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SubjectRe: [RFC PATCH 0/4] mtd: core: OTP nvmem provider support
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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