Re: [PATCH net-next v5 08/13] net: ethernet: oa_tc6: Use the read_mms/write_mms functions for C45

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] This problem wasn't introduced by this patch, but the function `oa_tc6_mdiobus_read` assigns the integer return value of `oa_tc6_read_register()` to a boolean variable `ret`, causing negative error codes to be incorrectly returned as `1`.
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--- Patch [8]: [PATCH net-next v5 08/13] net: ethernet: oa_tc6: Use the read_mms/write_mms functions for C45 ---
commit cf33489c74af705521abd2c30e1068ed10134f47
Author: Ciprian Regus <ciprian.regus@analog.com>

net: ethernet: oa_tc6: Use the read_mms/write_mms functions for C45

Accessing PHY MMD devices requires control transactions to registers in
a memory map other than 0. Replace the current formatting of the
register addresses with the oa_tc6_read_register_mms and
oa_tc6_write_register_mms functions.

> diff --git a/drivers/net/ethernet/oa_tc6.c b/drivers/net/ethernet/oa_tc6.c
> index 955148d3cefc4..417c15d1ff423 100644
> --- a/drivers/net/ethernet/oa_tc6.c
> +++ b/drivers/net/ethernet/oa_tc6.c

[Severity: High]
This is a pre-existing issue, but I noticed it while reviewing this area.
Could assigning the integer return value of oa_tc6_read_register to the
boolean variable ret in oa_tc6_mdiobus_read truncate negative error codes?

drivers/net/ethernet/oa_tc6.c:oa_tc6_mdiobus_read() {
    ...
    bool ret;

    ret = oa_tc6_read_register(tc6, OA_TC6_PHY_STD_REG_ADDR_BASE |
                   (regnum & OA_TC6_PHY_STD_REG_ADDR_MASK),
                   &regval);
    if (ret)
        return ret;
    ...
}

If a read operation encounters an error and returns a negative error code
like -EIO or -ETIMEDOUT, will this boolean conversion cause the function to
incorrectly return 1 on failure?

Since the MDIO core interprets a positive return value as a successfully
read 16-bit register value, returning 1 could cause read failures to be
silently presented to the networking stack as successfully reading the value
0x0001, breaking error propagation on the MDIO bus.

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/20260708-adin1140-driver-v5-0-4aca7b51a58b@analog.com?part=8