fdt_find_max_phandle
int fdt_find_max_phandle(const void *fdt, uint32_t *phandle);
err = fdt_find_max_phandle(fdt, &phandle);
ret = fdt_find_max_phandle(fdt, &delta);
err = fdt_find_max_phandle(fdt, &max);