Re: [PATCH v5 00/21] nvmem: core: introduce NVMEM layouts

Michael Walle
2023-01-05T21:11:07Z

Hi,

Am 2023-01-05 13:21, schrieb Alexander Stein:
> Am Donnerstag, 5. Januar 2023, 13:11:37 CET schrieb Michael Walle:
>> thanks for debugging. I'm not yet sure what is going wrong, so
>> I have some more questions below.
>>
>> >> This causes the following errors on existing boards (imx8mq-tqma8mq-
>> >> mba8mx.dtb):
>> >> root@tqma8-common:~# uname -r
>> >> 6.2.0-rc2-next-20230105
>> >>
>> >> > OF: /soc@0: could not get #nvmem-cell-cells for /soc@0/bus@30000000/
>> >>
>> >> efuse@30350000/soc-uid@4
>> >>
>> >> > OF: /soc@0/bus@30800000/ethernet@30be0000: could not get
>> >> > #nvmem-cell-cells
>> >>
>> >> for /soc@0/bus@30000000/efuse@30350000/mac-address@90
>> >>
>> >> These are caused because '#nvmem-cell-cells = <0>;' is not explicitly
>> >> set in
>> >> DT.
>> >>
>> >> > TI DP83867 30be0000.ethernet-1:0e: error -EINVAL: failed to get nvmem
>> >> > cell
>> >>
>> >> io_impedance_ctrl
>> >>
>> >> > TI DP83867: probe of 30be0000.ethernet-1:0e failed with error -22
>> >>
>> >> These are caused because of_nvmem_cell_get() now returns -EINVAL
>> >> instead of -
>> >> ENODEV if the requested nvmem cell is not available.
>>
>> What do you mean with not available? Not yet available because of
>> probe
>> order?
>
> Ah, I was talking about there is no nvmem cell being used in my PHY
> node, e.g.
> no 'nvmem-cells' nor 'nvmem-cell-names' (set to 'io_impedance_ctrl').
> That's
> why of_property_match_string returns -EINVAL.

Ahh I see. You mean ENOENT instead of ENODEV, right?

>> > Should we just assume #nvmem-cell-cells = <0> by default? I guess it's
>> > a safe assumption.
>>
>> Actually, that's what patch 2/21 is for.
>>
>> Alexander, did you verify that the EINVAL is returned by
>> of_parse_phandle_with_optional_args()?
>
> Yep.
>
> --8<--
> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> index 1b61c8bf0de4..f2a85a31d039 100644
> --- a/drivers/nvmem/core.c
> +++ b/drivers/nvmem/core.c
> @@ -1339,9 +1339,11 @@ struct nvmem_cell *of_nvmem_cell_get(struct
> device_node
> *np, const char *id)
> if (id)
> index = of_property_match_string(np,
> "nvmem-cell-names", id);
>
> + pr_info("%s: index: %d\n", __func__, index);
> ret = of_parse_phandle_with_optional_args(np, "nvmem-cells",
> "#nvmem-cell-cells",
> index, &cell_spec);
> + pr_info("%s: of_parse_phandle_with_optional_args: %d\n",
> __func__,
> ret);
> if (ret)
> return ERR_PTR(ret);
> --8<--
>
> Results in:
>> [ 1.861896] of_nvmem_cell_get: index: -22
>> [ 1.865934] of_nvmem_cell_get: of_parse_phandle_with_optional_args:
>> -22
>> [ 1.872595] TI DP83867 30be0000.ethernet-1:0e: error -EINVAL:
>> failed to
> get nvmem cell io_impedance_ctrl
>> [ 2.402575] TI DP83867: probe of 30be0000.ethernet-1:0e failed with
>> error
> -22
>
> So, the index is wrong in the first place, but this was no problem
> until now.

Thanks, could you try the following patch:

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 1b61c8bf0de4..1085abfcd9b1 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -1336,8 +1336,11 @@ struct nvmem_cell *of_nvmem_cell_get(struct
device_node *np, const char *id)
int ret;

/* if cell name exists, find index to the name */
- if (id)
+ if (id) {
index = of_property_match_string(np, "nvmem-cell-names",
id);
+ if (index < 0)
+ return ERR_PTR(-ENOENT);
+ }

ret = of_parse_phandle_with_optional_args(np, "nvmem-cells",
"#nvmem-cell-cells",

Before patch 6/21, the -EINVAL was passed as index to of_parse_phandle()
which then returned NULL, which caused the nvmem core to return ENOENT.
I have a vague memory, that I made sure, that
of_parse_phandle_with_optional_args() will also propagate the
wrong index to its return code. But now, it won't be converted
to ENOENT.

-michael