Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[Hugues FRUCHET]

On 06/28/2017 01:24 PM, H. Nikolaus Schaller wrote:
> 
>> Am 28.06.2017 um 12:50 schrieb Sylwester Nawrocki :
>>
>> On 06/28/2017 11:12 AM, H. Nikolaus Schaller wrote:
 Am 28.06.2017 um 00:57 schrieb Sylwester Nawrocki :
 On 06/27/2017 07:48 AM, H. Nikolaus Schaller wrote:
>> Am 26.06.2017 um 22:04 schrieb Sylwester Nawrocki :
>> On 06/26/2017 12:35 PM, Hugues FRUCHET wrote:
 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:
>>
>>> 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.
>>
>> Since you are about to add voltage supplies to the DT binding I'd suggest
>> to include all three voltage supplies of the sensor chip. Looking at the 
>> OV9650
>> and the OV9655 datasheet there are following names used for the voltage 
>> supply
>> pins:
>>
>> AVDD - Analog power supply,
>> DVDD - Power supply for digital core logic,
>> DOVDD - Digital power supply for I/O.
>
> The latter two are usually not independently switchable from the SoC power
> the module is connected to.
>
> And sometimes DVDD and DOVDD are connected together.
>
> So the driver can't make much use of knowing or requesting them because 
> the
> 1.8V supply is always active, even during suspend.
>
>>
>> I doubt the sensor can work without any of these voltage supplies, thus
>> regulator_get_optional() should not be used. I would just use the 
>> regulator
>> bulk API to handle all three power supplies.
>
> The digital part works with AVDD turned off. So the LDO supplying AVDD 
> should
> be switchable to save power ( on the GTA04 device).>
> But not all designs can switch it off. Hence the idea to define it as an
> /optional/ regulator. If it is not defined by DT, the driver simply 
> assumes
> it is always powered on.

 I didn't say we can't define regulator supply properties as optional in 
 the DT
 binding.  If we define them as such and any of these *-supply properties is
 missing in DT with regulator_get() the regulator core will use dummy 
 regulator
 for that particular voltage supply.  While with regulator_get_optional()
 -ENODEV is returned when the regulator cannot be found.
>>>
>>> Ah, ok. I see.
>>>
>>> I had thought that it is the right thing to do like 
>>> devm_gpiod_get_optional().
>>>
>>> That one it is described as:
>>>
>>> "* This is equivalent to gpiod_get(), except that when no GPIO was assigned 
>>> to
>>>   * the requested function it will return NULL. This is convenient for 
>>> drivers
>>>   * that need to handle optional GPIOs."
>>>
>>> Seems to be inconsistent definition of what "optional" means.
>>
>> Indeed, this commit explains it further:
>>
>> commit de1dd9fd2156874b45803299b3b27e65d5defdd9
>> regulator: core: Provide hints to the core about optional supplies
>>
>>> So we indeed should use devm_regulator_get() in this case. Thanks for > 
>>> pointing out!
>>
> So in summary we only need AVDD switched for the GTA04 - but it does not
> matter if the others are optional properties. We would not use them.
>
> It does matter if they are mandatory because it adds DT complexity (size
> and processing) without added function.

 We should not be defining DT binding only with selected use cases/board
 designs in mind.  IMO all three voltage supplies should be listed in the
 binding, presumably all can be made optional, with an assumption that when
 the property is missing selected pin is hooked up to a fixed regulator.
>>>
>>> Ok, then it should just be defined in the bindings but not used by
>>> the driver?
>>
>> Yes, I think so. So we have a possibly complete binding right from the
>> beginning. I someone needs handling other supplies than AVDD they could
>> update the driver in future.
> 
> Fine! I have sent some patches to Hughues so that he can integrate it in
> his next version of the patch series.
> 
> BR and thanks,
> Nikolaus
> 

OK got it, I'll push in v2.

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[H. Nikolaus Schaller]

> Am 28.06.2017 um 12:50 schrieb Sylwester Nawrocki :
> 
> On 06/28/2017 11:12 AM, H. Nikolaus Schaller wrote:
>>> Am 28.06.2017 um 00:57 schrieb Sylwester Nawrocki :
>>> On 06/27/2017 07:48 AM, H. Nikolaus Schaller wrote:
> Am 26.06.2017 um 22:04 schrieb Sylwester Nawrocki :
> On 06/26/2017 12:35 PM, Hugues FRUCHET wrote:
>>> 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:
> 
>> 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.
> 
> Since you are about to add voltage supplies to the DT binding I'd suggest
> to include all three voltage supplies of the sensor chip. Looking at the 
> OV9650
> and the OV9655 datasheet there are following names used for the voltage 
> supply
> pins:
> 
> AVDD - Analog power supply,
> DVDD - Power supply for digital core logic,
> DOVDD - Digital power supply for I/O.
 
 The latter two are usually not independently switchable from the SoC power
 the module is connected to.
 
 And sometimes DVDD and DOVDD are connected together.
 
 So the driver can't make much use of knowing or requesting them because the
 1.8V supply is always active, even during suspend.
 
> 
> I doubt the sensor can work without any of these voltage supplies, thus
> regulator_get_optional() should not be used. I would just use the 
> regulator
> bulk API to handle all three power supplies.
 
