[PATCH v4 0/2] media: i2c: Add ov2735 camera sensor driver

[PATCH v4 0/2] media: i2c: Add ov2735 camera sensor driver

[Hardevsinh Palaniya]

Add a v4l2 subdevice driver for the Omnivision OV2735 sensor.

The Omnivision OV2735 is a 1/2.7-Inch CMOS image sensor with an
active array size of 1920 x 1080.

The following features are supported:
- Manual exposure an gain control support.
- vblank/hblank control support.
- Test pattern support control.
- Supported resolution: 1920 x 1080 @ 30fps (SGRBG10).

The driver is tested on mainline branch v6.14-rc6 on IMX8MP Debix Model a.

v3 -> v4

In Patch 1/2:
- Removed the clock-names property from the device tree binding.
- Added link-frequencies property to the port node.
- Cleaned up the example by removing unnecessary entries.

In Patch 2/2:
- Removed the cci_ prefix from read/write functions and custom page macros.
- Corrected error handling in the ov2735_page_access() function.
- Calculated PLL parameters dynamically based on the specified link frequency.
- Set resolution registers from format and crop instead of hardcoding.
- Fixed a memory leak in ov2735_parse_endpoint().
- Switched to devm_pm_runtime_*() functions for runtime PM handling.
- Added documentation for the use of msleep() in the power_on() function.
- Corrected GPIO polarity handling in the power_off() function.

v2 -> v3

In Patch 1/2:
- Renamed pwdn pin to enable pin.
- Changed supply names to lowercase and added them to required properties.

In Patch 2/2:
- Stored page number in CCI private bits.
- Added helper functions to handle page switching in cci_read() and cci_write().
- Removed ov2735_mbus_codes.
- Corrected control count to 9.

v1 -> v2

- Added necessary header files.
- Corrected indentation.
- Used the ret parameter in cci_write and cci_read functions.

Hardevsinh Palaniya (1):
  media: i2c: add ov2735 image sensor driver

Himanshu Bhavani (1):
  dt-bindings: media: i2c: Add ov2735 sensor

 .../bindings/media/i2c/ovti,ov2735.yaml       |  109 ++
 MAINTAINERS                                   |    9 +
 drivers/media/i2c/Kconfig                     |   10 +
 drivers/media/i2c/Makefile                    |    1 +
 drivers/media/i2c/ov2735.c                    | 1067 +++++++++++++++++
 5 files changed, 1196 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/i2c/ovti,ov2735.yaml
 create mode 100644 drivers/media/i2c/ov2735.c

-- 
2.34.1

[PATCH v4 1/2] dt-bindings: media: i2c: Add ov2735 sensor

[Hardevsinh Palaniya]

From: Himanshu Bhavani <himanshu.bhavani@siliconsignals.io>

Add bindings for Omnivision OV2735 sensor.

Signed-off-by: Himanshu Bhavani <himanshu.bhavani@siliconsignals.io>
Signed-off-by: Hardevsinh Palaniya <hardevsinh.palaniya@siliconsignals.io>
---
 .../bindings/media/i2c/ovti,ov2735.yaml       | 109 ++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/i2c/ovti,ov2735.yaml

diff --git a/Documentation/devicetree/bindings/media/i2c/ovti,ov2735.yaml b/Documentation/devicetree/bindings/media/i2c/ovti,ov2735.yaml
new file mode 100644
index 000000000000..9236829cc00d
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/i2c/ovti,ov2735.yaml
@@ -0,0 +1,109 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/media/i2c/ovti,ov2735.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: OmniVision OV2735 Image Sensor
+
+maintainers:
+  - Himanshu Bhavani <himanshu.bhavani@siliconsignals.io>
+
+description:
+  The OmniVision OV2735 is a 2MP (1920x1080) color CMOS image sensor controlled
+  through an I2C-compatible SCCB bus. it outputs RAW10 format and uses a 1/2.7"
+  optical format.
+
+properties:
+  compatible:
+    const: ovti,ov2735
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: XVCLK clock
+
+  avdd-supply:
+    description: Analog Domain Power Supply
+
+  dovdd-supply:
+    description: I/O Domain Power Supply
+
+  dvdd-supply:
+    description: Digital Domain Power Supply
+
+  reset-gpios:
+    maxItems: 1
+    description: Reset Pin GPIO Control (active low)
+
+  enable-gpios:
+    maxItems: 1
+    description:
+      Active-low enable pin. Labeled as 'PWDN' in the datasheet, but acts as
+      an enable signal. During power rail ramp-up, the device remains powered
+      down. Once power rails are stable, pulling this pin low powers on the
+      device.
+
+  port:
+    description: MIPI CSI-2 transmitter port
+    $ref: /schemas/graph.yaml#/$defs/port-base
+    additionalProperties: false
+
+    properties:
+      endpoint:
+        $ref: /schemas/media/video-interfaces.yaml#
+        unevaluatedProperties: false
+
+        properties:
+          data-lanes:
+            items:
+              - const: 1
+              - const: 2
+          link-frequencies: true
+
+        required:
+          - data-lanes
+          - link-frequencies
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - avdd-supply
+  - dovdd-supply
+  - dvdd-supply
+  - port
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        camera-sensor@3c {
+            compatible = "ovti,ov2735";
+            reg = <0x3c>;
+            clocks = <&ov2735_clk>;
+
+            avdd-supply = <&ov2735_avdd>;
+            dovdd-supply = <&ov2735_dovdd>;
+            dvdd-supply = <&ov2735_dvdd>;
+
+            reset-gpios = <&gpio1 6 GPIO_ACTIVE_LOW>;
+            enable-gpios = <&gpio2 11 GPIO_ACTIVE_LOW>;
+
+            port {
+                cam_out: endpoint {
+                    remote-endpoint = <&mipi_in_cam>;
+                    data-lanes = <1 2>;
+                    link-frequencies = /bits/ 64 <420000000>;
+                };
+            };
+        };
+    };
-- 
2.34.1

Re: [PATCH v4 1/2] dt-bindings: media: i2c: Add ov2735 sensor

[Hardevsinh Palaniya]

Hi Krzysztof

> From: Himanshu Bhavani <himanshu.bhavani@siliconsignals.io>
> 
> Add bindings for Omnivision OV2735 sensor.
> 
> Signed-off-by: Himanshu Bhavani <himanshu.bhavani@siliconsignals.io>
> Signed-off-by: Hardevsinh Palaniya <hardevsinh.palaniya@siliconsignals.io>

I haven't added your Reviewed-by tag yet, as I made some modifications to the DT bindings.

Could you please review the updated changes?

Best Regards,
Hardev

> ---
>  .../bindings/media/i2c/ovti,ov2735.yaml       | 109 ++++++++++++++++++
>  1 file changed, 109 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/i2c/ovti,ov2735.yaml
> 
> diff --git a/Documentation/devicetree/bindings/media/i2c/ovti,ov2735.yaml b/Documentation/devicetree/bindings/media/i2c/ovti,ov2735.yaml
> new file mode 100644
> index 000000000000..9236829cc00d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/ovti,ov2735.yaml
> @@ -0,0 +1,109 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/media/i2c/ovti,ov2735.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: OmniVision OV2735 Image Sensor
> +
> +maintainers:
> +  - Himanshu Bhavani <himanshu.bhavani@siliconsignals.io>
> +
> +description:
> +  The OmniVision OV2735 is a 2MP (1920x1080) color CMOS image sensor controlled
> +  through an I2C-compatible SCCB bus. it outputs RAW10 format and uses a 1/2.7"
> +  optical format.
> +
> +properties:
> +  compatible:
> +    const: ovti,ov2735
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    items:
> +      - description: XVCLK clock
> +
> +  avdd-supply:
> +    description: Analog Domain Power Supply
> +
> +  dovdd-supply:
> +    description: I/O Domain Power Supply
> +
> +  dvdd-supply:
> +    description: Digital Domain Power Supply
> +
> +  reset-gpios:
> +    maxItems: 1
> +    description: Reset Pin GPIO Control (active low)
> +
> +  enable-gpios:
> +    maxItems: 1
> +    description:
> +      Active-low enable pin. Labeled as 'PWDN' in the datasheet, but acts as
> +      an enable signal. During power rail ramp-up, the device remains powered
> +      down. Once power rails are stable, pulling this pin low powers on the
> +      device.
> +
> +  port:
> +    description: MIPI CSI-2 transmitter port
> +    $ref: /schemas/graph.yaml#/$defs/port-base
> +    additionalProperties: false
> +
> +    properties:
> +      endpoint:
> +        $ref: /schemas/media/video-interfaces.yaml#
> +        unevaluatedProperties: false
> +
> +        properties:
> +          data-lanes:
> +            items:
> +              - const: 1
> +              - const: 2
> +          link-frequencies: true
> +
> +        required:
> +          - data-lanes
> +          - link-frequencies
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - avdd-supply
> +  - dovdd-supply
> +  - dvdd-supply
> +  - port
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        camera-sensor@3c {
> +            compatible = "ovti,ov2735";
> +            reg = <0x3c>;
> +            clocks = <&ov2735_clk>;
> +
> +            avdd-supply = <&ov2735_avdd>;
> +            dovdd-supply = <&ov2735_dovdd>;
> +            dvdd-supply = <&ov2735_dvdd>;
> +
> +            reset-gpios = <&gpio1 6 GPIO_ACTIVE_LOW>;
> +            enable-gpios = <&gpio2 11 GPIO_ACTIVE_LOW>;
> +
> +            port {
> +                cam_out: endpoint {
> +                    remote-endpoint = <&mipi_in_cam>;
> +                    data-lanes = <1 2>;
> +                    link-frequencies = /bits/ 64 <420000000>;
> +                };
> +            };
> +        };
> +    };
> --
> 2.34.1

Re: [PATCH v4 1/2] dt-bindings: media: i2c: Add ov2735 sensor

[Krzysztof Kozlowski]

On Wed, Jul 16, 2025 at 01:58:52PM +0000, Hardevsinh Palaniya wrote:
> Hi Krzysztof
> 
> > From: Himanshu Bhavani <himanshu.bhavani@siliconsignals.io>
> > 
> > Add bindings for Omnivision OV2735 sensor.
> > 
> > Signed-off-by: Himanshu Bhavani <himanshu.bhavani@siliconsignals.io>
> > Signed-off-by: Hardevsinh Palaniya <hardevsinh.palaniya@siliconsignals.io>
> 
> I haven't added your Reviewed-by tag yet, as I made some modifications to the DT bindings.

What modifications? You must be specific in the changelog which
modifications caused tag dropping. I don't see such information at all.

Please read submitting patches before posting next version.

I already provided you to exact documentation paragraph explaining this.
Did you clicked the link I gave you or just ignored?

Best regards,
Krzysztof

Re: [PATCH v4 1/2] dt-bindings: media: i2c: Add ov2735 sensor

[Krzysztof Kozlowski]

On Wed, Jul 16, 2025 at 07:14:16PM +0530, Hardevsinh Palaniya wrote:
> +        properties:
> +          data-lanes:
> +            items:
> +              - const: 1
> +              - const: 2
> +          link-frequencies: true

Drop

I don't understand why this appeared. I don't think anyone asked for it?

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

Best regards,
Krzysztof

Re: [PATCH v4 1/2] dt-bindings: media: i2c: Add ov2735 sensor

[Hardevsinh Palaniya]

Hi Krzysztof,

> On Wed, Jul 16, 2025 at 07:14:16PM +0530, Hardevsinh Palaniya wrote:
> > +        properties:
> > +          data-lanes:
> > +            items:
> > +              - const: 1
> > +              - const: 2
> > +          link-frequencies: true
> 
> Drop
> 
> I don't understand why this appeared. I don't think anyone asked for it?

