Messages in this thread | | | Date | Fri, 16 Apr 2021 21:26:03 +0200 | From | Michael Walle <> | Subject | Re: [PATCH 0/5] mtd: core: OTP nvmem provider support |
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Hi Rob,
Am 2021-04-16 20:44, schrieb Rob Herring: > On Fri, Apr 16, 2021 at 01:49:23PM +0200, Michael Walle wrote: >> The goal is to fetch a (base) MAC address from the OTP region of a SPI >> NOR >> flash. >> >> This is the first part, where I try to add the nvmem provider support >> to >> the MTD core. >> >> I'm not sure about the device tree bindings. Consider the following >> two >> variants: >> >> (1) >> flash@0 { >> .. >> >> otp { >> compatible = "mtd-user-otp"; > > mtd is a linuxism. Why not just 'nvmem-cells' here or as a fallback if > we come up with a better name?
There are two different compatibles: "mtd-user-otp" and "mtd-factory-otp" to differentiate what kind of OTP should be used (and both are possible at the same time). Thus nvmem-cells alone won't be enough. We could drop the "mtd-" prefix though.
Is there a benefit of having the following? compatible = "user-otp", "nvmem-cells";
>> #address-cells = <1>; >> #size-cells = <1>; >> >> serial-number@0 { >> reg = <0x0 0x8>; >> }; >> }; >> }; >> >> (2) >> flash@0 { >> .. >> >> otp { >> compatible = "mtd-user-otp"; >> #address-cells = <1>; >> #size-cells = <1>; >> >> some-useful-name { >> compatible = "nvmem-cells"; >> >> serial-number@0 { >> reg = <0x0 0x8>; >> }; >> }; >> }; >> }; >> >> Both bindings use a subnode "opt[-N]". We cannot have the nvmem cells >> as >> children to the flash node because of the legacy partition binding. >> >> (1) seems to be the form which is used almost everywhere in the >> kernel. >> That is, the nvmem cells are just children of the parent node. >> >> (2) seem to be more natural, because there might also be other >> properties >> inside the otp subnode and might be more future-proof. >> >> At the moment this patch implements (1). > > I think approach (1) seems fine.
ok
-michael
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