[PATCH v2 0/2] phy: add support for TH1520 USB PHY

[PATCH v2 0/2] phy: add support for TH1520 USB PHY

[Icenowy Zheng]

This patchset is splitted from the "Add TH1520 USB support" patchset,
with only the PHY binding/driver part.

Icenowy Zheng (2):
  dt-bindings: phy: add binding for T-Head TH1520 USB PHY
  phy: add a driver for T-Head TH1520 USB PHY

 .../bindings/phy/thead,th1520-usb-phy.yaml    |  73 +++++++
 drivers/phy/Kconfig                           |   1 +
 drivers/phy/Makefile                          |   1 +
 drivers/phy/thead/Kconfig                     |  11 ++
 drivers/phy/thead/Makefile                    |   2 +
 drivers/phy/thead/phy-th1520-usb.c            | 180 ++++++++++++++++++
 6 files changed, 268 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml
 create mode 100644 drivers/phy/thead/Kconfig
 create mode 100644 drivers/phy/thead/Makefile
 create mode 100644 drivers/phy/thead/phy-th1520-usb.c

-- 
2.52.0

[PATCH v2 0/2] phy: add support for TH1520 USB PHY

[Icenowy Zheng]

This patchset is splitted from the "Add TH1520 USB support" patchset,
with only the PHY binding/driver part.

Icenowy Zheng (2):
  dt-bindings: phy: add binding for T-Head TH1520 USB PHY
  phy: add a driver for T-Head TH1520 USB PHY

 .../bindings/phy/thead,th1520-usb-phy.yaml    |  73 +++++++
 drivers/phy/Kconfig                           |   1 +
 drivers/phy/Makefile                          |   1 +
 drivers/phy/thead/Kconfig                     |  11 ++
 drivers/phy/thead/Makefile                    |   2 +
 drivers/phy/thead/phy-th1520-usb.c            | 180 ++++++++++++++++++
 6 files changed, 268 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml
 create mode 100644 drivers/phy/thead/Kconfig
 create mode 100644 drivers/phy/thead/Makefile
 create mode 100644 drivers/phy/thead/phy-th1520-usb.c

-- 
2.52.0


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[PATCH v2 1/2] dt-bindings: phy: add binding for T-Head TH1520 USB PHY

[Icenowy Zheng]

The TH1520 SoC features a Synopsys USB 3.0 FemtoPHY with some custom
glue logic configuring PHY parameters.

Add a binding for it.

Signed-off-by: Icenowy Zheng <zhengxingda@iscas.ac.cn>
---
Changes in v2:
- Lifted avdd33-usb3-supply from required properties list. Because of
  this the R-b from Conor isn't added yet for reconfirmation. (The
  related regulator isn't yet controllable because no driver is
  available.)

 .../bindings/phy/thead,th1520-usb-phy.yaml    | 73 +++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml

diff --git a/Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml b/Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml
new file mode 100644
index 0000000000000..1a7a946fe503d
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml
@@ -0,0 +1,73 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/thead,th1520-usb-phy.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: T-Head TH1520 USB PHY
+
+description: |
+  The T-HEAD TH1520 USB PHY is a Synopsys USB 3.0 FemtoPHY glued with some
+  custom logic to configure PHY parameters.
+
+maintainers:
+  - Icenowy Zheng <zhengxingda@iscas.ac.cn>
+  - Wei Fu <wefu@redhat.com>
+  - Drew Fustini <dfustini@tenstorrent.com>
+
+properties:
+  compatible:
+    const: thead,th1520-usb-phy
+
+  reg:
+    maxItems: 1
+
+  "#phy-cells":
+    const: 0
+
+  clocks:
+    items:
+      - description: PHY bus clock
+      - description: PHY reference clock
+
+  clock-names:
+    items:
+      - const: bus
+      - const: ref
+
+  resets:
+    items:
+      - description: PHY bus reset
+      - description: PHY reset
+
+  reset-names:
+    items:
+      - const: bus
+      - const: phy
+
+  avdd33-usb3-supply:
+    description: |
+      3.3V power supply for the PHY, named AVDD33_USB3 in the SoC pin list.
+
+required:
+  - compatible
+  - "#phy-cells"
+  - clocks
+  - clock-names
+  - resets
+  - reset-names
+
+additionalProperties: false
+
+examples:
+  - |
+    phy@ec030000 {
+      compatible = "thead,th1520-usb-phy";
+      reg = <0xec030000 0x10000>;
+      #phy-cells = <0>;
+      clocks = <&clk_misc 1>, <&clk_misc 3>;
+      clock-names = "bus", "ref";
+      resets = <&rst_misc 6>, <&rst_misc 7>;
+      reset-names = "bus", "phy";
+      avdd33-usb3-supply = <&avdd33_usb3>;
+    };
-- 
2.52.0

[PATCH v2 1/2] dt-bindings: phy: add binding for T-Head TH1520 USB PHY

[Icenowy Zheng]

The TH1520 SoC features a Synopsys USB 3.0 FemtoPHY with some custom
glue logic configuring PHY parameters.

Add a binding for it.

Signed-off-by: Icenowy Zheng <zhengxingda@iscas.ac.cn>
---
Changes in v2:
- Lifted avdd33-usb3-supply from required properties list. Because of
  this the R-b from Conor isn't added yet for reconfirmation. (The
  related regulator isn't yet controllable because no driver is
  available.)

 .../bindings/phy/thead,th1520-usb-phy.yaml    | 73 +++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml

diff --git a/Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml b/Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml
new file mode 100644
index 0000000000000..1a7a946fe503d
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml
@@ -0,0 +1,73 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/thead,th1520-usb-phy.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: T-Head TH1520 USB PHY
+
+description: |
+  The T-HEAD TH1520 USB PHY is a Synopsys USB 3.0 FemtoPHY glued with some
+  custom logic to configure PHY parameters.
+
+maintainers:
+  - Icenowy Zheng <zhengxingda@iscas.ac.cn>
+  - Wei Fu <wefu@redhat.com>
+  - Drew Fustini <dfustini@tenstorrent.com>
+
+properties:
+  compatible:
+    const: thead,th1520-usb-phy
+
+  reg:
+    maxItems: 1
+
+  "#phy-cells":
+    const: 0
+
+  clocks:
+    items:
+      - description: PHY bus clock
+      - description: PHY reference clock
+
+  clock-names:
+    items:
+      - const: bus
+      - const: ref
+
+  resets:
+    items:
+      - description: PHY bus reset
+      - description: PHY reset
+
+  reset-names:
+    items:
+      - const: bus
+      - const: phy
+
+  avdd33-usb3-supply:
+    description: |
+      3.3V power supply for the PHY, named AVDD33_USB3 in the SoC pin list.
+
+required:
+  - compatible
+  - "#phy-cells"
+  - clocks
+  - clock-names
+  - resets
+  - reset-names
+
+additionalProperties: false
+
+examples:
+  - |
+    phy@ec030000 {
+      compatible = "thead,th1520-usb-phy";
+      reg = <0xec030000 0x10000>;
+      #phy-cells = <0>;
+      clocks = <&clk_misc 1>, <&clk_misc 3>;
+      clock-names = "bus", "ref";
+      resets = <&rst_misc 6>, <&rst_misc 7>;
+      reset-names = "bus", "phy";
+      avdd33-usb3-supply = <&avdd33_usb3>;
+    };
-- 
2.52.0


