arch/powerpc/platforms/wsp/setup.c

   1 /*
   2  * Copyright 2010 Michael Ellerman, IBM Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version
   7  * 2 of the License, or (at your option) any later version.
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/of_platform.h>
  12
  13 #include "wsp.h"
  14
  15 /*
  16  * Find chip-id by walking up device tree looking for ibm,wsp-chip-id property.
  17  * Won't work for nodes that are not a descendant of a wsp node.
  18  */
  19 int wsp_get_chip_id(struct device_node *dn)
  20 {
  21         const u32 *p;
  22         int rc;
  23
  24         /* Start looking at the specified node, not its parent */
  25         dn = of_node_get(dn);
  26         while (dn && !(p = of_get_property(dn, "ibm,wsp-chip-id", NULL)))
  27                 dn = of_get_next_parent(dn);
  28
  29         if (!dn)
  30                 return -1;
  31
  32         rc = *p;
  33         of_node_put(dn);
  34
  35         return rc;
  36 }