On Fri, 2020-10-16 at 09:38 -0500, Rob Herring wrote: > On Thu, Oct 15, 2020 at 6:43 AM Nicolas Saenz Julienne > <nsaenzjulienne@xxxxxxx> wrote: > > 'simple-mfd' usage implies there might be some kind of resource sharing > > between the parent device and its children. > > It does? No! The reason behind simple-mfd was specifically because > there was no parent driver or dependency on the parent. No doubt > simple-mfd has been abused. Fair enough, so we're doing things wrong. Just for the record, I'm looking at RPi´s firmware interface: firmware: firmware { compatible = "raspberrypi,bcm2835-firmware", "simple-mfd"; #address-cells = <1>; #size-cells = <1>; mboxes = <&mailbox>; firmware_clocks: clocks { compatible = "raspberrypi,firmware-clocks"; #clock-cells = <1>; }; reset: reset { compatible = "raspberrypi,firmware-reset"; #reset-cells = <1>; }; [...] }; Note that "raspberrypi,bcm2835-firmware" has a driver, it's not just a placeholder. Consumer drivers get a handle to RPi's firmware interface through the supplier's API, rpi_firmware_get(). The handle to firmware becomes meaningless if it is unbinded, which I want to protect myself against. A simpler solution would be to manually create a device link between both devices ("raspberrypi,bcm2835-firmware" and "raspberrypi,firmware-clocks" for example) upon calling rpi_firmware_get(). But I wanted to try addressing the problem in a generic way first. Regards, Nicolas
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