 The digital part works with AVDD turned off. So the LDO supplying AVDD 
 should
 be switchable to save power ( on the GTA04 device).>
 But not all designs can switch it off. Hence the idea to define it as an
 /optional/ regulator. If it is not defined by DT, the driver simply assumes
 it is always powered on.
>>> 
>>> I didn't say we can't define regulator supply properties as optional in the 
>>> DT
>>> binding.  If we define them as such and any of these *-supply properties is
>>> missing in DT with regulator_get() the regulator core will use dummy 
>>> regulator
>>> for that particular voltage supply.  While with regulator_get_optional()
>>> -ENODEV is returned when the regulator cannot be found.
>> 
>> Ah, ok. I see.
>> 
>> I had thought that it is the right thing to do like 
>> devm_gpiod_get_optional().
>> 
>> That one it is described as:
>> 
>> "* This is equivalent to gpiod_get(), except that when no GPIO was assigned 
>> to
>>  * the requested function it will return NULL. This is convenient for drivers
>>  * that need to handle optional GPIOs."
>> 
>> Seems to be inconsistent definition of what "optional" means.
> 
> Indeed, this commit explains it further:
> 
> commit de1dd9fd2156874b45803299b3b27e65d5defdd9
> regulator: core: Provide hints to the core about optional supplies
> 
>> So we indeed should use devm_regulator_get() in this case. Thanks for > 
>> pointing out!
> 
 So in summary we only need AVDD switched for the GTA04 - but it does not
 matter if the others are optional properties. We would not use them.
 
 It does matter if they are mandatory because it adds DT complexity (size
 and processing) without added function.
>>> 
>>> We should not be defining DT binding only with selected use cases/board
>>> designs in mind.  IMO all three voltage supplies should be listed in the
>>> binding, presumably all can be made optional, with an assumption that when
>>> the property is missing selected pin is hooked up to a fixed regulator.
>> 
>> Ok, then it should just be defined in the bindings but not used by 
>> the driver?
> 
> Yes, I think so. So we have a possibly complete binding right from the 
> beginning. I someone needs handling other supplies than AVDD they could
> update the driver in future.

Fine! I have sent some patches to Hughues so that he can integrate it in
his next version of the patch series.

BR and thanks,
Nikolaus

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[Sylwester Nawrocki]

On 06/28/2017 11:12 AM, H. Nikolaus Schaller wrote:
>> Am 28.06.2017 um 00:57 schrieb Sylwester Nawrocki :
>> On 06/27/2017 07:48 AM, H. Nikolaus Schaller wrote:
 Am 26.06.2017 um 22:04 schrieb Sylwester Nawrocki :
 On 06/26/2017 12:35 PM, Hugues FRUCHET wrote:
>> 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:

> 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.

 Since you are about to add voltage supplies to the DT binding I'd suggest
 to include all three voltage supplies of the sensor chip. Looking at the 
 OV9650
 and the OV9655 datasheet there are following names used for the voltage 
 supply
 pins:

 AVDD - Analog power supply,
 DVDD - Power supply for digital core logic,
 DOVDD - Digital power supply for I/O.
>>>
>>> The latter two are usually not independently switchable from the SoC power
>>> the module is connected to.
>>>
>>> And sometimes DVDD and DOVDD are connected together.
>>>
>>> So the driver can't make much use of knowing or requesting them because the
>>> 1.8V supply is always active, even during suspend.
>>>

 I doubt the sensor can work without any of these voltage supplies, thus
 regulator_get_optional() should not be used. I would just use the regulator
 bulk API to handle all three power supplies.
>>>
>>> The digital part works with AVDD turned off. So the LDO supplying AVDD 
>>> should
>>> be switchable to save power ( on the GTA04 device).>
>>> But not all designs can switch it off. Hence the idea to define it as an
>>> /optional/ regulator. If it is not defined by DT, the driver simply assumes
>>> it is always powered on.
>>
>> I didn't say we can't define regulator supply properties as optional in the 
>> DT
>> binding.  If we define them as such and any of these *-supply properties is
>> missing in DT with regulator_get() the regulator core will use dummy 
>> regulator
>> for that particular voltage supply.  While with regulator_get_optional()
>> -ENODEV is returned when the regulator cannot be found.
> 
> Ah, ok. I see.
> 
> I had thought that it is the right thing to do like devm_gpiod_get_optional().
> 
> That one it is described as:
> 
> "* This is equivalent to gpiod_get(), except that when no GPIO was assigned to
>   * the requested function it will return NULL. This is convenient for drivers
>   * that need to handle optional GPIOs."
> 
> Seems to be inconsistent definition of what "optional" means.

Indeed, this commit explains it further:

commit de1dd9fd2156874b45803299b3b27e65d5defdd9
regulator: core: Provide hints to the core about optional supplies

> So we indeed should use devm_regulator_get() in this case. Thanks for > 
> pointing out!

>>> So in summary we only need AVDD switched for the GTA04 - but it does not
>>> matter if the others are optional properties. We would not use them.
>>>
>>> It does matter if they are mandatory because it adds DT complexity (size
>>> and processing) without added function.
>>
>> We should not be defining DT binding only with selected use cases/board
>> designs in mind.  IMO all three voltage supplies should be listed in the
>> binding, presumably all can be made optional, with an assumption that when
>> the property is missing selected pin is hooked up to a fixed regulator.
> 
> Ok, then it should just be defined in the bindings but not used by 
> the driver?

Yes, I think so. So we have a possibly complete binding right from the 
beginning. I someone needs handling other supplies than AVDD they could
update the driver in future.


