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-ansuels...@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