Laurent suggested validating the link frequency in the Device Tree.  

Link[1]: https://lore.kernel.org/linux-media/20250710212131.GG22436@pendragon.ideasonboard.com/

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

Best Regards,
Hardev

Re: [PATCH v4 1/2] dt-bindings: media: i2c: Add ov2735 sensor

[Krzysztof Kozlowski]

On 17/07/2025 09:28, Hardevsinh Palaniya wrote:
> Hi Krzysztof,
> 
>> On Wed, Jul 16, 2025 at 07:14:16PM +0530, Hardevsinh Palaniya wrote:
>>> +        properties:
>>> +          data-lanes:
>>> +            items:
>>> +              - const: 1
>>> +              - const: 2
>>> +          link-frequencies: true
>>
>> Drop
>>
>> I don't understand why this appeared. I don't think anyone asked for it?
> 
> Laurent suggested validating the link frequency in the Device Tree.  
> 
> Link[1]: https://lore.kernel.org/linux-media/20250710212131.GG22436@pendragon.ideasonboard.com/

... and I do not see here validation "that the link frequencies
specified in DT match".

How do you validate that 1111 Hz is not / is a valid link frequency? How
did you exactly resolve the comment about validating?

If your hardware operates on specific link frequencies, list them.
Otherwise this is redundant - validates nothing, changes nothing, does
not make the code more obvious.


Best regards,
Krzysztof

Re: [PATCH v4 1/2] dt-bindings: media: i2c: Add ov2735 sensor

[Hardevsinh Palaniya]

> On 17/07/2025 09:28, Hardevsinh Palaniya wrote:
> >  Hi Krzysztof,
> > 
> > > On Wed, Jul 16, 2025 at 07:14:16PM +0530, Hardevsinh Palaniya wrote:
> > > > +        properties:
> > > > +          data-lanes:
> > > > +            items:
> > > > +              - const: 1
> > > > +              - const: 2
> > > > +          link-frequencies: true
> > >
> > > Drop
> > >
> > > I don't understand why this appeared. I don't think anyone asked for it?
> >
> > Laurent suggested validating the link frequency in the Device Tree.
> >
> > Link[1]: https://lore.kernel.org/linux-media/20250710212131.GG22436@pendragon.ideasonboard.com/
> 
> ... and I do not see here validation "that the link frequencies
> specified in DT match".
> 
> How do you validate that 1111 Hz is not / is a valid link frequency? How
> did you exactly resolve the comment about validating?

In the ov2735_parse_endpoint() function, the driver validates the link frequency
from DT using `v4l2_link_freq_to_bitmap()`. If an unsupported value like 1111 Hz is
provided, it returns an error: 

ret = v4l2_link_freq_to_bitmap(ov2735->dev, bus_cfg.link_frequencies,
                               bus_cfg.nr_of_link_frequencies,
                               link_freq_menu_items,
                               ARRAY_SIZE(link_freq_menu_items),
                               &link_freq_bitmap);
if (ret) {
        ret = dev_err_probe(ov2735->dev,
                            -EINVAL, "only 420MHz frequency is available\n");
        goto error_out;
}

So, validation is already done in the driver.

I understand that `link-frequencies: true` in the schema only declares the property
without restricting values. Would you prefer the schema to explicitly allow only
420MHz like this?

link-frequencies:
  items:
  - const: 420000000

Best Regards,
Hardev

Re: [PATCH v4 1/2] dt-bindings: media: i2c: Add ov2735 sensor

[Krzysztof Kozlowski]

On 17/07/2025 13:55, Hardevsinh Palaniya wrote:
>> On 17/07/2025 09:28, Hardevsinh Palaniya wrote:
>>>  Hi Krzysztof,
>>>
>>>> On Wed, Jul 16, 2025 at 07:14:16PM +0530, Hardevsinh Palaniya wrote:
>>>>> +        properties:
>>>>> +          data-lanes:
>>>>> +            items:
>>>>> +              - const: 1
>>>>> +              - const: 2
>>>>> +          link-frequencies: true
>>>>
>>>> Drop
>>>>
>>>> I don't understand why this appeared. I don't think anyone asked for it?
>>>
>>> Laurent suggested validating the link frequency in the Device Tree.
>>>
>>> Link[1]: https://lore.kernel.org/linux-media/20250710212131.GG22436@pendragon.ideasonboard.com/
>>
>> ... and I do not see here validation "that the link frequencies
>> specified in DT match".
>>
>> How do you validate that 1111 Hz is not / is a valid link frequency? How
>> did you exactly resolve the comment about validating?
> 
> In the ov2735_parse_endpoint() function, the driver validates the link frequency
> from DT using `v4l2_link_freq_to_bitmap()`. If an unsupported value like 1111 Hz is
> provided, it returns an error: 


But that's driver. You said that you added this property based on
feedback on validation. There is no validation here, thus the reason of
this property is not fulfilled and that's why I was asking. I know now
the answer...



> 
> ret = v4l2_link_freq_to_bitmap(ov2735->dev, bus_cfg.link_frequencies,
>                                bus_cfg.nr_of_link_frequencies,
>                                link_freq_menu_items,
>                                ARRAY_SIZE(link_freq_menu_items),
>                                &link_freq_bitmap);
> if (ret) {
>         ret = dev_err_probe(ov2735->dev,
>                             -EINVAL, "only 420MHz frequency is available\n");
>         goto error_out;
> }
> 
> So, validation is already done in the driver.
> 
> I understand that `link-frequencies: true` in the schema only declares the property
> without restricting values. Would you prefer the schema to explicitly allow only
> 420MHz like this?


You missed the last paragraph of my last email. I don't want to have
here what the driver is doing, but what the hardware is/needs/requires.
It can also be missing completely, because we don't enforce such rules
on other bindings.


Best regards,
Krzysztof

Re: [PATCH v4 1/2] dt-bindings: media: i2c: Add ov2735 sensor

[Hardevsinh Palaniya]

> On 17/07/2025 13:55, Hardevsinh Palaniya wrote:
> > > On 17/07/2025 09:28, Hardevsinh Palaniya wrote:
> > > >  Hi Krzysztof,
> > > >
> > > > > On Wed, Jul 16, 2025 at 07:14:16PM +0530, Hardevsinh Palaniya wrote:
> > > > > > +        properties:
> > > > > > +          data-lanes:
> > > > > > +            items:
> > > > > > +              - const: 1
> > > > > > +              - const: 2
> > > > > > +          link-frequencies: true
> > > > >
> > > > > Drop
> > > > >
> > > > > I don't understand why this appeared. I don't think anyone asked for it?
> > > >
> > > > Laurent suggested validating the link frequency in the Device Tree.
> > > >
> > > > Link[1]: https://lore.kernel.org/linux-media/20250710212131.GG22436@pendragon.ideasonboard.com/
> > >
> > > ... and I do not see here validation "that the link frequencies
> > > specified in DT match".
> > >
> > > How do you validate that 1111 Hz is not / is a valid link frequency? How
> > > did you exactly resolve the comment about validating?
> >
> > In the ov2735_parse_endpoint() function, the driver validates the link frequency
> > from DT using `v4l2_link_freq_to_bitmap()`. If an unsupported value like 1111 Hz is
> > provided, it returns an error:
> 
> 
> But that's driver. You said that you added this property based on
> feedback on validation. There is no validation here, thus the reason of
> this property is not fulfilled and that's why I was asking. I know now
> the answer...

What I thought was: since the driver is validating the link-frequencies
property from DT, the DT must contain this property,so I added it to the
schema.

Also, I noticed that other camera dt schema follow a similar approach. 
 
> >
> > ret = v4l2_link_freq_to_bitmap(ov2735->dev, bus_cfg.link_frequencies,
> >                                bus_cfg.nr_of_link_frequencies,
> >                                link_freq_menu_items,
> >                                ARRAY_SIZE(link_freq_menu_items),
> >                                &link_freq_bitmap);
> > if (ret) {
> >         ret = dev_err_probe(ov2735->dev,
> >                             -EINVAL, "only 420MHz frequency is available\n");
> >         goto error_out;
> > }
> >
> > So, validation is already done in the driver.
> >
> > I understand that `link-frequencies: true` in the schema only declares the property
> > without restricting values. Would you prefer the schema to explicitly allow only
> > 420MHz like this?
> 
> 
> You missed the last paragraph of my last email. I don't want to have
> here what the driver is doing, but what the hardware is/needs/requires.
> It can also be missing completely, because we don't enforce such rules
> on other bindings.

However, the sensor itself supports multiple link frequencies, which is 
why I didn’t restrict it to just 420 MHz in the schema.

Currently, the driver only supports 420 MHz, so we handle validation 
there, not in the DT schema.

Please let me know what you suggest. Should I remove the link-frequencies 
property from the schema, or would you prefer a different approach?

Best regards,
Hardev

[PATCH v4 2/2] media: i2c: add ov2735 image sensor driver

[Hardevsinh Palaniya]

Add a v4l2 subdevice driver for the Omnivision OV2735 sensor.

The Omnivision OV2735 is a 1/2.7-Inch CMOS image sensor with an
active array size of 1920 x 1080.

The following features are supported:
- Manual exposure an gain control support
- vblank/hblank control support
- Test pattern support control
- Supported resolution: 1920 x 1080 @ 30fps (SGRBG10)

Co-developed-by: Himanshu Bhavani <himanshu.bhavani@siliconsignals.io>
Signed-off-by: Himanshu Bhavani <himanshu.bhavani@siliconsignals.io>
Signed-off-by: Hardevsinh Palaniya <hardevsinh.palaniya@siliconsignals.io>
---
 MAINTAINERS                |    9 +
 drivers/media/i2c/Kconfig  |   10 +
 drivers/media/i2c/Makefile |    1 +
 drivers/media/i2c/ov2735.c | 1067 ++++++++++++++++++++++++++++++++++++
 4 files changed, 1087 insertions(+)
 create mode 100644 drivers/media/i2c/ov2735.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 92e9d8c7708f..058bbfd9523b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18471,6 +18471,15 @@ T:	git git://linuxtv.org/media.git
 F:	Documentation/devicetree/bindings/media/i2c/ovti,ov2685.yaml
 F:	drivers/media/i2c/ov2685.c
 
+OMNIVISION OV2735 SENSOR DRIVER
+M:	Hardevsinh Palaniya <hardevsinh.palaniya@siliconsignals.io>
+M:	Himanshu Bhavani <himanshu.bhavani@siliconsignals.io>
+L:	linux-media@vger.kernel.org
+S:	Maintained
+T:	git git://linuxtv.org/media.git
+F:	Documentation/devicetree/bindings/media/i2c/ovti,ov2735.yaml
+F:	drivers/media/i2c/ov2735.c
+
 OMNIVISION OV2740 SENSOR DRIVER
 M:	Tianshu Qiu <tian.shu.qiu@intel.com>
 R:	Sakari Ailus <sakari.ailus@linux.intel.com>
diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index 4b4c199da6ea..9646eab1b177 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -446,6 +446,16 @@ config VIDEO_OV2685
 	  To compile this driver as a module, choose M here: the
 	  module will be called ov2685.
 
