extcon: Fix extcon_get_extcon_dev() error handling

[ Upstream commit 58e4a2d27d3255e4e8c507fdc13734dccc9fc4c7 ]

The extcon_get_extcon_dev() function returns error pointers on error,
NULL when it's a -EPROBE_DEFER defer situation, and ERR_PTR(-ENODEV)
when the CONFIG_EXTCON option is disabled.  This is very complicated for
the callers to handle and a number of them had bugs that would lead to
an Oops.

In real life, there are two things which prevented crashes.  First,
error pointers would only be returned if there was bug in the caller
where they passed a NULL "extcon_name" and none of them do that.
Second, only two out of the eight drivers will build when CONFIG_EXTCON
is disabled.

The normal way to write this would be to return -EPROBE_DEFER directly
when appropriate and return NULL when CONFIG_EXTCON is disabled.  Then
the error handling is simple and just looks like:

	dev->edev = extcon_get_extcon_dev(acpi_dev_name(adev));
	if (IS_ERR(dev->edev))
		return PTR_ERR(dev->edev);

For the two drivers which can build with CONFIG_EXTCON disabled, then
extcon_get_extcon_dev() will now return NULL which is not treated as an
error and the probe will continue successfully.  Those two drivers are
"typec_fusb302" and "max8997-battery".  In the original code, the
typec_fusb302 driver had an 800ms hang in tcpm_get_current_limit() but
now that function is a no-op.  For the max8997-battery driver everything
should continue working as is.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/extcon/extcon-axp288.c b/drivers/extcon/extcon-axp288.c
index fdb3195..8073bc7 100644 (file)
--- a/drivers/extcon/extcon-axp288.c
+++ b/drivers/extcon/extcon-axp288.c
@@ -375,8 +375,8 @@ static int axp288_extcon_probe(struct platform_device *pdev)
                if (adev) {
                        info->id_extcon = extcon_get_extcon_dev(acpi_dev_name(adev));
                        put_device(&adev->dev);
-                       if (!info->id_extcon)
-                               return -EPROBE_DEFER;
+                       if (IS_ERR(info->id_extcon))
+                               return PTR_ERR(info->id_extcon);
 
                        dev_info(dev, "controlling USB role\n");
                } else {

diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
index e7a9561..9eb9299 100644 (file)
--- a/drivers/extcon/extcon.c
+++ b/drivers/extcon/extcon.c
@@ -863,6 +863,8 @@ EXPORT_SYMBOL_GPL(extcon_set_property_capability);
  * @extcon_name:       the extcon name provided with extcon_dev_register()
  *
  * Return the pointer of extcon device if success or ERR_PTR(err) if fail.
+ * NOTE: This function returns -EPROBE_DEFER so it may only be called from
+ * probe() functions.
  */
 struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
 {
@@ -876,7 +878,7 @@ struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
                if (!strcmp(sd->name, extcon_name))
                        goto out;
        }
-       sd = NULL;
+       sd = ERR_PTR(-EPROBE_DEFER);
 out:
        mutex_unlock(&extcon_dev_list_lock);
        return sd;

diff --git a/drivers/power/supply/axp288_charger.c b/drivers/power/supply/axp288_charger.c
index fb9db7f..22378da 100644 (file)
--- a/drivers/power/supply/axp288_charger.c
+++ b/drivers/power/supply/axp288_charger.c
@@ -832,17 +832,20 @@ static int axp288_charger_probe(struct platform_device *pdev)
        info->regmap_irqc = axp20x->regmap_irqc;
 
        info->cable.edev = extcon_get_extcon_dev(AXP288_EXTCON_DEV_NAME);
-       if (info->cable.edev == NULL) {
-               dev_dbg(dev, "%s is not ready, probe deferred\n",
-                       AXP288_EXTCON_DEV_NAME);
-               return -EPROBE_DEFER;
+       if (IS_ERR(info->cable.edev)) {
+               dev_err_probe(dev, PTR_ERR(info->cable.edev),
+                             "extcon_get_extcon_dev(%s) failed\n",
+                             AXP288_EXTCON_DEV_NAME);
+               return PTR_ERR(info->cable.edev);
        }
 
        if (acpi_dev_present(USB_HOST_EXTCON_HID, NULL, -1)) {
                info->otg.cable = extcon_get_extcon_dev(USB_HOST_EXTCON_NAME);
-               if (info->otg.cable == NULL) {
-                       dev_dbg(dev, "EXTCON_USB_HOST is not ready, probe deferred\n");
-                       return -EPROBE_DEFER;
+               if (IS_ERR(info->otg.cable)) {
+                       dev_err_probe(dev, PTR_ERR(info->otg.cable),
+                                     "extcon_get_extcon_dev(%s) failed\n",
+                                     USB_HOST_EXTCON_NAME);
+                       return PTR_ERR(info->otg.cable);
                }
                dev_info(dev, "Using " USB_HOST_EXTCON_HID " extcon for usb-id\n");
        }