Regards,
Sylwester

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[H. Nikolaus Schaller]

> Am 28.06.2017 um 00:57 schrieb Sylwester Nawrocki :
> 
> On 06/27/2017 07:48 AM, H. Nikolaus Schaller wrote:
>>> Am 26.06.2017 um 22:04 schrieb Sylwester Nawrocki :
>>> 
>>> On 06/26/2017 12:35 PM, Hugues FRUCHET wrote:
> 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:
>>> 
 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.
>>> 
>>> Since you are about to add voltage supplies to the DT binding I'd suggest
>>> to include all three voltage supplies of the sensor chip. Looking at the 
>>> OV9650
>>> and the OV9655 datasheet there are following names used for the voltage 
>>> supply
>>> pins:
>>> 
>>> AVDD - Analog power supply,
>>> DVDD - Power supply for digital core logic,
>>> DOVDD - Digital power supply for I/O.
>> 
>> The latter two are usually not independently switchable from the SoC power
>> the module is connected to.
>> 
>> And sometimes DVDD and DOVDD are connected together.
>> 
>> So the driver can't make much use of knowing or requesting them because the
>> 1.8V supply is always active, even during suspend.
>> 
>>> 
>>> I doubt the sensor can work without any of these voltage supplies, thus
>>> regulator_get_optional() should not be used. I would just use the regulator
>>> bulk API to handle all three power supplies.
>> 
>> The digital part works with AVDD turned off. So the LDO supplying AVDD should
>> be switchable to save power ( on the GTA04 device).>
>> But not all designs can switch it off. Hence the idea to define it as an
>> /optional/ regulator. If it is not defined by DT, the driver simply assumes
>> it is always powered on.
> 
> I didn't say we can't define regulator supply properties as optional in the 
> DT 
> binding.  If we define them as such and any of these *-supply properties is 
> missing in DT with regulator_get() the regulator core will use dummy 
> regulator 
> for that particular voltage supply.  While with regulator_get_optional() 
> -ENODEV is returned when the regulator cannot be found. 

Ah, ok. I see.

I had thought that it is the right thing to do like devm_gpiod_get_optional().

That one it is described as:

"* This is equivalent to gpiod_get(), except that when no GPIO was assigned to
 * the requested function it will return NULL. This is convenient for drivers
 * that need to handle optional GPIOs."

Seems to be inconsistent definition of what "optional" means.

So we indeed should use devm_regulator_get() in this case. Thanks for pointing 
out!

> 
>> So in summary we only need AVDD switched for the GTA04 - but it does not
>> matter if the others are optional properties. We would not use them.
>> 
>> It does matter if they are mandatory because it adds DT complexity (size
>> and processing) without added function.
> 
> We should not be defining DT binding only with selected use cases/board
> designs in mind.  IMO all three voltage supplies should be listed in the
> binding, presumably all can be made optional, with an assumption that when
> the property is missing selected pin is hooked up to a fixed regulator.

Ok, then it should just be defined in the bindings but not used by the driver?

BR and thanks,
Nikolaus

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[Sylwester Nawrocki]

On 06/27/2017 07:48 AM, H. Nikolaus Schaller wrote:
>> Am 26.06.2017 um 22:04 schrieb Sylwester Nawrocki :
>>
>> On 06/26/2017 12:35 PM, Hugues FRUCHET wrote:
 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:
>>
>>> 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.
>>
>> Since you are about to add voltage supplies to the DT binding I'd suggest
>> to include all three voltage supplies of the sensor chip. Looking at the 
>> OV9650
>> and the OV9655 datasheet there are following names used for the voltage 
>> supply
>> pins:
>>
>> AVDD - Analog power supply,
>> DVDD - Power supply for digital core logic,
>> DOVDD - Digital power supply for I/O.
> 
> The latter two are usually not independently switchable from the SoC power
> the module is connected to.
> 
> And sometimes DVDD and DOVDD are connected together.
> 
> So the driver can't make much use of knowing or requesting them because the
> 1.8V supply is always active, even during suspend.
> 
>>
>> I doubt the sensor can work without any of these voltage supplies, thus
>> regulator_get_optional() should not be used. I would just use the regulator
>> bulk API to handle all three power supplies.
> 
> The digital part works with AVDD turned off. So the LDO supplying AVDD should
> be switchable to save power ( on the GTA04 device).>
> But not all designs can switch it off. Hence the idea to define it as an
> /optional/ regulator. If it is not defined by DT, the driver simply assumes
> it is always powered on.

I didn't say we can't define regulator supply properties as optional in the DT 
binding.  If we define them as such and any of these *-supply properties is 
missing in DT with regulator_get() the regulator core will use dummy regulator 
for that particular voltage supply.  While with regulator_get_optional() 
-ENODEV is returned when the regulator cannot be found. 

> So in summary we only need AVDD switched for the GTA04 - but it does not
> matter if the others are optional properties. We would not use them.
> 
> It does matter if they are mandatory because it adds DT complexity (size
> and processing) without added function.
 
We should not be defining DT binding only with selected use cases/board
designs in mind.  IMO all three voltage supplies should be listed in the
binding, presumably all can be made optional, with an assumption that when
the property is missing selected pin is hooked up to a fixed regulator.