+config VIDEO_OV2735
+	tristate "OmniVision OV2735 sensor support"
+	select V4L2_CCI_I2C
+	help
+	  This is a Video4Linux2 sensor driver for the Sony
+	  OV2735 camera.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ov2735.
+
 config VIDEO_OV2740
 	tristate "OmniVision OV2740 sensor support"
 	depends on ACPI || COMPILE_TEST
diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
index 5873d29433ee..1adb27743fa1 100644
--- a/drivers/media/i2c/Makefile
+++ b/drivers/media/i2c/Makefile
@@ -93,6 +93,7 @@ obj-$(CONFIG_VIDEO_OV2640) += ov2640.o
 obj-$(CONFIG_VIDEO_OV2659) += ov2659.o
 obj-$(CONFIG_VIDEO_OV2680) += ov2680.o
 obj-$(CONFIG_VIDEO_OV2685) += ov2685.o
+obj-$(CONFIG_VIDEO_OV2735) += ov2735.o
 obj-$(CONFIG_VIDEO_OV2740) += ov2740.o
 obj-$(CONFIG_VIDEO_OV4689) += ov4689.o
 obj-$(CONFIG_VIDEO_OV5640) += ov5640.o
diff --git a/drivers/media/i2c/ov2735.c b/drivers/media/i2c/ov2735.c
new file mode 100644
index 000000000000..5107b70fd3c6
--- /dev/null
+++ b/drivers/media/i2c/ov2735.c
@@ -0,0 +1,1067 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * V4L2 Support for the OV2735
+ *
+ * Copyright (C) 2025 Silicon Signals Pvt. Ltd.
+ *
+ * Based on Rockchip ov2735 Camera Driver
+ * Copyright (C) 2017 Fuzhou Rockchip Electronics Co., Ltd.
+ *
+ * Inspired from ov8858, imx219, imx283 camera drivers
+ */
+
+#include <linux/array_size.h>
+#include <linux/clk.h>
+#include <linux/container_of.h>
+#include <linux/delay.h>
+#include <linux/device/devres.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/pm_runtime.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+#include <linux/units.h>
+#include <linux/types.h>
+
+#include <media/v4l2-cci.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-fwnode.h>
+#include <media/v4l2-mediabus.h>
+
+#define OV2735_XCLK_FREQ			(24 * HZ_PER_MHZ)
+
+/* Add page number in CCI private bits [31:28] of the register address */
+#define OV2735_PAGE_REG8(p, x)			(((p) << CCI_REG_PRIVATE_SHIFT) | CCI_REG8(x))
+#define OV2735_PAGE_REG16(p, x)			(((p) << CCI_REG_PRIVATE_SHIFT) | CCI_REG16(x))
+
+#define OV2735_REG_PAGE_SELECT			CCI_REG8(0xfd)
+
+/* Page 0 */
+#define OV2735_REG_CHIPID			OV2735_PAGE_REG16(0x00, 0x02)
+#define OV2735_CHIPID				0x2735
+
+#define OV2735_REG_SOFT_REST			OV2735_PAGE_REG8(0x00, 0x20)
+
+/* Clock Settings */
+#define OV2735_REG_PLL_CTRL			OV2735_PAGE_REG8(0x00, 0x2f)
+#define OV2735_REG_PLL_ENABLE			0x7f
+#define OV2735_REG_PLL_OUTDIV			OV2735_PAGE_REG8(0x00, 0x34)
+#define OV2735_REG_CLK_MODE			OV2735_PAGE_REG8(0x00, 0x30)
+#define OV2735_REG_CLOCK_REG1			OV2735_PAGE_REG8(0x00, 0x33)
+#define OV2735_REG_CLOCK_REG2			OV2735_PAGE_REG8(0x00, 0x35)
+
+/* Page 1 */
+#define OV2735_REG_STREAM_CTRL			OV2735_PAGE_REG8(0x01, 0xa0)
+#define OV2735_STREAM_ON			0x01
+#define OV2735_STREAM_OFF			0x00
+
+#define OV2735_REG_UPDOWN_MIRROR		OV2735_PAGE_REG8(0x01, 0x3f)
+#define OV2735_REG_BINNING_DAC_CODE_MODE	OV2735_PAGE_REG8(0x01, 0x30)
+#define OV2735_REG_FRAME_LENGTH			OV2735_PAGE_REG16(0x01, 0x0e)
+#define OV2735_VTS_MAX				0x0fff
+#define OV2735_REG_FRAME_EXP_SEPERATE_EN	OV2735_PAGE_REG8(0x01, 0x0d)
+#define OV2735_FRAME_EXP_SEPERATE_EN		0x10
+#define OV2735_REG_FRAME_SYNC			OV2735_PAGE_REG8(0x01, 0x01)
+
+#define OV2735_REG_HBLANK			OV2735_PAGE_REG16(0x01, 0x09)
+
+#define OV2735_REG_HS_MIPI			OV2735_PAGE_REG8(0x01, 0xb1)
+#define OV2735_REG_MIPI_CTRL1			OV2735_PAGE_REG8(0x01, 0x92)
+#define OV2735_REG_MIPI_CTRL2			OV2735_PAGE_REG8(0x01, 0x94)
+#define OV2735_REG_MIPI_CTRL3			OV2735_PAGE_REG8(0x01, 0xa1)
+#define OV2735_REG_MIPI_CTRL4			OV2735_PAGE_REG8(0x01, 0xb2)
+#define OV2735_REG_MIPI_CTRL5			OV2735_PAGE_REG8(0x01, 0xb3)
+#define OV2735_REG_MIPI_CTRL6			OV2735_PAGE_REG8(0x01, 0xb4)
+#define OV2735_REG_MIPI_CTRL7			OV2735_PAGE_REG8(0x01, 0xb5)
+#define OV2735_REG_PREPARE			OV2735_PAGE_REG8(0x01, 0x95)
+#define OV2735_REG_R_HS_ZERO			OV2735_PAGE_REG8(0x01, 0x96)
+#define OV2735_REG_TRAIL			OV2735_PAGE_REG8(0x01, 0x98)
+#define OV2735_REG_R_CLK_ZERO			OV2735_PAGE_REG8(0x01, 0x9c)
+#define OV2735_REG_MIPI_COLOMN_NUMBER		OV2735_PAGE_REG16(0x01, 0x8e)
+#define OV2735_REG_MIPI_LINE_NUMBER		OV2735_PAGE_REG16(0x01, 0x90)
+
+#define OV2735_REG_ANALOG_CTRL3			OV2735_PAGE_REG8(0x01, 0x25)
+#define OV2735_REG_VNCP				OV2735_PAGE_REG8(0x01, 0x20)
+
+/* BLC registers */
+#define OV2735_REG_BLC_GAIN_BLUE		OV2735_PAGE_REG8(0x01, 0x86)
+#define OV2735_REG_BLC_GAIN_RED			OV2735_PAGE_REG8(0x01, 0x87)
+#define OV2735_REG_BLC_GAIN_GR			OV2735_PAGE_REG8(0x01, 0x88)
+#define OV2735_REG_BLC_GAIN_GB			OV2735_PAGE_REG8(0x01, 0x89)
+#define OV2735_REG_GB_SUBOFFSET			OV2735_PAGE_REG8(0x01, 0xf0)
+#define OV2735_REG_BLUE_SUBOFFSET		OV2735_PAGE_REG8(0x01, 0xf1)
+#define OV2735_REG_RED_SUBOFFSET		OV2735_PAGE_REG8(0x01, 0xf2)
+#define OV2735_REG_GR_SUBOFFSET			OV2735_PAGE_REG8(0x01, 0xf3)
+#define OV2735_REG_BLC_BPC_TH_P			OV2735_PAGE_REG8(0x01, 0xfc)
+#define OV2735_REG_BLC_BPC_TH_N			OV2735_PAGE_REG8(0x01, 0xfe)
+
+#define OV2735_REG_TEST_PATTERN			OV2735_PAGE_REG8(0x01, 0xb2)
+#define OV2735_TEST_PATTERN_ENABLE		0x01
+#define OV2735_TEST_PATTERN_DISABLE		0xfe
+
+#define OV2735_REG_LONG_EXPOSURE		OV2735_PAGE_REG16(0x01, 0x03)
+#define	OV2735_EXPOSURE_MIN			4
+#define	OV2735_EXPOSURE_STEP			1
+
+#define OV2735_REG_ANALOG_GAIN                  OV2735_PAGE_REG8(0x01, 0x24)
+#define	OV2735_ANALOG_GAIN_MIN			0x10
+#define	OV2735_ANALOG_GAIN_MAX			0xff
+#define	OV2735_ANALOG_GAIN_STEP			1
+#define	OV2735_ANALOG_GAIN_DEFAULT		0x10
+
+/* Page 2 */
+#define OV2735_REG_V_START			OV2735_PAGE_REG16(0x02, 0xa0)
+#define OV2735_REG_V_SIZE			OV2735_PAGE_REG16(0x02, 0xa2)
+#define OV2735_REG_H_START			OV2735_PAGE_REG16(0x02, 0xa4)
+#define OV2735_REG_H_SIZE			OV2735_PAGE_REG16(0x02, 0xa6)
+
+#define OV2735_LINK_FREQ_420MHZ			(420 * HZ_PER_MHZ)
+#define OV2735_PIXEL_RATE			(168 * HZ_PER_MHZ)
+
+/* OV2735 native and active pixel array size. */
+static const struct v4l2_rect ov2735_native_area = {
+	.top = 0,
+	.left = 0,
+	.width = 1936,
+	.height = 1096,
+};
+
+static const struct v4l2_rect ov2735_active_area = {
+	.top = 8,
+	.left = 8,
+	.width = 1920,
+	.height = 1080,
+};
+
+static const char * const ov2735_supply_name[] = {
+	"avdd",		/* Analog power */
+	"dovdd",	/* Digital I/O power */
+	"dvdd",		/* Digital core power */
+};
+
+/* PLL_OUT = [PLL_IN * (pll_nc +3)] / [(pll_mc + 1) * (pll_outdiv + 1)] */
+struct ov2735_pll_parameters {
+	u8 pll_nc;
+	u8 pll_mc;
+	u8 pll_outdiv;
+};
+
+struct ov2735 {
+	struct device *dev;
+	struct regmap *cci;
+	struct v4l2_subdev sd;
+	struct media_pad pad;
+	struct i2c_client *client;
+	struct clk *xclk;
+	struct gpio_desc *reset_gpio;
+	struct gpio_desc *enable_gpio;
+	struct regulator_bulk_data supplies[ARRAY_SIZE(ov2735_supply_name)];
+
+	/* V4L2 Controls */
+	struct v4l2_ctrl_handler handler;
+	struct v4l2_ctrl *link_freq;
+	struct v4l2_ctrl *pixel_rate;
+	struct v4l2_ctrl *hblank;
+	struct v4l2_ctrl *vblank;
+	struct v4l2_ctrl *gain;
+	struct v4l2_ctrl *exposure;
+	struct v4l2_ctrl *test_pattern;
+
+	u32 link_freq_index;
+
+	u8 current_page;
+	struct mutex page_lock;
+};
+
+struct ov2735_mode {
+	u32 width;
+	u32 height;
+	u32 hts_def;
+	u32 vts_def;
+	u32 exp_def;
+	struct v4l2_rect crop;
+};
+
+static struct cci_reg_sequence ov2735_common_regs[] = {
+	{ OV2735_REG_CLK_MODE,			0x15 },
+	{ OV2735_REG_CLOCK_REG1,		0x01 },
+	{ OV2735_REG_CLOCK_REG2,		0x20 },
+	{ OV2735_REG_BINNING_DAC_CODE_MODE,	0x00 },
+	{ OV2735_PAGE_REG8(0x01, 0xfb),		0x73 },
+	{ OV2735_REG_FRAME_SYNC,		0x01 },
+
+	/* Timing ctrl */
+	{ OV2735_PAGE_REG8(0x01, 0x1a),		0x6b },
+	{ OV2735_PAGE_REG8(0x01, 0x1c),		0xea },
+	{ OV2735_PAGE_REG8(0x01, 0x16),		0x0c },
+	{ OV2735_PAGE_REG8(0x01, 0x21),		0x00 },
+	{ OV2735_PAGE_REG8(0x01, 0x11),		0x63 },
+	{ OV2735_PAGE_REG8(0x01, 0x19),		0xc3 },
+
+	/* Analog ctrl */
+	{ OV2735_PAGE_REG8(0x01, 0x26),		0x5a },
+	{ OV2735_PAGE_REG8(0x01, 0x29),		0x01 },
+	{ OV2735_PAGE_REG8(0x01, 0x33),		0x6f },
