On Thu, Mar 30, 2023 at 03:26:13PM +0200, Geert Uytterhoeven wrote: > When loading a DT overlay that creates a device, the device is not > probed, unless the DT overlay is unloaded and reloaded again. > > After the recent refactoring to improve fw_devlink, it no longer depends > on the "compatible" property to identify which device tree nodes will > become struct devices. fw_devlink now picks up dangling consumers > (consumers pointing to descendent device tree nodes of a device that > aren't converted to child devices) when a device is successfully bound > to a driver. See __fw_devlink_pickup_dangling_consumers(). > > However, during DT overlay, a device's device tree node can have > sub-nodes added/removed without unbinding/rebinding the driver. This > difference in behavior between the normal device instantiation and > probing flow vs. the DT overlay flow has a bunch of implications that > are pointed out elsewhere[1]. One of them is that the fw_devlink logic > to pick up dangling consumers is never exercised. > > This patch solves the fw_devlink issue by marking all DT nodes added by > DT overlays with FWNODE_FLAG_NOT_DEVICE (fwnode that won't become > device), and by clearing the flag when a struct device is actually > created for the DT node. This way, fw_devlink knows not to have > consumers waiting on these newly added DT nodes, and to propagate the > dependency to an ancestor DT node that has the corresponding struct > device. > > Based on a patch by Saravana Kannan, which covered only platform and spi > devices. > > [1] https://lore.kernel.org/r/CAGETcx_bkuFaLCiPrAWCPQz+w79ccDp6=9e881qmK=vx3hBMyg@xxxxxxxxxxxxxx > > Fixes: 4a032827daa89350 ("of: property: Simplify of_link_to_phandle()") > Link: https://lore.kernel.org/r/CAGETcx_+rhHvaC_HJXGrr5_WAd2+k5f=rWYnkCZ6z5bGX-wj4w@xxxxxxxxxxxxxx > Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> > Acked-by: Mark Brown <broonie@xxxxxxxxxx> > Acked-by: Wolfram Sang <wsa@xxxxxxxxxx> # for I2C Here is my use-case: a bunch of FPGA-based devices, which are SPI slaves, WEIM childs and other platform devices, described in DTS with status = "disabled"; in run-time DT-overlay with status = "okay" for these devices is loaded via ConfigFS with help of out-of-tree patch. Although without this patch I had no issues probing overlay-enabled devices, it won't hurt either. Tested-by: Ivan Bornyakov <i.bornyakov@xxxxxxxxxxx>
