[PATCH v5 0/6] RTL9300 support for reboot and i2c

[PATCH v5 0/6] RTL9300 support for reboot and i2c

[Chris Packham]

As requested I've combined my two series into a single one to provide some
better context for reviewers. I'm not sure which trees the patches should go in
via. The first two are reasonably independent and could go in via linux-pm. I
guess technically the last one could go via linux-i2c but it needs the and the
bindings/dts updates which would probably make sense to come via linux-mips.

--
2.46.1

Chris Packham (6):
  dt-bindings: reset: syscon-reboot: Add reg property
  power: reset: syscon-reboot: Accept reg property
  dt-bindings: mfd: Add Realtek RTL9300 switch peripherals
  mips: dts: realtek: Add syscon-reboot node
  mips: dts: realtek: Add I2C controllers
  i2c: Add driver for the RTL9300 I2C controller

 .../bindings/i2c/realtek,rtl9300-i2c.yaml     |  98 ++++
 .../bindings/mfd/realtek,rtl9300-switch.yaml  | 115 +++++
 .../bindings/power/reset/syscon-reboot.yaml   |  11 +-
 MAINTAINERS                                   |   7 +
 .../cameo-rtl9302c-2x-rtl8224-2xge.dts        |   2 +-
 arch/mips/boot/dts/realtek/rtl9302c.dtsi      |  15 +
 arch/mips/boot/dts/realtek/rtl930x.dtsi       |  29 ++
 drivers/i2c/busses/Kconfig                    |  10 +
 drivers/i2c/busses/Makefile                   |   1 +
 drivers/i2c/busses/i2c-rtl9300.c              | 422 ++++++++++++++++++
 drivers/power/reset/syscon-reboot.c           |   3 +-
 11 files changed, 710 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/i2c/realtek,rtl9300-i2c.yaml
 create mode 100644 Documentation/devicetree/bindings/mfd/realtek,rtl9300-switch.yaml
 create mode 100644 arch/mips/boot/dts/realtek/rtl9302c.dtsi
 create mode 100644 drivers/i2c/busses/i2c-rtl9300.c

-- 
2.46.2

[PATCH v5 1/6] dt-bindings: reset: syscon-reboot: Add reg property

[Chris Packham]

The syscon-reboot binding used 'offset' for historical reasons. Having a
reg property is appropriate when these nodes are children of a MMIO bus.
Add a reg property and modify the constraints so that one of 'reg' or
'offset' is expected.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---

Notes:
    Changes in v5:
    - New, suggested by Krzysztof

 .../bindings/power/reset/syscon-reboot.yaml           | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/power/reset/syscon-reboot.yaml b/Documentation/devicetree/bindings/power/reset/syscon-reboot.yaml
index 75061124d9a8..19d3093e6cd2 100644
--- a/Documentation/devicetree/bindings/power/reset/syscon-reboot.yaml
+++ b/Documentation/devicetree/bindings/power/reset/syscon-reboot.yaml
@@ -31,6 +31,10 @@ properties:
     $ref: /schemas/types.yaml#/definitions/uint32
     description: Offset in the register map for the reboot register (in bytes).
 
+  reg:
+    maxItems: 1
+    description: Base address and size for the reboot register.
+
   regmap:
     $ref: /schemas/types.yaml#/definitions/phandle
     deprecated: true
@@ -45,9 +49,14 @@ properties:
   priority:
     default: 192
 
+oneOf:
+  - required:
+      - offset
+  - required:
+      - reg
+
 required:
   - compatible
-  - offset
 
 additionalProperties: false
 
-- 
2.46.2

Re: [PATCH v5 1/6] dt-bindings: reset: syscon-reboot: Add reg property

[Krzysztof Kozlowski]

On Thu, Sep 26, 2024 at 09:58:42AM +1200, Chris Packham wrote:
> The syscon-reboot binding used 'offset' for historical reasons. Having a
> reg property is appropriate when these nodes are children of a MMIO bus.
> Add a reg property and modify the constraints so that one of 'reg' or
> 'offset' is expected.
> 
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> ---
> 
> Notes:
>     Changes in v5:
>     - New, suggested by Krzysztof

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

[PATCH v5 2/6] power: reset: syscon-reboot: Accept reg property

[Chris Packham]

For historical reasons syscon-reboot has used an 'offset' property. As a
child on a MMIO bus having a 'reg' property is more appropriate. Accept
'reg' as an alternative to 'offset'.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---

Notes:
    Changes in v5:
    - New, making the driver accept the updated binding

 drivers/power/reset/syscon-reboot.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/power/reset/syscon-reboot.c b/drivers/power/reset/syscon-reboot.c
index 4d622c19bc48..d623d77e657e 100644
--- a/drivers/power/reset/syscon-reboot.c
+++ b/drivers/power/reset/syscon-reboot.c
@@ -61,7 +61,8 @@ static int syscon_reboot_probe(struct platform_device *pdev)
 		priority = 192;
 
 	if (of_property_read_u32(pdev->dev.of_node, "offset", &ctx->offset))
-		return -EINVAL;
+		if (of_property_read_u32(pdev->dev.of_node, "reg", &ctx->offset))
+			return -EINVAL;
 
 	value_err = of_property_read_u32(pdev->dev.of_node, "value", &ctx->value);
 	mask_err = of_property_read_u32(pdev->dev.of_node, "mask", &ctx->mask);
-- 
2.46.2

Re: [PATCH v5 2/6] power: reset: syscon-reboot: Accept reg property

[Krzysztof Kozlowski]

On Thu, Sep 26, 2024 at 09:58:43AM +1200, Chris Packham wrote:
> For historical reasons syscon-reboot has used an 'offset' property. As a
> child on a MMIO bus having a 'reg' property is more appropriate. Accept
> 'reg' as an alternative to 'offset'.
> 
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> ---
> 
> Notes:
>     Changes in v5:
>     - New, making the driver accept the updated binding

Thanks for doing this.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

[PATCH v5 3/6] dt-bindings: mfd: Add Realtek RTL9300 switch peripherals

[Chris Packham]

Add device tree schema for the Realtek RTL9300 switches. The RTL9300
family is made up of the RTL9301, RTL9302B, RTL9302C and RTL9303. These
have the same SoC differ in the Ethernet switch/SERDES arrangement.

Currently the only supported features are the syscon-reboot and i2c
controllers. The syscon-reboot is needed to be able to reboot the board.
The I2C controllers are slightly unusual because they each own an SCL
pin (GPIO8 for the first controller, GPIO 17 for the second) but have 8
common SDA pins which can be assigned to either controller (but not
both).

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---

Notes:
    Changes in v5:
      I've combined the two series I had in flight so this is the
      combination of adding the switch syscon, the reboot and i2c. It makes
      the changelog a bit meaningless so I've dropped the earlier
      commentary.
    
      As requested I've put a more complete example in the main
      rtl9300-switch.yaml.
    
      I've kept rtl9300-i2c.yaml separate for now but link to it with a $ref
      from rtl9300-switch.yaml to reduce clutter. The example in
      rtl9300-i2c.yaml is technically duplicating part of the example from
      rtl9300-switch.yaml but I feel it's nice to be able to see the example
      next to where the properties are defined.

