Hi Martin, On 25-11-19, Martin Kepplinger wrote: > hi, > > When there's a panel/touchscreen combination that is sold as a combinded > module (with the reset line shared even), how would I connect the 2 > drivers and make sure the touchscreen driver probes after the panel is ready? > > I have the feeling there is > https://docs.kernel.org/driver-api/device_link.html > for such cases. Can you show me examples of 2 "random" drivers connected > in this case?
are you aware of the "struct drm_panel_follower" API? This doesn't ensure that the touchscreen driver is probed after the panel driver, but it ensures that the touchscreen power-state follows the panel power-state. > In the past I also played with CONFIG_RESET_GPIO using the reset-controller > logic, but I *think* this is more for 2+ of the *same* devices connected. Unfortunately sharing the same reset line for different devices is not uncommon. We saw this on NXP IW61x WiFi/BT chips as well. In that particular case, the API was changed to the reset API which you linked above, to gain refcount support. This works very well. > Might there be yet a different way in devicetree I'm not aware of? You an check for the 'panel' property within the Documentation/devicetree/bindings/input/. Regards, Marco > > The below patches - for completeness - are only the workaround for what I'd > like to do, exposing the state of the panel so that the touchscreen can query > it. > > thank you very much for any hints, > > martin > > > > Guido Günther (2): > hack: drm: panel: mantix: Allow to query enabled state > hack: Input: edt-ft5x06: hackery to probe after panel > > Martin Kepplinger (2): > hack: edt-ft5x06 / panel-mantix-mlaf057we51: declare > mantix_panel_prepared() in drm_panel.h > hack: arm64: dts: imx8mq-librem5: add purism,panel-librem5-workaround > > .../boot/dts/freescale/imx8mq-librem5.dtsi | 1 + > .../gpu/drm/panel/panel-mantix-mlaf057we51.c | 12 ++++++++++ > drivers/input/touchscreen/edt-ft5x06.c | 22 +++++++++++++++++++ > include/drm/drm_panel.h | 2 ++ > 4 files changed, 37 insertions(+) > > -- > 2.47.3 > > > -- #gernperDu #CallMeByMyFirstName Pengutronix e.K. | | Steuerwalder Str. 21 | https://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-9 |
