Messages in this thread | | | Date | Tue, 30 Mar 2021 11:49:16 +0200 | From | Michael Walle <> | Subject | Re: [RFC PATCH 0/4] mtd: core: OTP nvmem provider support |
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Hi Srinivas,
Am 2021-03-30 11:42, schrieb Srinivas Kandagatla: > On 22/03/2021 18:19, 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"; >> #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). >> > > > Have you looked at this series[1], are you both trying to do the same > thing?
Yes, I've seen these, but they are for MTD partitions. OTP regions are not MTD partitions (and cannot be mapped to them).
-michael
> > [1] > https://lore.kernel.org/linux-mtd/20210312062830.20548-2-ansuelsmth@gmail.com/T/ > > --srini > > >> Michael Walle (4): >> nvmem: core: allow specifying of_node >> dt-bindings: mtd: add YAML schema for the generic MTD bindings >> dt-bindings: mtd: add OTP bindings >> mtd: core: add OTP nvmem provider support >> >> .../devicetree/bindings/mtd/common.txt | 16 +- >> .../devicetree/bindings/mtd/mtd.yaml | 110 +++++++++++++ >> drivers/mtd/mtdcore.c | 149 >> ++++++++++++++++++ >> drivers/nvmem/core.c | 4 +- >> include/linux/mtd/mtd.h | 2 + >> include/linux/nvmem-provider.h | 2 + >> 6 files changed, 267 insertions(+), 16 deletions(-) >> create mode 100644 Documentation/devicetree/bindings/mtd/mtd.yaml >>
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