 .../bindings/i2c/realtek,rtl9300-i2c.yaml     |  98 +++++++++++++++
 .../bindings/mfd/realtek,rtl9300-switch.yaml  | 115 ++++++++++++++++++
 2 files changed, 213 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/realtek,rtl9300-i2c.yaml
 create mode 100644 Documentation/devicetree/bindings/mfd/realtek,rtl9300-switch.yaml

diff --git a/Documentation/devicetree/bindings/i2c/realtek,rtl9300-i2c.yaml b/Documentation/devicetree/bindings/i2c/realtek,rtl9300-i2c.yaml
new file mode 100644
index 000000000000..e8cf328b2710
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/realtek,rtl9300-i2c.yaml
@@ -0,0 +1,98 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/i2c/realtek,rtl9300-i2c.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Realtek RTL I2C Controller
+
+maintainers:
+  - Chris Packham <chris.packham@alliedtelesis.co.nz>
+
+description:
+  The RTL9300 SoC has two I2C controllers. Each of these has an SCL line (which
+  if not-used for SCL can be a GPIO). There are 8 common SDA lines that can be
+  assigned to either I2C controller.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - realtek,rtl9301-i2c
+          - realtek,rtl9302b-i2c
+          - realtek,rtl9302c-i2c
+          - realtek,rtl9303-i2c
+      - const: realtek,rtl9300-i2c
+
+  reg:
+    description: Register offset and size this I2C controller.
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+patternProperties:
+  '^i2c@[0-7]$':
+    $ref: /schemas/i2c/i2c-controller.yaml
+    unevaluatedProperties: false
+
+    properties:
+      reg:
+        description: The SDA pin associated with the I2C bus.
+        maxItems: 1
+
+    required:
+      - reg
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    i2c@36c {
+      compatible = "realtek,rtl9302c-i2c", "realtek,rtl9300-i2c";
+      reg = <0x36c 0x14>;
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      i2c@0 {
+        reg = <0>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+        gpio@20 {
+          compatible = "nxp,pca9555";
+          gpio-controller;
+          #gpio-cells = <2>;
+          reg = <0x20>;
+        };
+      };
+
+      i2c@2 {
+        reg = <2>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+        gpio@20 {
+          compatible = "nxp,pca9555";
+          gpio-controller;
+          #gpio-cells = <2>;
+          reg = <0x20>;
+        };
+      };
+    };
+    i2c@388 {
+      compatible = "realtek,rtl9302c-i2c", "realtek,rtl9300-i2c";
+      reg = <0x388 0x14>;
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      i2c@7 {
+        reg = <7>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+      };
+    };
diff --git a/Documentation/devicetree/bindings/mfd/realtek,rtl9300-switch.yaml b/Documentation/devicetree/bindings/mfd/realtek,rtl9300-switch.yaml
new file mode 100644
index 000000000000..a8e75b1bd286
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/realtek,rtl9300-switch.yaml
@@ -0,0 +1,115 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/realtek,rtl9300-switch.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Realtek Switch with Internal CPU
+
+maintainers:
+  - Chris Packham <chris.packham@alliedtelesis.co.nz>
+
+description:
+  The RTL9302 is an Ethernet switch with an integrated CPU. A number of
+  different peripherals are accessed through a common register block,
+  represented here as a syscon node.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - realtek,rtl9301-switch
+          - realtek,rtl9302b-switch
+          - realtek,rtl9302c-switch
+          - realtek,rtl9303-switch
+      - const: realtek,rtl9300-switch
+      - const: syscon
+      - const: simple-mfd
+
+  reg:
+    maxItems: 1
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 1
+
+patternProperties:
+  'reboot@[0-9a-f]+$':
+    $ref: /schemas/power/reset/syscon-reboot.yaml#
+
+  'i2c@[0-9a-f]+$':
+    $ref: /schemas/i2c/realtek,rtl9300-i2c.yaml#
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    ethernet-switch@1b000000 {
+      compatible = "realtek,rtl9302c-switch", "realtek,rtl9300-switch", "syscon", "simple-mfd";
+      reg = <0x1b000000 0x10000>;
+      #address-cells = <1>;
+      #size-cells = <1>;
+
+      reboot@c {
+        compatible = "syscon-reboot";
+        reg = <0x0c 0x4>;
+        value = <0x01>;
+      };
+
+      i2c@36c {
+        compatible = "realtek,rtl9302c-i2c", "realtek,rtl9300-i2c";
+        reg = <0x36c 0x14>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        i2c@0 {
+          reg = <0>;
+          #address-cells = <1>;
+          #size-cells = <0>;
+          gpio@20 {
+            compatible = "nxp,pca9555";
+            gpio-controller;
+            #gpio-cells = <2>;
+            reg = <0x20>;
+          };
+        };
+
+        i2c@2 {
+          reg = <2>;
+          #address-cells = <1>;
+          #size-cells = <0>;
+          gpio@20 {
+            compatible = "nxp,pca9555";
+            gpio-controller;
+            #gpio-cells = <2>;
+            reg = <0x20>;
+          };
+        };
+      };
+
+      i2c@388 {
+        compatible = "realtek,rtl9302c-i2c", "realtek,rtl9300-i2c";
+        reg = <0x388 0x14>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        i2c@7 {
+          reg = <7>;
+          #address-cells = <1>;
+          #size-cells = <0>;
+          gpio@20 {
+            compatible = "nxp,pca9555";
+            gpio-controller;
+            #gpio-cells = <2>;
+            reg = <0x20>;
+          };
+        };
+      };
+    };
+
-- 
2.46.2

Re: [PATCH v5 3/6] dt-bindings: mfd: Add Realtek RTL9300 switch peripherals

[Krzysztof Kozlowski]

On Thu, Sep 26, 2024 at 09:58:44AM +1200, Chris Packham wrote:
> Add device tree schema for the Realtek RTL9300 switches. The RTL9300
> family is made up of the RTL9301, RTL9302B, RTL9302C and RTL9303. These
> have the same SoC differ in the Ethernet switch/SERDES arrangement.
> 
> Currently the only supported features are the syscon-reboot and i2c
> controllers. The syscon-reboot is needed to be able to reboot the board.
> The I2C controllers are slightly unusual because they each own an SCL
> pin (GPIO8 for the first controller, GPIO 17 for the second) but have 8
> common SDA pins which can be assigned to either controller (but not
> both).
> 
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> ---
> 
> Notes:
>     Changes in v5:
>       I've combined the two series I had in flight so this is the
>       combination of adding the switch syscon, the reboot and i2c. It makes
>       the changelog a bit meaningless so I've dropped the earlier
>       commentary.
>     
>       As requested I've put a more complete example in the main
>       rtl9300-switch.yaml.
>     
>       I've kept rtl9300-i2c.yaml separate for now but link to it with a $ref
>       from rtl9300-switch.yaml to reduce clutter. The example in
>       rtl9300-i2c.yaml is technically duplicating part of the example from
>       rtl9300-switch.yaml but I feel it's nice to be able to see the example
>       next to where the properties are defined.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

Re: [PATCH v5 3/6] dt-bindings: mfd: Add Realtek RTL9300 switch peripherals

[Lee Jones]

Intentional top-post.

These replies all came in without the original mail.

Does anyone have any idea why that would have been?

