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[v11,1/2] dt-bindings: media: Add Allwinner V3s Camera Sensor Interface (CSI)

Message ID 1537951204-24672-1-git-send-email-yong.deng@magewell.com (mailing list archive)
State New, archived
Headers show
Series [v11,1/2] dt-bindings: media: Add Allwinner V3s Camera Sensor Interface (CSI) | expand

Commit Message

yong Sept. 26, 2018, 8:40 a.m. UTC
Add binding documentation for Allwinner V3s CSI.

Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Yong Deng <yong.deng@magewell.com>
---
 .../devicetree/bindings/media/sun6i-csi.txt        | 59 ++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/sun6i-csi.txt

Comments

Laurent Pinchart Sept. 26, 2018, 10:19 a.m. UTC | #1
Hi Yong,

Thank you for the patch.

On Wednesday, 26 September 2018 11:40:04 EEST Yong Deng wrote:
> Add binding documentation for Allwinner V3s CSI.
> 
> Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Reviewed-by: Rob Herring <robh@kernel.org>
> Signed-off-by: Yong Deng <yong.deng@magewell.com>
> ---
>  .../devicetree/bindings/media/sun6i-csi.txt        | 59 +++++++++++++++++++
>  1 file changed, 59 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/sun6i-csi.txt
> 
> diff --git a/Documentation/devicetree/bindings/media/sun6i-csi.txt
> b/Documentation/devicetree/bindings/media/sun6i-csi.txt new file mode
> 100644
> index 000000000000..2ff47a9507a6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/sun6i-csi.txt
> @@ -0,0 +1,59 @@
> +Allwinner V3s Camera Sensor Interface
> +-------------------------------------
> +
> +Allwinner V3s SoC features two CSI module. CSI0 is used for MIPI CSI-2
> +interface and CSI1 is used for parallel interface.
> +
> +Required properties:
> +  - compatible: value must be "allwinner,sun8i-v3s-csi"
> +  - reg: base address and size of the memory-mapped region.
> +  - interrupts: interrupt associated to this IP
> +  - clocks: phandles to the clocks feeding the CSI
> +    * bus: the CSI interface clock
> +    * mod: the CSI module clock
> +    * ram: the CSI DRAM clock
> +  - clock-names: the clock names mentioned above
> +  - resets: phandles to the reset line driving the CSI
> +
> +Each CSI node should contain one 'port' child node with one child
> 'endpoint' +node, according to the bindings defined in
> +Documentation/devicetree/bindings/media/video-interfaces.txt. As mentioned
> +above, the endpoint's bus type should be MIPI CSI-2 for CSI0 and parallel
> or
> +Bt656 for CSI1.

Nitpicking, BT.656 is parallel as well. We should use BT.601 instead of 
parallel, to differentiate between embedded sync and external sync. This is a 
problem in Documentation/devicetree/bindings/media/video-interfaces.txt in the 
first place, so I won't ask you to modify these bindings. I'll try to submit a 
patch for video-interfaces.txt.

> +Endpoint node properties for CSI1
> +---------------------------------

Should you list the CSI0 properties as well ? As the driver in patch 2/2 
doesn't support the CSI-2 interface I assume you have left out CSI0 for now, 
but it should still be listed in the bindings. I'm fine with fixing this as a 
follow-up patch to avoid missing the v4.20 merge window, but if you end up 
resubmitting the series, could you please address the problem ?

With this fixed,

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> +- remote-endpoint	: (required) a phandle to the bus receiver's endpoint
> +			   node
> +- bus-width:		: (required) must be 8, 10, 12 or 16
> +- pclk-sample		: (optional) (default: sample on falling edge)
> +- hsync-active		: (only required for parallel)
> +- vsync-active		: (only required for parallel)
>
> +Example:
> +
> +csi1: csi@1cb4000 {
> +	compatible = "allwinner,sun8i-v3s-csi";
> +	reg = <0x01cb4000 0x1000>;
> +	interrupts = <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>;
> +	clocks = <&ccu CLK_BUS_CSI>,
> +		 <&ccu CLK_CSI1_SCLK>,
> +		 <&ccu CLK_DRAM_CSI>;
> +	clock-names = "bus", "mod", "ram";
> +	resets = <&ccu RST_BUS_CSI>;
> +
> +	port {
> +		/* Parallel bus endpoint */
> +		csi1_ep: endpoint {
> +			remote-endpoint = <&adv7611_ep>;
> +			bus-width = <16>;
> +
> +			/* If hsync-active/vsync-active are missing,
> +			   embedded BT.656 sync is used */
> +			hsync-active = <0>; /* Active low */
> +			vsync-active = <0>; /* Active low */
> +			pclk-sample = <1>;  /* Rising */
> +		};
> +	};
> +};
Maxime Ripard Sept. 26, 2018, 10:35 a.m. UTC | #2
On Wed, Sep 26, 2018 at 01:19:34PM +0300, Laurent Pinchart wrote:
> > +Endpoint node properties for CSI1
> > +---------------------------------
> 
> Should you list the CSI0 properties as well ? As the driver in patch 2/2 
> doesn't support the CSI-2 interface I assume you have left out CSI0 for now, 
> but it should still be listed in the bindings. I'm fine with fixing this as a 
> follow-up patch to avoid missing the v4.20 merge window, but if you end up 
> resubmitting the series, could you please address the problem ?

That driver is not available, and the documentation isn't either, so
there's no easy way to tell which properties are going to be needed
before doing the actual work of reverse engineering it and writing a
driver for it. Unfortunately...

Maxime
Laurent Pinchart Sept. 26, 2018, 10:38 a.m. UTC | #3
Hi Maxime,

On Wednesday, 26 September 2018 13:35:47 EEST maxime.ripard@bootlin.com wrote:
> On Wed, Sep 26, 2018 at 01:19:34PM +0300, Laurent Pinchart wrote:
> > > +Endpoint node properties for CSI1
> > > +---------------------------------
> > 
> > Should you list the CSI0 properties as well ? As the driver in patch 2/2
> > doesn't support the CSI-2 interface I assume you have left out CSI0 for
> > now, but it should still be listed in the bindings. I'm fine with fixing
> > this as a follow-up patch to avoid missing the v4.20 merge window, but if
> > you end up resubmitting the series, could you please address the problem
> > ?
> 
> That driver is not available, and the documentation isn't either, so
> there's no easy way to tell which properties are going to be needed
> before doing the actual work of reverse engineering it and writing a
> driver for it. Unfortunately...