diff --git a/drivers/power/supply/charger-manager.c b/drivers/power/supply/charger-manager.c
index d67edb7..92db794 100644 (file)
--- a/drivers/power/supply/charger-manager.c
+++ b/drivers/power/supply/charger-manager.c
@@ -985,13 +985,10 @@ static int charger_extcon_init(struct charger_manager *cm,
        cable->nb.notifier_call = charger_extcon_notifier;
 
        cable->extcon_dev = extcon_get_extcon_dev(cable->extcon_name);
-       if (IS_ERR_OR_NULL(cable->extcon_dev)) {
+       if (IS_ERR(cable->extcon_dev)) {
                pr_err("Cannot find extcon_dev for %s (cable: %s)\n",
                        cable->extcon_name, cable->name);
-               if (cable->extcon_dev == NULL)
-                       return -EPROBE_DEFER;
-               else
-                       return PTR_ERR(cable->extcon_dev);
+               return PTR_ERR(cable->extcon_dev);
        }
 
        for (i = 0; i < ARRAY_SIZE(extcon_mapping); i++) {

diff --git a/drivers/power/supply/max8997_charger.c b/drivers/power/supply/max8997_charger.c
index 25207fe..bfa7a57 100644 (file)
--- a/drivers/power/supply/max8997_charger.c
+++ b/drivers/power/supply/max8997_charger.c
@@ -248,10 +248,10 @@ static int max8997_battery_probe(struct platform_device *pdev)
                dev_info(&pdev->dev, "couldn't get charger regulator\n");
        }
        charger->edev = extcon_get_extcon_dev("max8997-muic");
-       if (IS_ERR_OR_NULL(charger->edev)) {
-               if (!charger->edev)
-                       return -EPROBE_DEFER;
-               dev_info(charger->dev, "couldn't get extcon device\n");
+       if (IS_ERR(charger->edev)) {
+               dev_err_probe(charger->dev, PTR_ERR(charger->edev),
+                             "couldn't get extcon device: max8997-muic\n");
+               return PTR_ERR(charger->edev);
        }
 
        if (!IS_ERR(charger->reg) && !IS_ERR_OR_NULL(charger->edev)) {

diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
index f148b03..81ff21b 100644 (file)
--- a/drivers/usb/dwc3/drd.c
+++ b/drivers/usb/dwc3/drd.c
@@ -454,13 +454,8 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
         * This device property is for kernel internal use only and
         * is expected to be set by the glue code.
         */
-       if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
-               edev = extcon_get_extcon_dev(name);
-               if (!edev)
-                       return ERR_PTR(-EPROBE_DEFER);
-
-               return edev;
-       }
+       if (device_property_read_string(dev, "linux,extcon-name", &name) == 0)
+               return extcon_get_extcon_dev(name);
 
        /*
         * Try to get an extcon device from the USB PHY controller's "port"

diff --git a/drivers/usb/phy/phy-omap-otg.c b/drivers/usb/phy/phy-omap-otg.c
index ee0863c..6e6ef8c 100644 (file)
--- a/drivers/usb/phy/phy-omap-otg.c
+++ b/drivers/usb/phy/phy-omap-otg.c
@@ -95,8 +95,8 @@ static int omap_otg_probe(struct platform_device *pdev)
                return -ENODEV;
 
        extcon = extcon_get_extcon_dev(config->extcon);
-       if (!extcon)
-               return -EPROBE_DEFER;
+       if (IS_ERR(extcon))
+               return PTR_ERR(extcon);
 
        otg_dev = devm_kzalloc(&pdev->dev, sizeof(*otg_dev), GFP_KERNEL);
        if (!otg_dev)

diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
index 72f9001..96c55ea 100644 (file)
--- a/drivers/usb/typec/tcpm/fusb302.c
+++ b/drivers/usb/typec/tcpm/fusb302.c
@@ -1708,8 +1708,8 @@ static int fusb302_probe(struct i2c_client *client,
         */
        if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
                chip->extcon = extcon_get_extcon_dev(name);
-               if (!chip->extcon)
-                       return -EPROBE_DEFER;
+               if (IS_ERR(chip->extcon))
+                       return PTR_ERR(chip->extcon);
        }
 
        chip->vbus = devm_regulator_get(chip->dev, "vbus");

diff --git a/include/linux/extcon.h b/include/linux/extcon.h
index 0c19010..685401d 100644 (file)
--- a/include/linux/extcon.h
+++ b/include/linux/extcon.h
@@ -296,7 +296,7 @@ static inline void devm_extcon_unregister_notifier_all(struct device *dev,
 
 static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
 {
-       return ERR_PTR(-ENODEV);
+       return NULL;
 }
 
 static inline struct extcon_dev *extcon_find_edev_by_node(struct device_node *node)