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Re: [PATCH v2 1/2] dt-bindings: phy: add binding for T-Head TH1520 USB PHY

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Medium] The 'reg' property is omitted from the 'required' list for a memory-mapped PHY.
- [Medium] The 'avdd33-usb3-supply' is omitted from the 'required' list based on software limitations rather than hardware description.
--

--- Patch [1]: [PATCH v2 1/2] dt-bindings: phy: add binding for T-Head TH1520 USB PHY ---
commit 91b4840ee15364137facb1905580d4df2ba57663
Author: Icenowy Zheng <zhengxingda@iscas.ac.cn>

dt-bindings: phy: add binding for T-Head TH1520 USB PHY

This commit adds a device tree binding for the T-Head TH1520 USB PHY,
which is a Synopsys USB 3.0 FemtoPHY with custom glue logic.

> Changes in v2:
> - Lifted avdd33-usb3-supply from required properties list. Because of
>   this the R-b from Conor isn't added yet for reconfirmation. (The
>   related regulator isn't yet controllable because no driver is
>   available.)

[Severity: Medium]
Since device tree bindings must describe hardware independently of software
state, shouldn't this physical supply be required if the hardware mandates it?

Software limitations are typically handled in the board DTS (e.g., using a
fixed-regulator), rather than compromising the generic hardware schema.

> diff --git a/Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml b/Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml
> new file mode 100644
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml
[ ... ]
> +required:
> +  - compatible
> +  - "#phy-cells"
> +  - clocks
> +  - clock-names
> +  - resets
> +  - reset-names

[Severity: Medium]
Since this is a memory-mapped PHY, shouldn't the reg property be included in
the required list?

Without it, device tree nodes missing the reg property will silently pass
schema validation, leading to incomplete hardware descriptions that fail at
runtime.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260723084316.3573714-1-zhengxingda@iscas.ac.cn?part=1

Re: [PATCH v2 1/2] dt-bindings: phy: add binding for T-Head TH1520 USB PHY

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Medium] The 'reg' property is omitted from the 'required' list for a memory-mapped PHY.
- [Medium] The 'avdd33-usb3-supply' is omitted from the 'required' list based on software limitations rather than hardware description.
--

--- Patch [1]: [PATCH v2 1/2] dt-bindings: phy: add binding for T-Head TH1520 USB PHY ---
commit 91b4840ee15364137facb1905580d4df2ba57663
Author: Icenowy Zheng <zhengxingda@iscas.ac.cn>

dt-bindings: phy: add binding for T-Head TH1520 USB PHY

This commit adds a device tree binding for the T-Head TH1520 USB PHY,
which is a Synopsys USB 3.0 FemtoPHY with custom glue logic.

> Changes in v2:
> - Lifted avdd33-usb3-supply from required properties list. Because of
>   this the R-b from Conor isn't added yet for reconfirmation. (The
>   related regulator isn't yet controllable because no driver is
>   available.)

[Severity: Medium]
Since device tree bindings must describe hardware independently of software
state, shouldn't this physical supply be required if the hardware mandates it?

Software limitations are typically handled in the board DTS (e.g., using a
fixed-regulator), rather than compromising the generic hardware schema.

> diff --git a/Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml b/Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml
> new file mode 100644
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/phy/thead,th1520-usb-phy.yaml
[ ... ]
> +required:
> +  - compatible
> +  - "#phy-cells"
> +  - clocks
> +  - clock-names
> +  - resets
> +  - reset-names

[Severity: Medium]
Since this is a memory-mapped PHY, shouldn't the reg property be included in
the required list?

Without it, device tree nodes missing the reg property will silently pass
schema validation, leading to incomplete hardware descriptions that fail at
runtime.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260723084316.3573714-1-zhengxingda@iscas.ac.cn?part=1

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Re: [PATCH v2 1/2] dt-bindings: phy: add binding for T-Head TH1520 USB PHY

[Icenowy Zheng]

在 2026-07-23四的 08:47 +0000，sashiko-bot@kernel.org写道：
> Thank you for your contribution! Sashiko AI review found 2 potential
> issue(s) to consider:
> - [Medium] The 'reg' property is omitted from the 'required' list for
> a memory-mapped PHY.
> - [Medium] The 'avdd33-usb3-supply' is omitted from the 'required'
> list based on software limitations rather than hardware description.

Well this is also to workaround the problem raised by Sashiko yourself
at [1].

I didn't mention it in the log because I am not sure whether this is a
real problem.

[1]
https://sashiko.dev/#/patchset/20260507081710.4090814-1-zhengxingda%40iscas.ac.cn?part=6

> --
> 
> --- Patch [1]: [PATCH v2 1/2] dt-bindings: phy: add binding for T-
> Head TH1520 USB PHY ---
> commit 91b4840ee15364137facb1905580d4df2ba57663
> Author: Icenowy Zheng <zhengxingda@iscas.ac.cn>
> 
> dt-bindings: phy: add binding for T-Head TH1520 USB PHY
> 
> This commit adds a device tree binding for the T-Head TH1520 USB PHY,
> which is a Synopsys USB 3.0 FemtoPHY with custom glue logic.
> 
> > Changes in v2:
> > - Lifted avdd33-usb3-supply from required properties list. Because
> > of
> >   this the R-b from Conor isn't added yet for reconfirmation. (The
> >   related regulator isn't yet controllable because no driver is
> >   available.)
> 
> [Severity: Medium]
> Since device tree bindings must describe hardware independently of
> software
> state, shouldn't this physical supply be required if the hardware
> mandates it?
> 
> Software limitations are typically handled in the board DTS (e.g.,
> using a
> fixed-regulator), rather than compromising the generic hardware
> schema.
> 
> > diff --git a/Documentation/devicetree/bindings/phy/thead,th1520-
> > usb-phy.yaml b/Documentation/devicetree/bindings/phy/thead,th1520-
> > usb-phy.yaml
> > new file mode 100644
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/phy/thead,th1520-usb-
> > phy.yaml
> [ ... ]
> > +required:
> > +  - compatible
> > +  - "#phy-cells"
> > +  - clocks
> > +  - clock-names
> > +  - resets
> > +  - reset-names
> 
> [Severity: Medium]
> Since this is a memory-mapped PHY, shouldn't the reg property be
> included in
> the required list?
> 
> Without it, device tree nodes missing the reg property will silently
> pass
> schema validation, leading to incomplete hardware descriptions that
> fail at
> runtime.

