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    SubjectRe: [PATCH 1/6] of: base: Add function to check for status = "reserved"
    On Wed, Sep 29, 2021 at 6:54 AM Zev Weiss <zev@bewilderbeest.net> wrote:
    >
    > Per v0.3 of the Devicetree Specification [0]:
    >
    > Indicates that the device is operational, but should not be used.
    > Typically this is used for devices that are controlled by another
    > software component, such as platform firmware.
    >
    > One use-case for this is in OpenBMC, where certain devices (such as a
    > BIOS flash chip) may be shared by the host and the BMC, but cannot be
    > accessed by the BMC during its usual boot-time device probing, because
    > they require additional (potentially elaborate) coordination with the
    > host to arbitrate which processor is controlling the device.
    >
    > Devices marked with this status should thus be instantiated, but not
    > have a driver bound to them or be otherwise touched.
    >
    > [0] https://github.com/devicetree-org/devicetree-specification/releases/download/v0.3/devicetree-specification-v0.3.pdf
    >
    > Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
    > ---
    > drivers/of/base.c | 53 +++++++++++++++++++++++++++++++++++++++-------
    > include/linux/of.h | 6 ++++++
    > 2 files changed, 51 insertions(+), 8 deletions(-)
    >
    > diff --git a/drivers/of/base.c b/drivers/of/base.c
    > index f720c0d246f2..c5cc178fc6bd 100644
    > --- a/drivers/of/base.c
    > +++ b/drivers/of/base.c
    > @@ -579,14 +579,18 @@ int of_machine_is_compatible(const char *compat)
    > EXPORT_SYMBOL(of_machine_is_compatible);
    >
    > /**
    > - * __of_device_is_available - check if a device is available for use
    > + * __of_device_check_status - check if a device's status matches a particular string
    > *
    > - * @device: Node to check for availability, with locks already held
    > + * @device: Node to check status of, with locks already held
    > + * @val: Status string to check for
    > + * @alt: Optional alternate status string to check for (NULL to check only @val)
    > + * @dflt: default to return if status property absent
    > *
    > - * Return: True if the status property is absent or set to "okay" or "ok",
    > - * false otherwise
    > + * Return: True if status property exists and matches either @val or @alt.
    > + * @dflt if status property is absent. False otherwise.
    > */
    > -static bool __of_device_is_available(const struct device_node *device)
    > +static bool __of_device_check_status(const struct device_node *device, const char *val,
    > + const char *alt, bool dflt)

    How about val==NULL means available/okay and then you can get rid of
    alt and dflt.

    Otherwise, I'd simply not try to share the implementation here and
    just add of_device_is_reserved().

    Rob

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