On 06/23/2017 12:25 PM, H. Nikolaus Schaller wrote:
> Hi Hugues,
>
>> Am 22.06.2017 um 17:05 schrieb Hugues Fruchet <hugues.fruc...@st.com>:
>>
>> From: "H. Nikolaus Schaller" <h...@goldelico.com>
>>
>> This adds documentation of device tree bindings
>> for the OV965X family camera sensor module.
>>
>> Signed-off-by: H. Nikolaus Schaller <h...@goldelico.com>
>> Signed-off-by: Hugues Fruchet <hugues.fruc...@st.com>
>> ---
>> .../devicetree/bindings/media/i2c/ov965x.txt | 37
>> ++++++++++++++++++++++
>> 1 file changed, 37 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/media/i2c/ov965x.txt
>>
>> diff --git a/Documentation/devicetree/bindings/media/i2c/ov965x.txt
>> b/Documentation/devicetree/bindings/media/i2c/ov965x.txt
>> new file mode 100644
>> index 0000000..0e0de1f
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/media/i2c/ov965x.txt
>> @@ -0,0 +1,37 @@
>> +* Omnivision OV9650/9652/9655 CMOS sensor
>> +
>> +The Omnivision OV965x sensor support multiple resolutions output, such as
>> +CIF, SVGA, UXGA. It also can support YUV422/420, RGB565/555 or raw RGB
>> +output format.
>> +
>> +Required Properties:
>> +- compatible: should be one of
>> + "ovti,ov9650"
>> + "ovti,ov9652"
>> + "ovti,ov9655"
>> +- clocks: reference to the mclk input clock.
>
> I wonder why you have removed the clock-frequency property?
>
> In some situations the camera driver must be able to tell the clock source
> which frequency it wants to see.
>
> For example we connect the camera to an OMAP3-ISP (image signal processor) and
> there it is assumed that camera modules know the frequency and set the clock,
> e.g.:
>
> http://elixir.free-electrons.com/linux/v4.4/source/Documentation/devicetree/bindings/media/i2c/nokia,smia.txt#L52
> http://elixir.free-electrons.com/linux/v3.14/source/Documentation/devicetree/bindings/media/i2c/mt9p031.txt
>
> If your clock is constant and defined elsewhere we should make this
> property optional instead of required. But it should not be missing.
>
> Here is a hack to get it into your code:
>
> http://git.goldelico.com/?p=gta04-kernel.git;a=blobdiff;f=drivers/media/i2c/ov9650.c;h=b7ab46c775b9e40087e427ae0777e9f7c283694a;hp=1846bcbb19ae71ce686dade320aa06ce2e429ca4;hb=ca85196f6fd9a77e5a0f796aeaf7aa2cde60ce91;hpb=8a71f21b75543a6d99102be1ae4677b28c478ac9
>
Here is how it is used on my DT, the camera clock is a fixed crystal 24M
clock:
+ clocks {
+ clk_ext_camera: clk-ext-camera {
+ #clock-cells = <0>;
+ compatible = "fixed-clock";
+ clock-frequency = <24000000>;
+ };
+ };
[...]
+ ov9655: camera@30 {
+ compatible = "ovti,ov9655";
+ reg = <0x30>;
+ pwdn-gpios = <&gpioh 13 GPIO_ACTIVE_HIGH>;
+ clocks = <&clk_ext_camera>;
+ status = "okay";
+
+ port {
+ ov9655_0: endpoint {
+ remote-endpoint = <&dcmi_0>;
+ };
+ };
+ };
>> +
>> +Optional Properties:
>> +- resetb-gpios: reference to the GPIO connected to the resetb pin, if any.
>> +- pwdn-gpios: reference to the GPIO connected to the pwdn pin, if any.
>
> Here I wonder why you did split that up into two gpios. Each "*-gpios" can
> have
> multiple entries and if one is not used, a 0 can be specified to make it
> being ignored.
>
> But it is up to DT maintainers what they prefer: separate single gpios or a
> single gpio array.
I have followed the ov2640 binding, which have the same pins naming
(resetb/pwdn).
As far as I see, separate single gpios are commonly used in
Documentation/devicetree/bindings/media/i2c/
>
>
> What I am missing to support the GTA04 camera is the control of the optional
> "vana-supply".
> So the driver does not power up the camera module when needed and therefore
> probing fails.
>
> - vana-supply: a regulator to power up the camera module.
>
> Driver code is not complex to add:
>
> http://git.goldelico.com/?p=gta04-kernel.git;a=blobdiff;f=drivers/media/i2c/ov9650.c;h=1846bcbb19ae71ce686dade320aa06ce2e429ca4;hp=c0819afdcefcb19da351741d51dad00aaf909254;hb=8a71f21b75543a6d99102be1ae4677b28c478ac9;hpb=6db55fc472eea2ec6db03833df027aecf6649f88
Yes, I saw it in your code, but as I don't have any programmable power
supply on my setup, I have not pushed this commit.
And I also don't have a clock to enable/disable -fixed clock-, I need to
check the behaviour when disabling/enabling a fixed clock, I will give
it a try.
>
>> +
>> +The device node must contain one 'port' child node for its digital output
>> +video port, in accordance with the video interface bindings defined in
>> +Documentation/devicetree/bindings/media/video-interfaces.txt.
>> +
>> +Example:
>> +
>> +&i2c2 {
>> + ov9655: camera@30 {
>> + compatible = "ovti,ov9655";
>> + reg = <0x30>;
>> + pwdn-gpios = <&gpioh 13 GPIO_ACTIVE_HIGH>;
>> + clocks = <&clk_ext_camera>;
>> +
>> + port {
>> + ov9655: endpoint {
>> + remote-endpoint = <&dcmi_0>;
>> + };
>> + };
>> + };
>> +};
>> --
>> 1.9.1
>>
>
> BR and thanks,
> Nikolaus
>