+	{ OV2735_PAGE_REG8(0x01, 0x2a),		0xd2 },
+	{ OV2735_PAGE_REG8(0x01, 0x2c),		0x40 },
+	{ OV2735_PAGE_REG8(0x01, 0xd0),		0x02 },
+	{ OV2735_PAGE_REG8(0x01, 0xd1),		0x01 },
+	{ OV2735_PAGE_REG8(0x01, 0xd2),		0x20 },
+	{ OV2735_PAGE_REG8(0x01, 0xd3),		0x04 },
+	{ OV2735_PAGE_REG8(0x01, 0xd4),		0x2a },
+	{ OV2735_PAGE_REG8(0x01, 0x50),		0x00 },
+	{ OV2735_PAGE_REG8(0x01, 0x51),		0x2c },
+	{ OV2735_PAGE_REG8(0x01, 0x52),		0x29 },
+	{ OV2735_PAGE_REG8(0x01, 0x53),		0x00 },
+	{ OV2735_PAGE_REG8(0x01, 0x55),		0x44 },
+	{ OV2735_PAGE_REG8(0x01, 0x58),		0x29 },
+	{ OV2735_PAGE_REG8(0x01, 0x5a),		0x00 },
+	{ OV2735_PAGE_REG8(0x01, 0x5b),		0x00 },
+	{ OV2735_PAGE_REG8(0x01, 0x5d),		0x00 },
+	{ OV2735_PAGE_REG8(0x01, 0x64),		0x2f },
+	{ OV2735_PAGE_REG8(0x01, 0x66),		0x62 },
+	{ OV2735_PAGE_REG8(0x01, 0x68),		0x5b },
+	{ OV2735_PAGE_REG8(0x01, 0x75),		0x46 },
+	{ OV2735_PAGE_REG8(0x01, 0x76),		0x36 },
+	{ OV2735_PAGE_REG8(0x01, 0x77),		0x4f },
+	{ OV2735_PAGE_REG8(0x01, 0x78),		0xef },
+	{ OV2735_PAGE_REG8(0x01, 0x72),		0xcf },
+	{ OV2735_PAGE_REG8(0x01, 0x73),		0x36 },
+	{ OV2735_PAGE_REG8(0x01, 0x7d),		0x0d },
+	{ OV2735_PAGE_REG8(0x01, 0x7e),		0x0d },
+	{ OV2735_PAGE_REG8(0x01, 0x8a),		0x77 },
+	{ OV2735_PAGE_REG8(0x01, 0x8b),		0x77 },
+
+	{ OV2735_REG_HS_MIPI,			0x83 },
+	{ OV2735_REG_MIPI_CTRL5,		0x0b },
+	{ OV2735_REG_MIPI_CTRL6,		0x14 },
+	{ OV2735_PAGE_REG8(0x01, 0x9d),		0x40 },
+	{ OV2735_REG_MIPI_CTRL3,		0x05 },
+	{ OV2735_REG_MIPI_CTRL2,		0x44 },
+	{ OV2735_REG_PREPARE,			0x33 },
+	{ OV2735_REG_R_HS_ZERO,			0x1f },
+	{ OV2735_REG_TRAIL,			0x45 },
+	{ OV2735_REG_R_CLK_ZERO,		0x10 },
+	{ OV2735_REG_MIPI_CTRL7,		0x70 },
+	{ OV2735_REG_ANALOG_CTRL3,		0xe0 },
+	{ OV2735_REG_VNCP,			0x7b },
+
+	/* BLC */
+	{ OV2735_REG_BLC_GAIN_BLUE,		0x77 },
+	{ OV2735_REG_BLC_GAIN_GB,		0x77 },
+	{ OV2735_REG_BLC_GAIN_RED,		0x74 },
+	{ OV2735_REG_BLC_GAIN_GR,		0x74 },
+	{ OV2735_REG_BLC_BPC_TH_P,		0xe0 },
+	{ OV2735_REG_BLC_BPC_TH_N,		0xe0 },
+	{ OV2735_REG_GB_SUBOFFSET,		0x40 },
+	{ OV2735_REG_BLUE_SUBOFFSET,		0x40 },
+	{ OV2735_REG_RED_SUBOFFSET,		0x40 },
+	{ OV2735_REG_GR_SUBOFFSET,		0x40 },
+};
+
+static const struct ov2735_mode supported_modes[] = {
+	{
+		.width = 1920,
+		.height = 1080,
+		.exp_def = 399,
+		.hts_def = 2200,
+		.vts_def = 2545,
+		.crop = {
+			.top = 8,
+			.left = 8,
+			.width = 1920,
+			.height = 1080,
+		},
+	},
+};
+
+static const s64 link_freq_menu_items[] = {
+	OV2735_LINK_FREQ_420MHZ,
+};
+
+struct ov2735_pll_parameters pll_configs[] = {
+	/* For 420MHz pll_configs. */
+	{
+		.pll_nc = 4,
+		.pll_mc = 0,
+		.pll_outdiv = 1,
+	},
+};
+
+static const char * const ov2735_test_pattern_menu[] = {
+	"Disabled",
+	"Vertical Color",
+};
+
+static int ov2735_page_access(struct ov2735 *ov2735,
+			      u32 reg, void *val, int *err, bool is_read)
+{
+	u8 page = (reg >> CCI_REG_PRIVATE_SHIFT) & 0xff;
+	u32 addr = reg & ~CCI_REG_PRIVATE_MASK;
+	int ret = 0;
+
+	if (err && *err)
+		return *err;
+
+	mutex_lock(&ov2735->page_lock);
+
+	/* Perform page access before read/write */
+	if (ov2735->current_page != page) {
+		ret = cci_write(ov2735->cci, OV2735_REG_PAGE_SELECT, page, &ret);
+		if (ret)
+			goto err_mutex_unlock;
+		ov2735->current_page = page;
+	}
+
+	if (is_read)
+		ret = cci_read(ov2735->cci, addr, (u64 *)val, err);
+	else
+		ret = cci_write(ov2735->cci, addr, *(u64 *)val, err);
+
+err_mutex_unlock:
+	if (ret && err)
+		*err = ret;
+
+	mutex_unlock(&ov2735->page_lock);
+	return ret;
+}
+
+static int ov2735_read(struct ov2735 *ov2735, u32 reg, u64 *val, int *err)
+{
+	return ov2735_page_access(ov2735, reg, val, err, true);
+}
+
+static int ov2735_write(struct ov2735 *ov2735, u32 reg, u64 val, int *err)
+{
+	return ov2735_page_access(ov2735, reg, (void *)&val, err, false);
+}
+
+static int ov2735_multi_reg_write(struct ov2735 *ov2735,
+				  const struct cci_reg_sequence *regs,
+				  unsigned int num_regs, int *err)
+{
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < num_regs; i++) {
+		ret = ov2735_write(ov2735, regs[i].reg, regs[i].val, err);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static inline struct ov2735 *to_ov2735(struct v4l2_subdev *_sd)
+{
+	return container_of(_sd, struct ov2735, sd);
+}
+
+static int ov2735_enable_test_pattern(struct ov2735 *ov2735, u32 pattern)
+{
+	int ret;
+	u64 val;
+
+	ret = ov2735_read(ov2735, OV2735_REG_TEST_PATTERN, &val, NULL);
+	if (ret)
+		return ret;
+
+	switch (pattern) {
+	case 0:
+		val &= ~OV2735_TEST_PATTERN_ENABLE;
+		break;
+	case 1:
+		val |= OV2735_TEST_PATTERN_ENABLE;
+		break;
+	}
+
+	return ov2735_write(ov2735, OV2735_REG_TEST_PATTERN, val, NULL);
+}
+
+static int ov2735_set_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct ov2735 *ov2735 = container_of(ctrl->handler, struct ov2735,
+					     handler);
+	struct v4l2_mbus_framefmt *fmt;
+	struct v4l2_subdev_state *state;
+	u64 vts;
+	int ret = 0;
+
+	state = v4l2_subdev_get_locked_active_state(&ov2735->sd);
+	fmt = v4l2_subdev_state_get_format(state, 0);
+
+	if (ctrl->id == V4L2_CID_VBLANK) {
+		/* Honour the VBLANK limits when setting exposure. */
+		s64 max = fmt->height + ctrl->val - 4;
+
+		ret = __v4l2_ctrl_modify_range(ov2735->exposure,
+					       ov2735->exposure->minimum, max,
+					       ov2735->exposure->step,
+					       ov2735->exposure->default_value);
+		if (ret)
+			return ret;
+	}
+
+	/*
+	 * Applying V4L2 control value only happens
+	 * when power is up for streaming.
+	 */
+	if (pm_runtime_get_if_in_use(ov2735->dev) == 0)
+		return 0;
+
+	switch (ctrl->id) {
+	case V4L2_CID_EXPOSURE:
+		ov2735_write(ov2735, OV2735_REG_LONG_EXPOSURE, ctrl->val, &ret);
+		break;
+	case V4L2_CID_ANALOGUE_GAIN:
+		ov2735_write(ov2735, OV2735_REG_ANALOG_GAIN, ctrl->val, &ret);
+		break;
+	case V4L2_CID_HBLANK:
+		ov2735_write(ov2735, OV2735_REG_HBLANK, ctrl->val, &ret);
+		break;
+	case V4L2_CID_VBLANK:
+		vts = ctrl->val + fmt->height;
+		ov2735_write(ov2735, OV2735_REG_FRAME_EXP_SEPERATE_EN,
+			     OV2735_FRAME_EXP_SEPERATE_EN, &ret);
+		ov2735_write(ov2735, OV2735_REG_FRAME_LENGTH, vts, &ret);
+		break;
+	case V4L2_CID_TEST_PATTERN:
+		ret = ov2735_enable_test_pattern(ov2735, ctrl->val);
+		break;
+	default:
+		dev_err(ov2735->dev, "ctrl(id:0x%x, val:0x%x) is not handled\n",
+			ctrl->id, ctrl->val);
+		break;
+	}
+	ov2735_write(ov2735, OV2735_REG_FRAME_SYNC, 0x01, &ret);
+
+	pm_runtime_put(ov2735->dev);
+
+	return ret;
+}
+
+static const struct v4l2_ctrl_ops ov2735_ctrl_ops = {
+	.s_ctrl = ov2735_set_ctrl,
+};
+
+static int ov2735_init_controls(struct ov2735 *ov2735)
+{
+	struct v4l2_ctrl_handler *ctrl_hdlr;
+	struct v4l2_fwnode_device_properties props;
+	const struct ov2735_mode *mode = &supported_modes[0];
+	u64 hblank_def, vblank_def, exp_max;
+	int ret;
+
+	ctrl_hdlr = &ov2735->handler;
+	ret = v4l2_ctrl_handler_init(ctrl_hdlr, 9);
+	if (ret)
+		return ret;
+
+	ov2735->pixel_rate = v4l2_ctrl_new_std(ctrl_hdlr, &ov2735_ctrl_ops,
+					       V4L2_CID_PIXEL_RATE, 0, OV2735_PIXEL_RATE,
+					       1, OV2735_PIXEL_RATE);
+
+	ov2735->link_freq = v4l2_ctrl_new_int_menu(ctrl_hdlr, &ov2735_ctrl_ops,
+						   V4L2_CID_LINK_FREQ,
+						   ov2735->link_freq_index,
+						   0, link_freq_menu_items);
+	if (ov2735->link_freq)
+		ov2735->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
+
+	hblank_def = mode->hts_def - mode->width;
+	ov2735->hblank = v4l2_ctrl_new_std(ctrl_hdlr, &ov2735_ctrl_ops, V4L2_CID_HBLANK,
+					   hblank_def, hblank_def, 1, hblank_def);
+
+	vblank_def = mode->vts_def - mode->height;
+	ov2735->vblank = v4l2_ctrl_new_std(ctrl_hdlr, &ov2735_ctrl_ops,
+					   V4L2_CID_VBLANK, vblank_def,
+					   OV2735_VTS_MAX - mode->height,
+					   1, vblank_def);
+
+	exp_max = mode->vts_def - 4;
+	ov2735->exposure = v4l2_ctrl_new_std(ctrl_hdlr, &ov2735_ctrl_ops,
+					     V4L2_CID_EXPOSURE, OV2735_EXPOSURE_MIN,
+					     exp_max, OV2735_EXPOSURE_STEP, mode->exp_def);
+