While DT bindings should be independent from driver implementations, I agree 
it's difficult to develop good bindings without hardware documentation and 
without at least one working driver implementation.

How about just explicitly stating that these bindings don't support CSI0 yet ?
Maxime Ripard Sept. 26, 2018, 10:40 a.m. UTC | #4
On Wed, Sep 26, 2018 at 01:38:08PM +0300, Laurent Pinchart wrote:
> Hi Maxime,
> 
> On Wednesday, 26 September 2018 13:35:47 EEST maxime.ripard@bootlin.com wrote:
> > On Wed, Sep 26, 2018 at 01:19:34PM +0300, Laurent Pinchart wrote:
> > > > +Endpoint node properties for CSI1
> > > > +---------------------------------
> > > 
> > > Should you list the CSI0 properties as well ? As the driver in patch 2/2
> > > doesn't support the CSI-2 interface I assume you have left out CSI0 for
> > > now, but it should still be listed in the bindings. I'm fine with fixing
> > > this as a follow-up patch to avoid missing the v4.20 merge window, but if
> > > you end up resubmitting the series, could you please address the problem
> > > ?
> > 
> > That driver is not available, and the documentation isn't either, so
> > there's no easy way to tell which properties are going to be needed
> > before doing the actual work of reverse engineering it and writing a
> > driver for it. Unfortunately...
> 
> While DT bindings should be independent from driver implementations, I agree 
> it's difficult to develop good bindings without hardware documentation and 
> without at least one working driver implementation.
> 
> How about just explicitly stating that these bindings don't support CSI0 yet ?

Yep, that would work
yong Sept. 27, 2018, 12:59 a.m. UTC | #5
Hi,

On Wed, 26 Sep 2018 13:38:08 +0300
Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote:

> Hi Maxime,
> 
> On Wednesday, 26 September 2018 13:35:47 EEST maxime.ripard@bootlin.com wrote:
> > On Wed, Sep 26, 2018 at 01:19:34PM +0300, Laurent Pinchart wrote:
> > > > +Endpoint node properties for CSI1
> > > > +---------------------------------
> > > 
> > > Should you list the CSI0 properties as well ? As the driver in patch 2/2
> > > doesn't support the CSI-2 interface I assume you have left out CSI0 for
> > > now, but it should still be listed in the bindings. I'm fine with fixing
> > > this as a follow-up patch to avoid missing the v4.20 merge window, but if
> > > you end up resubmitting the series, could you please address the problem
> > > ?
> > 
> > That driver is not available, and the documentation isn't either, so
> > there's no easy way to tell which properties are going to be needed
> > before doing the actual work of reverse engineering it and writing a
> > driver for it. Unfortunately...
> 
> While DT bindings should be independent from driver implementations, I agree 
> it's difficult to develop good bindings without hardware documentation and 
> without at least one working driver implementation.
> 
> How about just explicitly stating that these bindings don't support CSI0 yet ?

OK.

Thanks,
Yong
Sakari Ailus Sept. 28, 2018, 9:38 a.m. UTC | #6
Hi Yong,

On Wed, Sep 26, 2018 at 04:40:04PM +0800, Yong Deng wrote:
> Add binding documentation for Allwinner V3s CSI.
> 
> Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>

I know... but I have a few more comments.

> Reviewed-by: Rob Herring <robh@kernel.org>
> Signed-off-by: Yong Deng <yong.deng@magewell.com>
> ---
>  .../devicetree/bindings/media/sun6i-csi.txt        | 59 ++++++++++++++++++++++
>  1 file changed, 59 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/sun6i-csi.txt
> 
> diff --git a/Documentation/devicetree/bindings/media/sun6i-csi.txt b/Documentation/devicetree/bindings/media/sun6i-csi.txt
> new file mode 100644
> index 000000000000..2ff47a9507a6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/sun6i-csi.txt
> @@ -0,0 +1,59 @@
> +Allwinner V3s Camera Sensor Interface
> +-------------------------------------
> +
> +Allwinner V3s SoC features two CSI module. CSI0 is used for MIPI CSI-2
> +interface and CSI1 is used for parallel interface.
> +
> +Required properties:
> +  - compatible: value must be "allwinner,sun8i-v3s-csi"
> +  - reg: base address and size of the memory-mapped region.
> +  - interrupts: interrupt associated to this IP
> +  - clocks: phandles to the clocks feeding the CSI
> +    * bus: the CSI interface clock
> +    * mod: the CSI module clock
> +    * ram: the CSI DRAM clock
> +  - clock-names: the clock names mentioned above
> +  - resets: phandles to the reset line driving the CSI
> +
> +Each CSI node should contain one 'port' child node with one child 'endpoint'
> +node, according to the bindings defined in
> +Documentation/devicetree/bindings/media/video-interfaces.txt. As mentioned
> +above, the endpoint's bus type should be MIPI CSI-2 for CSI0 and parallel or
> +Bt656 for CSI1.

Which port represents CSI0 and which one is CSI1? That needs to be
documented.

> +
> +Endpoint node properties for CSI1

How about CSI0? I'd expect at least data-lanes, and clock-lanes as well if
the hardware supports lane mapping.

> +---------------------------------
> +
> +- remote-endpoint	: (required) a phandle to the bus receiver's endpoint
> +			   node
> +- bus-width:		: (required) must be 8, 10, 12 or 16
> +- pclk-sample		: (optional) (default: sample on falling edge)

Could you add that video-interfaces.txt contains documentation of these
properties as well? There's a reference above but only discusses port and
endpoint nodes.

> +- hsync-active		: (only required for parallel)
> +- vsync-active		: (only required for parallel)

As you support both Bt656 and parallel (with sync signals), you can detect
the interface type from the presence of these properties. I think you
should also say that these properties are not allowed on Bt656. So I'd
change this to e.g.

