From 58e4a2d27d3255e4e8c507fdc13734dccc9fc4c7 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 17 Dec 2021 09:28:46 +0300 Subject: 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: Dan Carpenter Reviewed-by: Hans de Goede Reviewed-by: Heikki Krogerus Reviewed-by: Guenter Roeck Acked-by: Sebastian Reichel Signed-off-by: Chanwoo Choi --- drivers/usb/dwc3/drd.c | 9 ++------- drivers/usb/phy/phy-omap-otg.c | 4 ++-- drivers/usb/typec/tcpm/fusb302.c | 4 ++-- 3 files changed, 6 insertions(+), 11 deletions(-) (limited to 'drivers/usb') diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c index 8cad9e7d3368..4982edd13047 100644 --- a/drivers/usb/dwc3/drd.c +++ b/drivers/usb/dwc3/drd.c @@ -455,13 +455,8 @@ 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 ee0863c6553e..6e6ef8c0bc7e 100644 --- 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 72f9001b0792..96c55eaf3f80 100644 --- 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"); -- cgit v1.2.3