ofw_bus_is_compatible(9)                     FreeBSD Kernel Developer's Manual

NAME
     ofw_bus_is_compatible, ofw_bus_is_compatible_strict,
     ofw_bus_node_is_compatible, ofw_bus_search_compatible - check device tree
     nodes for compatibility with drivers

SYNOPSIS
     #include <dev/ofw/openfirm.h>
     #include <dev/ofw/ofw_bus.h>
     #include <dev/ofw/ofw_bus_subr.h>

     int
     ofw_bus_is_compatible(device_t dev, const char *compatstr);

     int
     ofw_bus_is_compatible_strict(device_t dev, const char *compatstr);

     int
     ofw_bus_node_is_compatible(phandle_t node, const char *compatstr);

     const struct ofw_compat_data *
     ofw_bus_search_compatible(device_t dev,
         const struct ofw_compat_data *compat);

DESCRIPTION
     The "compatible" property of the device tree node is used to identify the
     type of the device the node represents.  The property is a list of one or
     more strings that represent hardware types the device is compatible with.
     The common format for such strings is "vendor,hardware" where "vendor" is
     an abbreviated name of the manufacturer and "hardware" is a device
     identifier, for instance, "fsl" for "Freescale" and "imx6ul-i2c" for the
     I2C controller.  More than one string is required for compatibility with
     older revisions of the driver.  If hardware revision B is backward
     compatible with revision A device tree node can signal this compatibility
     by providing both "vndr,hrdwrA" and "vndr,hrdwrB" strings in the
     "compatibile" property value.  This way older driver can use features
     available only in revision A, and the new version of the driver can take
     advantage of revision B feature set.

     ofw_bus_is_compatible() returns 1 if the compatstr value occurs in the
     "compatible" property list of the device tree node associated with the
     device dev, and 0 otherwise.

     ofw_bus_is_compatible_strict() return 1 if the "compatible" property of
     the device tree node associated with the device dev consists of only one
     string and this string is equal to compatstr, and 0 otherwise.

     ofw_bus_node_is_compatible() returns 1 if the compatstr value occurs in
     the "compatible" property list of the device tree node node, and 0
     otherwise.

     ofw_bus_search_compatible() returns pointer to the first entry of the
     compat table whose ocd_str field occurs in "compatible" property of the
     device tree node associated with the device dev.  The compat table is an
     array of struct ofw_compat_data elements defined as follows:

           struct ofw_compat_data {
                   const char *ocd_str;
                   uintptr_t  ocd_data;
           };
     The compat table must be terminated by the entry with ocd_str set to
     NULL.  If the device tree node is not compatible with any of the entries,
     the function returns the pointer to the terminating entry.

EXAMPLES
           static struct ofw_compat_data compat_data[] = {
                   {"arm,hrdwrA",          FEATURE_A},
                   {"arm,hrdwrB",          FEATURE_A | FEATURE_B},
                   {NULL,                  0}
           };

           static int
           hrdwr_probe(device_t dev)
           {
                   ...
                   if (!ofw_bus_search_compatible(dev, compat_data)->ocd_data)
                           return (ENXIO);
                   ...
           }

           static int
           hrdwr_attach(device_t dev)
           {
                   ...
                   sc = device_get_softc(dev);
                   sc->sc_features = ofw_bus_search_compatible(dev, compat_data)->ocd_data;
                   ...
           }

SEE ALSO
     ofw_bus_find_compatible(9)

AUTHORS
     This manual page was written by Oleksandr Tymoshenko.

FreeBSD 13.1-RELEASE-p6          April 8, 2018         FreeBSD 13.1-RELEASE-p6