Re: [PATCH v2 1/2] dt-bindings: phy: add binding for T-Head TH1520 USB PHY

[Icenowy Zheng]

在 2026-07-23四的 08:47 +0000，sashiko-bot@kernel.org写道：
> Thank you for your contribution! Sashiko AI review found 2 potential
> issue(s) to consider:
> - [Medium] The 'reg' property is omitted from the 'required' list for
> a memory-mapped PHY.
> - [Medium] The 'avdd33-usb3-supply' is omitted from the 'required'
> list based on software limitations rather than hardware description.

Well this is also to workaround the problem raised by Sashiko yourself
at [1].

I didn't mention it in the log because I am not sure whether this is a
real problem.

[1]
https://sashiko.dev/#/patchset/20260507081710.4090814-1-zhengxingda%40iscas.ac.cn?part=6

> --
> 
> --- Patch [1]: [PATCH v2 1/2] dt-bindings: phy: add binding for T-
> Head TH1520 USB PHY ---
> commit 91b4840ee15364137facb1905580d4df2ba57663
> Author: Icenowy Zheng <zhengxingda@iscas.ac.cn>
> 
> dt-bindings: phy: add binding for T-Head TH1520 USB PHY
> 
> This commit adds a device tree binding for the T-Head TH1520 USB PHY,
> which is a Synopsys USB 3.0 FemtoPHY with custom glue logic.
> 
> > Changes in v2:
> > - Lifted avdd33-usb3-supply from required properties list. Because
> > of
> >   this the R-b from Conor isn't added yet for reconfirmation. (The
> >   related regulator isn't yet controllable because no driver is
> >   available.)
> 
> [Severity: Medium]
> Since device tree bindings must describe hardware independently of
> software
> state, shouldn't this physical supply be required if the hardware
> mandates it?
> 
> Software limitations are typically handled in the board DTS (e.g.,
> using a
> fixed-regulator), rather than compromising the generic hardware
> schema.
> 
> > diff --git a/Documentation/devicetree/bindings/phy/thead,th1520-
> > usb-phy.yaml b/Documentation/devicetree/bindings/phy/thead,th1520-
> > usb-phy.yaml
> > new file mode 100644
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/phy/thead,th1520-usb-
> > phy.yaml
> [ ... ]
> > +required:
> > +  - compatible
> > +  - "#phy-cells"
> > +  - clocks
> > +  - clock-names
> > +  - resets
> > +  - reset-names
> 
> [Severity: Medium]
> Since this is a memory-mapped PHY, shouldn't the reg property be
> included in
> the required list?
> 
> Without it, device tree nodes missing the reg property will silently
> pass
> schema validation, leading to incomplete hardware descriptions that
> fail at
> runtime.


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Re: [PATCH v2 1/2] dt-bindings: phy: add binding for T-Head TH1520 USB PHY

[Drew Fustini]

On Thu, Jul 23, 2026 at 10:05:24PM +0800, Icenowy Zheng wrote: > 在 2026-07-23四的 08:47 +0000，sashiko-bot@kernel.org写道：
> > Thank you for your contribution! Sashiko AI review found 2 potential
> > issue(s) to consider:
> > - [Medium] The 'reg' property is omitted from the 'required' list for
> > a memory-mapped PHY.
> > - [Medium] The 'avdd33-usb3-supply' is omitted from the 'required'
> > list based on software limitations rather than hardware description.
> 
> Well this is also to workaround the problem raised by Sashiko yourself
> at [1].
> 
> I didn't mention it in the log because I am not sure whether this is a
> real problem.
> 
> [1]
> https://sashiko.dev/#/patchset/20260507081710.4090814-1-zhengxingda%40iscas.ac.cn?part=6

I think Sashiko's comment on v1 was incorrect, and avdd33-usb3-supply
should be required.

Sashiko claimed that making avdd33-usb3-supply required would break
dtbs_check for boards that include th1520.dtsi but do not provide the
regulator. However, dtschema does not warn about missing properties if
the node is disabled [1]. Therefore, only boards that enable the usb phy
node would need to provide avdd33-usb3-supply.

Thanks,
Drew

[1] https://github.com/devicetree-org/dt-schema/blob/eb0e53d1c5b071865abbf7d251721431e8e6bd71/dtschema/dtb_validate.py#L256

Re: [PATCH v2 1/2] dt-bindings: phy: add binding for T-Head TH1520 USB PHY

[Drew Fustini]

On Thu, Jul 23, 2026 at 10:05:24PM +0800, Icenowy Zheng wrote: > 在 2026-07-23四的 08:47 +0000，sashiko-bot@kernel.org写道：
> > Thank you for your contribution! Sashiko AI review found 2 potential
> > issue(s) to consider:
> > - [Medium] The 'reg' property is omitted from the 'required' list for
> > a memory-mapped PHY.
> > - [Medium] The 'avdd33-usb3-supply' is omitted from the 'required'
> > list based on software limitations rather than hardware description.
> 
> Well this is also to workaround the problem raised by Sashiko yourself
> at [1].
> 
> I didn't mention it in the log because I am not sure whether this is a
> real problem.
> 
> [1]
> https://sashiko.dev/#/patchset/20260507081710.4090814-1-zhengxingda%40iscas.ac.cn?part=6

I think Sashiko's comment on v1 was incorrect, and avdd33-usb3-supply
should be required.

Sashiko claimed that making avdd33-usb3-supply required would break
dtbs_check for boards that include th1520.dtsi but do not provide the
regulator. However, dtschema does not warn about missing properties if
the node is disabled [1]. Therefore, only boards that enable the usb phy
node would need to provide avdd33-usb3-supply.