On Thu, 26 Sep 2024, Krzysztof Kozlowski wrote:

> On Thu, Sep 26, 2024 at 09:58:44AM +1200, Chris Packham wrote:
> > Add device tree schema for the Realtek RTL9300 switches. The RTL9300
> > family is made up of the RTL9301, RTL9302B, RTL9302C and RTL9303. These
> > have the same SoC differ in the Ethernet switch/SERDES arrangement.
> > 
> > Currently the only supported features are the syscon-reboot and i2c
> > controllers. The syscon-reboot is needed to be able to reboot the board.
> > The I2C controllers are slightly unusual because they each own an SCL
> > pin (GPIO8 for the first controller, GPIO 17 for the second) but have 8
> > common SDA pins which can be assigned to either controller (but not
> > both).
> > 
> > Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> > ---
> > 
> > Notes:
> >     Changes in v5:
> >       I've combined the two series I had in flight so this is the
> >       combination of adding the switch syscon, the reboot and i2c. It makes
> >       the changelog a bit meaningless so I've dropped the earlier
> >       commentary.
> >     
> >       As requested I've put a more complete example in the main
> >       rtl9300-switch.yaml.
> >     
> >       I've kept rtl9300-i2c.yaml separate for now but link to it with a $ref
> >       from rtl9300-switch.yaml to reduce clutter. The example in
> >       rtl9300-i2c.yaml is technically duplicating part of the example from
> >       rtl9300-switch.yaml but I feel it's nice to be able to see the example
> >       next to where the properties are defined.
> 
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> 
> Best regards,
> Krzysztof
> 

-- 
Lee Jones [李琼斯]

Re: [PATCH v5 3/6] dt-bindings: mfd: Add Realtek RTL9300 switch peripherals

[Krzysztof Kozlowski]

On 26/09/2024 09:45, Lee Jones wrote:
> Intentional top-post.
> 
> These replies all came in without the original mail.
> 
> Does anyone have any idea why that would have been?

Spam folder?

Lists got them:
https://lore.kernel.org/all/20240925215847.3594898-4-chris.packham@alliedtelesis.co.nz/

Best regards,
Krzysztof

[PATCH v5 4/6] mips: dts: realtek: Add syscon-reboot node

[Chris Packham]

The board level reset on systems using the RTL9302 can be driven via the
switch. Use a syscon-reboot node to represent this.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---

Notes:
    Changes in v5:
    - Krzysztof did technically give a r-by on v4 but given the changes to
      the rest of the series I haven't included it.
    - Use reg instead of offset
    - Add a rtl9302c.dtsi for the specific chip which pulls in the generic
      rtl930x.dtsi and updates a few of the compatibles on the way through.
    - Update Cameo board to use rtl9302c.dtsi
    Changes in v4:
    - None
    Changes in v3:
    - None
    Changes in v2:
    - drop redundant status = "okay"

 .../dts/realtek/cameo-rtl9302c-2x-rtl8224-2xge.dts  |  2 +-
 arch/mips/boot/dts/realtek/rtl9302c.dtsi            |  7 +++++++
 arch/mips/boot/dts/realtek/rtl930x.dtsi             | 13 +++++++++++++
 3 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 arch/mips/boot/dts/realtek/rtl9302c.dtsi

diff --git a/arch/mips/boot/dts/realtek/cameo-rtl9302c-2x-rtl8224-2xge.dts b/arch/mips/boot/dts/realtek/cameo-rtl9302c-2x-rtl8224-2xge.dts
index 77d2566545f2..6789bf374044 100644
--- a/arch/mips/boot/dts/realtek/cameo-rtl9302c-2x-rtl8224-2xge.dts
+++ b/arch/mips/boot/dts/realtek/cameo-rtl9302c-2x-rtl8224-2xge.dts
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 /dts-v1/;
 
-#include "rtl930x.dtsi"
+#include "rtl9302c.dtsi"
 
 #include <dt-bindings/input/input.h>
 #include <dt-bindings/gpio/gpio.h>
diff --git a/arch/mips/boot/dts/realtek/rtl9302c.dtsi b/arch/mips/boot/dts/realtek/rtl9302c.dtsi
new file mode 100644
index 000000000000..80d9f407e758
--- /dev/null
+++ b/arch/mips/boot/dts/realtek/rtl9302c.dtsi
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR BSD-2-Clause
+
+#include "rtl930x.dtsi"
+
+&switch0 {
+	compatible = "realtek,rtl9302c-switch", "realtek,rtl9300-switch", "syscon", "simple-mfd";
+};
diff --git a/arch/mips/boot/dts/realtek/rtl930x.dtsi b/arch/mips/boot/dts/realtek/rtl930x.dtsi
index f271940f82be..89b8854596cd 100644
--- a/arch/mips/boot/dts/realtek/rtl930x.dtsi
+++ b/arch/mips/boot/dts/realtek/rtl930x.dtsi
@@ -29,6 +29,19 @@ lx_clk: clock-175mhz {
 		#clock-cells = <0>;
 		clock-frequency  = <175000000>;
 	};
+
+	switch0: switch@1b000000 {
+		compatible = "realtek,rtl9300-switch", "syscon", "simple-mfd";
+		reg = <0x1b000000 0x10000>;
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		reboot@c {
+			compatible = "syscon-reboot";
+			reg = <0x0c 0x4>;
+			value = <0x01>;
+		};
+	};
 };
 
 &soc {
-- 
2.46.2

Re: [PATCH v5 4/6] mips: dts: realtek: Add syscon-reboot node

[Krzysztof Kozlowski]

On Thu, Sep 26, 2024 at 09:58:45AM +1200, Chris Packham wrote:
> The board level reset on systems using the RTL9302 can be driven via the
> switch. Use a syscon-reboot node to represent this.
> 
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> ---
> 
> Notes:
>     Changes in v5:
>     - Krzysztof did technically give a r-by on v4 but given the changes to
>       the rest of the series I haven't included it.
>     - Use reg instead of offset
>     - Add a rtl9302c.dtsi for the specific chip which pulls in the generic
>       rtl930x.dtsi and updates a few of the compatibles on the way through.
>     - Update Cameo board to use rtl9302c.dtsi
>     Changes in v4:
>     - None
>     Changes in v3:
>     - None
>     Changes in v2:
>     - drop redundant status = "okay"

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

[PATCH v5 5/6] mips: dts: realtek: Add I2C controllers

[Chris Packham]

Add the I2C controllers that are part of the RTL9300 SoC.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---

