Messages in this thread | | | Date | Mon, 2 Oct 2023 11:35:02 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH v10 1/3] nvmem: core: Rework layouts to become platform devices |
| |
On Fri, Sep 22, 2023 at 07:48:52PM +0200, Miquel Raynal wrote: > Current layout support was initially written without modules support in > mind. When the requirement for module support rose, the existing base > was improved to adopt modularization support, but kind of a design flaw > was introduced. With the existing implementation, when a storage device > registers into NVMEM, the core tries to hook a layout (if any) and > populates its cells immediately. This means, if the hardware description > expects a layout to be hooked up, but no driver was provided for that, > the storage medium will fail to probe and try later from > scratch. Technically, the layouts are more like a "plus" and, even we > consider that the hardware description shall be correct, we could still > probe the storage device (especially if it contains the rootfs). > > One way to overcome this situation is to consider the layouts as > devices, and leverage the existing notifier mechanism. When a new NVMEM > device is registered, we can: > - populate its nvmem-layout child, if any > - try to modprobe the relevant driver, if relevant > - try to hook the NVMEM device with a layout in the notifier > And when a new layout is registered: > - try to hook all the existing NVMEM devices which are not yet hooked to > a layout with the new layout > This way, there is no strong order to enforce, any NVMEM device creation > or NVMEM layout driver insertion will be observed as a new event which > may lead to the creation of additional cells, without disturbing the > probes with costly (and sometimes endless) deferrals. > > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Did I miss why these were decided to be platform devices and not normal devices on their own "bus" that are attached to the parent device properly? Why platform for a dynamic thing?
If I did agree with this, it should be documented here in the changelog why this is required to be this way so I don't ask the question again in the future :)
thanks,
greg k-h
| |