Thanks,
Drew

[1] https://github.com/devicetree-org/dt-schema/blob/eb0e53d1c5b071865abbf7d251721431e8e6bd71/dtschema/dtb_validate.py#L256

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Re: [PATCH v2 1/2] dt-bindings: phy: add binding for T-Head TH1520 USB PHY

[Icenowy Zheng]

在 2026-07-23四的 08:47 +0000，sashiko-bot@kernel.org写道：
> Thank you for your contribution! Sashiko AI review found 2 potential
> issue(s) to consider:
> - [Medium] The 'reg' property is omitted from the 'required' list for
> a memory-mapped PHY.
> - [Medium] The 'avdd33-usb3-supply' is omitted from the 'required'
> list based on software limitations rather than hardware description.

BTW the power rail is expected to be always on at least according to
the schematics of multiple boards, as mentioned in the next patch.

Thanks,
Icenowy

> --
> 
> --- Patch [1]: [PATCH v2 1/2] dt-bindings: phy: add binding for T-
> Head TH1520 USB PHY ---
> commit 91b4840ee15364137facb1905580d4df2ba57663
> Author: Icenowy Zheng <zhengxingda@iscas.ac.cn>
> 
> dt-bindings: phy: add binding for T-Head TH1520 USB PHY
> 
> This commit adds a device tree binding for the T-Head TH1520 USB PHY,
> which is a Synopsys USB 3.0 FemtoPHY with custom glue logic.
> 
> > Changes in v2:
> > - Lifted avdd33-usb3-supply from required properties list. Because
> > of
> >   this the R-b from Conor isn't added yet for reconfirmation. (The
> >   related regulator isn't yet controllable because no driver is
> >   available.)
> 
> [Severity: Medium]
> Since device tree bindings must describe hardware independently of
> software
> state, shouldn't this physical supply be required if the hardware
> mandates it?
> 
> Software limitations are typically handled in the board DTS (e.g.,
> using a
> fixed-regulator), rather than compromising the generic hardware
> schema.
> 
> > diff --git a/Documentation/devicetree/bindings/phy/thead,th1520-
> > usb-phy.yaml b/Documentation/devicetree/bindings/phy/thead,th1520-
> > usb-phy.yaml
> > new file mode 100644
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/phy/thead,th1520-usb-
> > phy.yaml
> [ ... ]
> > +required:
> > +  - compatible
> > +  - "#phy-cells"
> > +  - clocks
> > +  - clock-names
> > +  - resets
> > +  - reset-names
> 
> [Severity: Medium]
> Since this is a memory-mapped PHY, shouldn't the reg property be
> included in
> the required list?
> 
> Without it, device tree nodes missing the reg property will silently
> pass
> schema validation, leading to incomplete hardware descriptions that
> fail at
> runtime.

Re: [PATCH v2 1/2] dt-bindings: phy: add binding for T-Head TH1520 USB PHY

[Icenowy Zheng]

在 2026-07-23四的 08:47 +0000，sashiko-bot@kernel.org写道：
> Thank you for your contribution! Sashiko AI review found 2 potential
> issue(s) to consider:
> - [Medium] The 'reg' property is omitted from the 'required' list for
> a memory-mapped PHY.
> - [Medium] The 'avdd33-usb3-supply' is omitted from the 'required'
> list based on software limitations rather than hardware description.

BTW the power rail is expected to be always on at least according to
the schematics of multiple boards, as mentioned in the next patch.

Thanks,
Icenowy

> --
> 
> --- Patch [1]: [PATCH v2 1/2] dt-bindings: phy: add binding for T-
> Head TH1520 USB PHY ---
> commit 91b4840ee15364137facb1905580d4df2ba57663
> Author: Icenowy Zheng <zhengxingda@iscas.ac.cn>
> 
> dt-bindings: phy: add binding for T-Head TH1520 USB PHY
> 
> This commit adds a device tree binding for the T-Head TH1520 USB PHY,
> which is a Synopsys USB 3.0 FemtoPHY with custom glue logic.
> 
> > Changes in v2:
> > - Lifted avdd33-usb3-supply from required properties list. Because
> > of
> >   this the R-b from Conor isn't added yet for reconfirmation. (The
> >   related regulator isn't yet controllable because no driver is
> >   available.)
> 
> [Severity: Medium]
> Since device tree bindings must describe hardware independently of
> software
> state, shouldn't this physical supply be required if the hardware
> mandates it?
> 
> Software limitations are typically handled in the board DTS (e.g.,
> using a
> fixed-regulator), rather than compromising the generic hardware
> schema.
> 
> > diff --git a/Documentation/devicetree/bindings/phy/thead,th1520-
> > usb-phy.yaml b/Documentation/devicetree/bindings/phy/thead,th1520-
> > usb-phy.yaml
> > new file mode 100644
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/phy/thead,th1520-usb-
> > phy.yaml
> [ ... ]
> > +required:
> > +  - compatible
> > +  - "#phy-cells"
> > +  - clocks
> > +  - clock-names
> > +  - resets
> > +  - reset-names
> 
> [Severity: Medium]
> Since this is a memory-mapped PHY, shouldn't the reg property be
> included in
> the required list?
> 
> Without it, device tree nodes missing the reg property will silently
> pass
> schema validation, leading to incomplete hardware descriptions that
> fail at
> runtime.


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Re: [PATCH v2 1/2] dt-bindings: phy: add binding for T-Head TH1520 USB PHY

[Drew Fustini]

On Thu, Jul 23, 2026 at 10:09:48PM +0800, Icenowy Zheng wrote:
> 在 2026-07-23四的 08:47 +0000，sashiko-bot@kernel.org写道：
> > Thank you for your contribution! Sashiko AI review found 2 potential
> > issue(s) to consider:
> > - [Medium] The 'reg' property is omitted from the 'required' list for
> > a memory-mapped PHY.
> > - [Medium] The 'avdd33-usb3-supply' is omitted from the 'required'
> > list based on software limitations rather than hardware description.
> 
> BTW the power rail is expected to be always on at least according to
> the schematics of multiple boards, as mentioned in the next patch.
> 
> Thanks,
> Icenowy

That makes sense for the supply. However, I think the earlier point
about 'reg' property is probably valid. Woudln't all users of this
compatible need the base address?

