phy common properties
Vladimir Oltean <vladimir.oltean@nxp.com> wrote:
Introduce "rx-polarity" and "tx-polarity" device tree properties with
Kunit tests
Add helpers in the generic PHY folder which can be used using 'select
PHY_COMMON_PROPS' from Kconfig, without otherwise needing to
enable GENERIC_PHY.
These helpers need to deal with the slight messiness of the fact that
the polarity properties are arrays per protocol, and with the fact that
there is no default value mandated by the standard properties, all
default values depend on driver and protocol (PHY_POL_NORMAL may be a
good default for SGMII, whereas PHY_POL_AUTO may be a good default for
PCIe).
Push the supported mask of polarities to these helpers, to simplify
drivers such that they don't need to validate what's in the device tree
(or other firmware description).
Add a KUnit test suite to make sure that the API produces the expected
results. The fact that we use fwnode structures means we can validate
with software nodes, and as opposed to the device_property API, we can
bypass the need to have a device structure.
Co-developed-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20260111093940.975359-6-vladimir.oltean@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Differential signaling is a technique for high-speed protocols to be
more resilient to noise. At the transmit side we have a positive and a
negative signal which are mirror images of each other. At the receiver,
if we subtract the negative signal (say of amplitude -A) from the
positive signal (say +A), we recover the original single-ended signal at
twice its original amplitude. But any noise, like one coming from EMI
from outside sources, is supposed to have an almost equal impact upon
the positive (A + E, E being for "error") and negative signal (-A + E).
So (A + E) - (-A + E) eliminates this noise, and this is what makes
differential signaling useful.
Except that in order to work, there must be strict requirements observed
during PCB design and layout, like the signal traces needing to have the
same length and be physically close to each other, and many others.
Sometimes it is not easy to fulfill all these requirements, a simple
case to understand is when on chip A's pins, the positive pin is on the
left and the negative is on the right, but on the chip B's pins (with
which A tries to communicate), positive is on the right and negative on
the left. The signals would need to cross, using vias and other ugly
stuff that affects signal integrity (introduces impedance
discontinuities which cause reflections, etc).
So sometimes, board designers intentionally connect differential lanes
the wrong way, and expect somebody else to invert that signal to recover
useful data. This is where RX and TX polarity inversion comes in as a
generic concept that applies to any high-speed serial protocol as long
as it uses differential signaling.
I've stopped two attempts to introduce more vendor-specific descriptions
of this only in the past month:
https://lore.kernel.org/linux-phy/20251110110536.2596490-1-horatiu.vultur@microchip.com/https://lore.kernel.org/netdev/20251028000959.3kiac5kwo5pcl4ft@skbuf/
and in the kernel we already have merged:
- "st,px_rx_pol_inv"
- "st,pcie-tx-pol-inv"
- "st,sata-tx-pol-inv"
- "mediatek,pnswap"
- "airoha,pnswap-rx"
- "airoha,pnswap-tx"
and maybe more. So it is pretty general.
One additional element of complexity is introduced by the fact that for
some protocols, receivers can automatically detect and correct for an
inverted lane polarity (example: the PCIe LTSSM does this in the
Polling.Configuration state; the USB 3.1 Link Layer Test Specification
says that the detection and correction of the lane polarity inversion in
SuperSpeed operation shall be enabled in Polling.RxEQ.). Whereas for
other protocols (SGMII, SATA, 10GBase-R, etc etc), the polarity is all
manual and there is no detection mechanism mandated by their respective
standards.
So why would one even describe rx-polarity and tx-polarity for protocols
like PCIe, if it had to always be PHY_POL_AUTO?
Related question: why would we define the polarity as an array per
protocol? Isn't the physical PCB layout protocol-agnostic, and aren't we
describing the same physical reality from the lens of different protocols?
The answer to both questions is because multi-protocol PHYs exist
(supporting e.g. USB2 and USB3, or SATA and PCIe, or PCIe and Ethernet
over the same lane), one would need to manually set the polarity for
SATA/Ethernet, while leaving it at auto for PCIe/USB 3.0+.
I also investigated from another angle: what if polarity inversion in
the PHY is one layer, and then the PCIe/USB3 LTSSM polarity detection is
another layer on top? Then rx-polarity = <PHY_POL_AUTO> doesn't make
sense, it can still be rx-polarity = <PHY_POL_NORMAL> or <PHY_POL_INVERT>,
and the link training state machine figures things out on top of that.
