ARM: tegra: thermal: fix therm_est_activ polling

During bootup, deadlock happens with "thermal_list_lock" while trying to
finding zones for sub_devs. This change fixes the deadlock issue and
also removes zone lookup which happens on every temperature reading.

Bug 1415692

Change-Id: I13a81de7ef9051e8d7a0fe0f2c59febdea0fa1d5
Signed-off-by: Hyungwoo Yang <hyungwooy@nvidia.com>
Reviewed-on: http://git-master/r/361188

2 files changed, 14 insertions, 7 deletions

diff --git a/drivers/misc/therm_est.c b/drivers/misc/therm_est.c
index c4dfbdab6..471d626ff 100644
--- a/drivers/misc/therm_est.c
+++ b/drivers/misc/therm_est.c
@@ -108,12 +108,9 @@ static int therm_est_subdev_match(struct thermal_zone_device *thz, void *data)
         return strcmp((char *)data, thz->type) == 0;
 }
 
-static int therm_est_subdev_get_temp(void *data, long *temp)
+static int therm_est_subdev_get_temp(struct thermal_zone_device *thz,
+                                        long *temp)
 {
-        struct thermal_zone_device *thz;
-
-        thz = thermal_zone_device_find(data, therm_est_subdev_match);
-
         if (!thz || thz->ops->get_temp(thz, temp))
                 *temp = 25000;
 
@@ -249,7 +246,7 @@ static void therm_est_work_func(struct work_struct *work)
                                         therm_est_work);
 
         for (i = 0; i < est->ndevs; i++) {
-                if (therm_est_subdev_get_temp(est->devs[i].dev_data, &temp))
+                if (therm_est_subdev_get_temp(est->devs[i].sub_thz, &temp))
                         continue;
                 est->devs[i].hist[(est->ntemp % HIST_LEN)] = temp;
         }
@@ -475,7 +472,7 @@ static int therm_est_init_history(struct therm_estimator *est)
         for (i = 0; i < est->ndevs; i++) {
                 dev = &est->devs[i];
 
-                if (therm_est_subdev_get_temp(dev->dev_data, &temp))
+                if (therm_est_subdev_get_temp(dev->sub_thz, &temp))
                         return -EINVAL;
 
                 for (j = 0; j < HIST_LEN; j++)
@@ -777,6 +774,7 @@ static int therm_est_probe(struct platform_device *pdev)
         int i;
         struct therm_estimator *est;
         struct therm_est_data *data;
+        struct thermal_zone_device *thz;
 
         est = kzalloc(sizeof(struct therm_estimator), GFP_KERNEL);
         if (IS_ERR_OR_NULL(est))
@@ -786,6 +784,14 @@ static int therm_est_probe(struct platform_device *pdev)
 
         data = pdev->dev.platform_data;
 
+        for (i = 0; i < data->ndevs; i++) {
+                thz = thermal_zone_device_find(data->devs[i].dev_data,
+                                                        therm_est_subdev_match);
+                if (!thz)
+                        goto err;
+                data->devs[i].sub_thz = thz;
+        }
+
         est->devs = data->devs;
         est->ndevs = data->ndevs;
         est->toffset = data->toffset;
diff --git a/include/linux/therm_est.h b/include/linux/therm_est.h
index 7526aa9b7..b89ca44cb 100644
--- a/include/linux/therm_est.h
+++ b/include/linux/therm_est.h
@@ -28,6 +28,7 @@
 
 struct therm_est_subdevice {
         void *dev_data;
+        struct thermal_zone_device *sub_thz;
         long coeffs[HIST_LEN];
         long hist[HIST_LEN];
 };