+	ov2735->gain = v4l2_ctrl_new_std(ctrl_hdlr, &ov2735_ctrl_ops,
+					 V4L2_CID_ANALOGUE_GAIN, OV2735_ANALOG_GAIN_MIN,
+					 OV2735_ANALOG_GAIN_MAX, OV2735_ANALOG_GAIN_STEP,
+					 OV2735_ANALOG_GAIN_DEFAULT);
+
+	ov2735->test_pattern = v4l2_ctrl_new_std_menu_items(ctrl_hdlr,
+						&ov2735_ctrl_ops, V4L2_CID_TEST_PATTERN,
+						ARRAY_SIZE(ov2735_test_pattern_menu) - 1,
+						0, 0, ov2735_test_pattern_menu);
+	if (ctrl_hdlr->error) {
+		ret = ctrl_hdlr->error;
+		dev_err(ov2735->dev, "control init failed (%d)\n", ret);
+		goto err_handler_free;
+	}
+
+	ret = v4l2_fwnode_device_parse(ov2735->dev, &props);
+	if (ret)
+		goto err_handler_free;
+
+	ret = v4l2_ctrl_new_fwnode_properties(ctrl_hdlr,
+					      &ov2735_ctrl_ops, &props);
+	if (ret)
+		goto err_handler_free;
+
+	ov2735->sd.ctrl_handler = ctrl_hdlr;
+
+	return 0;
+
+err_handler_free:
+	v4l2_ctrl_handler_free(ctrl_hdlr);
+
+	return ret;
+}
+
+static int ov2735_set_pll_ctrl(struct ov2735 *ov2735)
+{
+	struct ov2735_pll_parameters *pll_parameters;
+	u8 pll_ctrl;
+	u8 pll_outdiv;
+	int ret = 0;
+
+	pll_parameters = &pll_configs[ov2735->link_freq_index];
+
+	/* BIT[7]: pll_clk_sel, BIT[6:2]: pll_nc, BIT[1:0]: pll_mc */
+	pll_ctrl = ((pll_parameters->pll_nc << 2) |
+		    (pll_parameters->pll_mc)) & OV2735_REG_PLL_ENABLE;
+
+	pll_outdiv = pll_parameters->pll_outdiv;
+
+	ov2735_write(ov2735, OV2735_REG_PLL_CTRL, pll_ctrl, &ret);
+	ov2735_write(ov2735, OV2735_REG_PLL_OUTDIV, pll_outdiv, &ret);
+
+	return ret;
+}
+
+static int ov2735_set_framefmt(struct ov2735 *ov2735,
+			       struct v4l2_subdev_state *state)
+{
+	const struct v4l2_mbus_framefmt *format;
+	const struct v4l2_rect *crop;
+	int ret = 0;
+
+	format = v4l2_subdev_state_get_format(state, 0);
+	crop = v4l2_subdev_state_get_crop(state, 0);
+
+	ov2735_write(ov2735, OV2735_REG_V_START, crop->top, &ret);
+	ov2735_write(ov2735, OV2735_REG_V_SIZE, format->height, &ret);
+	ov2735_write(ov2735, OV2735_REG_MIPI_LINE_NUMBER, format->height, &ret);
+	ov2735_write(ov2735, OV2735_REG_H_START, crop->left, &ret);
+	/* OV2735_REG_H_SIZE: Image half horizontal size */
+	ov2735_write(ov2735, OV2735_REG_H_SIZE, (format->width / 2), &ret);
+	ov2735_write(ov2735, OV2735_REG_MIPI_COLOMN_NUMBER, format->width, &ret);
+
+	return ret;
+}
+
+static int ov2735_enable_streams(struct v4l2_subdev *sd,
+				 struct v4l2_subdev_state *state, u32 pad,
+				 u64 streams_mask)
+{
+	struct ov2735 *ov2735 = to_ov2735(sd);
+	const struct ov2735_mode *mode;
+	const struct v4l2_mbus_framefmt *fmt;
+	int ret;
+
+	fmt = v4l2_subdev_state_get_format(state, 0);
+	mode = v4l2_find_nearest_size(supported_modes,
+				      ARRAY_SIZE(supported_modes),
+				      width, height,
+				      fmt->width, fmt->height);
+
+	ret = pm_runtime_resume_and_get(ov2735->dev);
+	if (ret < 0)
+		return ret;
+
+	/* Apply pll settings. */
+	ret = ov2735_set_pll_ctrl(ov2735);
+	if (ret) {
+		dev_err(ov2735->dev, "failed to set frame format: %d\n", ret);
+		goto err_rpm_put;
+	}
+
+	ret = ov2735_multi_reg_write(ov2735, ov2735_common_regs,
+				     ARRAY_SIZE(ov2735_common_regs), NULL);
+	if (ret) {
+		dev_err(ov2735->dev, "%s failed to send mfg header\n", __func__);
+		goto err_rpm_put;
+	}
+
+	/* Apply format settings. */
+	ret = ov2735_set_framefmt(ov2735, state);
+	if (ret) {
+		dev_err(ov2735->dev, "failed to set frame format: %d\n", ret);
+		goto err_rpm_put;
+	}
+
+	/* Apply customized values from user */
+	ret = __v4l2_ctrl_handler_setup(ov2735->sd.ctrl_handler);
+	if (ret)
+		goto err_rpm_put;
+
+	/* set stream on register */
+	ret = ov2735_write(ov2735, OV2735_REG_STREAM_CTRL, OV2735_STREAM_ON, NULL);
+	if (ret)
+		goto err_rpm_put;
+
+	return 0;
+
+err_rpm_put:
+	pm_runtime_put(ov2735->dev);
+	return ret;
+}
+
+static int ov2735_disable_streams(struct v4l2_subdev *sd,
+				  struct v4l2_subdev_state *state, u32 pad,
+				  u64 streams_mask)
+{
+	struct ov2735 *ov2735 = to_ov2735(sd);
+	int ret;
+
+	/* set stream off register */
+	ret = ov2735_write(ov2735, OV2735_REG_STREAM_CTRL, OV2735_STREAM_OFF, NULL);
+	if (ret)
+		dev_err(ov2735->dev, "%s failed to set stream\n", __func__);
+
+	pm_runtime_put(ov2735->dev);
+
+	return ret;
+}
+
+static int ov2735_get_selection(struct v4l2_subdev *sd,
+				struct v4l2_subdev_state *sd_state,
+				struct v4l2_subdev_selection *sel)
+{
+	switch (sel->target) {
+	case V4L2_SEL_TGT_CROP: {
+		sel->r = *v4l2_subdev_state_get_crop(sd_state, 0);
+		return 0;
+	}
+
+	case V4L2_SEL_TGT_NATIVE_SIZE:
+		sel->r = ov2735_native_area;
+		return 0;
+
+	case V4L2_SEL_TGT_CROP_DEFAULT:
+	case V4L2_SEL_TGT_CROP_BOUNDS:
+		sel->r = ov2735_active_area;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ov2735_enum_mbus_code(struct v4l2_subdev *sd,
+				 struct v4l2_subdev_state *sd_state,
+				 struct v4l2_subdev_mbus_code_enum *code)
+{
+	if (code->index >= 0)
+		return -EINVAL;
+
+	code->code = MEDIA_BUS_FMT_SGRBG10_1X10;
+
+	return 0;
+}
+
+static int ov2735_enum_frame_size(struct v4l2_subdev *sd,
+				  struct v4l2_subdev_state *sd_state,
+				  struct v4l2_subdev_frame_size_enum *fse)
+{
+	u32 code;
+
+	if (fse->index >= ARRAY_SIZE(supported_modes))
+		return -EINVAL;
+
+	code = MEDIA_BUS_FMT_SGRBG10_1X10;
+	if (fse->code != code)
+		return -EINVAL;
+
+	fse->min_width = supported_modes[fse->index].width;
+	fse->max_width = fse->min_width;
+	fse->min_height = supported_modes[fse->index].height;
+	fse->max_height = fse->min_height;
+
+	return 0;
+}
+
+static void ov2735_set_framing_limits(struct ov2735 *ov2735,
+				      const struct ov2735_mode *mode)
+{
+	u32 hblank, vblank_def;
+
+	hblank = mode->hts_def - mode->width;
+	__v4l2_ctrl_modify_range(ov2735->hblank, hblank, hblank, 1, hblank);
+
+	vblank_def = mode->vts_def - mode->height;
+	__v4l2_ctrl_modify_range(ov2735->vblank, vblank_def,
+				 OV2735_VTS_MAX - mode->height, 1, vblank_def);
+}
+
+static int ov2735_set_pad_format(struct v4l2_subdev *sd,
+				 struct v4l2_subdev_state *sd_state,
+				 struct v4l2_subdev_format *fmt)
+{
+	struct v4l2_mbus_framefmt *format;
+	const struct ov2735_mode *mode;
+	struct v4l2_rect *crop;
+	struct ov2735 *ov2735 = to_ov2735(sd);
+
+	format = v4l2_subdev_state_get_format(sd_state, 0);
+
+	mode = v4l2_find_nearest_size(supported_modes,
+				      ARRAY_SIZE(supported_modes),
+				      width, height,
+				      fmt->format.width, fmt->format.height);
+
+	fmt->format.width = mode->width;
+	fmt->format.height = mode->height;
+	fmt->format.field = V4L2_FIELD_NONE;
+	fmt->format.colorspace = V4L2_COLORSPACE_RAW;
+	fmt->format.quantization = V4L2_QUANTIZATION_FULL_RANGE;
+	fmt->format.xfer_func = V4L2_XFER_FUNC_NONE;
+
+	if (fmt->which == V4L2_SUBDEV_FORMAT_ACTIVE)
+		ov2735_set_framing_limits(ov2735, mode);
+
+	*format = fmt->format;
+
+	/* Initialize crop rectangle */
+	crop = v4l2_subdev_state_get_crop(sd_state, 0);
+	*crop = mode->crop;
+
+	return 0;
+}
+
+static int ov2735_init_state(struct v4l2_subdev *sd,
+			     struct v4l2_subdev_state *state)
+{
+	struct v4l2_subdev_format fmt = {
+		.which = V4L2_SUBDEV_FORMAT_TRY,
+		.pad = 0,
+		.format = {
+			.code = MEDIA_BUS_FMT_SGRBG10_1X10,
+			.width = supported_modes[0].width,
+			.height = supported_modes[0].height,
+		},
+	};
+
+	ov2735_set_pad_format(sd, state, &fmt);
+
+	return 0;
+}
+
+static const struct v4l2_subdev_video_ops ov2735_video_ops = {
+	.s_stream = v4l2_subdev_s_stream_helper,
+};
+
+static const struct v4l2_subdev_pad_ops ov2735_pad_ops = {
+	.enum_mbus_code = ov2735_enum_mbus_code,
+	.get_fmt = v4l2_subdev_get_fmt,
+	.set_fmt = ov2735_set_pad_format,
+	.get_selection = ov2735_get_selection,
+	.enum_frame_size = ov2735_enum_frame_size,
+	.enable_streams = ov2735_enable_streams,
+	.disable_streams = ov2735_disable_streams,
+};
+
+static const struct v4l2_subdev_ops ov2735_subdev_ops = {
+	.video = &ov2735_video_ops,
+	.pad = &ov2735_pad_ops,
+};
+
+static const struct v4l2_subdev_internal_ops ov2735_internal_ops = {
+	.init_state = ov2735_init_state,
