lkml.org 
[lkml]   [2021]   [Apr]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 0/5] mtd: core: OTP nvmem provider support
    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

    \
     
     \ /
      Last update: 2021-04-16 21:26    [W:5.945 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site