Thanks,
Drew

Re: [PATCH v2 1/2] dt-bindings: phy: add binding for T-Head TH1520 USB PHY

[Drew Fustini]

On Thu, Jul 23, 2026 at 10:09:48PM +0800, Icenowy Zheng wrote:
> 在 2026-07-23四的 08:47 +0000，sashiko-bot@kernel.org写道：
> > Thank you for your contribution! Sashiko AI review found 2 potential
> > issue(s) to consider:
> > - [Medium] The 'reg' property is omitted from the 'required' list for
> > a memory-mapped PHY.
> > - [Medium] The 'avdd33-usb3-supply' is omitted from the 'required'
> > list based on software limitations rather than hardware description.
> 
> BTW the power rail is expected to be always on at least according to
> the schematics of multiple boards, as mentioned in the next patch.
> 
> Thanks,
> Icenowy

That makes sense for the supply. However, I think the earlier point
about 'reg' property is probably valid. Woudln't all users of this
compatible need the base address?

Thanks,
Drew

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[PATCH v2 2/2] phy: add a driver for T-Head TH1520 USB PHY

[Icenowy Zheng]

The USB PHY on T-Head TH1520 SoC is a Synopsys USB 3.0 FemtoPHY, with
some PHY parameters exported as another system controller along with it.

As a few PHY parameters' default value isn't ready to work, add a driver
configuring them before letting the PHY run, in addition to
clock/reset/regulator management.

Signed-off-by: Icenowy Zheng <zhengxingda@iscas.ac.cn>
---
Changes in v2:
- Removed unreferenced register names.
- Changed the behavior to leaving bus clock on instead of binding it to
  the regmap.
- Removed early return for reset deassert failure in phy exit callback.
- Tweaked the Kconfig item (removed default value and added "select
  REGMAP_MMIO).

 drivers/phy/Kconfig                |   1 +
 drivers/phy/Makefile               |   1 +
 drivers/phy/thead/Kconfig          |  11 ++
 drivers/phy/thead/Makefile         |   2 +
 drivers/phy/thead/phy-th1520-usb.c | 180 +++++++++++++++++++++++++++++
 5 files changed, 195 insertions(+)
 create mode 100644 drivers/phy/thead/Kconfig
 create mode 100644 drivers/phy/thead/Makefile
 create mode 100644 drivers/phy/thead/phy-th1520-usb.c

diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index 19f3b7d12b7d4..a05019020ee09 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -200,6 +200,7 @@ source "drivers/phy/st/Kconfig"
 source "drivers/phy/starfive/Kconfig"
 source "drivers/phy/sunplus/Kconfig"
 source "drivers/phy/tegra/Kconfig"
+source "drivers/phy/thead/Kconfig"
 source "drivers/phy/ti/Kconfig"
 source "drivers/phy/xilinx/Kconfig"
 
diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
index d7aa516bcc49e..0ac5b21477619 100644
--- a/drivers/phy/Makefile
+++ b/drivers/phy/Makefile
@@ -52,5 +52,6 @@ obj-$(CONFIG_GENERIC_PHY)		+= allwinner/	\
 					   starfive/	\
 					   sunplus/	\
 					   tegra/	\
+					   thead/	\
 					   ti/		\
 					   xilinx/
diff --git a/drivers/phy/thead/Kconfig b/drivers/phy/thead/Kconfig
new file mode 100644
index 0000000000000..3c2c797c50c0b
--- /dev/null
+++ b/drivers/phy/thead/Kconfig
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config PHY_TH1520_USB
+	tristate "USB PHY driver for T-Head TH1520 SoC"
+	depends on ARCH_THEAD || COMPILE_TEST
+	depends on COMMON_CLK
+	depends on HAS_IOMEM
+	depends on OF
+	depends on RESET_CONTROLLER
+	select GENERIC_PHY
+	select REGMAP_MMIO
+	help
+	  Enable support for the USB PHY on the T-Head TH1520 SoC.
diff --git a/drivers/phy/thead/Makefile b/drivers/phy/thead/Makefile
new file mode 100644
index 0000000000000..5b459bc7004bd
--- /dev/null
+++ b/drivers/phy/thead/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_PHY_TH1520_USB) += phy-th1520-usb.o
diff --git a/drivers/phy/thead/phy-th1520-usb.c b/drivers/phy/thead/phy-th1520-usb.c
new file mode 100644
index 0000000000000..802af72353a11
--- /dev/null
+++ b/drivers/phy/thead/phy-th1520-usb.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2026 Institute of Software, Chinese Academy of Sciences (ISCAS)
+ *
+ * Authors:
+ * Icenowy Zheng <zhengxingda@iscas.ac.cn>
+ */
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/reset.h>
+
+#define USB_SYSCON_OFFSET		0xf000
+
+/* All the below registers are in the USB syscon region */
+#define USB_SSP_EN			0x34
+#define USB_SSP_EN_REF_SSP_EN		BIT(0)
+
+#define USB_SYS				0x3c
+#define USB_SYS_COMMONONN		BIT(0)
+
+/* The last register according to the manual */
+#define USB_TEST_REG3			0x5c
+
+struct th1520_usb_phy {
+	struct platform_device *pdev;
+	struct phy *phy;
+	struct regmap *regmap;
+	struct clk *ref_clk;
+	struct reset_control *phy_reset;
+};
+
+static int th1520_usb_phy_init(struct phy *phy)
+{
+	struct th1520_usb_phy *th1520_phy = phy_get_drvdata(phy);
+	int ret;
+
+	ret = clk_prepare_enable(th1520_phy->ref_clk);
+	if (ret)
+		return ret;
+
+	ret = reset_control_assert(th1520_phy->phy_reset);
+	if (ret)
+		goto err_disable_clk;
+
+	/*
+	 * Do some initial PHY setup:
+	 * - Set COMMONONN to allow the PHY to automatically power down.
+	 * - Set REF_SSP_EN to enable feeding reference clock to SuperSpeed
+	 *   PHY clock PLL.
+	 */
+	regmap_set_bits(th1520_phy->regmap, USB_SYS, USB_SYS_COMMONONN);
+	regmap_set_bits(th1520_phy->regmap, USB_SSP_EN, USB_SSP_EN_REF_SSP_EN);
+
+	ret = reset_control_deassert(th1520_phy->phy_reset);
+	if (ret)
+		goto err_disable_clk;
+
+	udelay(10);
+
+	return 0;
+
+err_disable_clk:
+	clk_disable_unprepare(th1520_phy->ref_clk);
+	return ret;
+}
+
+static int th1520_usb_phy_exit(struct phy *phy)
+{
+	struct th1520_usb_phy *th1520_phy = phy_get_drvdata(phy);
+	int ret;
+
+	ret = reset_control_assert(th1520_phy->phy_reset);
+	clk_disable_unprepare(th1520_phy->ref_clk);
+
+	return ret;
+}
+
+static const struct phy_ops th1520_usb_phy_ops = {
+	.init		= th1520_usb_phy_init,
+	.exit		= th1520_usb_phy_exit,
+	.owner		= THIS_MODULE,
+};
+
+static const struct regmap_config phy_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = USB_TEST_REG3,
+};
+
+static int th1520_usb_phy_probe(struct platform_device *pdev)
+{
+	struct phy_provider *phy_provider;
+	struct device *dev = &pdev->dev;
+	struct th1520_usb_phy *th1520_phy;
+	struct reset_control *bus_reset;
+	struct clk *bus_clk;
+	void __iomem *base;
+	int ret;
+
+	th1520_phy = devm_kzalloc(dev, sizeof(*th1520_phy), GFP_KERNEL);
+	if (!th1520_phy)
+		return -ENOMEM;
+
+	th1520_phy->pdev = pdev;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	th1520_phy->ref_clk = devm_clk_get(dev, "ref");
+	if (IS_ERR(th1520_phy->ref_clk))
+		return PTR_ERR(th1520_phy->ref_clk);
+
+	/* Enable the bus clock and leave it that way */
+	bus_clk = devm_clk_get_enabled(dev, "bus");
+	if (IS_ERR(bus_clk))
+		return PTR_ERR(bus_clk);
+
+	/* De-assert the bus reset and leave it that way */
+	bus_reset = devm_reset_control_get_exclusive_deasserted(dev, "bus");
+	if (IS_ERR(bus_reset))
+		return PTR_ERR(bus_reset);
+
+	th1520_phy->phy_reset = devm_reset_control_get_exclusive(dev, "phy");
+	if (IS_ERR(th1520_phy->phy_reset))
+		return PTR_ERR(th1520_phy->phy_reset);
+
+	/*
+	 * Schematics of several boards (Lichee Module 4A/Milk-V Meles)
+	 * describe this power rail as always-on.
+	 */
+	ret = devm_regulator_get_enable(dev, "avdd33-usb3");
+	if (ret)
+		return ret;
+
+	th1520_phy->regmap = devm_regmap_init_mmio(dev,
+						   base + USB_SYSCON_OFFSET,
+						   &phy_regmap_config);
+	if (IS_ERR(th1520_phy->regmap))
+		return dev_err_probe(dev, PTR_ERR(th1520_phy->regmap),
+				     "Failed to init regmap\n");
+
+	th1520_phy->phy = devm_phy_create(dev, dev->of_node, &th1520_usb_phy_ops);
+	if (IS_ERR(th1520_phy->phy)) {
+		dev_err(dev, "failed to create PHY\n");
+		return PTR_ERR(th1520_phy->phy);
+	}
+
+	phy_set_drvdata(th1520_phy->phy, th1520_phy);
+
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static const struct of_device_id th1520_usb_phy_of_table[] = {
+	{ .compatible = "thead,th1520-usb-phy" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, th1520_usb_phy_of_table);
+
+static struct platform_driver th1520_usb_phy_driver = {
+	.driver = {
+		.name = "th1520-usb-phy",
+		.of_match_table = th1520_usb_phy_of_table,
+	},
+	.probe = th1520_usb_phy_probe,
+};
+
+module_platform_driver(th1520_usb_phy_driver);
+
+MODULE_DESCRIPTION("T-Head TH1520 USB PHY driver");
+MODULE_LICENSE("GPL");
-- 
2.52.0

