arch/powerpc/sysdev/mpc5xxx_clocks.c

   1 /**
   2  *      mpc5xxx_get_bus_frequency - Find the bus frequency for a device
   3  *      @node:  device node
   4  *
   5  *      Returns bus frequency (IPS on MPC512x, IPB on MPC52xx),
   6  *      or 0 if the bus frequency cannot be found.
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/of_platform.h>
  11
  12 unsigned int
  13 mpc5xxx_get_bus_frequency(struct device_node *node)
  14 {
  15         struct device_node *np;
  16         const unsigned int *p_bus_freq = NULL;
  17
  18         of_node_get(node);
  19         while (node) {
  20                 p_bus_freq = of_get_property(node, "bus-frequency", NULL);
  21                 if (p_bus_freq)
  22                         break;
  23
  24                 np = of_get_parent(node);
  25                 of_node_put(node);
  26                 node = np;
  27         }
  28         if (node)
  29                 of_node_put(node);
  30
  31         return p_bus_freq ? *p_bus_freq : 0;
  32 }
  33 EXPORT_SYMBOL(mpc5xxx_get_bus_frequency);