+};
+
+static int ov2735_power_on(struct device *dev)
+{
+	struct v4l2_subdev *sd = dev_get_drvdata(dev);
+	struct ov2735 *ov2735 = to_ov2735(sd);
+	int ret;
+
+	gpiod_set_value_cansleep(ov2735->enable_gpio, 0);
+	/* Ensure device is inactive (PWDN high) before enabling power rails.
+	 * As per datasheet, the PWDN pin (named 'enable_gpio' here) should be
+	 * pulled low only after all power rails are stable.
+	 */
+	fsleep(3000);
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(ov2735_supply_name),
+				    ov2735->supplies);
+	if (ret) {
+		dev_err(ov2735->dev, "failed to enable regulators\n");
+		return ret;
+	}
+
+	gpiod_set_value_cansleep(ov2735->enable_gpio, 1);
+	/* T4: Delay from PWDN pulling low to RSTB pulling high. */
+	fsleep(4000);
+
+	ret = clk_prepare_enable(ov2735->xclk);
+	if (ret) {
+		dev_err(ov2735->dev, "failed to enable clock\n");
+		goto err_regulator_off;
+	}
+
+	gpiod_set_value_cansleep(ov2735->reset_gpio, 0);
+	/* T5: Delay from RSTB pulling high to first I2C command. */
+	fsleep(5000);
+
+	return 0;
+
+err_regulator_off:
+	regulator_bulk_disable(ARRAY_SIZE(ov2735_supply_name), ov2735->supplies);
+	return ret;
+}
+
+static int ov2735_power_off(struct device *dev)
+{
+	struct v4l2_subdev *sd = dev_get_drvdata(dev);
+	struct ov2735 *ov2735 = to_ov2735(sd);
+
+	gpiod_set_value_cansleep(ov2735->enable_gpio, 0);
+	clk_disable_unprepare(ov2735->xclk);
+	gpiod_set_value_cansleep(ov2735->reset_gpio, 1);
+	regulator_bulk_disable(ARRAY_SIZE(ov2735_supply_name), ov2735->supplies);
+
+	return 0;
+}
+
+static int ov2735_get_regulators(struct ov2735 *ov2735)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(ov2735_supply_name); i++)
+		ov2735->supplies[i].supply = ov2735_supply_name[i];
+
+	return devm_regulator_bulk_get(ov2735->dev,
+				       ARRAY_SIZE(ov2735_supply_name),
+				       ov2735->supplies);
+}
+
+static int ov2735_identify_module(struct ov2735 *ov2735)
+{
+	u64 chip_id;
+	int ret;
+
+	ret = ov2735_read(ov2735, OV2735_REG_CHIPID, &chip_id, NULL);
+	if (ret)
+		return dev_err_probe(ov2735->dev, ret, "failed to read chip id %x\n",
+				     OV2735_CHIPID);
+
+	if (chip_id != OV2735_CHIPID)
+		return dev_err_probe(ov2735->dev, -EIO, "chip id mismatch: %x!=%llx\n",
+				     OV2735_CHIPID, chip_id);
+
+	return 0;
+}
+
+static int ov2735_parse_endpoint(struct ov2735 *ov2735)
+{
+	struct fwnode_handle *fwnode;
+	struct v4l2_fwnode_endpoint bus_cfg = {
+		.bus_type = V4L2_MBUS_CSI2_DPHY,
+	};
+	struct fwnode_handle *ep;
+	unsigned long link_freq_bitmap;
+	int ret;
+
+	fwnode = dev_fwnode(ov2735->dev);
+	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
+	if (!ep)
+		return dev_err_probe(ov2735->dev,
+				     -ENXIO, "Failed to get next endpoint\n");
+
+	ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
+	fwnode_handle_put(ep);
+	if (ret)
+		return ret;
+
+	if (bus_cfg.bus.mipi_csi2.num_data_lanes != 2) {
+		ret = dev_err_probe(ov2735->dev,
+				    -EINVAL, "only 2 data lanes are supported\n");
+		goto error_out;
+	}
+
+	ret = v4l2_link_freq_to_bitmap(ov2735->dev, bus_cfg.link_frequencies,
+				       bus_cfg.nr_of_link_frequencies,
+				       link_freq_menu_items,
+				       ARRAY_SIZE(link_freq_menu_items),
+				       &link_freq_bitmap);
+	if (ret) {
+		ret = dev_err_probe(ov2735->dev,
+				    -EINVAL, "only 420MHz frequency is available\n");
+		goto error_out;
+	}
+
+	ov2735->link_freq_index = __ffs(link_freq_bitmap);
+
+error_out:
+	v4l2_fwnode_endpoint_free(&bus_cfg);
+
+	return ret;
+};
+
+static int ov2735_probe(struct i2c_client *client)
+{
+	struct ov2735 *ov2735;
+	unsigned int xclk_freq;
+	int ret;
+
+	ov2735 = devm_kzalloc(&client->dev, sizeof(*ov2735), GFP_KERNEL);
+	if (!ov2735)
+		return -ENOMEM;
+
+	ov2735->client = client;
+	ov2735->dev = &client->dev;
+
+	v4l2_i2c_subdev_init(&ov2735->sd, client, &ov2735_subdev_ops);
+	ov2735->sd.internal_ops = &ov2735_internal_ops;
+
+	ov2735->cci = devm_cci_regmap_init_i2c(client, 8);
+	if (IS_ERR(ov2735->cci))
+		return dev_err_probe(ov2735->dev, PTR_ERR(ov2735->cci),
+				     "failed to initialize CCI\n");
+
+	/* Set Current page to 0 */
+	ov2735->current_page = 0;
+
+	ret = devm_mutex_init(ov2735->dev, &ov2735->page_lock);
+		if (ret)
+			return dev_err_probe(ov2735->dev, ret,
+					     "Failed to initialize lock\n");
+
+	/* Get system clock (xvclk) */
+	ov2735->xclk = devm_v4l2_sensor_clk_get(ov2735->dev, NULL);
+	if (IS_ERR(ov2735->xclk))
+		return dev_err_probe(ov2735->dev, PTR_ERR(ov2735->xclk),
+				     "failed to get xclk\n");
+
+	xclk_freq = clk_get_rate(ov2735->xclk);
+	if (xclk_freq != OV2735_XCLK_FREQ)
+		return dev_err_probe(ov2735->dev, -EINVAL,
+				     "xclk frequency not supported: %d Hz\n",
+				     xclk_freq);
+
+	ret = ov2735_get_regulators(ov2735);
+	if (ret)
+		return dev_err_probe(ov2735->dev, ret, "failed to get regulators\n");
+
+	ret = ov2735_parse_endpoint(ov2735);
+	if (ret)
+		return dev_err_probe(ov2735->dev, ret,
+				     "failed to parse endpoint configuration\n");
+
+	ov2735->reset_gpio = devm_gpiod_get_optional(ov2735->dev,
+						     "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(ov2735->reset_gpio))
+		return dev_err_probe(ov2735->dev, PTR_ERR(ov2735->reset_gpio),
+				     "failed to get reset GPIO\n");
+
+	ov2735->enable_gpio = devm_gpiod_get_optional(ov2735->dev,
+						      "enable", GPIOD_OUT_LOW);
+	if (IS_ERR(ov2735->enable_gpio))
+		return dev_err_probe(ov2735->dev, PTR_ERR(ov2735->enable_gpio),
+				     "failed to get enable GPIO\n");
+
+	ret = ov2735_power_on(ov2735->dev);
+	if (ret)
+		return ret;
+
+	ret = ov2735_identify_module(ov2735);
+	if (ret)
+		goto error_power_off;
+
+	ret = ov2735_init_controls(ov2735);
+	if (ret)
+		goto error_power_off;
+
+	/* Initialize subdev */
+	ov2735->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	ov2735->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
+	ov2735->pad.flags = MEDIA_PAD_FL_SOURCE;
+
+	ret = media_entity_pads_init(&ov2735->sd.entity, 1, &ov2735->pad);
+	if (ret) {
+		dev_err_probe(ov2735->dev, ret, "failed to init entity pads\n");
+		goto error_handler_free;
+	}
+
+	ov2735->sd.state_lock = ov2735->handler.lock;
+	ret = v4l2_subdev_init_finalize(&ov2735->sd);
+	if (ret) {
+		dev_err_probe(ov2735->dev, ret, "subdev init error\n");
+		goto error_media_entity;
+	}
+
+	devm_pm_runtime_set_active_enabled(ov2735->dev);
+	devm_pm_runtime_get_noresume(ov2735->dev);
+
+	ret = v4l2_async_register_subdev_sensor(&ov2735->sd);
+	if (ret) {
+		dev_err_probe(ov2735->dev, ret,
+			      "failed to register ov2735 sub-device\n");
+		goto error_subdev_cleanup;
+	}
+
+	return 0;
+
+error_subdev_cleanup:
+	v4l2_subdev_cleanup(&ov2735->sd);
+
+error_media_entity:
+	media_entity_cleanup(&ov2735->sd.entity);
+
+error_handler_free:
+	v4l2_ctrl_handler_free(ov2735->sd.ctrl_handler);
+
+error_power_off:
+	ov2735_power_off(ov2735->dev);
+
+	return ret;
+}
+
+static void ov2735_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct ov2735 *ov2735 = to_ov2735(sd);
+
+	v4l2_async_unregister_subdev(sd);
+	v4l2_subdev_cleanup(&ov2735->sd);
+	media_entity_cleanup(&sd->entity);
+	v4l2_ctrl_handler_free(ov2735->sd.ctrl_handler);
+}
+
+static DEFINE_RUNTIME_DEV_PM_OPS(ov2735_pm_ops,
+				 ov2735_power_off, ov2735_power_on, NULL);
+
+static const struct of_device_id ov2735_id[] = {
+	{ .compatible = "ovti,ov2735" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ov2735_id);
+
+static struct i2c_driver ov2735_driver = {
+	.driver = {
+		.name = "ov2735",
+		.pm = pm_ptr(&ov2735_pm_ops),
+		.of_match_table = ov2735_id,
+	},
+	.probe = ov2735_probe,
+	.remove = ov2735_remove,
+};
+module_i2c_driver(ov2735_driver);
+
+MODULE_DESCRIPTION("OV2735 Camera Sensor Driver");
+MODULE_AUTHOR("Hardevsinh Palaniya <hardevsinh.palaniya@siliconsignals.io>");
+MODULE_AUTHOR("Himanshu Bhavani <himanshu.bhavani@siliconsignals.io>");
+MODULE_LICENSE("GPL");
-- 
2.34.1