[PATCH v2 2/2] phy: add a driver for T-Head TH1520 USB PHY

[Icenowy Zheng]

The USB PHY on T-Head TH1520 SoC is a Synopsys USB 3.0 FemtoPHY, with
some PHY parameters exported as another system controller along with it.

As a few PHY parameters' default value isn't ready to work, add a driver
configuring them before letting the PHY run, in addition to
clock/reset/regulator management.

Signed-off-by: Icenowy Zheng <zhengxingda@iscas.ac.cn>
---
Changes in v2:
- Removed unreferenced register names.
- Changed the behavior to leaving bus clock on instead of binding it to
  the regmap.
- Removed early return for reset deassert failure in phy exit callback.
- Tweaked the Kconfig item (removed default value and added "select
  REGMAP_MMIO).

 drivers/phy/Kconfig                |   1 +
 drivers/phy/Makefile               |   1 +
 drivers/phy/thead/Kconfig          |  11 ++
 drivers/phy/thead/Makefile         |   2 +
 drivers/phy/thead/phy-th1520-usb.c | 180 +++++++++++++++++++++++++++++
 5 files changed, 195 insertions(+)
 create mode 100644 drivers/phy/thead/Kconfig
 create mode 100644 drivers/phy/thead/Makefile
 create mode 100644 drivers/phy/thead/phy-th1520-usb.c

diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index 19f3b7d12b7d4..a05019020ee09 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -200,6 +200,7 @@ source "drivers/phy/st/Kconfig"
 source "drivers/phy/starfive/Kconfig"
 source "drivers/phy/sunplus/Kconfig"
 source "drivers/phy/tegra/Kconfig"
+source "drivers/phy/thead/Kconfig"
 source "drivers/phy/ti/Kconfig"
 source "drivers/phy/xilinx/Kconfig"
 
diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
index d7aa516bcc49e..0ac5b21477619 100644
--- a/drivers/phy/Makefile
+++ b/drivers/phy/Makefile
@@ -52,5 +52,6 @@ obj-$(CONFIG_GENERIC_PHY)		+= allwinner/	\
 					   starfive/	\
 					   sunplus/	\
 					   tegra/	\
+					   thead/	\
 					   ti/		\
 					   xilinx/
diff --git a/drivers/phy/thead/Kconfig b/drivers/phy/thead/Kconfig
new file mode 100644
index 0000000000000..3c2c797c50c0b
--- /dev/null
+++ b/drivers/phy/thead/Kconfig
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config PHY_TH1520_USB
+	tristate "USB PHY driver for T-Head TH1520 SoC"
+	depends on ARCH_THEAD || COMPILE_TEST
+	depends on COMMON_CLK
+	depends on HAS_IOMEM
+	depends on OF
+	depends on RESET_CONTROLLER
+	select GENERIC_PHY
+	select REGMAP_MMIO
+	help
+	  Enable support for the USB PHY on the T-Head TH1520 SoC.
diff --git a/drivers/phy/thead/Makefile b/drivers/phy/thead/Makefile
new file mode 100644
index 0000000000000..5b459bc7004bd
--- /dev/null
+++ b/drivers/phy/thead/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_PHY_TH1520_USB) += phy-th1520-usb.o
diff --git a/drivers/phy/thead/phy-th1520-usb.c b/drivers/phy/thead/phy-th1520-usb.c
new file mode 100644
index 0000000000000..802af72353a11
--- /dev/null
+++ b/drivers/phy/thead/phy-th1520-usb.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2026 Institute of Software, Chinese Academy of Sciences (ISCAS)
+ *
+ * Authors:
+ * Icenowy Zheng <zhengxingda@iscas.ac.cn>
+ */
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/reset.h>
+
+#define USB_SYSCON_OFFSET		0xf000
+
+/* All the below registers are in the USB syscon region */
+#define USB_SSP_EN			0x34
+#define USB_SSP_EN_REF_SSP_EN		BIT(0)
+
+#define USB_SYS				0x3c
+#define USB_SYS_COMMONONN		BIT(0)
+
+/* The last register according to the manual */
+#define USB_TEST_REG3			0x5c
+
+struct th1520_usb_phy {
+	struct platform_device *pdev;
+	struct phy *phy;
+	struct regmap *regmap;
+	struct clk *ref_clk;
+	struct reset_control *phy_reset;
+};
+
+static int th1520_usb_phy_init(struct phy *phy)
+{
+	struct th1520_usb_phy *th1520_phy = phy_get_drvdata(phy);
+	int ret;
+
+	ret = clk_prepare_enable(th1520_phy->ref_clk);
+	if (ret)
+		return ret;
+
+	ret = reset_control_assert(th1520_phy->phy_reset);
+	if (ret)
+		goto err_disable_clk;
+
+	/*
+	 * Do some initial PHY setup:
+	 * - Set COMMONONN to allow the PHY to automatically power down.
+	 * - Set REF_SSP_EN to enable feeding reference clock to SuperSpeed
+	 *   PHY clock PLL.
+	 */
+	regmap_set_bits(th1520_phy->regmap, USB_SYS, USB_SYS_COMMONONN);
+	regmap_set_bits(th1520_phy->regmap, USB_SSP_EN, USB_SSP_EN_REF_SSP_EN);
+
+	ret = reset_control_deassert(th1520_phy->phy_reset);
+	if (ret)
+		goto err_disable_clk;
+
+	udelay(10);
+
+	return 0;
+
+err_disable_clk:
+	clk_disable_unprepare(th1520_phy->ref_clk);
+	return ret;
+}
+
+static int th1520_usb_phy_exit(struct phy *phy)
+{
+	struct th1520_usb_phy *th1520_phy = phy_get_drvdata(phy);
+	int ret;
+
+	ret = reset_control_assert(th1520_phy->phy_reset);
+	clk_disable_unprepare(th1520_phy->ref_clk);
+
+	return ret;
+}
+
+static const struct phy_ops th1520_usb_phy_ops = {
+	.init		= th1520_usb_phy_init,
+	.exit		= th1520_usb_phy_exit,
+	.owner		= THIS_MODULE,
+};
+
+static const struct regmap_config phy_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = USB_TEST_REG3,
+};
+
+static int th1520_usb_phy_probe(struct platform_device *pdev)
+{
+	struct phy_provider *phy_provider;
+	struct device *dev = &pdev->dev;
+	struct th1520_usb_phy *th1520_phy;
+	struct reset_control *bus_reset;
+	struct clk *bus_clk;
+	void __iomem *base;
+	int ret;
+
+	th1520_phy = devm_kzalloc(dev, sizeof(*th1520_phy), GFP_KERNEL);
+	if (!th1520_phy)
+		return -ENOMEM;
+
+	th1520_phy->pdev = pdev;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	th1520_phy->ref_clk = devm_clk_get(dev, "ref");
+	if (IS_ERR(th1520_phy->ref_clk))
+		return PTR_ERR(th1520_phy->ref_clk);
+
+	/* Enable the bus clock and leave it that way */
+	bus_clk = devm_clk_get_enabled(dev, "bus");
+	if (IS_ERR(bus_clk))
+		return PTR_ERR(bus_clk);
+
+	/* De-assert the bus reset and leave it that way */
+	bus_reset = devm_reset_control_get_exclusive_deasserted(dev, "bus");
+	if (IS_ERR(bus_reset))
+		return PTR_ERR(bus_reset);
+
+	th1520_phy->phy_reset = devm_reset_control_get_exclusive(dev, "phy");
+	if (IS_ERR(th1520_phy->phy_reset))
+		return PTR_ERR(th1520_phy->phy_reset);
+
+	/*
+	 * Schematics of several boards (Lichee Module 4A/Milk-V Meles)
+	 * describe this power rail as always-on.
+	 */
+	ret = devm_regulator_get_enable(dev, "avdd33-usb3");
+	if (ret)
+		return ret;
+
+	th1520_phy->regmap = devm_regmap_init_mmio(dev,
+						   base + USB_SYSCON_OFFSET,
+						   &phy_regmap_config);
+	if (IS_ERR(th1520_phy->regmap))
+		return dev_err_probe(dev, PTR_ERR(th1520_phy->regmap),
+				     "Failed to init regmap\n");
+
+	th1520_phy->phy = devm_phy_create(dev, dev->of_node, &th1520_usb_phy_ops);
+	if (IS_ERR(th1520_phy->phy)) {
+		dev_err(dev, "failed to create PHY\n");
+		return PTR_ERR(th1520_phy->phy);
+	}
+
+	phy_set_drvdata(th1520_phy->phy, th1520_phy);
+
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static const struct of_device_id th1520_usb_phy_of_table[] = {
+	{ .compatible = "thead,th1520-usb-phy" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, th1520_usb_phy_of_table);
+
+static struct platform_driver th1520_usb_phy_driver = {
+	.driver = {
+		.name = "th1520-usb-phy",
+		.of_match_table = th1520_usb_phy_of_table,
+	},
+	.probe = th1520_usb_phy_probe,
+};
+
+module_platform_driver(th1520_usb_phy_driver);
+
+MODULE_DESCRIPTION("T-Head TH1520 USB PHY driver");
+MODULE_LICENSE("GPL");
-- 
2.52.0


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Re: [PATCH v2 2/2] phy: add a driver for T-Head TH1520 USB PHY

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Missing explicit inclusion of `<linux/delay.h>` for `udelay()`.
--

--- Patch [2]: [PATCH v2 2/2] phy: add a driver for T-Head TH1520 USB PHY ---
commit 0212e7cbab21327c62c749f25a7e96aa29c7d1a3
Author: Icenowy Zheng <zhengxingda@iscas.ac.cn>

phy: add a driver for T-Head TH1520 USB PHY
    
The USB PHY on T-Head TH1520 SoC is a Synopsys USB 3.0 FemtoPHY, with
some PHY parameters exported as another system controller along with it.
This commit adds a driver configuring these parameters before letting the
PHY run, in addition to clock/reset/regulator management.