This would radically simplify the design, as the elimination of
PHY_POL_AUTO inherently means that the need for a property array per
protocol also goes away.
I don't know how things are in the general case, but at least in the 10G
and 28G Lynx SerDes blocks from NXP Layerscape devices, this isn't the
case, and there's only a single level of RX polarity inversion: in the
SerDes lane. In the case of PCIe, the controller is in charge of driving
the RDAT_INV bit autonomously, and it is read-only to software.
So the existence of this kind of SerDes lane proves the need for
PHY_POL_AUTO to be a third state.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20260111093940.975359-5-vladimir.oltean@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Rob Herring points out that "The default for .*-names is the entries
don't have to be unique.":
https://lore.kernel.org/linux-phy/20251204155219.GA1533839-robh@kernel.org/
Let's use uniqueItems: true to make sure the schema enforces this. It
doesn't make sense in this case to have duplicate properties for the
same SerDes protocol.
Note that this can only be done with the $defs + $ref pattern as
established by the previous commit. When the tx-p2p-microvolt-names
constraints were expressed directly under "properties", it would have
been validated by the string-array meta-schema, which does not support
the 'uniqueItems' keyword as can be seen below.
properties:tx-p2p-microvolt-names: Additional properties are not allowed ('uniqueItems' was unexpected)
from schema $id: http://devicetree.org/meta-schemas/string-array.yaml
Suggested-by: Rob Herring <robh@kernel.org>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20260111093940.975359-4-vladimir.oltean@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
I would like to add more properties similar to tx-p2p-microvolt, and I
don't think it makes sense to create one schema for each such property
(transmit-amplitude.yaml, lane-polarity.yaml, transmit-equalization.yaml
etc).
Instead, let's rename to phy-common-props.yaml, which makes it a more
adequate host schema for all the above properties.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20260111093940.975359-2-vladimir.oltean@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Add register sequences for PCIe + XAUI multilink configuration for
100MHz reference clock.
The register sequences are fetched from a table by indexing entries based
on unique 'keys' generated by the Bitwise OR defined below:
REFCLK0_RATE | REFCLK1_RATE | LINK0_TYPE | LINK1_TYPE | SSC_TYPE
As of now, LINK_TYPE is a 3-bit value corresponding to the PHY type.
With the introduction of TYPE_XAUI, we need a 4-bit value to represent
the LINK_TYPE as TYPE_XAUI has the numerical value 8. Hence, extend the
LINKx_MASK macros to 4-bit masks. While at it, extend REFCLKx_MASK macros
as well to 4-bit masks to support reference clock frequencies that will be
added in the future.
Adjust the 'LINKx_SHIFT' and the 'REFCLKx_SHIFT' macros to account for
the aforementioned changes made to the masks.
Signed-off-by: Swapnil Jakhade <sjakhade@cadence.com>
[s-vadapalli: elaborated on changes made to macros in the commit message]
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20260112054636.108027-3-s-vadapalli@ti.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
XAUI (eXtended Attachment Unit Interface) is a high-speed serial interface
standard for 10 Gigabit Ethernet (10GbE). It uses four lanes with each
lane operating at 3.125 Gbps (totaling 10 Gbps), to extend the XGMII
interface across circuit boards, commonly used in backplanes for
networking switches and high-performance computing. XAUI is defined as a
standardized instantiation of XGMII Extender in the IEEE 802.3
specification.
Add definition for XAUI PHY type.
Signed-off-by: Swapnil Jakhade <sjakhade@cadence.com>
[s-vadapalli: added detailed description of XAUI in the commit message]
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20260112054636.108027-2-s-vadapalli@ti.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Currently if a user enqueues a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.
This lack of consistency cannot be addressed without refactoring the API.
This patch continues the effort to refactor worqueue APIs, which has begun
with the change introducing new workqueues and a new alloc_workqueue flag:
commit 128ea9f6cc ("workqueue: Add system_percpu_wq and system_dfl_wq")
commit 930c2ea566 ("workqueue: Add new WQ_PERCPU flag")
Replace system_wq with system_percpu_wq, keeping the same behavior.
The old wq (system_wq) will be kept for a few release cycles.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://patch.msgid.link/20251105152023.259813-1-marco.crivellari@suse.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
On X Elite, the DP PHY needs another clock called ref, while all other
platforms do not.