Re: [PATCH v4 2/2] media: i2c: add ov2735 image sensor driver

[Andy Shevchenko]

On Wed, Jul 16, 2025 at 07:14:17PM +0530, Hardevsinh Palaniya wrote:
> Add a v4l2 subdevice driver for the Omnivision OV2735 sensor.
> 
> The Omnivision OV2735 is a 1/2.7-Inch CMOS image sensor with an
> active array size of 1920 x 1080.
> 
> The following features are supported:
> - Manual exposure an gain control support
> - vblank/hblank control support
> - Test pattern support control
> - Supported resolution: 1920 x 1080 @ 30fps (SGRBG10)

...

> +static int ov2735_page_access(struct ov2735 *ov2735,
> +			      u32 reg, void *val, int *err, bool is_read)
> +{
> +	u8 page = (reg >> CCI_REG_PRIVATE_SHIFT) & 0xff;
> +	u32 addr = reg & ~CCI_REG_PRIVATE_MASK;
> +	int ret = 0;
> +
> +	if (err && *err)
> +		return *err;
> +
> +	mutex_lock(&ov2735->page_lock);
> +
> +	/* Perform page access before read/write */
> +	if (ov2735->current_page != page) {
> +		ret = cci_write(ov2735->cci, OV2735_REG_PAGE_SELECT, page, &ret);
> +		if (ret)
> +			goto err_mutex_unlock;
> +		ov2735->current_page = page;
> +	}
> +
> +	if (is_read)
> +		ret = cci_read(ov2735->cci, addr, (u64 *)val, err);
> +	else
> +		ret = cci_write(ov2735->cci, addr, *(u64 *)val, err);
> +
> +err_mutex_unlock:

> +	if (ret && err)

Why do you need to check for ret != 0?

> +		*err = ret;
> +
> +	mutex_unlock(&ov2735->page_lock);
> +	return ret;
> +}

...

> +{
> +	struct ov2735_pll_parameters *pll_parameters;
> +	u8 pll_ctrl;
> +	u8 pll_outdiv;
> +	int ret = 0;
> +
> +	pll_parameters = &pll_configs[ov2735->link_freq_index];
> +
> +	/* BIT[7]: pll_clk_sel, BIT[6:2]: pll_nc, BIT[1:0]: pll_mc */
> +	pll_ctrl = ((pll_parameters->pll_nc << 2) |
> +		    (pll_parameters->pll_mc)) & OV2735_REG_PLL_ENABLE;

Not sure why here are the parentheses. Perhaps you wanted to show the 0 shift?

		    (pll_parameters->pll_mc << 0)) & OV2735_REG_PLL_ENABLE;

> +	pll_outdiv = pll_parameters->pll_outdiv;
> +
> +	ov2735_write(ov2735, OV2735_REG_PLL_CTRL, pll_ctrl, &ret);
> +	ov2735_write(ov2735, OV2735_REG_PLL_OUTDIV, pll_outdiv, &ret);
> +
> +	return ret;
> +}

...

> +static int ov2735_get_selection(struct v4l2_subdev *sd,
> +				struct v4l2_subdev_state *sd_state,
> +				struct v4l2_subdev_selection *sel)
> +{
> +	switch (sel->target) {

> +	case V4L2_SEL_TGT_CROP: {
> +		sel->r = *v4l2_subdev_state_get_crop(sd_state, 0);
> +		return 0;
> +	}

Why {} ?

> +	case V4L2_SEL_TGT_NATIVE_SIZE:
> +		sel->r = ov2735_native_area;
> +		return 0;

> +

This blank line is inconsistent with the rest.

> +	case V4L2_SEL_TGT_CROP_DEFAULT:
> +	case V4L2_SEL_TGT_CROP_BOUNDS:
> +		sel->r = ov2735_active_area;
> +		return 0;
> +	default:
> +		return -EINVAL;
> +	}
> +}

...

> +static int ov2735_init_state(struct v4l2_subdev *sd,
> +			     struct v4l2_subdev_state *state)
> +{
> +	struct v4l2_subdev_format fmt = {
> +		.which = V4L2_SUBDEV_FORMAT_TRY,

> +		.pad = 0,

It's zeroed by default.

> +		.format = {
> +			.code = MEDIA_BUS_FMT_SGRBG10_1X10,
> +			.width = supported_modes[0].width,
> +			.height = supported_modes[0].height,
> +		},
> +	};

> +	ov2735_set_pad_format(sd, state, &fmt);
> +
> +	return 0;
> +}

...

> +static int ov2735_power_on(struct device *dev)
> +{
> +	struct v4l2_subdev *sd = dev_get_drvdata(dev);
> +	struct ov2735 *ov2735 = to_ov2735(sd);
> +	int ret;
> +
> +	gpiod_set_value_cansleep(ov2735->enable_gpio, 0);
> +	/* Ensure device is inactive (PWDN high) before enabling power rails.
> +	 * As per datasheet, the PWDN pin (named 'enable_gpio' here) should be
> +	 * pulled low only after all power rails are stable.
> +	 */

/*
 * Use correct multi-line style
 * for the comments. Here is an
 * example.
 *.

> +	fsleep(3000);

Here and everywhere else consider using

	fsleep(3 * USEC_PER_MSEC);

which will hint the user what is the units of the value
(i.e. 3ms in this case).

> +	ret = regulator_bulk_enable(ARRAY_SIZE(ov2735_supply_name),
> +				    ov2735->supplies);
> +	if (ret) {
> +		dev_err(ov2735->dev, "failed to enable regulators\n");
> +		return ret;
> +	}
> +
> +	gpiod_set_value_cansleep(ov2735->enable_gpio, 1);
> +	/* T4: Delay from PWDN pulling low to RSTB pulling high. */
> +	fsleep(4000);
> +
> +	ret = clk_prepare_enable(ov2735->xclk);
> +	if (ret) {
> +		dev_err(ov2735->dev, "failed to enable clock\n");
> +		goto err_regulator_off;
> +	}
> +
> +	gpiod_set_value_cansleep(ov2735->reset_gpio, 0);
> +	/* T5: Delay from RSTB pulling high to first I2C command. */
> +	fsleep(5000);
> +
> +	return 0;
> +
> +err_regulator_off:
> +	regulator_bulk_disable(ARRAY_SIZE(ov2735_supply_name), ov2735->supplies);
> +	return ret;
> +}

...

> +static int ov2735_parse_endpoint(struct ov2735 *ov2735)
> +{
> +	struct fwnode_handle *fwnode;
> +	struct v4l2_fwnode_endpoint bus_cfg = {
> +		.bus_type = V4L2_MBUS_CSI2_DPHY,
> +	};
> +	struct fwnode_handle *ep;
> +	unsigned long link_freq_bitmap;
> +	int ret;

> +	fwnode = dev_fwnode(ov2735->dev);

This one can be combined with the definition:

	struct fwnode_handle *fwnode;= dev_fwnode(ov2735->dev);

> +	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
> +	if (!ep)
> +		return dev_err_probe(ov2735->dev,
> +				     -ENXIO, "Failed to get next endpoint\n");

There is a room for the return code on the previous line.

> +	ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
> +	fwnode_handle_put(ep);
> +	if (ret)
> +		return ret;
> +
> +	if (bus_cfg.bus.mipi_csi2.num_data_lanes != 2) {
> +		ret = dev_err_probe(ov2735->dev,
> +				    -EINVAL, "only 2 data lanes are supported\n");

Ditto.

> +		goto error_out;
> +	}
> +
> +	ret = v4l2_link_freq_to_bitmap(ov2735->dev, bus_cfg.link_frequencies,
> +				       bus_cfg.nr_of_link_frequencies,
> +				       link_freq_menu_items,
> +				       ARRAY_SIZE(link_freq_menu_items),
> +				       &link_freq_bitmap);
> +	if (ret) {
> +		ret = dev_err_probe(ov2735->dev,
> +				    -EINVAL, "only 420MHz frequency is available\n");

Ditto.

> +		goto error_out;
> +	}
> +
> +	ov2735->link_freq_index = __ffs(link_freq_bitmap);
> +
> +error_out:
> +	v4l2_fwnode_endpoint_free(&bus_cfg);
> +
> +	return ret;
> +};

...

> +static int ov2735_probe(struct i2c_client *client)
> +{
> +	struct ov2735 *ov2735;
> +	unsigned int xclk_freq;
> +	int ret;
> +
> +	ov2735 = devm_kzalloc(&client->dev, sizeof(*ov2735), GFP_KERNEL);
> +	if (!ov2735)
> +		return -ENOMEM;

> +	ov2735->client = client;

I have found no used of this. Seems a dead field in the structure.

> +	ov2735->dev = &client->dev;
> +
> +	v4l2_i2c_subdev_init(&ov2735->sd, client, &ov2735_subdev_ops);
> +	ov2735->sd.internal_ops = &ov2735_internal_ops;
> +
> +	ov2735->cci = devm_cci_regmap_init_i2c(client, 8);
> +	if (IS_ERR(ov2735->cci))
> +		return dev_err_probe(ov2735->dev, PTR_ERR(ov2735->cci),
> +				     "failed to initialize CCI\n");
> +
> +	/* Set Current page to 0 */
> +	ov2735->current_page = 0;
> +
> +	ret = devm_mutex_init(ov2735->dev, &ov2735->page_lock);

> +		if (ret)
> +			return dev_err_probe(ov2735->dev, ret,
> +					     "Failed to initialize lock\n");

Wrong indentation.

> +	/* Get system clock (xvclk) */
> +	ov2735->xclk = devm_v4l2_sensor_clk_get(ov2735->dev, NULL);
> +	if (IS_ERR(ov2735->xclk))
> +		return dev_err_probe(ov2735->dev, PTR_ERR(ov2735->xclk),
> +				     "failed to get xclk\n");
> +
> +	xclk_freq = clk_get_rate(ov2735->xclk);
> +	if (xclk_freq != OV2735_XCLK_FREQ)
> +		return dev_err_probe(ov2735->dev, -EINVAL,
> +				     "xclk frequency not supported: %d Hz\n",

Please, revisit all printf() specifiers. Are you sure that xclk_freq can ever
be negative?