	(required; parallel-only)

> +
> +Example:
> +
> +csi1: csi@1cb4000 {
> +	compatible = "allwinner,sun8i-v3s-csi";
> +	reg = <0x01cb4000 0x1000>;
> +	interrupts = <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>;
> +	clocks = <&ccu CLK_BUS_CSI>,
> +		 <&ccu CLK_CSI1_SCLK>,
> +		 <&ccu CLK_DRAM_CSI>;
> +	clock-names = "bus", "mod", "ram";
> +	resets = <&ccu RST_BUS_CSI>;
> +
> +	port {
> +		/* Parallel bus endpoint */
> +		csi1_ep: endpoint {
> +			remote-endpoint = <&adv7611_ep>;
> +			bus-width = <16>;
> +
> +			/* If hsync-active/vsync-active are missing,
> +			   embedded BT.656 sync is used */
> +			hsync-active = <0>; /* Active low */
> +			vsync-active = <0>; /* Active low */
> +			pclk-sample = <1>;  /* Rising */
> +		};
> +	};
> +};
Laurent Pinchart Sept. 28, 2018, 9:45 a.m. UTC | #7
Hi Sakari,

On Friday, 28 September 2018 12:38:33 EEST Sakari Ailus wrote:
> On Wed, Sep 26, 2018 at 04:40:04PM +0800, Yong Deng wrote:
> > Add binding documentation for Allwinner V3s CSI.
> > 
> > Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
> > Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> 
> I know... but I have a few more comments.
> 
> > Reviewed-by: Rob Herring <robh@kernel.org>
> > Signed-off-by: Yong Deng <yong.deng@magewell.com>
> > ---
> > 
> >  .../devicetree/bindings/media/sun6i-csi.txt        | 59 +++++++++++++++++
> >  1 file changed, 59 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/media/sun6i-csi.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > b/Documentation/devicetree/bindings/media/sun6i-csi.txt new file mode
> > 100644
> > index 000000000000..2ff47a9507a6
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > @@ -0,0 +1,59 @@
> > +Allwinner V3s Camera Sensor Interface
> > +-------------------------------------
> > +
> > +Allwinner V3s SoC features two CSI module. CSI0 is used for MIPI CSI-2
> > +interface and CSI1 is used for parallel interface.
> > +
> > +Required properties:
> > +  - compatible: value must be "allwinner,sun8i-v3s-csi"
> > +  - reg: base address and size of the memory-mapped region.
> > +  - interrupts: interrupt associated to this IP
> > +  - clocks: phandles to the clocks feeding the CSI
> > +    * bus: the CSI interface clock
> > +    * mod: the CSI module clock
> > +    * ram: the CSI DRAM clock
> > +  - clock-names: the clock names mentioned above
> > +  - resets: phandles to the reset line driving the CSI
> > +
> > +Each CSI node should contain one 'port' child node with one child
> > 'endpoint' +node, according to the bindings defined in
> > +Documentation/devicetree/bindings/media/video-interfaces.txt. As
> > mentioned
> > +above, the endpoint's bus type should be MIPI CSI-2 for CSI0 and parallel
> > or +Bt656 for CSI1.
> 
> Which port represents CSI0 and which one is CSI1? That needs to be
> documented.

There are two CSI devices, named CSI0 and CSI1, with one port each. The CSI0 
device supports CSI-2 only, and the CSI1 device parallel (BT.601 or BT.656) 
only.

> > +
> > +Endpoint node properties for CSI1
> 
> How about CSI0? I'd expect at least data-lanes, and clock-lanes as well if
> the hardware supports lane mapping.

I enquired about that too. As far as I understand, CSI0 isn't supported yet in 
the driver due to lack of documentation and lack of open-source vendor-
provided source code. While DT bindings are not tied to driver 
implementations, it's not the best idea to design DT bindings without at least 
one working implementation to test them. I thus proposed just listing CSI0 as 
being unsupported for now.

> > +---------------------------------
> > +
> > +- remote-endpoint	: (required) a phandle to the bus receiver's endpoint
> > +			   node
> > +- bus-width:		: (required) must be 8, 10, 12 or 16
> > +- pclk-sample		: (optional) (default: sample on falling edge)
> 
> Could you add that video-interfaces.txt contains documentation of these
> properties as well? There's a reference above but only discusses port and
> endpoint nodes.
> 
> > +- hsync-active		: (only required for parallel)
> > +- vsync-active		: (only required for parallel)
> 
> As you support both Bt656 and parallel (with sync signals), you can detect
> the interface type from the presence of these properties. I think you
> should also say that these properties are not allowed on Bt656. So I'd
> change this to e.g.
> 
> 	(required; parallel-only)
> 
> > +
> > +Example:
> > +
> > +csi1: csi@1cb4000 {
> > +	compatible = "allwinner,sun8i-v3s-csi";
> > +	reg = <0x01cb4000 0x1000>;
> > +	interrupts = <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>;
> > +	clocks = <&ccu CLK_BUS_CSI>,
> > +		 <&ccu CLK_CSI1_SCLK>,
> > +		 <&ccu CLK_DRAM_CSI>;
> > +	clock-names = "bus", "mod", "ram";
> > +	resets = <&ccu RST_BUS_CSI>;
> > +
> > +	port {
> > +		/* Parallel bus endpoint */
> > +		csi1_ep: endpoint {
> > +			remote-endpoint = <&adv7611_ep>;
> > +			bus-width = <16>;
> > +
> > +			/* If hsync-active/vsync-active are missing,
> > +			   embedded BT.656 sync is used */
> > +			hsync-active = <0>; /* Active low */
> > +			vsync-active = <0>; /* Active low */
> > +			pclk-sample = <1>;  /* Rising */
> > +		};
> > +	};
> > +};
Sakari Ailus Sept. 28, 2018, 10:23 a.m. UTC | #8
Hi Laurent,