The current X Elite devices supported upstream work fine without this
clock, because the boot firmware leaves this clock enabled. But we should
not rely on that. Also, even though this change breaks the ABI, it is
needed in order to make the driver disables this clock along with the
other ones, for a proper bring-down of the entire PHY.
So in order to handle these clocks on different platforms, make the driver
get all the clocks regardless of how many there are provided.
Cc: stable@vger.kernel.org # v6.10
Fixes: db83c107dc ("phy: qcom: edp: Add v6 specific ops and X1E80100 platform support")
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://patch.msgid.link/20251224-phy-qcom-edp-add-missing-refclk-v5-2-3f45d349b5ac@oss.qualcomm.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
On X Elite platform, the eDP PHY uses one more clock called ref.
The current X Elite devices supported upstream work fine without this
clock, because the boot firmware leaves this clock enabled. But we should
not rely on that. Also, even though this change breaks the ABI, it is
needed in order to make the driver disables this clock along with the
other ones, for a proper bring-down of the entire PHY.
So attach the this ref clock to the PHY.
Cc: stable@vger.kernel.org # v6.10
Fixes: 5d56078613 ("dt-bindings: phy: qcom-edp: Add X1E80100 PHY compatibles")
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://patch.msgid.link/20251224-phy-qcom-edp-add-missing-refclk-v5-1-3f45d349b5ac@oss.qualcomm.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The SpacemiT K1 SoC includes three USB ports:
- One USB2.0 OTG port
- One USB2.0 host-only port
- One USB3.0 port with an integrated USB2.0 DRD interface
Each of these ports is connected to a USB2.0 PHY responsible for USB2
transmission.
This commit adds support for the SpacemiT K1 USB2.0 PHY, which is
compliant with the USB 2.0 specification and supports both 8-bit 60MHz
and 16-bit 30MHz parallel interfaces.
Signed-off-by: Ze Huang <huang.ze@linux.dev>
Tested-by: Aurelien Jarno <aurelien@aurel32.net>
Tested-by: Junzhong Pan <panjunzhong@linux.spacemit.com>
Link: https://patch.msgid.link/20251017-k1-usb2phy-v6-2-7cf9ea2477a1@linux.dev
Signed-off-by: Vinod Koul <vkoul@kernel.org>
On Koelsch (R-Car M2-W), during boot and s2ram:
phy phy-e6590100.usb-phy-controller.0: Runtime PM usage count underflow!
While phy_pm_runtime_get{,_sync}() and phy_pm_runtime_put_sync() still
contain pm_runtime_enabled() checks, the same check in
phy_pm_runtime_put() was deemed redundant and removed, causing count
underflows with PHY drivers like drivers/phy/renesas/phy-rcar-gen2.c
that do not use Runtime PM yet,
Fix this by reinstating the check.
Fixes: caad07ae07 ("phy: core: Discard pm_runtime_put() return values")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/3ca9f8166d21685bfbf97535da30172f74822130.1767107014.git.geert+renesas@glider.be
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Starting with Glymur, the PCIe and DP PHYs qserdes register offsets differ
for the same version number. So in order to be able to differentiate
between them, add these ones with DP prefix.
Add the necessary PHY setting tables for enabling the DP path within the
QMP subsystem. Introduced some new callbacks for v8 specific sequences,
such as for clock configurations based on the different link speeds.
Wesley Cheng added some updated settings from the hardware programming
guides on existing PHY tables and clock settings.
Co-developed-by: Wesley Cheng <wesley.cheng@oss.qualcomm.com>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Wesley Cheng <wesley.cheng@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20251209-linux-next-12825-v8-9-42133596bda0@oss.qualcomm.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
For SuperSpeed USB to work properly, there is a set of HW settings that
need to be programmed into the USB blocks within the QMP PHY. Ensure that
these settings follow the latest settings mentioned in the HW programming
guide. The QMP USB PHY on Glymur is a USB43 based PHY that will have some
new ways to define certain registers, such as the replacement of TXA/RXA
and TXB/RXB register sets. This was replaced with the LALB register set.
There are also some PHY init updates to modify the PCS MISC register space.
Without these, the QMP PHY PLL locking fails.
Signed-off-by: Wesley Cheng <wesley.cheng@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20251209-linux-next-12825-v8-8-42133596bda0@oss.qualcomm.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