Notes:
    Changes in v5:
    - Update compatibles
    Changes in v4:
    - Skipped due to combining patch series
    Changes in v3:
    - None
    Changes in v2:
    - Use reg property

 arch/mips/boot/dts/realtek/rtl9302c.dtsi |  8 ++++++++
 arch/mips/boot/dts/realtek/rtl930x.dtsi  | 16 ++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/arch/mips/boot/dts/realtek/rtl9302c.dtsi b/arch/mips/boot/dts/realtek/rtl9302c.dtsi
index 80d9f407e758..56c35e8b8b62 100644
--- a/arch/mips/boot/dts/realtek/rtl9302c.dtsi
+++ b/arch/mips/boot/dts/realtek/rtl9302c.dtsi
@@ -5,3 +5,11 @@
 &switch0 {
 	compatible = "realtek,rtl9302c-switch", "realtek,rtl9300-switch", "syscon", "simple-mfd";
 };
+
+&i2c0 {
+	compatible = "realtek,rtl9302c-i2c", "realtek,rtl9300-i2c";
+};
+
+&i2c1 {
+	compatible = "realtek,rtl9302c-i2c", "realtek,rtl9300-i2c";
+};
diff --git a/arch/mips/boot/dts/realtek/rtl930x.dtsi b/arch/mips/boot/dts/realtek/rtl930x.dtsi
index 89b8854596cd..2fb8461af575 100644
--- a/arch/mips/boot/dts/realtek/rtl930x.dtsi
+++ b/arch/mips/boot/dts/realtek/rtl930x.dtsi
@@ -41,6 +41,22 @@ reboot@c {
 			reg = <0x0c 0x4>;
 			value = <0x01>;
 		};
+
+		i2c0: i2c@36c {
+			compatible = "realtek,rtl9300-i2c";
+			reg = <0x36c 0x14>;
+			status = "disabled";
+			#address-cells = <1>;
+			#size-cells = <0>;
+		};
+
+		i2c1: i2c@388 {
+			compatible = "realtek,rtl9300-i2c";
+			reg = <0x388 0x14>;
+			status = "disabled";
+			#address-cells = <1>;
+			#size-cells = <0>;
+		};
 	};
 };
 
-- 
2.46.2

Re: [PATCH v5 5/6] mips: dts: realtek: Add I2C controllers

[Krzysztof Kozlowski]

On Thu, Sep 26, 2024 at 09:58:46AM +1200, Chris Packham wrote:
> Add the I2C controllers that are part of the RTL9300 SoC.
> 
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> ---
> 
> Notes:
>     Changes in v5:
>     - Update compatibles
>     Changes in v4:
>     - Skipped due to combining patch series
>     Changes in v3:
>     - None
>     Changes in v2:
>     - Use reg property
> 
>  arch/mips/boot/dts/realtek/rtl9302c.dtsi |  8 ++++++++
>  arch/mips/boot/dts/realtek/rtl930x.dtsi  | 16 ++++++++++++++++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/arch/mips/boot/dts/realtek/rtl9302c.dtsi b/arch/mips/boot/dts/realtek/rtl9302c.dtsi
> index 80d9f407e758..56c35e8b8b62 100644
> --- a/arch/mips/boot/dts/realtek/rtl9302c.dtsi
> +++ b/arch/mips/boot/dts/realtek/rtl9302c.dtsi
> @@ -5,3 +5,11 @@
>  &switch0 {
>  	compatible = "realtek,rtl9302c-switch", "realtek,rtl9300-switch", "syscon", "simple-mfd";
>  };
> +
> +&i2c0 {
> +	compatible = "realtek,rtl9302c-i2c", "realtek,rtl9300-i2c";
> +};
> +
> +&i2c1 {
> +	compatible = "realtek,rtl9302c-i2c", "realtek,rtl9300-i2c";
> +};
> diff --git a/arch/mips/boot/dts/realtek/rtl930x.dtsi b/arch/mips/boot/dts/realtek/rtl930x.dtsi
> index 89b8854596cd..2fb8461af575 100644
> --- a/arch/mips/boot/dts/realtek/rtl930x.dtsi
> +++ b/arch/mips/boot/dts/realtek/rtl930x.dtsi
> @@ -41,6 +41,22 @@ reboot@c {
>  			reg = <0x0c 0x4>;
>  			value = <0x01>;
>  		};
> +
> +		i2c0: i2c@36c {
> +			compatible = "realtek,rtl9300-i2c";
> +			reg = <0x36c 0x14>;
> +			status = "disabled";

Usual convention is to have status the last. Maybe MIPS has different,
so keep whatever is consistent in your case.

Anyway:

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

Re: [PATCH v5 5/6] mips: dts: realtek: Add I2C controllers

[Chris Packham]

On 26/09/24 18:37, Krzysztof Kozlowski wrote:
> On Thu, Sep 26, 2024 at 09:58:46AM +1200, Chris Packham wrote:
>> Add the I2C controllers that are part of the RTL9300 SoC.
>>
>> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
>> ---
>>
>> Notes:
>>      Changes in v5:
>>      - Update compatibles
>>      Changes in v4:
>>      - Skipped due to combining patch series
>>      Changes in v3:
>>      - None
>>      Changes in v2:
>>      - Use reg property
>>
>>   arch/mips/boot/dts/realtek/rtl9302c.dtsi |  8 ++++++++
>>   arch/mips/boot/dts/realtek/rtl930x.dtsi  | 16 ++++++++++++++++
>>   2 files changed, 24 insertions(+)
>>
>> diff --git a/arch/mips/boot/dts/realtek/rtl9302c.dtsi b/arch/mips/boot/dts/realtek/rtl9302c.dtsi
>> index 80d9f407e758..56c35e8b8b62 100644
>> --- a/arch/mips/boot/dts/realtek/rtl9302c.dtsi
>> +++ b/arch/mips/boot/dts/realtek/rtl9302c.dtsi
>> @@ -5,3 +5,11 @@
>>   &switch0 {
>>   	compatible = "realtek,rtl9302c-switch", "realtek,rtl9300-switch", "syscon", "simple-mfd";
>>   };
>> +
>> +&i2c0 {
>> +	compatible = "realtek,rtl9302c-i2c", "realtek,rtl9300-i2c";
>> +};
>> +
>> +&i2c1 {
>> +	compatible = "realtek,rtl9302c-i2c", "realtek,rtl9300-i2c";
>> +};
>> diff --git a/arch/mips/boot/dts/realtek/rtl930x.dtsi b/arch/mips/boot/dts/realtek/rtl930x.dtsi
>> index 89b8854596cd..2fb8461af575 100644
>> --- a/arch/mips/boot/dts/realtek/rtl930x.dtsi
>> +++ b/arch/mips/boot/dts/realtek/rtl930x.dtsi
>> @@ -41,6 +41,22 @@ reboot@c {
>>   			reg = <0x0c 0x4>;
>>   			value = <0x01>;
>>   		};
>> +
>> +		i2c0: i2c@36c {
>> +			compatible = "realtek,rtl9300-i2c";
>> +			reg = <0x36c 0x14>;
>> +			status = "disabled";
> Usual convention is to have status the last. Maybe MIPS has different,
> so keep whatever is consistent in your case.

I'll send out a fixup patch that can be folded into this. Hopefully 
Thomas can combine them at his end (or if there is a need for a v6 I can).

I'll probably have other series touching this file so if the fixup 
doesn't make it now I can include it in a future series.