On Fri, Sep 28, 2018 at 12:45:12PM +0300, Laurent Pinchart wrote:
> Hi Sakari,
> 
> On Friday, 28 September 2018 12:38:33 EEST Sakari Ailus wrote:
> > On Wed, Sep 26, 2018 at 04:40:04PM +0800, Yong Deng wrote:
> > > Add binding documentation for Allwinner V3s CSI.
> > > 
> > > Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
> > > Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > 
> > I know... but I have a few more comments.
> > 
> > > Reviewed-by: Rob Herring <robh@kernel.org>
> > > Signed-off-by: Yong Deng <yong.deng@magewell.com>
> > > ---
> > > 
> > >  .../devicetree/bindings/media/sun6i-csi.txt        | 59 +++++++++++++++++
> > >  1 file changed, 59 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > 
> > > diff --git a/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > b/Documentation/devicetree/bindings/media/sun6i-csi.txt new file mode
> > > 100644
> > > index 000000000000..2ff47a9507a6
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > @@ -0,0 +1,59 @@
> > > +Allwinner V3s Camera Sensor Interface
> > > +-------------------------------------
> > > +
> > > +Allwinner V3s SoC features two CSI module. CSI0 is used for MIPI CSI-2
> > > +interface and CSI1 is used for parallel interface.
> > > +
> > > +Required properties:
> > > +  - compatible: value must be "allwinner,sun8i-v3s-csi"
> > > +  - reg: base address and size of the memory-mapped region.
> > > +  - interrupts: interrupt associated to this IP
> > > +  - clocks: phandles to the clocks feeding the CSI
> > > +    * bus: the CSI interface clock
> > > +    * mod: the CSI module clock
> > > +    * ram: the CSI DRAM clock
> > > +  - clock-names: the clock names mentioned above
> > > +  - resets: phandles to the reset line driving the CSI
> > > +
> > > +Each CSI node should contain one 'port' child node with one child
> > > 'endpoint' +node, according to the bindings defined in
> > > +Documentation/devicetree/bindings/media/video-interfaces.txt. As
> > > mentioned
> > > +above, the endpoint's bus type should be MIPI CSI-2 for CSI0 and parallel
> > > or +Bt656 for CSI1.
> > 
> > Which port represents CSI0 and which one is CSI1? That needs to be
> > documented.
> 
> There are two CSI devices, named CSI0 and CSI1, with one port each. The CSI0 
> device supports CSI-2 only, and the CSI1 device parallel (BT.601 or BT.656) 
> only.
> 
> > > +
> > > +Endpoint node properties for CSI1
> > 
> > How about CSI0? I'd expect at least data-lanes, and clock-lanes as well if
> > the hardware supports lane mapping.
> 
> I enquired about that too. As far as I understand, CSI0 isn't supported yet in 
> the driver due to lack of documentation and lack of open-source vendor-
> provided source code. While DT bindings are not tied to driver 
> implementations, it's not the best idea to design DT bindings without at least 
> one working implementation to test them. I thus proposed just listing CSI0 as 
> being unsupported for now.

Ack.

We should still define which receiver corresponds to a given port. Probably
1 for CSI1 would make sense, in order to avoid changing the order the
hardware already uses. 0 doesn't need to be documented no IMO.

What do you think?

> 
> > > +---------------------------------
> > > +
> > > +- remote-endpoint	: (required) a phandle to the bus receiver's endpoint
> > > +			   node
> > > +- bus-width:		: (required) must be 8, 10, 12 or 16
> > > +- pclk-sample		: (optional) (default: sample on falling edge)
> > 
> > Could you add that video-interfaces.txt contains documentation of these
> > properties as well? There's a reference above but only discusses port and
> > endpoint nodes.
> > 
> > > +- hsync-active		: (only required for parallel)
> > > +- vsync-active		: (only required for parallel)
> > 
> > As you support both Bt656 and parallel (with sync signals), you can detect
> > the interface type from the presence of these properties. I think you
> > should also say that these properties are not allowed on Bt656. So I'd
> > change this to e.g.
> > 
> > 	(required; parallel-only)
> > 
> > > +
> > > +Example:
> > > +
> > > +csi1: csi@1cb4000 {
> > > +	compatible = "allwinner,sun8i-v3s-csi";
> > > +	reg = <0x01cb4000 0x1000>;
> > > +	interrupts = <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>;
> > > +	clocks = <&ccu CLK_BUS_CSI>,
> > > +		 <&ccu CLK_CSI1_SCLK>,
> > > +		 <&ccu CLK_DRAM_CSI>;
> > > +	clock-names = "bus", "mod", "ram";
> > > +	resets = <&ccu RST_BUS_CSI>;
> > > +
> > > +	port {
> > > +		/* Parallel bus endpoint */
> > > +		csi1_ep: endpoint {
> > > +			remote-endpoint = <&adv7611_ep>;
> > > +			bus-width = <16>;
> > > +
> > > +			/* If hsync-active/vsync-active are missing,
> > > +			   embedded BT.656 sync is used */
> > > +			hsync-active = <0>; /* Active low */
> > > +			vsync-active = <0>; /* Active low */
> > > +			pclk-sample = <1>;  /* Rising */
> > > +		};
> > > +	};
> > > +};
Chen-Yu Tsai Sept. 28, 2018, 11:10 a.m. UTC | #9
On Fri, Sep 28, 2018 at 6:23 PM Sakari Ailus
<sakari.ailus@linux.intel.com> wrote:
>
> Hi Laurent,
>
> On Fri, Sep 28, 2018 at 12:45:12PM +0300, Laurent Pinchart wrote:
> > Hi Sakari,
> >
> > On Friday, 28 September 2018 12:38:33 EEST Sakari Ailus wrote:
> > > On Wed, Sep 26, 2018 at 04:40:04PM +0800, Yong Deng wrote:
> > > > Add binding documentation for Allwinner V3s CSI.
> > > >
> > > > Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
> > > > Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > >
> > > I know... but I have a few more comments.
> > >
> > > > Reviewed-by: Rob Herring <robh@kernel.org>
> > > > Signed-off-by: Yong Deng <yong.deng@magewell.com>
> > > > ---
> > > >
> > > >  .../devicetree/bindings/media/sun6i-csi.txt        | 59 +++++++++++++++++
> > > >  1 file changed, 59 insertions(+)
> > > >  create mode 100644 Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > b/Documentation/devicetree/bindings/media/sun6i-csi.txt new file mode
> > > > 100644
> > > > index 000000000000..2ff47a9507a6
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > @@ -0,0 +1,59 @@
> > > > +Allwinner V3s Camera Sensor Interface
> > > > +-------------------------------------
> > > > +
> > > > +Allwinner V3s SoC features two CSI module. CSI0 is used for MIPI CSI-2
> > > > +interface and CSI1 is used for parallel interface.
> > > > +
> > > > +Required properties:
> > > > +  - compatible: value must be "allwinner,sun8i-v3s-csi"
> > > > +  - reg: base address and size of the memory-mapped region.
> > > > +  - interrupts: interrupt associated to this IP
> > > > +  - clocks: phandles to the clocks feeding the CSI
> > > > +    * bus: the CSI interface clock
> > > > +    * mod: the CSI module clock
> > > > +    * ram: the CSI DRAM clock
> > > > +  - clock-names: the clock names mentioned above
> > > > +  - resets: phandles to the reset line driving the CSI
> > > > +
> > > > +Each CSI node should contain one 'port' child node with one child
> > > > 'endpoint' +node, according to the bindings defined in
> > > > +Documentation/devicetree/bindings/media/video-interfaces.txt. As
> > > > mentioned
> > > > +above, the endpoint's bus type should be MIPI CSI-2 for CSI0 and parallel
> > > > or +Bt656 for CSI1.
> > >
> > > Which port represents CSI0 and which one is CSI1? That needs to be
> > > documented.
> >
> > There are two CSI devices, named CSI0 and CSI1, with one port each. The CSI0
> > device supports CSI-2 only, and the CSI1 device parallel (BT.601 or BT.656)
> > only.
> >
> > > > +
> > > > +Endpoint node properties for CSI1
> > >
> > > How about CSI0? I'd expect at least data-lanes, and clock-lanes as well if
> > > the hardware supports lane mapping.
> >
> > I enquired about that too. As far as I understand, CSI0 isn't supported yet in
> > the driver due to lack of documentation and lack of open-source vendor-
> > provided source code. While DT bindings are not tied to driver
> > implementations, it's not the best idea to design DT bindings without at least
> > one working implementation to test them. I thus proposed just listing CSI0 as
> > being unsupported for now.
>
> Ack.
>
> We should still define which receiver corresponds to a given port. Probably
> 1 for CSI1 would make sense, in order to avoid changing the order the
> hardware already uses. 0 doesn't need to be documented no IMO.
>
> What do you think?

AFAICT it would be a completely seperate node, since they have different address
spaces, clocks and reset controls. So there's no possibility of confusion.

According to Yong, CSI0 is tied internally to some unknown MIPI CSI2-receiver,
which is the undocumented part. CSI1 has its parallel data pins exposed to the
outside.

ChenYu

> >
> > > > +---------------------------------
> > > > +
> > > > +- remote-endpoint        : (required) a phandle to the bus receiver's endpoint
> > > > +                    node
> > > > +- bus-width:             : (required) must be 8, 10, 12 or 16
> > > > +- pclk-sample            : (optional) (default: sample on falling edge)
> > >
> > > Could you add that video-interfaces.txt contains documentation of these
> > > properties as well? There's a reference above but only discusses port and
> > > endpoint nodes.
> > >
> > > > +- hsync-active           : (only required for parallel)
> > > > +- vsync-active           : (only required for parallel)
> > >
> > > As you support both Bt656 and parallel (with sync signals), you can detect
> > > the interface type from the presence of these properties. I think you
> > > should also say that these properties are not allowed on Bt656. So I'd
> > > change this to e.g.
> > >
> > >     (required; parallel-only)
> > >
> > > > +
> > > > +Example:
> > > > +
> > > > +csi1: csi@1cb4000 {
> > > > + compatible = "allwinner,sun8i-v3s-csi";
> > > > + reg = <0x01cb4000 0x1000>;
> > > > + interrupts = <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>;
> > > > + clocks = <&ccu CLK_BUS_CSI>,
> > > > +          <&ccu CLK_CSI1_SCLK>,
> > > > +          <&ccu CLK_DRAM_CSI>;
> > > > + clock-names = "bus", "mod", "ram";
> > > > + resets = <&ccu RST_BUS_CSI>;
> > > > +
> > > > + port {
> > > > +         /* Parallel bus endpoint */
> > > > +         csi1_ep: endpoint {
> > > > +                 remote-endpoint = <&adv7611_ep>;
> > > > +                 bus-width = <16>;
> > > > +
> > > > +                 /* If hsync-active/vsync-active are missing,
> > > > +                    embedded BT.656 sync is used */
> > > > +                 hsync-active = <0>; /* Active low */
> > > > +                 vsync-active = <0>; /* Active low */
> > > > +                 pclk-sample = <1>;  /* Rising */
> > > > +         };
> > > > + };
> > > > +};
>
> --
> Terveisin,
>
> Sakari Ailus
> sakari.ailus@linux.intel.com
Sakari Ailus Sept. 28, 2018, 12:56 p.m. UTC | #10
Hi Chen-Yu,

