Hello Uffe, On Friday, January 20, 2017, Ulf Hansson wrote: > > The reality is that the chip guys cut up the standard SDHI IP to add a > > 'cool new feature', but all I want to do is put it back the way it was. > > > > NOTE: The design guys like to reuse IP blocks from previous designs > > that they know worked and didn't have bugs. So, there is a good chance > > you will see this change in future RZ/A devices (or even other future > Renesas SoC devices). > > To remove an unwanted feature adds additional design risk of breaking > > something else....and given the cost of redoing silicon mask > > layers...no engineer wants that mistake on their hands. > > So, one should be aware of that runtime PM support in these case is going > to be suboptimal. > For example, when using this native card detect, you will need to keep the > controller runtime PM resumed as the be able to keep the clock on and to > be able to fetch the irq. Wasting power. Wolfram already pointed that out in a reply to Geert: On Tuesday, January 17, 2017, Wolfram Sang wrote: > > If we handle them as one, won't we miss card detect events due to the > > card detect clock being disabled while SDHI is idle? > > You mean this? > > 1208 /* > 1209 * While using internal tmio hardware logic for card > detection, we need > 1210 * to ensure it stays powered for it to work. > 1211 */ > 1212 if (_host->native_hotplug) > 1213 pm_runtime_get_noresume(&pdev->dev); As per your request, I'll go back and add some text to describing that even though this specific HW has a separate clock for card detect for PM, the existing driver infrastructure doesn't handle that so both clocks need to be treated as one. > Most SoC vendors are therefore using a GPIO card detect instead, although > I assume you already knew that. :-) My first objective for the RZ/A1 platform is to move things from a local custom BSP into upstream and get things 'working'. Later I can go back and tweak things here and there for runtime PM and such. Thank you, Chris
