hwmon: Deal with errors from the thermal subsystem

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>

diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index c9790e2c344016e91c26d02f4a69e6a15035b62a..af5123042990281c694311da2819107dd8336afb 100644 (file)
--- 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: