From 77622b4decae02def0907c02f462c9173631b824 Mon Sep 17 00:00:00 2001
From: faux123 <reioux@gmail.com>
Date: Thu, 22 Nov 2012 11:10:05 -0800
Subject: [PATCH] Voltage Control: add sysfs interface

Signed-off-by: faux123 <reioux@gmail.com>
---
 drivers/cpufreq/cpufreq.c | 83 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index d59b108c2a4..108c0848a14 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -619,6 +619,68 @@ static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
 	return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
 }
 
+#ifdef CONFIG_CPU_VOLTAGE_TABLE
+
+extern ssize_t acpuclk_get_vdd_levels_str(char *buf);
+extern void acpuclk_set_vdd(unsigned acpu_khz, int vdd);
+
+static ssize_t show_vdd_levels(struct kobject *a, struct attribute *b, char *buf) {
+	return acpuclk_get_vdd_levels_str(buf);
+}
+
+static ssize_t store_vdd_levels(struct kobject *a, struct attribute *b, const char *buf, size_t count) {
+
+	int i = 0, j;
+	int pair[2] = { 0, 0 };
+	int sign = 0;
+
+	if (count < 1)
+		return 0;
+
+	if (buf[0] == '-') {
+		sign = -1;
+		i++;
+	}
+	else if (buf[0] == '+') {
+		sign = 1;
+		i++;
+	}
+
+	for (j = 0; i < count; i++) {
+
+		char c = buf[i];
+
+		if ((c >= '0') && (c <= '9')) {
+			pair[j] *= 10;
+			pair[j] += (c - '0');
+		}
+		else if ((c == ' ') || (c == '\t')) {
+			if (pair[j] != 0) {
+				j++;
+
+				if ((sign != 0) || (j > 1))
+					break;
+			}
+		}
+		else
+			break;
+	}
+
+	if (sign != 0) {
+		if (pair[0] > 0)
+			acpuclk_set_vdd(0, sign * pair[0]);
+	}
+	else {
+		if ((pair[0] > 0) && (pair[1] > 0))
+			acpuclk_set_vdd((unsigned)pair[0], pair[1]);
+		else
+			return -EINVAL;
+	}
+	return count;
+}
+
+#endif	/* CONFIG_CPU_VOLTAGE_TABLE */
+
 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
 cpufreq_freq_attr_ro(cpuinfo_min_freq);
 cpufreq_freq_attr_ro(cpuinfo_max_freq);
@@ -634,6 +696,9 @@ cpufreq_freq_attr_rw(scaling_min_freq);
 cpufreq_freq_attr_rw(scaling_max_freq);
 cpufreq_freq_attr_rw(scaling_governor);
 cpufreq_freq_attr_rw(scaling_setspeed);
+#ifdef CONFIG_CPU_VOLTAGE_TABLE
+define_one_global_rw(vdd_levels);
+#endif
 
 static struct attribute *default_attrs[] = {
 	&cpuinfo_min_freq.attr,
@@ -651,6 +716,18 @@ static struct attribute *default_attrs[] = {
 	NULL
 };
 
+#ifdef CONFIG_CPU_VOLTAGE_TABLE
+static struct attribute *vddtbl_attrs[] = {
+	&vdd_levels.attr,
+	NULL
+};
+
+static struct attribute_group vddtbl_attr_group = {
+	.attrs = vddtbl_attrs,
+	.name = "vdd_table",
+};
+#endif	/* CONFIG_CPU_VOLTAGE_TABLE */
+
 struct kobject *cpufreq_global_kobject;
 EXPORT_SYMBOL(cpufreq_global_kobject);
 
@@ -1987,6 +2064,9 @@ EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
 static int __init cpufreq_core_init(void)
 {
 	int cpu;
+#ifdef CONFIG_CPU_VOLTAGE_TABLE
+	int rc;
+#endif	/* CONFIG_CPU_VOLTAGE_TABLE */
 
 	if (cpufreq_disabled())
 		return -ENODEV;
@@ -1999,6 +2079,9 @@ static int __init cpufreq_core_init(void)
 	cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
 	BUG_ON(!cpufreq_global_kobject);
 	register_syscore_ops(&cpufreq_syscore_ops);
+#ifdef CONFIG_CPU_VOLTAGE_TABLE
+	rc = sysfs_create_group(cpufreq_global_kobject, &vddtbl_attr_group);
+#endif	/* CONFIG_CPU_VOLTAGE_TABLE */
 
 	return 0;
 }