drivers: misc: Thermal estimator driver

Added driver which estimates temperature based on
a linear formula from other temperature sensors.

bug 1007726

Change-Id: Ic0d3ba7f0d369d4321f55b03e6326ff4efbb512e
Signed-off-by: Joshua Primero <jprimero@nvidia.com>
Reviewed-on: http://git-master/r/105988
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Sachin Nikam <snikam@nvidia.com>

4 files changed, 223 insertions, 0 deletions

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 7b7e948ff4f5..0e9992f09412 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -562,6 +562,12 @@ config MAX1749_VIBRATOR
 	---help---
 	Adds a timed output vibrator device node for MAX1749 vibrator motor
 
+config THERM_EST
+	bool "Thermal estimator driver"
+	default n
+	---help---
+	Thermal driver which estimates temperature based of other sensors.
+
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
 source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 5b3728ebcaee..9ba46dbd2c4b 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -58,3 +58,4 @@ obj-$(CONFIG_INV_SENSORS)      += inv_mpu/
 obj-$(CONFIG_TEGRA_CRYPTO_DEV)	+= tegra-cryptodev.o
 obj-$(CONFIG_TEGRA_BB_SUPPORT)	+= tegra-baseband/
 obj-$(CONFIG_MAX1749_VIBRATOR)	+= max1749.o
+obj-$(CONFIG_THERM_EST)		+= therm_est.o
diff --git a/drivers/misc/therm_est.c b/drivers/misc/therm_est.c
new file mode 100644
index 000000000000..fde61bc458ba
--- /dev/null
+++ b/drivers/misc/therm_est.c
@@ -0,0 +1,139 @@
+/*
+ * drivers/misc/therm_est.c
+ *
+ * Copyright (C) 2010-2012 NVIDIA Corporation.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/cpufreq.h>
+#include <linux/delay.h>
+#include <linux/mutex.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/therm_est.h>
+
+int therm_est_get_temp(struct therm_estimator *est, long *temp)
+{
+	*temp = est->cur_temp;
+	return 0;
+}
+
+int therm_est_set_limits(struct therm_estimator *est,
+				long lo_limit,
+				long hi_limit)
+{
+	est->therm_est_lo_limit = lo_limit;
+	est->therm_est_hi_limit = hi_limit;
+	return 0;
+}
+
+int therm_est_set_alert(struct therm_estimator *est,
+			void (*cb)(void *),
+			void *cb_data)
+{
+	if ((!cb) || est->callback)
+		BUG();
+
+	est->callback = cb;
+	est->callback_data = cb_data;
+
+	return 0;
+}
+
+static void therm_est_work_func(struct work_struct *work)
+{
+	int i, j, index, sum = 0;
+	long temp;
+	struct delayed_work *dwork = container_of (work,
+					struct delayed_work, work);
+	struct therm_estimator *est = container_of(
+					dwork,
+					struct therm_estimator,
+					therm_est_work);
+
+	for (i = 0; i < est->ndevs; i++) {
+		if (est->devs[i]->get_temp(est->devs[i]->dev_data, &temp))
+			continue;
+		est->devs[i]->hist[(est->ntemp % HIST_LEN)] = temp;
+	}
+
+	for (i = 0; i < est->ndevs; i++) {
+		for (j = 0; j < HIST_LEN; j++) {
+			index = (est->ntemp - j + HIST_LEN) % HIST_LEN;
+			sum += est->devs[i]->hist[index] *
+				est->devs[i]->coeffs[j];
+		}
+	}
+
+	est->cur_temp = sum / 100 + est->toffset;
+
+	est->ntemp++;
+
+	if (est->callback && ((est->cur_temp >= est->therm_est_hi_limit) ||
+			 (est->cur_temp <= est->therm_est_hi_limit)))
+		est->callback(est->callback_data);
+
+	queue_delayed_work(est->workqueue, &est->therm_est_work,
+				msecs_to_jiffies(est->polling_period));
+}
+
+struct therm_estimator *therm_est_register(
+			struct therm_est_subdevice **devs,
+			int ndevs,
+			long toffset,
+			long polling_period)
+{
+	int i, j;
+	long temp;
+	struct therm_estimator *est;
+	struct therm_est_subdevice *dev;
+
+	est = kzalloc(sizeof(struct therm_estimator), GFP_KERNEL);
+	if (IS_ERR_OR_NULL(est))
+		return ERR_PTR(-ENOMEM);
+
+	est->devs = devs;
+	est->ndevs = ndevs;
+	est->toffset = toffset;
+	est->polling_period = polling_period;
+
+	/* initialize history */
+	for (i = 0; i < ndevs; i++) {
+		dev = est->devs[i];
+
+		if (dev->get_temp(dev->dev_data, &temp)) {
+			kfree(est);
+			return ERR_PTR(-EINVAL);
+		}
+
+		for (j = 0; j < HIST_LEN; j++) {
+			dev->hist[j] = temp;
+		}
+	}
+
+	est->workqueue = alloc_workqueue("therm_est",
+				    WQ_HIGHPRI | WQ_UNBOUND | WQ_RESCUER, 1);
+	INIT_DELAYED_WORK(&est->therm_est_work, therm_est_work_func);
+
+	queue_delayed_work(est->workqueue,
+				&est->therm_est_work,
+				msecs_to_jiffies(est->polling_period));
+
+	return est;
+}
diff --git a/include/linux/therm_est.h b/include/linux/therm_est.h
new file mode 100644
index 000000000000..035b08fa9813
--- /dev/null
+++ b/include/linux/therm_est.h
@@ -0,0 +1,77 @@
+/*
+ * include/linux/therm_est.h
+ *
+ * Copyright (c) 2010-2012, NVIDIA Corporation.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _LINUX_THERM_EST_H
+#define _LINUX_THERM_EST_H
+
+#include <linux/workqueue.h>
+
+#define HIST_LEN (20)
+
+struct therm_est_subdevice {
+	void *dev_data;
+	int (*get_temp)(void *, long *);
+	long coeffs[HIST_LEN];
+	long hist[HIST_LEN];
+};
+
+struct therm_estimator {
+	long therm_est_lo_limit;
+	long therm_est_hi_limit;
+	void (*callback)(void *);
+	void *callback_data;
+	long cur_temp;
+	long polling_period;
+	struct workqueue_struct *workqueue;
+	struct delayed_work therm_est_work;
+	long toffset;
+	int ntemp;
+	int ndevs;
+	struct therm_est_subdevice **devs;
+};
+
+#ifdef CONFIG_THERM_EST
+struct therm_estimator *therm_est_register(
+			struct therm_est_subdevice **devs,
+			int ndevs,
+			long toffset,
+			long pperiod);
+int therm_est_get_temp(struct therm_estimator *est, long *temp);
+int therm_est_set_limits(struct therm_estimator *est,
+			long lo_limit,
+			long hi_limit);
+int therm_est_set_alert(struct therm_estimator *est,
+			void (*cb)(void *),
+			void *cb_data);
+#else
+static inline struct therm_estimator *therm_est_register(
+			struct therm_est_subdevice **devs,
+			int ndevs,
+			long toffset,
+			long pperiod)
+{ return NULL; }
+static inline int therm_est_get_temp(struct therm_estimator *est, long *temp)
+{ return -EINVAL; }
+static inline int therm_est_set_limits(struct therm_estimator *est,
+			long lo_limit,
+			long hi_limit)
+{ return -EINVAL; }
+static inline int therm_est_set_alert(struct therm_estimator *est,
+			void (*cb)(void *),
+			void *cb_data)
+{ return -EINVAL; }
+#endif
+#endif /* _LINUX_THERM_EST_H */