--
Thanks,
Sylwester

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[H. Nikolaus Schaller]

> Am 26.06.2017 um 22:04 schrieb Sylwester Nawrocki :
> 
> On 06/26/2017 12:35 PM, Hugues FRUCHET wrote:
>>> 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:
> 
>> 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.
> 
> Since you are about to add voltage supplies to the DT binding I'd suggest
> to include all three voltage supplies of the sensor chip. Looking at the 
> OV9650
> and the OV9655 datasheet there are following names used for the voltage supply
> pins:
> 
> AVDD - Analog power supply,
> DVDD - Power supply for digital core logic,
> DOVDD - Digital power supply for I/O.

The latter two are usually not independently switchable from the SoC power
the module is connected to.

And sometimes DVDD and DOVDD are connected together.

So the driver can't make much use of knowing or requesting them because the
1.8V supply is always active, even during suspend.

> 
> I doubt the sensor can work without any of these voltage supplies, thus
> regulator_get_optional() should not be used. I would just use the regulator
> bulk API to handle all three power supplies.

The digital part works with AVDD turned off. So the LDO supplying AVDD should
be switchable to save power ( on the GTA04 device).

But not all designs can switch it off. Hence the idea to define it as an
/optional/ regulator. If it is not defined by DT, the driver simply assumes
it is always powered on.

So in summary we only need AVDD switched for the GTA04 - but it does not
matter if the others are optional properties. We would not use them.

It does matter if they are mandatory because it adds DT complexity (size
and processing) without added function.

BR and thanks,
Nikolaus

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[Sylwester Nawrocki]

On 06/26/2017 12:35 PM, Hugues FRUCHET wrote:
>> 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:

> 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.

Since you are about to add voltage supplies to the DT binding I'd suggest
to include all three voltage supplies of the sensor chip. Looking at the OV9650
and the OV9655 datasheet there are following names used for the voltage supply
pins:

AVDD - Analog power supply,
DVDD - Power supply for digital core logic,
DOVDD - Digital power supply for I/O.

I doubt the sensor can work without any of these voltage supplies, thus
regulator_get_optional() should not be used. I would just use the regulator
bulk API to handle all three power supplies.

--
Regards,
Sylwester

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[Rob Herring]

On Fri, Jun 23, 2017 at 12:25:33PM +0200, H. Nikolaus Schaller wrote:
> Hi Hugues,
> 
> > Am 22.06.2017 um 17:05 schrieb Hugues Fruchet :
> > 
> > From: "H. Nikolaus Schaller" 
> > 
> > This adds documentation of device tree bindings
> > for the OV965X family camera sensor module.
> > 
> > Signed-off-by: H. Nikolaus Schaller 
> > Signed-off-by: Hugues Fruchet 
> > ---
> > .../devicetree/bindings/media/i2c/ov965x.txt   | 37 
> > ++
> > 1 file changed, 37 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/media/i2c/ov965x.txt

[...]

> > +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 think that is pretty clear if you survey a number of bindings (hint: 
it's the former).

Rob

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[Rob Herring]

On Thu, Jun 22, 2017 at 05:05:37PM +0200, Hugues Fruchet wrote:
> From: "H. Nikolaus Schaller" 
> 
> This adds documentation of device tree bindings
> for the OV965X family camera sensor module.
> 
> Signed-off-by: H. Nikolaus Schaller 
> Signed-off-by: Hugues Fruchet 
> ---
>  .../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 000..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.
> +
> +Optional Properties:
> +- resetb-gpios: reference to the GPIO connected to the resetb pin, if any.

reset-gpios and state it is active low.

> +- pwdn-gpios: reference to the GPIO connected to the pwdn pin, if any.

powerdown-gpios and state it is active ???.

Those are semi-standard names.

With that,

Acked-by: Rob Herring 

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[Hugues FRUCHET]

On 06/23/2017 12:25 PM, H. Nikolaus Schaller wrote:
> Hi Hugues,
> 
>> Am 22.06.2017 um 17:05 schrieb Hugues Fruchet :
>>
>> From: "H. Nikolaus Schaller" 
>>
>> This adds documentation of device tree bindings
>> for the OV965X family camera sensor module.
>>
>> Signed-off-by: H. Nikolaus Schaller 
>> Signed-off-by: Hugues Fruchet 
>> ---
>> .../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 000..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 = <2400>;
+   };
+   };
[...]
+   ov9655: camera@30 {
+   compatible = "ovti,ov9655";
+   reg = <0x30>;
+   pwdn-gpios = < 13 GPIO_ACTIVE_HIGH>;
+   clocks = <_ext_camera>;
+   status = "okay";
+
+   port {
+   ov9655_0: endpoint {
+   remote-endpoint = <_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:
>> +
>> + {
>> +ov9655: camera@30 {
>> +compatible = "ovti,ov9655";
>> +reg = <0x30>;
>> +

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[H. Nikolaus Schaller]

> Am 24.06.2017 um 00:24 schrieb Suman Anna :
> 
> On 06/23/2017 01:59 PM, H. Nikolaus Schaller wrote:
>> Hi Suman,
>> 
>>> Am 23.06.2017 um 20:05 schrieb Suman Anna :
>>> 
>> 
>> Or does it just mean that it defines the property name?
> 
> Please read the documentation link I sent - it's in the very bottom and
> should have an example.
 
 I have seen it but it does not give me a good clue how to translate that 
 into
 correct omap3isp node setup in a specific DT. Rather it raises more 
 questions.
 Maybe because I don't understand completely what it is talking about.
 
