On Wed, Sep 29, 2021 at 6:54 AM Zev Weiss <zev@xxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxx> > --- > 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