On Fri, Sep 28, 2018 at 07:10:58PM +0800, Chen-Yu Tsai wrote:
> On Fri, Sep 28, 2018 at 6:23 PM Sakari Ailus
> <sakari.ailus@linux.intel.com> wrote:
> >
> > Hi Laurent,
> >
> > On Fri, Sep 28, 2018 at 12:45:12PM +0300, Laurent Pinchart wrote:
> > > Hi Sakari,
> > >
> > > On Friday, 28 September 2018 12:38:33 EEST Sakari Ailus wrote:
> > > > On Wed, Sep 26, 2018 at 04:40:04PM +0800, Yong Deng wrote:
> > > > > Add binding documentation for Allwinner V3s CSI.
> > > > >
> > > > > Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
> > > > > Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > >
> > > > I know... but I have a few more comments.
> > > >
> > > > > Reviewed-by: Rob Herring <robh@kernel.org>
> > > > > Signed-off-by: Yong Deng <yong.deng@magewell.com>
> > > > > ---
> > > > >
> > > > >  .../devicetree/bindings/media/sun6i-csi.txt        | 59 +++++++++++++++++
> > > > >  1 file changed, 59 insertions(+)
> > > > >  create mode 100644 Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > >
> > > > > diff --git a/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > > b/Documentation/devicetree/bindings/media/sun6i-csi.txt new file mode
> > > > > 100644
> > > > > index 000000000000..2ff47a9507a6
> > > > > --- /dev/null
> > > > > +++ b/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > > @@ -0,0 +1,59 @@
> > > > > +Allwinner V3s Camera Sensor Interface
> > > > > +-------------------------------------
> > > > > +
> > > > > +Allwinner V3s SoC features two CSI module. CSI0 is used for MIPI CSI-2
> > > > > +interface and CSI1 is used for parallel interface.
> > > > > +
> > > > > +Required properties:
> > > > > +  - compatible: value must be "allwinner,sun8i-v3s-csi"
> > > > > +  - reg: base address and size of the memory-mapped region.
> > > > > +  - interrupts: interrupt associated to this IP
> > > > > +  - clocks: phandles to the clocks feeding the CSI
> > > > > +    * bus: the CSI interface clock
> > > > > +    * mod: the CSI module clock
> > > > > +    * ram: the CSI DRAM clock
> > > > > +  - clock-names: the clock names mentioned above
> > > > > +  - resets: phandles to the reset line driving the CSI
> > > > > +
> > > > > +Each CSI node should contain one 'port' child node with one child
> > > > > 'endpoint' +node, according to the bindings defined in
> > > > > +Documentation/devicetree/bindings/media/video-interfaces.txt. As
> > > > > mentioned
> > > > > +above, the endpoint's bus type should be MIPI CSI-2 for CSI0 and parallel
> > > > > or +Bt656 for CSI1.
> > > >
> > > > Which port represents CSI0 and which one is CSI1? That needs to be
> > > > documented.
> > >
> > > There are two CSI devices, named CSI0 and CSI1, with one port each. The CSI0
> > > device supports CSI-2 only, and the CSI1 device parallel (BT.601 or BT.656)
> > > only.
> > >
> > > > > +
> > > > > +Endpoint node properties for CSI1
> > > >
> > > > How about CSI0? I'd expect at least data-lanes, and clock-lanes as well if
> > > > the hardware supports lane mapping.
> > >
> > > I enquired about that too. As far as I understand, CSI0 isn't supported yet in
> > > the driver due to lack of documentation and lack of open-source vendor-
> > > provided source code. While DT bindings are not tied to driver
> > > implementations, it's not the best idea to design DT bindings without at least
> > > one working implementation to test them. I thus proposed just listing CSI0 as
> > > being unsupported for now.
> >
> > Ack.
> >
> > We should still define which receiver corresponds to a given port. Probably
> > 1 for CSI1 would make sense, in order to avoid changing the order the
> > hardware already uses. 0 doesn't need to be documented no IMO.
> >
> > What do you think?
> 
> AFAICT it would be a completely seperate node, since they have different address
> spaces, clocks and reset controls. So there's no possibility of confusion.
> 
> According to Yong, CSI0 is tied internally to some unknown MIPI CSI2-receiver,
> which is the undocumented part. CSI1 has its parallel data pins exposed to the
> outside.

Thanks for clearing up the confusion. If these are truly different kinds of
devices, then don't they also deserve different compatible strings? And
possibly also different DT binding documentation in a separate file.
Maxime Ripard Sept. 28, 2018, 1:36 p.m. UTC | #11
Hi Sakari,

Thanks for taking the time to review.

