From 47c332deb8e89f6c59b0bb2615945c6e7fad1a60 Mon Sep 17 00:00:00 2001
From: Linus Walleij <linus.walleij@linaro.org>
Date: Tue, 5 Dec 2017 09:36:14 +0100
Subject: [PATCH] hwmon: Deal with errors from the thermal subsystem
Git-commit: 47c332deb8e89f6c59b0bb2615945c6e7fad1a60
Patch-mainline: v4.15-rc6
References: bsc#1051510

If the thermal subsystem returne -EPROBE_DEFER or any other error
when hwmon calls devm_thermal_zone_of_sensor_register(), this is
silently ignored.

I ran into this with an incorrectly defined thermal zone, making
it non-existing and thus this call failed with -EPROBE_DEFER
assuming it would appear later. The sensor was still added
which is incorrect: sensors must strictly be added after the
thermal zones, so deferred probe must be respected.

Fixes: d560168b5d0f ("hwmon: (core) New hwmon registration API")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/hwmon/hwmon.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index c9790e2c3440..af5123042990 100644
--- a/drivers/hwmon/hwmon.c
+++ b/drivers/hwmon/hwmon.c
@@ -143,6 +143,7 @@ static int hwmon_thermal_add_sensor(struct device *dev,
 				    struct hwmon_device *hwdev, int index)
 {
 	struct hwmon_thermal_data *tdata;
+	struct thermal_zone_device *tzd;
 
 	tdata = devm_kzalloc(dev, sizeof(*tdata), GFP_KERNEL);
 	if (!tdata)
@@ -151,8 +152,14 @@ static int hwmon_thermal_add_sensor(struct device *dev,
 	tdata->hwdev = hwdev;
 	tdata->index = index;
 
-	devm_thermal_zone_of_sensor_register(&hwdev->dev, index, tdata,
-					     &hwmon_thermal_ops);
+	tzd = devm_thermal_zone_of_sensor_register(&hwdev->dev, index, tdata,
+						   &hwmon_thermal_ops);
+	/*
+	 * If CONFIG_THERMAL_OF is disabled, this returns -ENODEV,
+	 * so ignore that error but forward any other error.
+	 */
+	if (IS_ERR(tzd) && (PTR_ERR(tzd) != -ENODEV))
+		return PTR_ERR(tzd);
 
 	return 0;
 }
@@ -621,14 +628,20 @@ __hwmon_device_register(struct device *dev, const char *name, void *drvdata,
 				if (!chip->ops->is_visible(drvdata, hwmon_temp,
 							   hwmon_temp_input, j))
 					continue;
-				if (info[i]->config[j] & HWMON_T_INPUT)
-					hwmon_thermal_add_sensor(dev, hwdev, j);
+				if (info[i]->config[j] & HWMON_T_INPUT) {
+					err = hwmon_thermal_add_sensor(dev,
+								hwdev, j);
+					if (err)
+						goto free_device;
+				}
 			}
 		}
 	}
 
 	return hdev;
 
+free_device:
+	device_unregister(hdev);
 free_hwmon:
 	kfree(hwdev);
 ida_remove:
-- 
2.18.0