 The fundamental question is if this "assigned-clock-rates" is already
 handled by ov965x->clk = devm_clk_get(>dev, NULL); ?
 
 Or should we define that for the omap3isp node?
 
 Then of course we need no new code and just use the right property names.
 And N900, N9 camera DTs should be updated.
>>> 
>>> Look up of_clk_set_defaults() function in drivers/clk/clk-conf.c. This
>>> function gets invoked usually during clock registration, and also gets
>>> called in platform_drv_probe(), so the parents and clocks do get
>>> configured before your driver gets probed. So, this provides a default
>>> configuration if these properties are supplied (in either clock nodes or
>>> actual device nodes), and if your driver needs to change the rates at
>>> runtime, then you would have to do that in the driver itself.
>> 
>> Ok, now I understand. Thanks!
>> 
>> Quite hidden, but nice feature. I would never have thought that it exists.
>> Especially as there are no examples around omap3isp cameras...
>> 
>> And an fgrep assigned-clock-rates shows not many use cases outside CPU/SoC
>> include files.
>> 
>> But interestingly arch/arm/boot/dts/at91sam9g25ek.dts uses it for an 
>> ovti,ov2640 camera...
>> 
>> So it seems that we just have to write:
>> 
>>  ov9655@30 {
>>  compatible = "ovti,ov9655";
>>  reg = <0x30>;
>>  clocks = < 0>;  /* cam_clka */
>>  assigned-clocks = < 0>;
>>  assigned-clock-rates = <2400>;
>>  };
> 
> Yeah, that looks alright and should work.

I have tested and it works that way.

Thanks,
Nikolaus

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[Suman Anna]

On 06/23/2017 01:59 PM, H. Nikolaus Schaller wrote:
> Hi Suman,
> 
>> Am 23.06.2017 um 20:05 schrieb Suman Anna :
>>
>
> Or does it just mean that it defines the property name?

 Please read the documentation link I sent - it's in the very bottom and
 should have an example.
>>>
>>> I have seen it but it does not give me a good clue how to translate that 
>>> into
>>> correct omap3isp node setup in a specific DT. Rather it raises more 
>>> questions.
>>> Maybe because I don't understand completely what it is talking about.
>>>
>>> The fundamental question is if this "assigned-clock-rates" is already
>>> handled by ov965x->clk = devm_clk_get(>dev, NULL); ?
>>>
>>> Or should we define that for the omap3isp node?
>>>
>>> Then of course we need no new code and just use the right property names.
>>> And N900, N9 camera DTs should be updated.
>>
>> Look up of_clk_set_defaults() function in drivers/clk/clk-conf.c. This
>> function gets invoked usually during clock registration, and also gets
>> called in platform_drv_probe(), so the parents and clocks do get
>> configured before your driver gets probed. So, this provides a default
>> configuration if these properties are supplied (in either clock nodes or
>> actual device nodes), and if your driver needs to change the rates at
>> runtime, then you would have to do that in the driver itself.
> 
> Ok, now I understand. Thanks!
> 
> Quite hidden, but nice feature. I would never have thought that it exists.
> Especially as there are no examples around omap3isp cameras...
> 
> And an fgrep assigned-clock-rates shows not many use cases outside CPU/SoC
> include files.
> 
> But interestingly arch/arm/boot/dts/at91sam9g25ek.dts uses it for an 
> ovti,ov2640 camera...
> 
> So it seems that we just have to write:
> 
>   ov9655@30 {
>   compatible = "ovti,ov9655";
>   reg = <0x30>;
>   clocks = < 0>;  /* cam_clka */
>   assigned-clocks = < 0>;
>   assigned-clock-rates = <2400>;
>   };

Yeah, that looks alright and should work.

regards
Suman

> 
> instead of introducing a new clock-frequency property and code to handle it.
> 
> Or do I misinterpret what "parents" and "clocks" are in this context?

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[H. Nikolaus Schaller]

Hi Suman,

> Am 23.06.2017 um 20:05 schrieb Suman Anna :
> 
 
 Or does it just mean that it defines the property name?
>>> 
>>> Please read the documentation link I sent - it's in the very bottom and
>>> should have an example.
>> 
>> I have seen it but it does not give me a good clue how to translate that into
>> correct omap3isp node setup in a specific DT. Rather it raises more 
>> questions.
>> Maybe because I don't understand completely what it is talking about.
>> 
>> The fundamental question is if this "assigned-clock-rates" is already
>> handled by ov965x->clk = devm_clk_get(>dev, NULL); ?
>> 
>> Or should we define that for the omap3isp node?
>> 
>> Then of course we need no new code and just use the right property names.
>> And N900, N9 camera DTs should be updated.
> 
> Look up of_clk_set_defaults() function in drivers/clk/clk-conf.c. This
> function gets invoked usually during clock registration, and also gets
> called in platform_drv_probe(), so the parents and clocks do get
> configured before your driver gets probed. So, this provides a default
> configuration if these properties are supplied (in either clock nodes or
> actual device nodes), and if your driver needs to change the rates at
> runtime, then you would have to do that in the driver itself.

Ok, now I understand. Thanks!

Quite hidden, but nice feature. I would never have thought that it exists.
Especially as there are no examples around omap3isp cameras...

And an fgrep assigned-clock-rates shows not many use cases outside CPU/SoC
include files.