>
> Anyway:
>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>
> Best regards,
> Krzysztof
>

[PATCH v5] fixup! i2c: Add driver for the RTL9300 I2C controller

[Chris Packham]

---
 arch/mips/boot/dts/realtek/rtl930x.dtsi | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/boot/dts/realtek/rtl930x.dtsi b/arch/mips/boot/dts/realtek/rtl930x.dtsi
index 2fb8461af575..eae059540cec 100644
--- a/arch/mips/boot/dts/realtek/rtl930x.dtsi
+++ b/arch/mips/boot/dts/realtek/rtl930x.dtsi
@@ -45,17 +45,17 @@ reboot@c {
 		i2c0: i2c@36c {
 			compatible = "realtek,rtl9300-i2c";
 			reg = <0x36c 0x14>;
-			status = "disabled";
 			#address-cells = <1>;
 			#size-cells = <0>;
+			status = "disabled";
 		};
 
 		i2c1: i2c@388 {
 			compatible = "realtek,rtl9300-i2c";
 			reg = <0x388 0x14>;
-			status = "disabled";
 			#address-cells = <1>;
 			#size-cells = <0>;
+			status = "disabled";
 		};
 	};
 };
-- 
2.46.2

[PATCH v5 6/6] i2c: Add driver for the RTL9300 I2C controller

[Chris Packham]

Add support for the I2C controller on the RTL9300 SoC. There are two I2C
controllers in the RTL9300 that are part of the Ethernet switch register
block. Each of these controllers owns a SCL pin (GPIO8 for the fiorst
I2C controller, GPIO17 for the second). There are 8 possible SDA pins
(GPIO9-16) that can be assigned to either I2C controller. This
relationship is represented in the device tree with a child node for
each SDA line in use.

This is based on the openwrt implementation[1] but has been
significantly modified

[1] - https://git.openwrt.org/?p=openwrt/openwrt.git;a=blob;f=target/linux/realtek/files-5.15/drivers/i2c/busses/i2c-rtl9300.c

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---

Notes:
    Changes in v5:
    - Make lock part of struct rtl9300_i2c
    - Fix alignment in rtl9300_i2c_smbus_xfer
    Changes in v4:
    - skipped due to combining patch series
    Changes in v3:
    - None
    Changes in v2:
    - Replace a number of return 0; with tail calls
    - Add enum rtl9300_bus_freq
    - Use RTL9300_ prefix on new defines
    - Use reg property for register offset
    - Hard code RTL9300_I2C_MST_GLB_CTRL address as this does not need to
      come from DT binding
    - Use GENMASK() where appropriate
    - Propagate read/write errors through to rtl9300_i2c_smbus_xfer()
    - Don't error out on bad clock-frequency
    - Use devm_i2c_add_adapter()
    - Put more information in the commit message
    - Integrated multiplexing function, an adapter is created per SDA line

 MAINTAINERS                      |   7 +
 drivers/i2c/busses/Kconfig       |  10 +
 drivers/i2c/busses/Makefile      |   1 +
 drivers/i2c/busses/i2c-rtl9300.c | 422 +++++++++++++++++++++++++++++++
 4 files changed, 440 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-rtl9300.c

diff --git a/MAINTAINERS b/MAINTAINERS
index f328373463b0..9e123e9839a5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -19887,6 +19887,13 @@ S:	Maintained
 T:	git https://github.com/pkshih/rtw.git
 F:	drivers/net/wireless/realtek/rtl8xxxu/
 
+RTL9300 I2C DRIVER (rtl9300-i2c)
+M:	Chris Packham <chris.packham@alliedtelesis.co.nz>
+L:	linux-i2c@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/i2c/realtek,rtl9300-i2c.yaml
+F:	drivers/i2c/busses/i2c-rtl9300.c
+
 RTRS TRANSPORT DRIVERS
 M:	Md. Haris Iqbal <haris.iqbal@ionos.com>
 M:	Jack Wang <jinpu.wang@ionos.com>
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index a22f9125322a..927b583002c7 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1041,6 +1041,16 @@ config I2C_RK3X
 	  This driver can also be built as a module. If so, the module will
 	  be called i2c-rk3x.
 
