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Louis Chauvet
bdaadfd3fa
commit028e8ca7b2upstream. When the OTG USB port is used to power the SoC, configured as peripheral and used in gadget mode, there is a disconnection about 6 seconds after the gadget is configured and enumerated. The problem was observed on a Radxa Rock Pi S board, which can only be powered by the only USB-C connector. That connector is the only one usable in gadget mode. This implies the USB cable is connected from before boot and never disconnects while the kernel runs. The problem happens because of the PHY driver code flow, summarized as: * UDC start code (triggered via configfs at any time after boot) -> phy_init -> rockchip_usb2phy_init -> schedule_delayed_work(otg_sm_work [A], 6 sec) -> phy_power_on -> rockchip_usb2phy_power_on -> enable clock -> rockchip_usb2phy_reset * Now the gadget interface is up and running. * 6 seconds later otg_sm_work starts [A] -> rockchip_usb2phy_otg_sm_work(): if (B_IDLE state && VBUS present && ...): schedule_delayed_work(&rport->chg_work [B], 0); * immediately the chg_detect_work starts [B] -> rockchip_chg_detect_work(): if chg_state is UNDEFINED: if (!rport->suspended): rockchip_usb2phy_power_off() <--- [X] At [X], the PHY is powered off, causing a disconnection. This quickly triggers a new connection and following re-enumeration, but any connection that had been established during the 6 seconds is broken. The code already checks for !rport->suspended (which, somewhat counter-intuitively, means the PHY is powered on), so add a guard for VBUS as well to avoid a disconnection when a cable is connected. Fixes:98898f3bc8("phy: rockchip-inno-usb2: support otg-port for rk3399") Cc: stable@vger.kernel.org Closes: https://lore.kernel.org/lkml/20250414185458.7767aabc@booty/ Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com> Co-developed-by: Luca Ceresoli <luca.ceresoli@bootlin.com> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com> Reviewed-by: Théo Lebrun <theo.lebrun@bootlin.com> Link: https://patch.msgid.link/20251127-rk3308-fix-usb-gadget-phy-disconnect-v2-1-dac8a02cd2ca@bootlin.com Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.