thermal: add virtual temperature sensor

The new type of sensor allows to calculate temperature
of thermal zone container. It relays on real thermal zones
temperature and provides basic weighted avg algorithm.

Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>

diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 610344eb3e03378c69d56f60178ff8222f5d0435..c0d29120379a4abf6357b5999844684067471066 100644 (file)
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -27,6 +27,8 @@ thermal_sys-$(CONFIG_CLOCK_THERMAL)   += clock_cooling.o
 # devfreq cooling
 thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o
 
+obj-y  += virt_tsens.o
+
 # platform thermal drivers
 obj-y                          += broadcom/
 obj-$(CONFIG_QCOM_SPMI_TEMP_ALARM)     += qcom-spmi-temp-alarm.o

diff --git a/drivers/thermal/virt_tsens.c b/drivers/thermal/virt_tsens.c
new file mode 100644 (file)
index 0000000..59dffea
--- /dev/null
+++ b/drivers/thermal/virt_tsens.c
@@ -0,0 +1,126 @@
+/*license */
+
+#define pr_fmt(fmt) "VTSENS: " fmt
+
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/thermal.h>
+#include <linux/types.h>
+
+
+
+struct vtsens {
+       struct thermal_zone_device *tzd;
+       struct mutex lock;
+};
+
+static int vtsens_get_temp(void *p, int *temp)
+{
+       struct vtsens *vts = p;
+       struct thermal_zone_device *tzd = vts->tzd;
+       struct thermal_zone_device *tz;
+       int ret = 0;
+       int subtz_temp;
+       int avg_temp = 0;
+       int subzones_capacitance = 0;
+
+       /* We are virtual temp sensor so must relay on real sensors
+        * which are present in subzones. */
+       if (!tzd || !tzd->container)
+               return -EINVAL;
+
+
+       if (list_empty(&tzd->subzones))
+           return -EINVAL;
+
+       list_for_each_entry(tz, &tzd->subzones, subzones) {
+               /* Avoid checking the first entry and prevent from
+                  aggregating containers (circular dependencies, etc.) */
+               if (tz->container)
+                       continue;
+               ret = thermal_zone_get_temp(tz, &subtz_temp);
+               if (ret) {
+                       return ret;
+               }
+               avg_temp += tz->capacitance * subtz_temp;
+               subzones_capacitance += tz->capacitance;
+               /* pr_info("%s, subtz_temp = %d\n", tzd->type, subtz_temp); */
+       }
+
+       if (subzones_capacitance)
+               avg_temp /= subzones_capacitance;
+       else
+               ret = -EINVAL;
+
+       *temp = avg_temp;
+
+       return ret;
+}
+
+static const struct thermal_zone_of_device_ops vtsens_ops = {
+       .get_temp = vtsens_get_temp,
+};
+
+static int vtsens_probe(struct platform_device *pdev)
+{
+       struct vtsens *vts;
+       struct device *dev = &pdev->dev;
+       int ret;
+
+       if (!dev || !dev->of_node)
+               return -EINVAL;
+
+       vts = devm_kzalloc(&pdev->dev, sizeof(struct vtsens),
+                           GFP_KERNEL);
+       if (!vts)
+               return -ENOMEM;
+
+       platform_set_drvdata(pdev, vts);
+       mutex_init(&vts->lock);
+
+       vts->tzd = thermal_zone_of_sensor_register(&pdev->dev, 0, vts,
+                                                   &vtsens_ops);
+
+       if (IS_ERR(vts->tzd)) {
+               ret = PTR_ERR(vts->tzd);
+               dev_err(&pdev->dev, "Failed during registration of sensor %d\n",
+                       ret);
+               return ret;
+       }
+
+       return 0;
+}
+
+static int vtsens_remove(struct platform_device *pdev)
+{
+
+       return 0;
+}
+
+static const struct of_device_id of_virt_tsens_match[] = {
+       { .compatible = "thermal,virt-tsens", },
+       { /* end */ }
+};
+MODULE_DEVICE_TABLE(of, of_virt_tsens_match);
+
+
+static struct platform_driver vtsens_thermal = {
+       .driver = {
+               .name   = "vtsens_thermal",
+               .of_match_table = of_virt_tsens_match,
+       },
+       .probe          = vtsens_probe,
+       .remove         = vtsens_remove,
+};
+module_platform_driver(vtsens_thermal);
+
+MODULE_AUTHOR("Samsung, Inc.");
+MODULE_DESCRIPTION("Virtual temperature sensor driver for agregated thermal zones");
+MODULE_LICENSE("GPL v2");