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Date:   Thu, 05 Jan 2023 13:11:37 +0100
From:   Michael Walle <michael@walle.cc>
To:     Miquel Raynal <miquel.raynal@bootlin.com>
Cc:     Alexander Stein <alexander.stein@ew.tq-group.com>,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
        Dan Carpenter <error27@gmail.com>
Subject: Re: [PATCH v5 00/21] nvmem: core: introduce NVMEM layouts
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Hi Alexander,

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?

> 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()?

-michael