> +				     xclk_freq);
> +
> +	ret = ov2735_get_regulators(ov2735);
> +	if (ret)
> +		return dev_err_probe(ov2735->dev, ret, "failed to get regulators\n");
> +
> +	ret = ov2735_parse_endpoint(ov2735);
> +	if (ret)
> +		return dev_err_probe(ov2735->dev, ret,
> +				     "failed to parse endpoint configuration\n");
> +
> +	ov2735->reset_gpio = devm_gpiod_get_optional(ov2735->dev,
> +						     "reset", GPIOD_OUT_LOW);
> +	if (IS_ERR(ov2735->reset_gpio))
> +		return dev_err_probe(ov2735->dev, PTR_ERR(ov2735->reset_gpio),
> +				     "failed to get reset GPIO\n");
> +
> +	ov2735->enable_gpio = devm_gpiod_get_optional(ov2735->dev,
> +						      "enable", GPIOD_OUT_LOW);
> +	if (IS_ERR(ov2735->enable_gpio))
> +		return dev_err_probe(ov2735->dev, PTR_ERR(ov2735->enable_gpio),
> +				     "failed to get enable GPIO\n");
> +
> +	ret = ov2735_power_on(ov2735->dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = ov2735_identify_module(ov2735);
> +	if (ret)
> +		goto error_power_off;
> +
> +	ret = ov2735_init_controls(ov2735);
> +	if (ret)
> +		goto error_power_off;
> +
> +	/* Initialize subdev */
> +	ov2735->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	ov2735->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
> +	ov2735->pad.flags = MEDIA_PAD_FL_SOURCE;
> +
> +	ret = media_entity_pads_init(&ov2735->sd.entity, 1, &ov2735->pad);
> +	if (ret) {
> +		dev_err_probe(ov2735->dev, ret, "failed to init entity pads\n");
> +		goto error_handler_free;
> +	}
> +
> +	ov2735->sd.state_lock = ov2735->handler.lock;
> +	ret = v4l2_subdev_init_finalize(&ov2735->sd);
> +	if (ret) {
> +		dev_err_probe(ov2735->dev, ret, "subdev init error\n");
> +		goto error_media_entity;
> +	}
> +
> +	devm_pm_runtime_set_active_enabled(ov2735->dev);
> +	devm_pm_runtime_get_noresume(ov2735->dev);
> +
> +	ret = v4l2_async_register_subdev_sensor(&ov2735->sd);
> +	if (ret) {
> +		dev_err_probe(ov2735->dev, ret,
> +			      "failed to register ov2735 sub-device\n");
> +		goto error_subdev_cleanup;
> +	}
> +
> +	return 0;
> +
> +error_subdev_cleanup:
> +	v4l2_subdev_cleanup(&ov2735->sd);
> +
> +error_media_entity:
> +	media_entity_cleanup(&ov2735->sd.entity);
> +
> +error_handler_free:
> +	v4l2_ctrl_handler_free(ov2735->sd.ctrl_handler);
> +
> +error_power_off:
> +	ov2735_power_off(ov2735->dev);
> +
> +	return ret;
> +}

...

> +static void ov2735_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct ov2735 *ov2735 = to_ov2735(sd);
> +
> +	v4l2_async_unregister_subdev(sd);
> +	v4l2_subdev_cleanup(&ov2735->sd);
> +	media_entity_cleanup(&sd->entity);
> +	v4l2_ctrl_handler_free(ov2735->sd.ctrl_handler);
> +}

You can even wrap all of them to be managed resources, but since the order
looks okay to me it's up to you.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 2/2] media: i2c: add ov2735 image sensor driver

[Hardevsinh Palaniya]

Hi Andy,

> On Wed, Jul 16, 2025 at 07:14:17PM +0530, Hardevsinh Palaniya wrote:
> > Add a v4l2 subdevice driver for the Omnivision OV2735 sensor.
> >
> > The Omnivision OV2735 is a 1/2.7-Inch CMOS image sensor with an
> > active array size of 1920 x 1080.
> >
> > The following features are supported:
> > - Manual exposure an gain control support
> > - vblank/hblank control support
> > - Test pattern support control
> > - Supported resolution: 1920 x 1080 @ 30fps (SGRBG10)
> 
> ...
> 
> > +static int ov2735_page_access(struct ov2735 *ov2735,
> > +                           u32 reg, void *val, int *err, bool is_read)
> > +{
> > +     u8 page = (reg >> CCI_REG_PRIVATE_SHIFT) & 0xff;
> > +     u32 addr = reg & ~CCI_REG_PRIVATE_MASK;
> > +     int ret = 0;
> > +
> > +     if (err && *err)
> > +             return *err;
> > +
> > +     mutex_lock(&ov2735->page_lock);
> > +
> > +     /* Perform page access before read/write */
> > +     if (ov2735->current_page != page) {
> > +             ret = cci_write(ov2735->cci, OV2735_REG_PAGE_SELECT, page, &ret);
> > +             if (ret)
> > +                     goto err_mutex_unlock;
> > +             ov2735->current_page = page;
> > +     }
> > +
> > +     if (is_read)
> > +             ret = cci_read(ov2735->cci, addr, (u64 *)val, err);
> > +     else
> > +             ret = cci_write(ov2735->cci, addr, *(u64 *)val, err);
> > +
> > +err_mutex_unlock:
> 
> > +     if (ret && err)
> 
> Why do you need to check for ret != 0?

To prevents overwriting *err with 0 on successful operations, which could 
obscure previous errors. 

Best Regards,
Hardev

Re: [PATCH v4 2/2] media: i2c: add ov2735 image sensor driver

[Andy Shevchenko]

On Thu, Jul 17, 2025 at 07:26:49AM +0000, Hardevsinh Palaniya wrote:
> > On Wed, Jul 16, 2025 at 07:14:17PM +0530, Hardevsinh Palaniya wrote:

...

> > > +static int ov2735_page_access(struct ov2735 *ov2735,
> > > +                           u32 reg, void *val, int *err, bool is_read)
> > > +{
> > > +     u8 page = (reg >> CCI_REG_PRIVATE_SHIFT) & 0xff;
> > > +     u32 addr = reg & ~CCI_REG_PRIVATE_MASK;
> > > +     int ret = 0;
> > > +
> > > +     if (err && *err)
> > > +             return *err;
> > > +
> > > +     mutex_lock(&ov2735->page_lock);
> > > +
> > > +     /* Perform page access before read/write */
> > > +     if (ov2735->current_page != page) {
> > > +             ret = cci_write(ov2735->cci, OV2735_REG_PAGE_SELECT, page, &ret);
> > > +             if (ret)
> > > +                     goto err_mutex_unlock;
> > > +             ov2735->current_page = page;
> > > +     }
> > > +
> > > +     if (is_read)
> > > +             ret = cci_read(ov2735->cci, addr, (u64 *)val, err);
> > > +     else
> > > +             ret = cci_write(ov2735->cci, addr, *(u64 *)val, err);
> > > +
> > > +err_mutex_unlock:
> > 
> > > +     if (ret && err)
> > 
> > Why do you need to check for ret != 0?
> 
> To prevents overwriting *err with 0 on successful operations, which could 
> obscure previous errors. 

Can you elaborate a bit how the *err is not 0 at this point
(assuming err != NULL)?

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 2/2] media: i2c: add ov2735 image sensor driver

[Hardevsinh Palaniya]

Hi Andy,

> On Thu, Jul 17, 2025 at 07:26:49AM +0000, Hardevsinh Palaniya wrote:
> > > On Wed, Jul 16, 2025 at 07:14:17PM +0530, Hardevsinh Palaniya wrote:
> 
> ...
> 
> > > > +static int ov2735_page_access(struct ov2735 *ov2735,
> > > > +                           u32 reg, void *val, int *err, bool is_read)
> > > > +{
> > > > +     u8 page = (reg >> CCI_REG_PRIVATE_SHIFT) & 0xff;
> > > > +     u32 addr = reg & ~CCI_REG_PRIVATE_MASK;
> > > > +     int ret = 0;
> > > > +
> > > > +     if (err && *err)
> > > > +             return *err;
> > > > +
> > > > +     mutex_lock(&ov2735->page_lock);
> > > > +
> > > > +     /* Perform page access before read/write */
> > > > +     if (ov2735->current_page != page) {
> > > > +             ret = cci_write(ov2735->cci, OV2735_REG_PAGE_SELECT, page, &ret);
> > > > +             if (ret)
> > > > +                     goto err_mutex_unlock;
> > > > +             ov2735->current_page = page;
> > > > +     }
> > > > +
> > > > +     if (is_read)
> > > > +             ret = cci_read(ov2735->cci, addr, (u64 *)val, err);
> > > > +     else
> > > > +             ret = cci_write(ov2735->cci, addr, *(u64 *)val, err);
> > > > +
> > > > +err_mutex_unlock:
> > >
> > > > +     if (ret && err)
> > >
> > > Why do you need to check for ret != 0?
> >
> > To prevents overwriting *err with 0 on successful operations, which could
> > obscure previous errors.
> 
> Can you elaborate a bit how the *err is not 0 at this point
> (assuming err != NULL)?

A previous operation have already failed and stored a non-
zero error code in *err.

Assuming this function is used in a sequence of write (or read) 
operations. If the current operation succeeds (i.e., ret == 0) and we 
unconditionally write *err = ret, we would overwrite the 
existing error with 0, falsely indicating that all operations 
were successful.

Therefore, the condition if (ret && err) ensures that we only 
update *err when there's a new error, preserving any previously 
recorded failures.

Let me know if you have a different suggestion for how this should 
be handled.

Best Regards,
Hardev

Re: [PATCH v4 2/2] media: i2c: add ov2735 image sensor driver

[Andy Shevchenko]

On Thu, Jul 17, 2025 at 01:11:53PM +0000, Hardevsinh Palaniya wrote:
> > On Thu, Jul 17, 2025 at 07:26:49AM +0000, Hardevsinh Palaniya wrote:
> > > > On Wed, Jul 16, 2025 at 07:14:17PM +0530, Hardevsinh Palaniya wrote:

...

> > > > > +static int ov2735_page_access(struct ov2735 *ov2735,
> > > > > +                           u32 reg, void *val, int *err, bool is_read)
> > > > > +{
> > > > > +     u8 page = (reg >> CCI_REG_PRIVATE_SHIFT) & 0xff;
> > > > > +     u32 addr = reg & ~CCI_REG_PRIVATE_MASK;
> > > > > +     int ret = 0;

> > > > > +     if (err && *err)
> > > > > +             return *err;

^^^ (1)

> > > > > +     mutex_lock(&ov2735->page_lock);
> > > > > +
> > > > > +     /* Perform page access before read/write */
> > > > > +     if (ov2735->current_page != page) {
> > > > > +             ret = cci_write(ov2735->cci, OV2735_REG_PAGE_SELECT, page, &ret);
> > > > > +             if (ret)
> > > > > +                     goto err_mutex_unlock;
> > > > > +             ov2735->current_page = page;
> > > > > +     }
> > > > > +
> > > > > +     if (is_read)
> > > > > +             ret = cci_read(ov2735->cci, addr, (u64 *)val, err);
> > > > > +     else
> > > > > +             ret = cci_write(ov2735->cci, addr, *(u64 *)val, err);
> > > > > +
> > > > > +err_mutex_unlock:
> > > >
> > > > > +     if (ret && err)
> > > >
> > > > Why do you need to check for ret != 0?
> > >
> > > To prevents overwriting *err with 0 on successful operations, which could
> > > obscure previous errors.
> > 
> > Can you elaborate a bit how the *err is not 0 at this point
> > (assuming err != NULL)?
> 
> A previous operation have already failed and stored a non-
> zero error code in *err.

Right and this function is no-op already for this case.

> Assuming this function is used in a sequence of write (or read) 
> operations. If the current operation succeeds (i.e., ret == 0) and we 
> unconditionally write *err = ret, we would overwrite the 
> existing error with 0, falsely indicating that all operations 
> were successful.

I don't see this scenario. I see that we apply *err = 0 when *err == 0 already.

> Therefore, the condition if (ret && err) ensures that we only 
> update *err when there's a new error, preserving any previously 
> recorded failures.
> 
> Let me know if you have a different suggestion for how this should 
> be handled.

Have you taken into account 1) above?

-- 
With Best Regards,
Andy Shevchenko