On Fri, Sep 28, 2018 at 03:56:01PM +0300, Sakari Ailus wrote:
> Hi Chen-Yu,
> 
> On Fri, Sep 28, 2018 at 07:10:58PM +0800, Chen-Yu Tsai wrote:
> > On Fri, Sep 28, 2018 at 6:23 PM Sakari Ailus
> > <sakari.ailus@linux.intel.com> wrote:
> > >
> > > Hi Laurent,
> > >
> > > On Fri, Sep 28, 2018 at 12:45:12PM +0300, Laurent Pinchart wrote:
> > > > Hi Sakari,
> > > >
> > > > On Friday, 28 September 2018 12:38:33 EEST Sakari Ailus wrote:
> > > > > On Wed, Sep 26, 2018 at 04:40:04PM +0800, Yong Deng wrote:
> > > > > > Add binding documentation for Allwinner V3s CSI.
> > > > > >
> > > > > > Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
> > > > > > Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > > >
> > > > > I know... but I have a few more comments.
> > > > >
> > > > > > Reviewed-by: Rob Herring <robh@kernel.org>
> > > > > > Signed-off-by: Yong Deng <yong.deng@magewell.com>
> > > > > > ---
> > > > > >
> > > > > >  .../devicetree/bindings/media/sun6i-csi.txt        | 59 +++++++++++++++++
> > > > > >  1 file changed, 59 insertions(+)
> > > > > >  create mode 100644 Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > > >
> > > > > > diff --git a/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > > > b/Documentation/devicetree/bindings/media/sun6i-csi.txt new file mode
> > > > > > 100644
> > > > > > index 000000000000..2ff47a9507a6
> > > > > > --- /dev/null
> > > > > > +++ b/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > > > @@ -0,0 +1,59 @@
> > > > > > +Allwinner V3s Camera Sensor Interface
> > > > > > +-------------------------------------
> > > > > > +
> > > > > > +Allwinner V3s SoC features two CSI module. CSI0 is used for MIPI CSI-2
> > > > > > +interface and CSI1 is used for parallel interface.
> > > > > > +
> > > > > > +Required properties:
> > > > > > +  - compatible: value must be "allwinner,sun8i-v3s-csi"
> > > > > > +  - reg: base address and size of the memory-mapped region.
> > > > > > +  - interrupts: interrupt associated to this IP
> > > > > > +  - clocks: phandles to the clocks feeding the CSI
> > > > > > +    * bus: the CSI interface clock
> > > > > > +    * mod: the CSI module clock
> > > > > > +    * ram: the CSI DRAM clock
> > > > > > +  - clock-names: the clock names mentioned above
> > > > > > +  - resets: phandles to the reset line driving the CSI
> > > > > > +
> > > > > > +Each CSI node should contain one 'port' child node with one child
> > > > > > 'endpoint' +node, according to the bindings defined in
> > > > > > +Documentation/devicetree/bindings/media/video-interfaces.txt. As
> > > > > > mentioned
> > > > > > +above, the endpoint's bus type should be MIPI CSI-2 for CSI0 and parallel
> > > > > > or +Bt656 for CSI1.
> > > > >
> > > > > Which port represents CSI0 and which one is CSI1? That needs to be
> > > > > documented.
> > > >
> > > > There are two CSI devices, named CSI0 and CSI1, with one port each. The CSI0
> > > > device supports CSI-2 only, and the CSI1 device parallel (BT.601 or BT.656)
> > > > only.
> > > >
> > > > > > +
> > > > > > +Endpoint node properties for CSI1
> > > > >
> > > > > How about CSI0? I'd expect at least data-lanes, and clock-lanes as well if
> > > > > the hardware supports lane mapping.
> > > >
> > > > I enquired about that too. As far as I understand, CSI0 isn't supported yet in
> > > > the driver due to lack of documentation and lack of open-source vendor-
> > > > provided source code. While DT bindings are not tied to driver
> > > > implementations, it's not the best idea to design DT bindings without at least
> > > > one working implementation to test them. I thus proposed just listing CSI0 as
> > > > being unsupported for now.
> > >
> > > Ack.
> > >
> > > We should still define which receiver corresponds to a given port. Probably
> > > 1 for CSI1 would make sense, in order to avoid changing the order the
> > > hardware already uses. 0 doesn't need to be documented no IMO.
> > >
> > > What do you think?
> > 
> > AFAICT it would be a completely seperate node, since they have different address
> > spaces, clocks and reset controls. So there's no possibility of confusion.
> > 
> > According to Yong, CSI0 is tied internally to some unknown MIPI CSI2-receiver,
> > which is the undocumented part. CSI1 has its parallel data pins exposed to the
> > outside.
> 
> Thanks for clearing up the confusion. If these are truly different kinds of
> devices, then don't they also deserve different compatible strings? And
> possibly also different DT binding documentation in a separate file.

It can, and will if it's ever supported, but I'm not quite sure what's
confusing you about those bindings. It never claims to support CSI0,
and we will only add a new document and compatible and whatever is
needed when we'll have the need for it?

Maxime
Sakari Ailus Sept. 28, 2018, 1:42 p.m. UTC | #12
Hi Maxime,

On Fri, Sep 28, 2018 at 03:36:42PM +0200, Maxime Ripard wrote:
> Hi Sakari,
> 
> Thanks for taking the time to review.
> 
> On Fri, Sep 28, 2018 at 03:56:01PM +0300, Sakari Ailus wrote:
> > Hi Chen-Yu,
> > 
> > On Fri, Sep 28, 2018 at 07:10:58PM +0800, Chen-Yu Tsai wrote:
> > > On Fri, Sep 28, 2018 at 6:23 PM Sakari Ailus
> > > <sakari.ailus@linux.intel.com> wrote:
> > > >
> > > > Hi Laurent,
> > > >
> > > > On Fri, Sep 28, 2018 at 12:45:12PM +0300, Laurent Pinchart wrote:
> > > > > Hi Sakari,
> > > > >
> > > > > On Friday, 28 September 2018 12:38:33 EEST Sakari Ailus wrote:
> > > > > > On Wed, Sep 26, 2018 at 04:40:04PM +0800, Yong Deng wrote:
> > > > > > > Add binding documentation for Allwinner V3s CSI.
> > > > > > >
> > > > > > > Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
> > > > > > > Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > > > >
> > > > > > I know... but I have a few more comments.
> > > > > >
> > > > > > > Reviewed-by: Rob Herring <robh@kernel.org>
> > > > > > > Signed-off-by: Yong Deng <yong.deng@magewell.com>
> > > > > > > ---
> > > > > > >
> > > > > > >  .../devicetree/bindings/media/sun6i-csi.txt        | 59 +++++++++++++++++
> > > > > > >  1 file changed, 59 insertions(+)
> > > > > > >  create mode 100644 Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > > > >
> > > > > > > diff --git a/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > > > > b/Documentation/devicetree/bindings/media/sun6i-csi.txt new file mode
> > > > > > > 100644
> > > > > > > index 000000000000..2ff47a9507a6
> > > > > > > --- /dev/null
> > > > > > > +++ b/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > > > > @@ -0,0 +1,59 @@
> > > > > > > +Allwinner V3s Camera Sensor Interface
> > > > > > > +-------------------------------------
> > > > > > > +
> > > > > > > +Allwinner V3s SoC features two CSI module. CSI0 is used for MIPI CSI-2
> > > > > > > +interface and CSI1 is used for parallel interface.
> > > > > > > +
> > > > > > > +Required properties:
> > > > > > > +  - compatible: value must be "allwinner,sun8i-v3s-csi"
> > > > > > > +  - reg: base address and size of the memory-mapped region.
> > > > > > > +  - interrupts: interrupt associated to this IP
> > > > > > > +  - clocks: phandles to the clocks feeding the CSI
> > > > > > > +    * bus: the CSI interface clock
> > > > > > > +    * mod: the CSI module clock
> > > > > > > +    * ram: the CSI DRAM clock
> > > > > > > +  - clock-names: the clock names mentioned above
> > > > > > > +  - resets: phandles to the reset line driving the CSI
> > > > > > > +
> > > > > > > +Each CSI node should contain one 'port' child node with one child
> > > > > > > 'endpoint' +node, according to the bindings defined in
> > > > > > > +Documentation/devicetree/bindings/media/video-interfaces.txt. As
> > > > > > > mentioned
> > > > > > > +above, the endpoint's bus type should be MIPI CSI-2 for CSI0 and parallel
> > > > > > > or +Bt656 for CSI1.
> > > > > >
> > > > > > Which port represents CSI0 and which one is CSI1? That needs to be
> > > > > > documented.
> > > > >
> > > > > There are two CSI devices, named CSI0 and CSI1, with one port each. The CSI0
> > > > > device supports CSI-2 only, and the CSI1 device parallel (BT.601 or BT.656)
> > > > > only.
> > > > >
> > > > > > > +
> > > > > > > +Endpoint node properties for CSI1
> > > > > >
> > > > > > How about CSI0? I'd expect at least data-lanes, and clock-lanes as well if
> > > > > > the hardware supports lane mapping.
> > > > >
> > > > > I enquired about that too. As far as I understand, CSI0 isn't supported yet in
> > > > > the driver due to lack of documentation and lack of open-source vendor-
> > > > > provided source code. While DT bindings are not tied to driver
> > > > > implementations, it's not the best idea to design DT bindings without at least
> > > > > one working implementation to test them. I thus proposed just listing CSI0 as
> > > > > being unsupported for now.
> > > >
> > > > Ack.
> > > >
> > > > We should still define which receiver corresponds to a given port. Probably
> > > > 1 for CSI1 would make sense, in order to avoid changing the order the
> > > > hardware already uses. 0 doesn't need to be documented no IMO.
> > > >
> > > > What do you think?
> > > 
> > > AFAICT it would be a completely seperate node, since they have different address
> > > spaces, clocks and reset controls. So there's no possibility of confusion.
> > > 
> > > According to Yong, CSI0 is tied internally to some unknown MIPI CSI2-receiver,
> > > which is the undocumented part. CSI1 has its parallel data pins exposed to the
> > > outside.
> > 
> > Thanks for clearing up the confusion. If these are truly different kinds of
> > devices, then don't they also deserve different compatible strings? And
> > possibly also different DT binding documentation in a separate file.
> 
> It can, and will if it's ever supported, but I'm not quite sure what's
> confusing you about those bindings. It never claims to support CSI0,
> and we will only add a new document and compatible and whatever is
> needed when we'll have the need for it?

