On 30.10.2020 15:38, Nicolas Ferre wrote: > On 30/10/2020 at 12:07, Codrin Ciubotariu wrote: >> The "atmel,at91sam9260-usart" driver is a MFD driver, so it needs >> sub-nodes >> to match the registered platform device. For this reason, we add a serial >> subnode to all the "atmel,at91sam9260-usart" serial compatible nods. This >> will also remove the boot warning: >> "atmel_usart_serial: Failed to locate of_node [id: -2]" > > I don't remember this warning was raised previously even if the MFD > driver was added a while ago (Sept. 2018). > > I would say it's due to 466a62d7642f ("mfd: core: Make a best effort > attempt to match devices with the correct of_nodes") which was added on > mid August and corrected with 22380b65dc70 ("mfd: mfd-core: Ensure > disabled devices are ignored without error") but maybe not covering our > case. Well, it's not covering our enabled devices. > > So, well, I don't know what's the best option to this change. Moreover, > I would say that all other USART related properties go into the child > not if there is a need for one. > > Lee, I suspect that we're not the only ones experiencing this ugly > warning during the boot log: can you point us out how to deal with it > for our existing atmel_serial.c users? My understading is that platform devices registered by MFD should have a correspondig DT node. The parrent properties are also available for the other usart device (usart-spi), so I think we should keep them in the parrent. Best regards, Codrin