But interestingly arch/arm/boot/dts/at91sam9g25ek.dts uses it for an 
ovti,ov2640 camera...

So it seems that we just have to write:

ov9655@30 {
compatible = "ovti,ov9655";
reg = <0x30>;
clocks = < 0>;  /* cam_clka */
assigned-clocks = < 0>;
assigned-clock-rates = <2400>;
};

instead of introducing a new clock-frequency property and code to handle it.

Or do I misinterpret what "parents" and "clocks" are in this context?

BR and thanks,
Nikolaus

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[Suman Anna]

Hi Nikolaus,

On 06/23/2017 10:22 AM, H. Nikolaus Schaller wrote:
> Hi,
> 
>> Am 23.06.2017 um 16:57 schrieb Andreas Färber :
>>
>> Am 23.06.2017 um 16:53 schrieb H. Nikolaus Schaller:
>>> Hi Laurent,
>>>
 Am 23.06.2017 um 13:58 schrieb Laurent Pinchart 
 :

 Hi Nikolaus,

 On Friday 23 Jun 2017 12:59:24 H. Nikolaus Schaller wrote:
> Am 23.06.2017 um 12:46 schrieb Andreas Färber :
>> Am 23.06.2017 um 12:25 schrieb H. Nikolaus Schaller:
 diff --git a/Documentation/devicetree/bindings/media/i2c/ov965x.txt
 b/Documentation/devicetree/bindings/media/i2c/ov965x.txt new file mode
 100644
 index 000..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.
>>
>> That's what assigned-clock-rates property is for:
>>
>> https://www.kernel.org/doc/Documentation/devicetree/bindings/clock/clock-b
>> indings.txt
>>
>> AFAIU clock-frequency on devices is deprecated and equivalent to having
>> a clocks property pointing to a fixed-clock, which is different from a
>> clock with varying rate.
>
> I am not sure if that helps here. The OMAP3-ISP does not have a fixed 
> clock
> rate so we can only have the driver define what it wants to see.
>
> And common practise for OMAP3-ISP based camera modules (e.g. N900, N9) is
> that they do it in the driver.
>
> Maybe ISP developers can comment?

 The OMAP3 ISP is a variable-frequency clock provider. The clock frequency 
 is 
 controlled by the clock consumer. As such, it's up to the consumer to 
 decide 
 whether to compute and request the clock rate dynamically at runtime, or 
 use 
 the assigned-clock-rates property in DT.

 Some ISPs include a clock generator, others don't. It should make no 
 difference whether the clock is provided by the ISP, by a dedicated clock 
 source in the SoC or by a discrete on-board adjustable clock source.
>>>
>>> Thanks for explaining the background.
>>>
>>> Do you have an hint or example how to use the assigned-clock-rates property 
>>> in
>>> a DT for a camera module connected to the omap3isp?
>>>
>>> Or does it just mean that it defines the property name?
>>
>> Please read the documentation link I sent - it's in the very bottom and
>> should have an example.
> 
> I have seen it but it does not give me a good clue how to translate that into
> correct omap3isp node setup in a specific DT. Rather it raises more questions.
> Maybe because I don't understand completely what it is talking about.
> 
> The fundamental question is if this "assigned-clock-rates" is already
> handled by ov965x->clk = devm_clk_get(>dev, NULL); ?
> 
> Or should we define that for the omap3isp node?
> 
> Then of course we need no new code and just use the right property names.
> And N900, N9 camera DTs should be updated.

Look up of_clk_set_defaults() function in drivers/clk/clk-conf.c. This
function gets invoked usually during clock registration, and also gets
called in platform_drv_probe(), so the parents and clocks do get
configured before your driver gets probed. So, this provides a default
configuration if these properties are supplied (in either clock nodes or
actual device nodes), and if your driver needs to change the rates at
runtime, then you would have to do that in the driver itself.

regards
Suman

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[H. Nikolaus Schaller]

Hi,

> Am 23.06.2017 um 16:57 schrieb Andreas Färber :
> 
> Am 23.06.2017 um 16:53 schrieb H. Nikolaus Schaller:
>> Hi Laurent,
>> 
>>> Am 23.06.2017 um 13:58 schrieb Laurent Pinchart 
>>> :
>>> 
>>> Hi Nikolaus,
>>> 
>>> On Friday 23 Jun 2017 12:59:24 H. Nikolaus Schaller wrote:
 Am 23.06.2017 um 12:46 schrieb Andreas Färber :
> Am 23.06.2017 um 12:25 schrieb H. Nikolaus Schaller:
>>> diff --git a/Documentation/devicetree/bindings/media/i2c/ov965x.txt
>>> b/Documentation/devicetree/bindings/media/i2c/ov965x.txt new file mode
>>> 100644
>>> index 000..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.
> 
> That's what assigned-clock-rates property is for:
> 
> https://www.kernel.org/doc/Documentation/devicetree/bindings/clock/clock-b
> indings.txt
> 
> AFAIU clock-frequency on devices is deprecated and equivalent to having
> a clocks property pointing to a fixed-clock, which is different from a
> clock with varying rate.
 
 I am not sure if that helps here. The OMAP3-ISP does not have a fixed clock
 rate so we can only have the driver define what it wants to see.
 
 And common practise for OMAP3-ISP based camera modules (e.g. N900, N9) is
 that they do it in the driver.
 
