[PATCH 5.4 208/434] phy: qcom-usb-hs: Fix extcon double register after power cycle

Greg Kroah-Hartman
2019-12-29T18:06:37Z

From: Stephan Gerhold <stephan@gerhold.net>

[ Upstream commit 64f86b9978449ff05bfa6c64b4c5439e21e9c80b ]

Commit f0b5c2c96370 ("phy: qcom-usb-hs: Replace the extcon API")
switched from extcon_register_notifier() to the resource-managed
API, i.e. devm_extcon_register_notifier().

This is problematic in this case, because the extcon notifier
is dynamically registered/unregistered whenever the PHY is powered
on/off. The resource-managed API does not unregister the notifier
until the driver is removed, so as soon as the PHY is power cycled,
attempting to register the notifier again results in:

double register detected
WARNING: CPU: 1 PID: 182 at kernel/notifier.c:26 notifier_chain_register+0x74/0xa0
Call trace:
...
extcon_register_notifier+0x74/0xb8
devm_extcon_register_notifier+0x54/0xb8
qcom_usb_hs_phy_power_on+0x1fc/0x208
...

... and USB stops working after plugging the cable out and in
another time.

The easiest way to fix this is to make a partial revert of
commit f0b5c2c96370 ("phy: qcom-usb-hs: Replace the extcon API")
and avoid using the resource-managed API in this case.

Fixes: f0b5c2c96370 ("phy: qcom-usb-hs: Replace the extcon API")
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/phy/qualcomm/phy-qcom-usb-hs.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-usb-hs.c b/drivers/phy/qualcomm/phy-qcom-usb-hs.c
index b163b3a1558d..61054272a7c8 100644
--- a/drivers/phy/qualcomm/phy-qcom-usb-hs.c
+++ b/drivers/phy/qualcomm/phy-qcom-usb-hs.c
@@ -158,8 +158,8 @@ static int qcom_usb_hs_phy_power_on(struct phy *phy)
/* setup initial state */
qcom_usb_hs_phy_vbus_notifier(&uphy->vbus_notify, state,
uphy->vbus_edev);
- ret = devm_extcon_register_notifier(&ulpi->dev, uphy->vbus_edev,
- EXTCON_USB, &uphy->vbus_notify);
+ ret = extcon_register_notifier(uphy->vbus_edev, EXTCON_USB,
+ &uphy->vbus_notify);
if (ret)
goto err_ulpi;
}
@@ -180,6 +180,9 @@ static int qcom_usb_hs_phy_power_off(struct phy *phy)
{
struct qcom_usb_hs_phy *uphy = phy_get_drvdata(phy);

+ if (uphy->vbus_edev)
+ extcon_unregister_notifier(uphy->vbus_edev, EXTCON_USB,
+ &uphy->vbus_notify);
regulator_disable(uphy->v3p3);
regulator_disable(uphy->v1p8);
clk_disable_unprepare(uphy->sleep_clk);
--
2.20.1