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    Subject[PATCH 5.11 507/775] nvmem: core: skip child nodes not matching binding
    Date
    From: Ahmad Fatoum <a.fatoum@pengutronix.de>

    [ Upstream commit 0445efacec75b85c2a3c176957ee050ba9be53f0 ]

    The nvmem cell binding applies to all eeprom child nodes matching
    "^.*@[0-9a-f]+$" without taking a compatible into account.

    Linux drivers, like at24, are even more extensive and assume
    _all_ at24 eeprom child nodes to be nvmem cells since e888d445ac33
    ("nvmem: resolve cells from DT at registration time").

    Since df5f3b6f5357 ("dt-bindings: nvmem: stm32: new property for
    data access"), the additionalProperties: True means it's Ok to have
    other properties as long as they don't match "^.*@[0-9a-f]+$".

    The barebox bootloader extends the MTD partitions binding to
    EEPROM and can fix up following device tree node:

    &eeprom {
    partitions {
    compatible = "fixed-partitions";
    };
    };

    This is allowed binding-wise, but drivers using nvmem_register()
    like at24 will fail to parse because the function expects all child
    nodes to have a reg property present. This results in the whole
    EEPROM driver probe failing despite the device tree being correct.

    Fix this by skipping nodes lacking a reg property instead of
    returning an error. This effectively makes the drivers adhere
    to the binding because all nodes with a unit address must have
    a reg property and vice versa.

    Fixes: e888d445ac33 ("nvmem: resolve cells from DT at registration time").
    Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
    Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
    Link: https://lore.kernel.org/r/20210129171430.11328-6-srinivas.kandagatla@linaro.org
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/nvmem/core.c | 4 +++-
    1 file changed, 3 insertions(+), 1 deletion(-)

    diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
    index 68ae6f24b57fd..a5ab1e0c74cf6 100644
    --- a/drivers/nvmem/core.c
    +++ b/drivers/nvmem/core.c
    @@ -682,7 +682,9 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)

    for_each_child_of_node(parent, child) {
    addr = of_get_property(child, "reg", &len);
    - if (!addr || (len < 2 * sizeof(u32))) {
    + if (!addr)
    + continue;
    + if (len < 2 * sizeof(u32)) {
    dev_err(dev, "nvmem: invalid reg on %pOF\n", child);
    return -EINVAL;
    }
    --
    2.27.0


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