cpupower: Add the function to get the sysfs value from specific table

Expose the helper into cpufreq header, then cpufreq driver can use this
function to get the sysfs value if it has any specific sysfs interfaces.

Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Author: huangrui

tools/power/cpupower/lib/cpufreq.c

@@ -83,20 +83,21 @@ static const char *cpufreq_value_files[MAX_CPUFREQ_VALUE_READ_FILES] = {
 	[STATS_NUM_TRANSITIONS] = "stats/total_trans"
 };
 
-
-static unsigned long sysfs_cpufreq_get_one_value(unsigned int cpu,
-						 enum cpufreq_value which)
+unsigned long cpufreq_get_sysfs_value_from_table(unsigned int cpu,
+						 const char **table,
+						 unsigned int index,
+						 unsigned int size)
 {
 	unsigned long value;
 	unsigned int len;
 	char linebuf[MAX_LINE_LEN];
 	char *endp;
 
-	if (which >= MAX_CPUFREQ_VALUE_READ_FILES)
+	if (!table || index >= size || !table[index])
 		return 0;
 
-	len = sysfs_cpufreq_read_file(cpu, cpufreq_value_files[which],
-				linebuf, sizeof(linebuf));
+	len = sysfs_cpufreq_read_file(cpu, table[index], linebuf,
+				      sizeof(linebuf));
 
 	if (len == 0)
 		return 0;
@@ -109,6 +110,14 @@ static unsigned long sysfs_cpufreq_get_one_value(unsigned int cpu,
 	return value;
 }
 
+static unsigned long sysfs_cpufreq_get_one_value(unsigned int cpu,
+						 enum cpufreq_value which)
+{
+	return cpufreq_get_sysfs_value_from_table(cpu, cpufreq_value_files,
+						  which,
+						  MAX_CPUFREQ_VALUE_READ_FILES);
+}
+
 /* read access to files which contain one string */
 
 enum cpufreq_string {
@@ -124,7 +133,7 @@ static const char *cpufreq_string_files[MAX_CPUFREQ_STRING_FILES] = {
 
 
 static char *sysfs_cpufreq_get_one_string(unsigned int cpu,
-					   enum cpufreq_string which)
+					  enum cpufreq_string which)
 {
 	char linebuf[MAX_LINE_LEN];
 	char *result;

tools/power/cpupower/lib/cpufreq.h

@@ -203,6 +203,18 @@ int cpufreq_modify_policy_governor(unsigned int cpu, char *governor);
 int cpufreq_set_frequency(unsigned int cpu,
 				unsigned long target_frequency);
 
+/*
+ * get the sysfs value from specific table
+ *
+ * Read the value with the sysfs file name from specific table. Does
+ * only work if the cpufreq driver has the specific sysfs interfaces.
+ */
+
+unsigned long cpufreq_get_sysfs_value_from_table(unsigned int cpu,
+						 const char **table,
+						 unsigned int index,
+						 unsigned int size);
+
 #ifdef __cplusplus
 }
 #endif