+config I2C_RTL9300
+	tristate "Realtek RTL9300 I2C controller"
+	depends on MACH_REALTEK_RTL || COMPILE_TEST
+	help
+	  Say Y here to include support for the I2C controller in Realtek
+	  RTL9300 SoCs.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called i2c-rtl9300.
+
 config I2C_RZV2M
 	tristate "Renesas RZ/V2M adapter"
 	depends on ARCH_RENESAS || COMPILE_TEST
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 78d0561339e5..ac2f9f22803c 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -102,6 +102,7 @@ obj-$(CONFIG_I2C_QCOM_GENI)	+= i2c-qcom-geni.o
 obj-$(CONFIG_I2C_QUP)		+= i2c-qup.o
 obj-$(CONFIG_I2C_RIIC)		+= i2c-riic.o
 obj-$(CONFIG_I2C_RK3X)		+= i2c-rk3x.o
+obj-$(CONFIG_I2C_RTL9300)	+= i2c-rtl9300.o
 obj-$(CONFIG_I2C_RZV2M)		+= i2c-rzv2m.o
 obj-$(CONFIG_I2C_S3C2410)	+= i2c-s3c2410.o
 obj-$(CONFIG_I2C_SH7760)	+= i2c-sh7760.o
diff --git a/drivers/i2c/busses/i2c-rtl9300.c b/drivers/i2c/busses/i2c-rtl9300.c
new file mode 100644
index 000000000000..ed9a45a9d803
--- /dev/null
+++ b/drivers/i2c/busses/i2c-rtl9300.c
@@ -0,0 +1,422 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/bits.h>
+#include <linux/i2c.h>
+#include <linux/i2c-mux.h>
+#include <linux/mod_devicetable.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+enum rtl9300_bus_freq {
+	RTL9300_I2C_STD_FREQ,
+	RTL9300_I2C_FAST_FREQ,
+};
+
+struct rtl9300_i2c;
+
+struct rtl9300_i2c_chan {
+	struct i2c_adapter adap;
+	struct rtl9300_i2c *i2c;
+	enum rtl9300_bus_freq bus_freq;
+	u8 sda_pin;
+};
+
+#define RTL9300_I2C_MUX_NCHAN	8
+
+struct rtl9300_i2c {
+	struct regmap *regmap;
+	struct device *dev;
+	struct rtl9300_i2c_chan chans[RTL9300_I2C_MUX_NCHAN];
+	u32 reg_base;
+	u8 sda_pin;
+	struct mutex lock;
+};
+
+#define RTL9300_I2C_MST_CTRL1			0x0
+#define  RTL9300_I2C_MST_CTRL1_MEM_ADDR_OFS	8
+#define  RTL9300_I2C_MST_CTRL1_MEM_ADDR_MASK	GENMASK(31, 8)
+#define  RTL9300_I2C_MST_CTRL1_SDA_OUT_SEL_OFS	4
+#define  RTL9300_I2C_MST_CTRL1_SDA_OUT_SEL_MASK	GENMASK(6, 4)
+#define  RTL9300_I2C_MST_CTRL1_GPIO_SCL_SEL	BIT(3)
+#define  RTL9300_I2C_MST_CTRL1_RWOP		BIT(2)
+#define  RTL9300_I2C_MST_CTRL1_I2C_FAIL		BIT(1)
+#define  RTL9300_I2C_MST_CTRL1_I2C_TRIG		BIT(0)
+#define RTL9300_I2C_MST_CTRL2			0x4
+#define  RTL9300_I2C_MST_CTRL2_RD_MODE		BIT(15)
+#define  RTL9300_I2C_MST_CTRL2_DEV_ADDR_OFS	8
+#define  RTL9300_I2C_MST_CTRL2_DEV_ADDR_MASK	GENMASK(14, 8)
+#define  RTL9300_I2C_MST_CTRL2_DATA_WIDTH_OFS	4
+#define  RTL9300_I2C_MST_CTRL2_DATA_WIDTH_MASK	GENMASK(7, 4)
+#define  RTL9300_I2C_MST_CTRL2_MEM_ADDR_WIDTH_OFS	2
+#define  RTL9300_I2C_MST_CTRL2_MEM_ADDR_WIDTH_MASK	GENMASK(3, 2)
+#define  RTL9300_I2C_MST_CTRL2_SCL_FREQ_OFS	0
+#define  RTL9300_I2C_MST_CTRL2_SCL_FREQ_MASK	GENMASK(1, 0)
+#define RTL9300_I2C_MST_DATA_WORD0		0x8
+#define RTL9300_I2C_MST_DATA_WORD1		0xc
+#define RTL9300_I2C_MST_DATA_WORD2		0x10
+#define RTL9300_I2C_MST_DATA_WORD3		0x14
+
+#define RTL9300_I2C_MST_GLB_CTRL  0x384
+
+static int rtl9300_i2c_reg_addr_set(struct rtl9300_i2c *i2c, u32 reg, u16 len)
+{
+	u32 val, mask;
+	int ret;
+
+	val = len << RTL9300_I2C_MST_CTRL2_MEM_ADDR_WIDTH_OFS;
+	mask = RTL9300_I2C_MST_CTRL2_MEM_ADDR_WIDTH_MASK;
+
+	ret = regmap_update_bits(i2c->regmap, i2c->reg_base + RTL9300_I2C_MST_CTRL2, mask, val);
+	if (ret)
+		return ret;
+
+	val = reg << RTL9300_I2C_MST_CTRL1_MEM_ADDR_OFS;
+	mask = RTL9300_I2C_MST_CTRL1_MEM_ADDR_MASK;
+
+	return regmap_update_bits(i2c->regmap, i2c->reg_base + RTL9300_I2C_MST_CTRL1, mask, val);
+}
+
+static int rtl9300_i2c_config_io(struct rtl9300_i2c *i2c, u8 sda_pin)
+{
+	int ret;
+	u32 val, mask;
+
+	ret = regmap_update_bits(i2c->regmap, RTL9300_I2C_MST_GLB_CTRL, BIT(sda_pin), BIT(sda_pin));
+	if (ret)
+		return ret;
+
+	val = (sda_pin << RTL9300_I2C_MST_CTRL1_SDA_OUT_SEL_OFS) |
+		RTL9300_I2C_MST_CTRL1_GPIO_SCL_SEL;
+	mask = RTL9300_I2C_MST_CTRL1_SDA_OUT_SEL_MASK | RTL9300_I2C_MST_CTRL1_GPIO_SCL_SEL;
+
+	return regmap_update_bits(i2c->regmap, i2c->reg_base + RTL9300_I2C_MST_CTRL1, mask, val);
+}
+
+static int rtl9300_i2c_config_xfer(struct rtl9300_i2c *i2c, struct rtl9300_i2c_chan *chan,
+				   u16 addr, u16 len)
+{
+	u32 val, mask;
+
+	val = chan->bus_freq << RTL9300_I2C_MST_CTRL2_SCL_FREQ_OFS;
+	mask = RTL9300_I2C_MST_CTRL2_SCL_FREQ_MASK;
+
+	val |= addr << RTL9300_I2C_MST_CTRL2_DEV_ADDR_OFS;
+	mask |= RTL9300_I2C_MST_CTRL2_DEV_ADDR_MASK;
+
+	val |= ((len - 1) & 0xf) << RTL9300_I2C_MST_CTRL2_DATA_WIDTH_OFS;
+	mask |= RTL9300_I2C_MST_CTRL2_DATA_WIDTH_MASK;
+
+	mask |= RTL9300_I2C_MST_CTRL2_RD_MODE;
+
+	return regmap_update_bits(i2c->regmap, i2c->reg_base + RTL9300_I2C_MST_CTRL2, mask, val);
+}
+
+static int rtl9300_i2c_read(struct rtl9300_i2c *i2c, u8 *buf, int len)
+{
+	u32 vals[4] = {};
+	int i, ret;
+
+	if (len > 16)
+		return -EIO;
+
+	ret = regmap_bulk_read(i2c->regmap, i2c->reg_base + RTL9300_I2C_MST_DATA_WORD0,
+			       vals, ARRAY_SIZE(vals));
+	if (ret)
+		return ret;
+
+	for (i = 0; i < len; i++) {
+		buf[i] = vals[i/4] & 0xff;
+		vals[i/4] >>= 8;
+	}
+
+	return 0;
+}
+
+static int rtl9300_i2c_write(struct rtl9300_i2c *i2c, u8 *buf, int len)
+{
+	u32 vals[4] = {};
+	int i;
+
+	if (len > 16)
+		return -EIO;
+
+	for (i = 0; i < len; i++) {
+		if (i % 4 == 0)
+			vals[i/4] = 0;
+		vals[i/4] <<= 8;
+		vals[i/4] |= buf[i];
+	}
+
+	return regmap_bulk_write(i2c->regmap, i2c->reg_base + RTL9300_I2C_MST_DATA_WORD0,
+				vals, ARRAY_SIZE(vals));
+}
+
+static int rtl9300_i2c_writel(struct rtl9300_i2c *i2c, u32 data)
+{
+	return regmap_write(i2c->regmap, i2c->reg_base + RTL9300_I2C_MST_DATA_WORD0, data);
+}
+
+static int rtl9300_i2c_execute_xfer(struct rtl9300_i2c *i2c, char read_write,
+				int size, union i2c_smbus_data *data, int len)
+{
+	u32 val, mask;
+	int ret;
+
+	val = read_write == I2C_SMBUS_WRITE ? RTL9300_I2C_MST_CTRL1_RWOP : 0;
+	mask = RTL9300_I2C_MST_CTRL1_RWOP;
+
+	val |= RTL9300_I2C_MST_CTRL1_I2C_TRIG;
+	mask |= RTL9300_I2C_MST_CTRL1_I2C_TRIG;
+
+	ret = regmap_update_bits(i2c->regmap, i2c->reg_base + RTL9300_I2C_MST_CTRL1, mask, val);
+	if (ret)
+		return ret;
+
+	ret = regmap_read_poll_timeout(i2c->regmap, i2c->reg_base + RTL9300_I2C_MST_CTRL1,
