Hi Andy, Thanks for the explanation and help - now the PM runtime suspend and resume are triggered. It was indeed the combination of bad initialization and that I did not have "enter wakeup" on the read data. Currently, I view pm_runtime mode as a power saving mode (device should be in low power) and normal running as running mode. However, the sensor is able to report data in both modes - just reading is a bit different. I also do not have a problem with autosuspend after some time, but I do wonder how would user change the power mode from pm_runtime to normal mode (reading, in this case, should not change the mode). What is the recommended ABI for that? On Mon, 25 Jul 2022 at 23:45, Andy Shevchenko <andy.shevchenko@xxxxxxxxx> wrote: > > On Mon, Jul 25, 2022 at 11:36 PM Crt Mori <cmo@xxxxxxxxxxx> wrote: > > On Mon, 25 Jul 2022 at 23:27, Andy Shevchenko <andy.shevchenko@xxxxxxxxx> wrote: > > > On Mon, Jul 25, 2022 at 10:48 AM Crt Mori <cmo@xxxxxxxxxxx> wrote: > > > > > > > > Hi, > > > > I am implementing the power saving modes for mlx90632 device driver > > > > and while I have implemented routines for SET_RUNTIME_PM_OPS > > > > (runtime_pm_suspend and runtime_pm_resume) I am not able to find out > > > > how to trigger them from the terminal. > > > > > > > > It could be that my driver code for power management implementation is > > > > incomplete and I need to initialize something more. > > > > > > > > Maybe it is helpful, but the power submodule of the device contains below files: > > > > > > > > $ ls -al /sys/bus/iio/devices/iio\:device0/power > > > > total 0 > > > > drwxrwxr-x 2 root gpio 0 Apr 6 14:17 . > > > > drwxrwxr-x 3 root gpio 0 Apr 6 14:17 .. > > > > -rw-rw-r-- 1 root gpio 4096 Apr 6 14:17 async > > > > -rw-rw-r-- 1 root gpio 4096 Apr 6 14:17 autosuspend_delay_ms > > > > -rw-rw-r-- 1 root gpio 4096 Apr 6 14:18 control > > > > -r--r--r-- 1 root gpio 4096 Apr 6 14:17 runtime_active_kids > > > > -r--r--r-- 1 root gpio 4096 Apr 6 14:17 runtime_active_time > > > > -r--r--r-- 1 root gpio 4096 Apr 6 14:17 runtime_enabled > > > > -r--r--r-- 1 root gpio 4096 Apr 6 14:17 runtime_status > > > > -r--r--r-- 1 root gpio 4096 Apr 6 14:17 runtime_suspended_time > > > > -r--r--r-- 1 root gpio 4096 Apr 6 14:17 runtime_usage > > > > > > > > And control is already set to "auto" which according to documentation > > > > should allow the PM. > > > > > > 'auto' should enable it. So, whenever the driver thinks it's a time to > > > power off/on the device it will call the methods. > > > > > > You may hack a bit to enable autosuspend (which often is not a good > > > idea for IIO sensors) and see it done automatically after some time. > > > > So the idea is to wait? > > Yes. > > > How would I enable autosuspend - by lowering > > the autosusped_delay_ms? > > Yep, if you wish. The driver should enable it though. Is there a way for driver to attach a callback to power/autosuspend_delay_ms request or to power/control? > > > How does the driver decide that it is time to > > power off/on? > > I'm not a driver author, it seems you , who should answer this > question (as you are about to add PM there, am I right?). > > > Do I need something else enabled to have this done automatically? > > Autosuspend is 5000 in my case which would mean 5 seconds, so I am > > quite sure I waited that long and I did not see printk's from the > > driver. > > Something prevents it from doing (reference counting) or simply some > initialization / enablement is forgotten. For different buses > different PM runtime rules are applied (for example, IIRC, PCI core > does it for you, while platform bus is on what driver wants basis). > > -- > With Best Regards, > Andy Shevchenko
