sh: cpufreq: Support CPU clock frequency table.

This adds support for the frequency table provided by the clock framework
under the struct clk definition (if available). In cases where no table
is generated or otherwise supported, we fall back on coarse grained
scaling via clock framework rounding, as before.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/kernel/cpufreq.c

@@ -84,10 +84,32 @@ static int sh_cpufreq_target(struct cpufreq_policy *policy,
 	return 0;
 }
 
+static int sh_cpufreq_verify(struct cpufreq_policy *policy)
+{
+	struct clk *cpuclk = &per_cpu(sh_cpuclk, policy->cpu);
+	struct cpufreq_frequency_table *freq_table;
+
+	freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
+	if (freq_table)
+		return cpufreq_frequency_table_verify(policy, freq_table);
+
+	cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
+				     policy->cpuinfo.max_freq);
+
+	policy->min = (clk_round_rate(cpuclk, 1) + 500) / 1000;
+	policy->max = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
+
+	cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
+				     policy->cpuinfo.max_freq);
+
+	return 0;
+}
+
 static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy)
 {
 	unsigned int cpu = policy->cpu;
 	struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
+	struct cpufreq_frequency_table *freq_table;
 	struct device *dev;
 
 	if (!cpu_online(cpu))
@@ -101,24 +123,23 @@ static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy)
 		return PTR_ERR(cpuclk);
 	}
 
-	/* cpuinfo and default policy values */
+	policy->cur = policy->min = policy->max = sh_cpufreq_get(cpu);
+
+	freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
+	if (freq_table) {
+		int result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
+
+		if (!result)
+			cpufreq_frequency_table_get_attr(freq_table, cpu);
+	} else {
 		policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
 		policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
-	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+	}
 
-	policy->cur		= sh_cpufreq_get(cpu);
 	policy->min = policy->cpuinfo.min_freq;
 	policy->max = policy->cpuinfo.max_freq;
 
-	/*
-	 * Catch the cases where the clock framework hasn't been wired up
-	 * properly to support scaling.
-	 */
-	if (unlikely(policy->min == policy->max)) {
-		dev_err(dev, "rate rounding not supported on this CPU.\n");
-		clk_put(cpuclk);
-		return -EINVAL;
-	}
+	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 
 	dev_info(dev, "CPU Frequencies - Minimum %u.%03u MHz, "
 	       "Maximum %u.%03u MHz.\n",
@@ -128,28 +149,25 @@ static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	return 0;
 }
 
-static int sh_cpufreq_verify(struct cpufreq_policy *policy)
+static int sh_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 {
-	cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
-				     policy->cpuinfo.max_freq);
-	return 0;
-}
+	unsigned int cpu = policy->cpu;
+	struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
 
-static int sh_cpufreq_exit(struct cpufreq_policy *policy)
-{
-	struct clk *cpuclk = &per_cpu(sh_cpuclk, policy->cpu);
+	cpufreq_frequency_table_put_attr(cpu);
 	clk_put(cpuclk);
+
 	return 0;
 }
 
 static struct cpufreq_driver sh_cpufreq_driver = {
 	.owner		= THIS_MODULE,
 	.name		= "sh",
-	.init		= sh_cpufreq_cpu_init,
-	.verify		= sh_cpufreq_verify,
-	.target		= sh_cpufreq_target,
 	.get		= sh_cpufreq_get,
-	.exit		= sh_cpufreq_exit,
+	.target		= sh_cpufreq_target,
+	.verify		= sh_cpufreq_verify,
+	.init		= sh_cpufreq_cpu_init,
+	.exit		= sh_cpufreq_cpu_exit,
 };
 
 static int __init sh_cpufreq_module_init(void)