+/**
+ * cpufreq_suspend - let the low level driver prepare for suspend
+ */
+
+static int cpufreq_suspend(struct sys_device * sysdev, pm_message_t pmsg)
+{
+ int cpu = sysdev->id;
+ int ret = 0;
+ unsigned int cur_freq = 0;
+ struct cpufreq_policy *cpu_policy;
+
+ dprintk("suspending cpu %u\n", cpu);
+
+ if (!cpu_online(cpu))
+ return 0;
+
+ /* we may be lax here as interrupts are off. Nonetheless
+ * we need to grab the correct cpu policy, as to check
+ * whether we really run on this CPU.
+ */
+
+ cpu_policy = cpufreq_cpu_get(cpu);
+ if (!cpu_policy)
+ return -EINVAL;
+
+ /* only handle each CPU group once */
+ if (unlikely(cpu_policy->cpu != cpu)) {
+ cpufreq_cpu_put(cpu_policy);
+ return 0;
+ }
+
+ if (cpufreq_driver->suspend) {
+ ret = cpufreq_driver->suspend(cpu_policy, pmsg);
+ if (ret) {
+ printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
+ "step on CPU %u\n", cpu_policy->cpu);
+ cpufreq_cpu_put(cpu_policy);
+ return ret;
+ }
+ }
+
+
+ if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
+ goto out;
+
+ if (cpufreq_driver->get)
+ cur_freq = cpufreq_driver->get(cpu_policy->cpu);
+
+ if (!cur_freq || !cpu_policy->cur) {
+ printk(KERN_ERR "cpufreq: suspend failed to assert current "
+ "frequency is what timing core thinks it is.\n");
+ goto out;
+ }
+
+ if (unlikely(cur_freq != cpu_policy->cur)) {
+ struct cpufreq_freqs freqs;
+
+ if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
+ dprintk("Warning: CPU frequency is %u, "
+ "cpufreq assumed %u kHz.\n",
+ cur_freq, cpu_policy->cur);
+
+ freqs.cpu = cpu;
+ freqs.old = cpu_policy->cur;
+ freqs.new = cur_freq;
+
+ srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
+ CPUFREQ_SUSPENDCHANGE, &freqs);
+ adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
+
+ cpu_policy->cur = cur_freq;
+ }
+
+out:
+ cpufreq_cpu_put(cpu_policy);
+ return 0;
+}
+