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 #include <linux/export.h>
  12 #include <asm/mpc5xxx.h>
  13
  14 unsigned long mpc5xxx_get_bus_frequency(struct device_node *node)
  15 {
  16         struct device_node *np;
  17         const unsigned int *p_bus_freq = NULL;
  18
  19         of_node_get(node);
  20         while (node) {
  21                 p_bus_freq = of_get_property(node, "bus-frequency", NULL);
  22                 if (p_bus_freq)
  23                         break;
  24
  25                 np = of_get_parent(node);
  26                 of_node_put(node);
  27                 node = np;
  28         }
  29         if (node)
  30                 of_node_put(node);
  31
  32         return p_bus_freq ? *p_bus_freq : 0;
  33 }
  34 EXPORT_SYMBOL(mpc5xxx_get_bus_frequency);