 Maybe ISP developers can comment?
>>> 
>>> The OMAP3 ISP is a variable-frequency clock provider. The clock frequency 
>>> is 
>>> controlled by the clock consumer. As such, it's up to the consumer to 
>>> decide 
>>> whether to compute and request the clock rate dynamically at runtime, or 
>>> use 
>>> the assigned-clock-rates property in DT.
>>> 
>>> Some ISPs include a clock generator, others don't. It should make no 
>>> difference whether the clock is provided by the ISP, by a dedicated clock 
>>> source in the SoC or by a discrete on-board adjustable clock source.
>> 
>> Thanks for explaining the background.
>> 
>> Do you have an hint or example how to use the assigned-clock-rates property 
>> in
>> a DT for a camera module connected to the omap3isp?
>> 
>> Or does it just mean that it defines the property name?
> 
> Please read the documentation link I sent - it's in the very bottom and
> should have an example.

I have seen it but it does not give me a good clue how to translate that into
correct omap3isp node setup in a specific DT. Rather it raises more questions.
Maybe because I don't understand completely what it is talking about.

The fundamental question is if this "assigned-clock-rates" is already
handled by ov965x->clk = devm_clk_get(>dev, NULL); ?

Or should we define that for the omap3isp node?

Then of course we need no new code and just use the right property names.
And N900, N9 camera DTs should be updated.

BR and thanks,
Nikolaus

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[Andreas Färber]

Am 23.06.2017 um 16:53 schrieb H. Nikolaus Schaller:
> Hi Laurent,
> 
>> Am 23.06.2017 um 13:58 schrieb Laurent Pinchart 
>> :
>>
>> Hi Nikolaus,
>>
>> On Friday 23 Jun 2017 12:59:24 H. Nikolaus Schaller wrote:
>>> Am 23.06.2017 um 12:46 schrieb Andreas Färber :
 Am 23.06.2017 um 12:25 schrieb H. Nikolaus Schaller:
>> diff --git a/Documentation/devicetree/bindings/media/i2c/ov965x.txt
>> b/Documentation/devicetree/bindings/media/i2c/ov965x.txt new file mode
>> 100644
>> index 000..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.

 That's what assigned-clock-rates property is for:

 https://www.kernel.org/doc/Documentation/devicetree/bindings/clock/clock-b
 indings.txt

 AFAIU clock-frequency on devices is deprecated and equivalent to having
 a clocks property pointing to a fixed-clock, which is different from a
 clock with varying rate.
>>>
>>> I am not sure if that helps here. The OMAP3-ISP does not have a fixed clock
>>> rate so we can only have the driver define what it wants to see.
>>>
>>> And common practise for OMAP3-ISP based camera modules (e.g. N900, N9) is
>>> that they do it in the driver.
>>>
>>> Maybe ISP developers can comment?
>>
>> The OMAP3 ISP is a variable-frequency clock provider. The clock frequency is 
>> controlled by the clock consumer. As such, it's up to the consumer to decide 
>> whether to compute and request the clock rate dynamically at runtime, or use 
>> the assigned-clock-rates property in DT.
>>
>> Some ISPs include a clock generator, others don't. It should make no 
>> difference whether the clock is provided by the ISP, by a dedicated clock 
>> source in the SoC or by a discrete on-board adjustable clock source.
> 
> Thanks for explaining the background.
> 
> Do you have an hint or example how to use the assigned-clock-rates property in
> a DT for a camera module connected to the omap3isp?
> 
> Or does it just mean that it defines the property name?

Please read the documentation link I sent - it's in the very bottom and
should have an example.

Regards,
Andreas

-- 
SUSE Linux GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[H. Nikolaus Schaller]

Hi Laurent,

> Am 23.06.2017 um 13:58 schrieb Laurent Pinchart 
> :
> 
> Hi Nikolaus,
> 
> On Friday 23 Jun 2017 12:59:24 H. Nikolaus Schaller wrote:
>> Am 23.06.2017 um 12:46 schrieb Andreas Färber :
>>> Am 23.06.2017 um 12:25 schrieb H. Nikolaus Schaller:
> diff --git a/Documentation/devicetree/bindings/media/i2c/ov965x.txt
> b/Documentation/devicetree/bindings/media/i2c/ov965x.txt new file mode
> 100644
> index 000..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.
>>> 
>>> That's what assigned-clock-rates property is for:
>>> 
>>> https://www.kernel.org/doc/Documentation/devicetree/bindings/clock/clock-b
>>> indings.txt
>>> 
>>> AFAIU clock-frequency on devices is deprecated and equivalent to having
>>> a clocks property pointing to a fixed-clock, which is different from a
>>> clock with varying rate.
>> 
>> I am not sure if that helps here. The OMAP3-ISP does not have a fixed clock
>> rate so we can only have the driver define what it wants to see.
>> 
>> And common practise for OMAP3-ISP based camera modules (e.g. N900, N9) is
>> that they do it in the driver.
>> 
>> Maybe ISP developers can comment?
> 
> The OMAP3 ISP is a variable-frequency clock provider. The clock frequency is 
> controlled by the clock consumer. As such, it's up to the consumer to decide 
> whether to compute and request the clock rate dynamically at runtime, or use 
> the assigned-clock-rates property in DT.
> 
> Some ISPs include a clock generator, others don't. It should make no 
> difference whether the clock is provided by the ISP, by a dedicated clock 
> source in the SoC or by a discrete on-board adjustable clock source.

Thanks for explaining the background.

