cpufreq: at32ap: add frequency table

This patch adds a dynamically calculated frequency table to the at32ap driver. In short the architecture can scale in power of two between a maximum and minimum frequency. Min, max, and the steps in between are added to the table. Signed-off-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: at32ap: add frequency table
This patch adds a dynamically calculated frequency table to the at32ap driver. In short the architecture can scale in power of two between a maximum and minimum frequency. Min, max, and the steps in between are added to the table. Signed-off-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Hans-Christian Egtvedt · Rafael J. Wysocki
1 parent 2e6a5c80e6
Showing 1 changed file with 46 additions and 3 deletions Side-by-side Diff
drivers/cpufreq/at32ap-cpufreq.c
@@ -19,8 +19,10 @@
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/export.h>
+#include <linux/slab.h>
  
 static struct clk *cpuclk;
+static struct cpufreq_frequency_table *freq_table;
  
 static int at32_verify_speed(struct cpufreq_policy *policy)
 {
  
@@ -85,13 +87,17 @@
  
 static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
 {
+	unsigned int frequency, rate;
+	int retval, steps, i;
+
 	if (policy->cpu != 0)
 		return -EINVAL;
  
 	cpuclk = clk_get(NULL, "cpu");
 	if (IS_ERR(cpuclk)) {
 		pr_debug("cpufreq: could not get CPU clk\n");
-		return PTR_ERR(cpuclk);
+		retval = PTR_ERR(cpuclk);
+		goto out_err;
 	}
  
 	policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
  
@@ -101,9 +107,46 @@
 	policy->min = policy->cpuinfo.min_freq;
 	policy->max = policy->cpuinfo.max_freq;
  
-	printk("cpufreq: AT32AP CPU frequency driver\n");
+	/*
+	 * AVR32 CPU frequency rate scales in power of two between maximum and
+	 * minimum, also add space for the table end marker.
+	 *
+	 * Further validate that the frequency is usable, and append it to the
+	 * frequency table.
+	 */
+	steps = fls(policy->cpuinfo.max_freq / policy->cpuinfo.min_freq) + 1;
+	freq_table = kzalloc(steps * sizeof(struct cpufreq_frequency_table),
+			GFP_KERNEL);
+	if (!freq_table) {
+		retval = -ENOMEM;
+		goto out_err_put_clk;
+	}
  
-	return 0;
+	frequency = policy->cpuinfo.max_freq;
+	for (i = 0; i < (steps - 1); i++) {
+		rate = clk_round_rate(cpuclk, frequency * 1000) / 1000;
+
+		if (rate != frequency)
+			freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
+		else
+			freq_table[i].frequency = frequency;
+
+		frequency /= 2;
+	}
+
+	freq_table[steps - 1].frequency = CPUFREQ_TABLE_END;
+
+	retval = cpufreq_table_validate_and_show(policy, freq_table);
+	if (!retval) {
+		printk("cpufreq: AT32AP CPU frequency driver\n");
+		return 0;
+	}
+
+	kfree(freq_table);
+out_err_put_clk:
+	clk_put(cpuclk);
+out_err:
+	return retval;
 }
  
 static struct cpufreq_driver at32_driver = {
...	...	@@ -19,8 +19,10 @@
19	19	#include <linux/clk.h>
20	20	#include <linux/err.h>
21	21	#include <linux/export.h>
	22	+#include <linux/slab.h>
22	23
23	24	static struct clk *cpuclk;
	25	+static struct cpufreq_frequency_table *freq_table;
24	26
25	27	static int at32_verify_speed(struct cpufreq_policy *policy)
26	28	{
27	29
...	...	@@ -85,13 +87,17 @@
85	87
86	88	static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
87	89	{
	90	+ unsigned int frequency, rate;
	91	+ int retval, steps, i;
	92	+
88	93	if (policy->cpu != 0)
89	94	return -EINVAL;
90	95
91	96	cpuclk = clk_get(NULL, "cpu");
92	97	if (IS_ERR(cpuclk)) {
93	98	pr_debug("cpufreq: could not get CPU clk\n");
94		- return PTR_ERR(cpuclk);
	99	+ retval = PTR_ERR(cpuclk);
	100	+ goto out_err;
95	101	}
96	102
97	103	policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
98	104
...	...	@@ -101,9 +107,46 @@
101	107	policy->min = policy->cpuinfo.min_freq;
102	108	policy->max = policy->cpuinfo.max_freq;
103	109
104		- printk("cpufreq: AT32AP CPU frequency driver\n");
	110	+ /*
	111	+ * AVR32 CPU frequency rate scales in power of two between maximum and
	112	+ * minimum, also add space for the table end marker.
	113	+ *
	114	+ * Further validate that the frequency is usable, and append it to the
	115	+ * frequency table.
	116	+ */
	117	+ steps = fls(policy->cpuinfo.max_freq / policy->cpuinfo.min_freq) + 1;
	118	+ freq_table = kzalloc(steps * sizeof(struct cpufreq_frequency_table),
	119	+ GFP_KERNEL);
	120	+ if (!freq_table) {
	121	+ retval = -ENOMEM;
	122	+ goto out_err_put_clk;
	123	+ }
105	124
106		- return 0;
	125	+ frequency = policy->cpuinfo.max_freq;
	126	+ for (i = 0; i < (steps - 1); i++) {
	127	+ rate = clk_round_rate(cpuclk, frequency * 1000) / 1000;
	128	+
	129	+ if (rate != frequency)
	130	+ freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
	131	+ else
	132	+ freq_table[i].frequency = frequency;
	133	+
	134	+ frequency /= 2;
	135	+ }
	136	+
	137	+ freq_table[steps - 1].frequency = CPUFREQ_TABLE_END;
	138	+
	139	+ retval = cpufreq_table_validate_and_show(policy, freq_table);
	140	+ if (!retval) {
	141	+ printk("cpufreq: AT32AP CPU frequency driver\n");
	142	+ return 0;
	143	+ }
	144	+
	145	+ kfree(freq_table);
	146	+out_err_put_clk:
	147	+ clk_put(cpuclk);
	148	+out_err:
	149	+ return retval;
107	150	}
108	151
109	152	static struct cpufreq_driver at32_driver = {