Commit 58e4a2d2 authored by Dan Carpenter's avatar Dan Carpenter Committed by Chanwoo Choi
Browse files

extcon: Fix extcon_get_extcon_dev() error handling 



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: default avatarDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: default avatarHans de Goede <hdegoede@redhat.com>
Reviewed-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Acked-by: default avatarSebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
parent 672c0c51

drivers/extcon/extcon-axp288.c

+2 −2
Original line number Diff line number Diff line
@@ -394,8 +394,8 @@ 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 {

drivers/extcon/extcon.c

+3 −1
Original line number Diff line number Diff line
@@ -851,6 +851,8 @@ 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)

{
@@ -864,7 +866,7 @@ 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;

drivers/power/supply/axp288_charger.c

+10 −7
Original line number Diff line number Diff line
@@ -865,17 +865,20 @@ 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",

	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 -EPROBE_DEFER;

		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");

	}

drivers/power/supply/charger-manager.c

+2 −5
Original line number Diff line number Diff line
@@ -985,12 +985,9 @@ 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);

	}

drivers/power/supply/max8997_charger.c

+4 −4
Original line number Diff line number Diff line
@@ -242,10 +242,10 @@ 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)) {