Do you have an hint or example how to use the assigned-clock-rates property in
a DT for a camera module connected to the omap3isp?

Or does it just mean that it defines the property name?

BR,
Nikolaus

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[Laurent Pinchart]

Hi Nikolaus,

On Friday 23 Jun 2017 12:59:24 H. Nikolaus Schaller wrote:
> Am 23.06.2017 um 12:46 schrieb Andreas Färber :
> > Am 23.06.2017 um 12:25 schrieb H. Nikolaus Schaller:
> >>> diff --git a/Documentation/devicetree/bindings/media/i2c/ov965x.txt
> >>> b/Documentation/devicetree/bindings/media/i2c/ov965x.txt new file mode
> >>> 100644
> >>> index 000..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.
> > 
> > That's what assigned-clock-rates property is for:
> > 
> > https://www.kernel.org/doc/Documentation/devicetree/bindings/clock/clock-b
> > indings.txt
> > 
> > AFAIU clock-frequency on devices is deprecated and equivalent to having
> > a clocks property pointing to a fixed-clock, which is different from a
> > clock with varying rate.
> 
> I am not sure if that helps here. The OMAP3-ISP does not have a fixed clock
> rate so we can only have the driver define what it wants to see.
> 
> And common practise for OMAP3-ISP based camera modules (e.g. N900, N9) is
> that they do it in the driver.
> 
> Maybe ISP developers can comment?

The OMAP3 ISP is a variable-frequency clock provider. The clock frequency is 
controlled by the clock consumer. As such, it's up to the consumer to decide 
whether to compute and request the clock rate dynamically at runtime, or use 
the assigned-clock-rates property in DT.

Some ISPs include a clock generator, others don't. It should make no 
difference whether the clock is provided by the ISP, by a dedicated clock 
source in the SoC or by a discrete on-board adjustable clock source.

-- 
Regards,

Laurent Pinchart

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[H. Nikolaus Schaller]

> Am 23.06.2017 um 12:46 schrieb Andreas Färber :
> 
> Hi,
> 
> Am 23.06.2017 um 12:25 schrieb H. Nikolaus Schaller:
>>> diff --git a/Documentation/devicetree/bindings/media/i2c/ov965x.txt 
>>> b/Documentation/devicetree/bindings/media/i2c/ov965x.txt
>>> new file mode 100644
>>> index 000..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.
> 
> That's what assigned-clock-rates property is for:
> 
> https://www.kernel.org/doc/Documentation/devicetree/bindings/clock/clock-bindings.txt
> 
> AFAIU clock-frequency on devices is deprecated and equivalent to having
> a clocks property pointing to a fixed-clock, which is different from a
> clock with varying rate.

I am not sure if that helps here. The OMAP3-ISP does not have a fixed clock rate
so we can only have the driver define what it wants to see.

And common practise for OMAP3-ISP based camera modules (e.g. N900, N9) is that 
they do it in the driver.

Maybe ISP developers can comment?

BR,
Nikolaus

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[Andreas Färber]

Hi,

Am 23.06.2017 um 12:25 schrieb H. Nikolaus Schaller:
>> diff --git a/Documentation/devicetree/bindings/media/i2c/ov965x.txt 
>> b/Documentation/devicetree/bindings/media/i2c/ov965x.txt
>> new file mode 100644
>> index 000..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.

That's what assigned-clock-rates property is for:

https://www.kernel.org/doc/Documentation/devicetree/bindings/clock/clock-bindings.txt

AFAIU clock-frequency on devices is deprecated and equivalent to having
a clocks property pointing to a fixed-clock, which is different from a
clock with varying rate.

Regards,
Andreas

-- 
SUSE Linux GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)

Re: [PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[H. Nikolaus Schaller]

Hi Hugues,

> Am 22.06.2017 um 17:05 schrieb Hugues Fruchet :
> 
> From: "H. Nikolaus Schaller" 
> 
> This adds documentation of device tree bindings
> for the OV965X family camera sensor module.
> 
> Signed-off-by: H. Nikolaus Schaller 
> Signed-off-by: Hugues Fruchet 
> ---
> .../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 000..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

> +
> +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.


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

> +
> +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:
> +
> + {
> + ov9655: camera@30 {
> + compatible = "ovti,ov9655";
> + reg = <0x30>;
> + pwdn-gpios = < 13 GPIO_ACTIVE_HIGH>;
> + clocks = <_ext_camera>;
> +
> + port {
> + ov9655: endpoint {
> + remote-endpoint = <_0>;
> + };
> + };
> + };
> +};
> -- 
> 1.9.1
> 

BR and thanks,
Nikolaus

[PATCH v1 1/6] DT bindings: add bindings for ov965x camera module

[Hugues Fruchet]

From: "H. Nikolaus Schaller" 

This adds documentation of device tree bindings
for the OV965X family camera sensor module.

Signed-off-by: H. Nikolaus Schaller 
Signed-off-by: Hugues Fruchet 
---
 .../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 000..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.
+
+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.
+
+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:
+
+ {
+   ov9655: camera@30 {
+   compatible = "ovti,ov9655";
+   reg = <0x30>;
+   pwdn-gpios = < 13 GPIO_ACTIVE_HIGH>;
+   clocks = <_ext_camera>;
+
+   port {
+   ov9655: endpoint {
+   remote-endpoint = <_0>;
+   };
+   };
+   };
+};
-- 
1.9.1