Amelie DelaunayandGreg Kroah-Hartman fc86da757d usb: dwc2: drd: fix dwc2_drd_role_sw_set when clock could be disabled
[ Upstream commit 8d387f61b0 ]

In case of USB_DR_MODE_PERIPHERAL, the OTG clock is disabled at the end of
the probe (it is not the case if USB_DR_MODE_HOST or USB_DR_MODE_OTG).
The clock is then enabled on udc_start.
If dwc2_drd_role_sw_set is called before udc_start (it is the case if the
usb cable is plugged at boot), GOTGCTL and GUSBCFG registers cannot be
read/written, so session cannot be overridden.
To avoid this case, check the ll_hw_enabled value and enable the clock if
it is available, and disable it after the override.

Fixes: 17f934024e ("usb: dwc2: override PHY input signals with usb role switch support")
Acked-by: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://lore.kernel.org/r/20211005095305.66397-3-amelie.delaunay@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-11-18 14:04:20 +01:00

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.
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