lsmod Module Size Used by Not tainted omap_rng 3927 0 rng_core 6410 1 omap_rng rtc_ds1307 12121 0 root@arm:~# cat /sys/class/rtc/rtc0/device/modalias i2c:ds1307 root@arm:~# cat /sys/class/rtc/rtc0/date 2016-06-10 * Module autoload successful, * i2c read successful. Code tested at repository https://github.com/kbingham/linux.git tag i2c-dt/v4.7-rc2-relax-conversion-zero-test Is this what you were looking for? > Thanks, > > Wolfram > -- Regards Kieran Bingham