+				       val, !(val & RTL9300_I2C_MST_CTRL1_I2C_TRIG), 100, 2000);
+	if (ret)
+		return ret;
+
+	if (val & RTL9300_I2C_MST_CTRL1_I2C_FAIL)
+		return -EIO;
+
+	if (read_write == I2C_SMBUS_READ) {
+		if (size == I2C_SMBUS_BYTE || size == I2C_SMBUS_BYTE_DATA) {
+			ret = regmap_read(i2c->regmap,
+					  i2c->reg_base + RTL9300_I2C_MST_DATA_WORD0, &val);
+			if (ret)
+				return ret;
+			data->byte = val & 0xff;
+		} else if (size == I2C_SMBUS_WORD_DATA) {
+			ret = regmap_read(i2c->regmap,
+					  i2c->reg_base + RTL9300_I2C_MST_DATA_WORD0, &val);
+			if (ret)
+				return ret;
+			data->word = val & 0xffff;
+		} else {
+			ret = rtl9300_i2c_read(i2c, &data->block[0], len);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int rtl9300_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
+				  char read_write, u8 command, int size,
+				  union i2c_smbus_data *data)
+{
+	struct rtl9300_i2c_chan *chan = i2c_get_adapdata(adap);
+	struct rtl9300_i2c *i2c = chan->i2c;
+	int len = 0, ret;
+
+	mutex_lock(&i2c->lock);
+	if (chan->sda_pin != i2c->sda_pin) {
+		ret = rtl9300_i2c_config_io(i2c, chan->sda_pin);
+		if (ret)
+			goto out_unlock;
+		i2c->sda_pin = chan->sda_pin;
+	}
+
+	switch (size) {
+	case I2C_SMBUS_QUICK:
+		ret = rtl9300_i2c_config_xfer(i2c, chan, addr, 0);
+		if (ret)
+			goto out_unlock;
+		ret = rtl9300_i2c_reg_addr_set(i2c, 0, 0);
+		if (ret)
+			goto out_unlock;
+		break;
+
+	case I2C_SMBUS_BYTE:
+		if (read_write == I2C_SMBUS_WRITE) {
+			ret = rtl9300_i2c_config_xfer(i2c, chan, addr, 0);
+			if (ret)
+				goto out_unlock;
+			ret = rtl9300_i2c_reg_addr_set(i2c, command, 1);
+			if (ret)
+				goto out_unlock;
+		} else {
+			ret = rtl9300_i2c_config_xfer(i2c, chan, addr, 1);
+			if (ret)
+				goto out_unlock;
+			ret = rtl9300_i2c_reg_addr_set(i2c, 0, 0);
+			if (ret)
+				goto out_unlock;
+		}
+		break;
+
+	case I2C_SMBUS_BYTE_DATA:
+		ret = rtl9300_i2c_reg_addr_set(i2c, command, 1);
+		if (ret)
+			goto out_unlock;
+		ret = rtl9300_i2c_config_xfer(i2c, chan, addr, 1);
+		if (ret)
+			goto out_unlock;
+		if (read_write == I2C_SMBUS_WRITE) {
+			ret = rtl9300_i2c_writel(i2c, data->byte);
+			if (ret)
+				goto out_unlock;
+		}
+		break;
+
+	case I2C_SMBUS_WORD_DATA:
+		ret = rtl9300_i2c_reg_addr_set(i2c, command, 1);
+		if (ret)
+			goto out_unlock;
+		ret = rtl9300_i2c_config_xfer(i2c, chan, addr, 2);
+		if (ret)
+			goto out_unlock;
+		if (read_write == I2C_SMBUS_WRITE) {
+			ret = rtl9300_i2c_writel(i2c, data->word);
+			if (ret)
+				goto out_unlock;
+		}
+		break;
+
+	case I2C_SMBUS_BLOCK_DATA:
+		ret = rtl9300_i2c_reg_addr_set(i2c, command, 1);
+		if (ret)
+			goto out_unlock;
+		ret = rtl9300_i2c_config_xfer(i2c, chan, addr, data->block[0]);
+		if (ret)
+			goto out_unlock;
+		if (read_write == I2C_SMBUS_WRITE) {
+			ret = rtl9300_i2c_write(i2c, &data->block[1], data->block[0]);
+			if (ret)
+				goto out_unlock;
+		}
+		len = data->block[0];
+		break;
+
+	default:
+		dev_err(&adap->dev, "Unsupported transaction %d\n", size);
+		ret = -EOPNOTSUPP;
+		goto out_unlock;
+	}
+
+	ret = rtl9300_i2c_execute_xfer(i2c, read_write, size, data, len);
+
+out_unlock:
+	mutex_unlock(&i2c->lock);
+
+	return ret;
+}
+
+static u32 rtl9300_i2c_func(struct i2c_adapter *a)
+{
+	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
+	       I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
+	       I2C_FUNC_SMBUS_BLOCK_DATA;
+}
+
+static const struct i2c_algorithm rtl9300_i2c_algo = {
+	.smbus_xfer	= rtl9300_i2c_smbus_xfer,
+	.functionality	= rtl9300_i2c_func,
+};
+
+struct i2c_adapter_quirks rtl9300_i2c_quirks = {
+	.flags		= I2C_AQ_NO_CLK_STRETCH,
+	.max_read_len	= 16,
+	.max_write_len	= 16,
+};
+
+static int rtl9300_i2c_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rtl9300_i2c_chan *chan;
+	struct rtl9300_i2c *i2c;
+	struct i2c_adapter *adap;
+	u32 clock_freq, sda_pin;
+	int ret, i = 0;
+	struct fwnode_handle *child;
+
+	i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
+	if (!i2c)
+		return -ENOMEM;
+
+	i2c->regmap = syscon_node_to_regmap(dev->parent->of_node);
+	if (IS_ERR(i2c->regmap))
+		return PTR_ERR(i2c->regmap);
+	i2c->dev = dev;
+
+	mutex_init(&i2c->lock);
+
+	ret = device_property_read_u32(dev, "reg", &i2c->reg_base);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, i2c);
+
+	if (device_get_child_node_count(dev) >= RTL9300_I2C_MUX_NCHAN)
+		return dev_err_probe(dev, -EINVAL, "Too many channels\n");
+
+	device_for_each_child_node(dev, child) {
+		chan = &i2c->chans[i];
+		adap = &chan->adap;
+
+		ret = fwnode_property_read_u32(child, "reg", &sda_pin);
+		if (ret)
+			return ret;
+
+		ret = fwnode_property_read_u32(child, "clock-frequency", &clock_freq);
+		if (ret)
+			clock_freq = I2C_MAX_STANDARD_MODE_FREQ;
+
+		switch (clock_freq) {
+		case I2C_MAX_STANDARD_MODE_FREQ:
+			chan->bus_freq = RTL9300_I2C_STD_FREQ;
+			break;
+
+		case I2C_MAX_FAST_MODE_FREQ:
+			chan->bus_freq = RTL9300_I2C_FAST_FREQ;
+			break;
+		default:
+			dev_warn(i2c->dev, "SDA%d clock-frequency %d not supported using default\n",
+				 sda_pin, clock_freq);
+			break;
+		}
+
+		chan->sda_pin = sda_pin;
+		chan->i2c = i2c;
+		adap = &i2c->chans[i].adap;
+		adap->owner = THIS_MODULE;
+		adap->algo = &rtl9300_i2c_algo;
+		adap->quirks = &rtl9300_i2c_quirks;
+		adap->retries = 3;
+		adap->dev.parent = dev;
+		i2c_set_adapdata(adap, chan);
+		adap->dev.of_node = to_of_node(child);
+		snprintf(adap->name, sizeof(adap->name), "%s SDA%d\n", dev_name(dev), sda_pin);
+		i++;
+
+		ret = devm_i2c_add_adapter(dev, adap);
+		if (ret)
+			return ret;
+	}
+	i2c->sda_pin = 0xff;
+
+	return 0;
+}
+
+static const struct of_device_id i2c_rtl9300_dt_ids[] = {
+	{ .compatible = "realtek,rtl9300-i2c" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, i2c_rtl9300_dt_ids);
+
+static struct platform_driver rtl9300_i2c_driver = {
+	.probe = rtl9300_i2c_probe,
+	.driver = {
+		.name = "i2c-rtl9300",
+		.of_match_table = i2c_rtl9300_dt_ids,
+	},
+};
+
+module_platform_driver(rtl9300_i2c_driver);
+
+MODULE_DESCRIPTION("RTL9300 I2C controller driver");
+MODULE_LICENSE("GPL");
-- 
2.46.2