> diff --git a/drivers/phy/thead/phy-th1520-usb.c b/drivers/phy/thead/phy-th1520-usb.c
> new file mode 100644
> index 0000000000000..802af72353a11
> --- /dev/null
> +++ b/drivers/phy/thead/phy-th1520-usb.c
> @@ -0,0 +1,180 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2026 Institute of Software, Chinese Academy of Sciences (ISCAS)
> + *
> + * Authors:
> + * Icenowy Zheng <zhengxingda@iscas.ac.cn>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/reset.h>

[ ... ]

> +static int th1520_usb_phy_init(struct phy *phy)
> +{
> +	struct th1520_usb_phy *th1520_phy = phy_get_drvdata(phy);
> +	int ret;
> +
> +	ret = clk_prepare_enable(th1520_phy->ref_clk);
> +	if (ret)
> +		return ret;
> +
> +	ret = reset_control_assert(th1520_phy->phy_reset);
> +	if (ret)
> +		goto err_disable_clk;
> +
> +	/*
> +	 * Do some initial PHY setup:
> +	 * - Set COMMONONN to allow the PHY to automatically power down.
> +	 * - Set REF_SSP_EN to enable feeding reference clock to SuperSpeed
> +	 *   PHY clock PLL.
> +	 */
> +	regmap_set_bits(th1520_phy->regmap, USB_SYS, USB_SYS_COMMONONN);
> +	regmap_set_bits(th1520_phy->regmap, USB_SSP_EN, USB_SSP_EN_REF_SSP_EN);
> +
> +	ret = reset_control_deassert(th1520_phy->phy_reset);
> +	if (ret)
> +		goto err_disable_clk;
> +
> +	udelay(10);

[Severity: Low]
This isn't a bug, but this code uses udelay() without explicitly including
<linux/delay.h>.

While it currently compiles due to indirect inclusions, should the header be
explicitly included to prevent build failures if the include chain is later
refactored?

> +
> +	return 0;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260723084316.3573714-1-zhengxingda@iscas.ac.cn?part=2

Re: [PATCH v2 2/2] phy: add a driver for T-Head TH1520 USB PHY

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Missing explicit inclusion of `<linux/delay.h>` for `udelay()`.
--

--- Patch [2]: [PATCH v2 2/2] phy: add a driver for T-Head TH1520 USB PHY ---
commit 0212e7cbab21327c62c749f25a7e96aa29c7d1a3
Author: Icenowy Zheng <zhengxingda@iscas.ac.cn>

phy: add a driver for T-Head TH1520 USB PHY
    
The USB PHY on T-Head TH1520 SoC is a Synopsys USB 3.0 FemtoPHY, with
some PHY parameters exported as another system controller along with it.
This commit adds a driver configuring these parameters before letting the
PHY run, in addition to clock/reset/regulator management.

> diff --git a/drivers/phy/thead/phy-th1520-usb.c b/drivers/phy/thead/phy-th1520-usb.c
> new file mode 100644
> index 0000000000000..802af72353a11
> --- /dev/null
> +++ b/drivers/phy/thead/phy-th1520-usb.c
> @@ -0,0 +1,180 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2026 Institute of Software, Chinese Academy of Sciences (ISCAS)
> + *
> + * Authors:
> + * Icenowy Zheng <zhengxingda@iscas.ac.cn>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/reset.h>

[ ... ]

> +static int th1520_usb_phy_init(struct phy *phy)
> +{
> +	struct th1520_usb_phy *th1520_phy = phy_get_drvdata(phy);
> +	int ret;
> +
> +	ret = clk_prepare_enable(th1520_phy->ref_clk);
> +	if (ret)
> +		return ret;
> +
> +	ret = reset_control_assert(th1520_phy->phy_reset);
> +	if (ret)
> +		goto err_disable_clk;
> +
> +	/*
> +	 * Do some initial PHY setup:
> +	 * - Set COMMONONN to allow the PHY to automatically power down.
> +	 * - Set REF_SSP_EN to enable feeding reference clock to SuperSpeed
> +	 *   PHY clock PLL.
> +	 */
> +	regmap_set_bits(th1520_phy->regmap, USB_SYS, USB_SYS_COMMONONN);
> +	regmap_set_bits(th1520_phy->regmap, USB_SSP_EN, USB_SSP_EN_REF_SSP_EN);
> +
> +	ret = reset_control_deassert(th1520_phy->phy_reset);
> +	if (ret)
> +		goto err_disable_clk;
> +
> +	udelay(10);

[Severity: Low]
This isn't a bug, but this code uses udelay() without explicitly including
<linux/delay.h>.

While it currently compiles due to indirect inclusions, should the header be
explicitly included to prevent build failures if the include chain is later
refactored?

> +
> +	return 0;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260723084316.3573714-1-zhengxingda@iscas.ac.cn?part=2

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Re: [PATCH v2 2/2] phy: add a driver for T-Head TH1520 USB PHY

[Drew Fustini]

On Thu, Jul 23, 2026 at 04:43:16PM +0800, Icenowy Zheng wrote:
> The USB PHY on T-Head TH1520 SoC is a Synopsys USB 3.0 FemtoPHY, with
> some PHY parameters exported as another system controller along with it.
> 
> As a few PHY parameters' default value isn't ready to work, add a driver
> configuring them before letting the PHY run, in addition to
> clock/reset/regulator management.

The second paragragh might read better as:

"A few PHY parameters have unusable defaults. Add a driver that programs
them before releasing the PHY from reset. [..]"

Thanks,
Drew

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Re: [PATCH v2 2/2] phy: add a driver for T-Head TH1520 USB PHY

[Drew Fustini]

On Thu, Jul 23, 2026 at 04:43:16PM +0800, Icenowy Zheng wrote:
> The USB PHY on T-Head TH1520 SoC is a Synopsys USB 3.0 FemtoPHY, with
> some PHY parameters exported as another system controller along with it.
> 
> As a few PHY parameters' default value isn't ready to work, add a driver
> configuring them before letting the PHY run, in addition to
> clock/reset/regulator management.

The second paragragh might read better as:

"A few PHY parameters have unusable defaults. Add a driver that programs
them before releasing the PHY from reset. [..]"

Thanks,
Drew