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Arnd Bergmann c0443694ae phy: work around 'phys' references to usb-nop-xceiv devices
commit b7563e2796 upstream.

Stefan Wahren reports a problem with a warning fix that was merged
for v4.15: we had lots of device nodes with a 'phys' property pointing
to a device node that is not compliant with the binding documented in
Documentation/devicetree/bindings/phy/phy-bindings.txt

This generally works because USB HCD drivers that support both the generic
phy subsystem and the older usb-phy subsystem ignore most errors from
phy_get() and related calls and then use the usb-phy driver instead.

However, it turns out that making the usb-nop-xceiv device compatible with
the generic-phy binding changes the phy_get() return code from -EINVAL to
-EPROBE_DEFER, and the dwc2 usb controller driver for bcm2835 now returns
-EPROBE_DEFER from its probe function rather than ignoring the failure,
breaking all USB support on raspberry-pi when CONFIG_GENERIC_PHY is
enabled. The same code is used in the dwc3 driver and the usb_add_hcd()
function, so a reasonable assumption would be that many other platforms
are affected as well.

I have reviewed all the related patches and concluded that "usb-nop-xceiv"
is the only USB phy that is affected by the change, and since it is by far
the most commonly referenced phy, all the other USB phy drivers appear
to be used in ways that are are either safe in DT (they don't use the
'phys' property), or in the driver (they already ignore -EPROBE_DEFER
from generic-phy when usb-phy is available).

To work around the problem, this adds a special case to _of_phy_get()
so we ignore any PHY node that is compatible with "usb-nop-xceiv",
as we know that this can never load no matter how much we defer. In the
future, we might implement a generic-phy driver for "usb-nop-xceiv"
and then remove this workaround.

Since we generally want older kernels to also want to work with the
fixed devicetree files, it would be good to backport the patch into
stable kernels as well (3.13+ are possibly affected), even though they
don't contain any of the patches that may have caused regressions.

Fixes: 014d6da6cb ARM: dts: bcm283x: Fix DTC warnings about missing phy-cells
Fixes: c5bbf358b7 arm: dts: nspire: Add missing #phy-cells to usb-nop-xceiv
Fixes: 44e5dced2e arm: dts: marvell: Add missing #phy-cells to usb-nop-xceiv
Fixes: f568f6f554 ARM: dts: omap: Add missing #phy-cells to usb-nop-xceiv
Fixes: d745d5f277 ARM: dts: imx51-zii-rdu1: Add missing #phy-cells to usb-nop-xceiv
Fixes: 915fbe59cb ARM: dts: imx: Add missing #phy-cells to usb-nop-xceiv
Link: https://marc.info/?l=linux-usb&m=151518314314753&w=2
Link: https://patchwork.kernel.org/patch/10158145/
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Eric Anholt <eric@anholt.net>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Rob Herring <robh@kernel.org>
Tested-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2018-01-23 19:58:16 +01:00
arch x86/mm: Encrypt the initrd earlier for BSP microcode update 2018-01-23 19:58:15 +01:00
block block: don't let passthrough IO go into .make_request_fn() 2018-01-02 20:31:05 +01:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto crypto: algapi - fix NULL dereference in crypto_remove_spawns() 2018-01-17 09:45:23 +01:00
Documentation x86/spectre: Add boot time option to select Spectre v2 mitigation 2018-01-17 09:45:29 +01:00
drivers phy: work around 'phys' references to usb-nop-xceiv devices 2018-01-23 19:58:16 +01:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs pipe: avoid round_pipe_size() nr_pages overflow on 32-bit 2018-01-23 19:58:14 +01:00
include module: Add retpoline tag to VERMAGIC 2018-01-23 19:58:14 +01:00
init x86/mm/pti: Add infrastructure for page table isolation 2018-01-02 20:30:56 +01:00
ipc License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kernel tracing: Fix converting enum's from the map in trace_event_eval_update() 2018-01-23 19:58:16 +01:00
lib x86/unwind: Rename unwinder config options to 'CONFIG_UNWINDER_*' 2017-12-25 14:26:13 +01:00
mm mm/sparse.c: wrong allocation for mem_section 2018-01-10 09:31:17 +01:00
net af_key: fix buffer overread in parse_exthdrs() 2018-01-23 19:58:12 +01:00
samples samples/bpf: adjust rlimit RLIMIT_MEMLOCK for xdp1 2017-12-20 10:10:31 +01:00
scripts objtool: Fix seg fault with gold linker 2018-01-23 19:58:13 +01:00
security security/Kconfig: Correct the Documentation reference for PTI 2018-01-17 09:45:30 +01:00
sound ALSA: hda - Apply the existing quirk to iMac 14,1 2018-01-23 19:58:12 +01:00
tools objtool: Improve error message for bad file argument 2018-01-23 19:58:13 +01:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: Fix stack-out-of-bounds read in write_mmio 2018-01-17 09:45:17 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS Merge branch 'akpm' (patches from Andrew) 2017-11-09 18:26:51 -08:00
Makefile Linux 4.14.14 2018-01-17 09:45:30 +01:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.