Re: [PATCH v5 6/6] i2c: Add driver for the RTL9300 I2C controller

[kernel test robot]

Hi Chris,

kernel test robot noticed the following build warnings:

[auto build test WARNING on robh/for-next]
[also build test WARNING on andi-shyti/i2c/i2c-host sre-power-supply/for-next linus/master v6.11 next-20240927]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Chris-Packham/dt-bindings-reset-syscon-reboot-Add-reg-property/20240926-060355
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
patch link:    https://lore.kernel.org/r/20240925215847.3594898-7-chris.packham%40alliedtelesis.co.nz
patch subject: [PATCH v5 6/6] i2c: Add driver for the RTL9300 I2C controller
config: csky-randconfig-r111-20240929 (https://download.01.org/0day-ci/archive/20240929/202409291025.P4M4O1F2-lkp@intel.com/config)
compiler: csky-linux-gcc (GCC) 14.1.0
reproduce: (https://download.01.org/0day-ci/archive/20240929/202409291025.P4M4O1F2-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409291025.P4M4O1F2-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> drivers/i2c/busses/i2c-rtl9300.c:321:27: sparse: sparse: symbol 'rtl9300_i2c_quirks' was not declared. Should it be static?

vim +/rtl9300_i2c_quirks +321 drivers/i2c/busses/i2c-rtl9300.c

   320	
 > 321	struct i2c_adapter_quirks rtl9300_i2c_quirks = {
   322		.flags		= I2C_AQ_NO_CLK_STRETCH,
   323		.max_read_len	= 16,
   324		.max_write_len	= 16,
   325	};
   326	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v5 6/6] i2c: Add driver for the RTL9300 I2C controller

[Markus Elfring]

…
> +++ b/drivers/i2c/busses/i2c-rtl9300.c
> @@ -0,0 +1,422 @@
…
> +static int rtl9300_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
> +				  char read_write, u8 command, int size,
> +				  union i2c_smbus_data *data)
> +{
…
> +	mutex_lock(&i2c->lock);
> +	if (chan->sda_pin != i2c->sda_pin) {
…
> +out_unlock:
> +	mutex_unlock(&i2c->lock);
> +
> +	return ret;
> +}
…

Under which circumstances would you become interested to apply a statement
like “guard(mutex)(&i2c->lock);”?
https://elixir.bootlin.com/linux/v6.11/source/include/linux/mutex.h#L196

Regards,
Markus

Re: [PATCH v5 6/6] i2c: Add driver for the RTL9300 I2C controller

[Chris Packham]

Hi Markus,

On 29/09/24 21:45, Markus Elfring wrote:
> …
>> +++ b/drivers/i2c/busses/i2c-rtl9300.c
>> @@ -0,0 +1,422 @@
> …
>> +static int rtl9300_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
>> +				  char read_write, u8 command, int size,
>> +				  union i2c_smbus_data *data)
>> +{
> …
>> +	mutex_lock(&i2c->lock);
>> +	if (chan->sda_pin != i2c->sda_pin) {
> …
>> +out_unlock:
>> +	mutex_unlock(&i2c->lock);
>> +
>> +	return ret;
>> +}
> …
>
> Under which circumstances would you become interested to apply a statement
> like “guard(mutex)(&i2c->lock);”?
> https://elixir.bootlin.com/linux/v6.11/source/include/linux/mutex.h#L196

At this stage I don't what to change unless Andi insists that I do.

I can't find much mention of using guard() on 
https://www.kernel.org/doc/html/latest/ but I can see enough examples 
(although notably none in drivers/i2c) that I _think_ I can see how I 
could use it.

Re: [PATCH v5 6/6] i2c: Add driver for the RTL9300 I2C controller

[Markus Elfring]

>> …
>>> +++ b/drivers/i2c/busses/i2c-rtl9300.c
>>> @@ -0,0 +1,422 @@
>> …
>>> +static int rtl9300_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
>>> +                  char read_write, u8 command, int size,
>>> +                  union i2c_smbus_data *data)
>>> +{
>> …
>>> +    mutex_lock(&i2c->lock);
>>> +    if (chan->sda_pin != i2c->sda_pin) {
>> …
>>> +out_unlock:
>>> +    mutex_unlock(&i2c->lock);
>>> +
>>> +    return ret;
>>> +}
>> …
>>
>> Under which circumstances would you become interested to apply a statement
>> like “guard(mutex)(&i2c->lock);”?
>> https://elixir.bootlin.com/linux/v6.11/source/include/linux/mutex.h#L196
>
> At this stage I don't what to change unless Andi insists that I do.
>
> I can't find much mention of using guard() on https://www.kernel.org/doc/html/latest/

Do you find any other information sources more encouraging?


> but I can see enough examples (although notably none in drivers/i2c) that I _think_ I can see how I could use it.

See also (for example):
Article “Linux Kernel Development - Automatic Cleanup”
by Javier Carrasco Cruz
2024-06-17
https://javiercarrascocruz.github.io/kernel-auto-cleanup-2#2-automatic-mutex-handling

Regards,
Markus

Re: [PATCH v5 6/6] i2c: Add driver for the RTL9300 I2C controller

[Javier Carrasco]

On 30/09/2024 09:55, Markus Elfring wrote:
>>> …
>>>> +++ b/drivers/i2c/busses/i2c-rtl9300.c
>>>> @@ -0,0 +1,422 @@
>>> …
>>>> +static int rtl9300_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
>>>> +                  char read_write, u8 command, int size,
>>>> +                  union i2c_smbus_data *data)
>>>> +{
>>> …
>>>> +    mutex_lock(&i2c->lock);
>>>> +    if (chan->sda_pin != i2c->sda_pin) {
>>> …
>>>> +out_unlock:
>>>> +    mutex_unlock(&i2c->lock);
>>>> +
>>>> +    return ret;
>>>> +}
>>> …
>>>
>>> Under which circumstances would you become interested to apply a statement
>>> like “guard(mutex)(&i2c->lock);”?
>>> https://elixir.bootlin.com/linux/v6.11/source/include/linux/mutex.h#L196
>>
>> At this stage I don't what to change unless Andi insists that I do.
>>
>> I can't find much mention of using guard() on https://www.kernel.org/doc/html/latest/
> 
> Do you find any other information sources more encouraging?
> 
> 
>> but I can see enough examples (although notably none in drivers/i2c) that I _think_ I can see how I could use it.
> 
> See also (for example):
> Article “Linux Kernel Development - Automatic Cleanup”
> by Javier Carrasco Cruz
> 2024-06-17
> https://javiercarrascocruz.github.io/kernel-auto-cleanup-2#2-automatic-mutex-handling
> 
> Regards,
> Markus

My personal blog is definitely NOT an official or even reliable source
of information.

Thanks for referencing it, but please look for examples of guard() in
the kernel, because there are several examples for different kind of
mutexes. For example, IIO uses them widely. And they are really nice, so
I would recommend anyone using them whenever it makes sense.

Best regards,
Javier Carrasco