ARM: tegra: dvfs: Adjust VDD_CPU to offset aging

Add silicon aging for VDD_CPU, this recovers some of millivolts based on
the age of the chip.

BUG 1006420

Change-Id: Idddb5861ab039e7ece262dec3697a69c3534ccf2
Signed-off-by: Anshul Jain <anshulj@nvidia.com>
Reviewed-on: http://git-master/r/116911
Reviewed-by: Aleksandr Frid <afrid@nvidia.com>
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Diwakar Tundlam <dtundlam@nvidia.com>
GVS: Gerrit_Virtual_Submit

1 files changed, 91 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/timer.c b/arch/arm/mach-tegra/timer.c
index 83d0e17b50c1..5771bfc9bdde 100644
--- a/arch/arm/mach-tegra/timer.c
+++ b/arch/arm/mach-tegra/timer.c
@@ -31,6 +31,7 @@
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/syscore_ops.h>
+#include <linux/rtc.h>
 
 #include <asm/mach/time.h>
 #include <asm/localtimer.h>
@@ -238,6 +239,96 @@ void tegra_twd_resume(struct tegra_twd_context *context)
 }
 #endif
 
+#ifdef CONFIG_RTC_CLASS
+/**
+ * has_readtime - check rtc device has readtime ability
+ * @dev: current device
+ * @name_ptr: name to be returned
+ *
+ * This helper function checks to see if the rtc device can be
+ * used for reading time
+ */
+static int has_readtime(struct device *dev, void *name_ptr)
+{
+	struct rtc_device *candidate = to_rtc_device(dev);
+
+	if (!candidate->ops->read_time)
+		return 0;
+
+	return 1;
+}
+
+/**
+ * tegra_get_linear_age - helper function to return linear age
+ * from Jan 2012.
+ *
+ * @return
+ * 1 - Jan 2012,
+ * 2 - Feb 2012,
+ * .....
+ * 13 - Jan 2013
+ */
+int tegra_get_linear_age(void)
+{
+	struct rtc_time tm;
+	int year, month, linear_age;
+	struct rtc_device *rtc_dev = NULL;
+	const char *name = NULL;
+	int ret;
+	struct device *dev = NULL;
+
+	linear_age = -1;
+	year = month = 0;
+	dev = class_find_device(rtc_class, NULL, &name, has_readtime);
+
+	if (!dev) {
+		pr_err("DVFS: No device with readtime capability\n");
+		goto done;
+	}
+
+	name = dev_name(dev);
+
+	pr_info("DVFS: Got RTC device name:%s\n", name);
+
+	if (name)
+		rtc_dev = rtc_class_open((char *)name);
+
+	if (!rtc_dev) {
+		pr_err("DVFS: No RTC device\n");
+		goto error_dev;
+	}
+
+	ret = rtc_read_time(rtc_dev, &tm);
+
+	if (ret < 0) {
+		pr_err("DVFS: Can't read RTC time\n");
+		goto error_rtc;
+	}
+
+	year = tm.tm_year;
+	/*Normalize it to 2012*/
+	year -= 112;
+	month = tm.tm_mon + 1;
+
+	if (year >= 0)
+		linear_age = year * 12 + month;
+
+error_rtc:
+	rtc_class_close(rtc_dev);
+error_dev:
+	put_device(dev);
+done:
+	return linear_age;
+
+}
+
+#else
+int tegra_get_linear_age()
+{
+	return -1;
+}
+#endif
+
 static void __init tegra_init_timer(void)
 {
 	struct clk *clk;