Apart from the endpoint node documentation, the rest appears to apply to
both CSI0 and CSI1. If they're truly different kind of devices, then they
do need different compatible strings, don't they? Currently they're both
documented to be using the same.
Chen-Yu Tsai Sept. 28, 2018, 1:42 p.m. UTC | #13
Hi,

On Fri, Sep 28, 2018 at 8:56 PM Sakari Ailus
<sakari.ailus@linux.intel.com> wrote:
>
> Hi Chen-Yu,
>
> On Fri, Sep 28, 2018 at 07:10:58PM +0800, Chen-Yu Tsai wrote:
> > On Fri, Sep 28, 2018 at 6:23 PM Sakari Ailus
> > <sakari.ailus@linux.intel.com> wrote:
> > >
> > > Hi Laurent,
> > >
> > > On Fri, Sep 28, 2018 at 12:45:12PM +0300, Laurent Pinchart wrote:
> > > > Hi Sakari,
> > > >
> > > > On Friday, 28 September 2018 12:38:33 EEST Sakari Ailus wrote:
> > > > > On Wed, Sep 26, 2018 at 04:40:04PM +0800, Yong Deng wrote:
> > > > > > Add binding documentation for Allwinner V3s CSI.
> > > > > >
> > > > > > Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
> > > > > > Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > > >
> > > > > I know... but I have a few more comments.
> > > > >
> > > > > > Reviewed-by: Rob Herring <robh@kernel.org>
> > > > > > Signed-off-by: Yong Deng <yong.deng@magewell.com>
> > > > > > ---
> > > > > >
> > > > > >  .../devicetree/bindings/media/sun6i-csi.txt        | 59 +++++++++++++++++
> > > > > >  1 file changed, 59 insertions(+)
> > > > > >  create mode 100644 Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > > >
> > > > > > diff --git a/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > > > b/Documentation/devicetree/bindings/media/sun6i-csi.txt new file mode
> > > > > > 100644
> > > > > > index 000000000000..2ff47a9507a6
> > > > > > --- /dev/null
> > > > > > +++ b/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > > > @@ -0,0 +1,59 @@
> > > > > > +Allwinner V3s Camera Sensor Interface
> > > > > > +-------------------------------------
> > > > > > +
> > > > > > +Allwinner V3s SoC features two CSI module. CSI0 is used for MIPI CSI-2
> > > > > > +interface and CSI1 is used for parallel interface.
> > > > > > +
> > > > > > +Required properties:
> > > > > > +  - compatible: value must be "allwinner,sun8i-v3s-csi"
> > > > > > +  - reg: base address and size of the memory-mapped region.
> > > > > > +  - interrupts: interrupt associated to this IP
> > > > > > +  - clocks: phandles to the clocks feeding the CSI
> > > > > > +    * bus: the CSI interface clock
> > > > > > +    * mod: the CSI module clock
> > > > > > +    * ram: the CSI DRAM clock
> > > > > > +  - clock-names: the clock names mentioned above
> > > > > > +  - resets: phandles to the reset line driving the CSI
> > > > > > +
> > > > > > +Each CSI node should contain one 'port' child node with one child
> > > > > > 'endpoint' +node, according to the bindings defined in
> > > > > > +Documentation/devicetree/bindings/media/video-interfaces.txt. As
> > > > > > mentioned
> > > > > > +above, the endpoint's bus type should be MIPI CSI-2 for CSI0 and parallel
> > > > > > or +Bt656 for CSI1.
> > > > >
> > > > > Which port represents CSI0 and which one is CSI1? That needs to be
> > > > > documented.
> > > >
> > > > There are two CSI devices, named CSI0 and CSI1, with one port each. The CSI0
> > > > device supports CSI-2 only, and the CSI1 device parallel (BT.601 or BT.656)
> > > > only.
> > > >
> > > > > > +
> > > > > > +Endpoint node properties for CSI1
> > > > >
> > > > > How about CSI0? I'd expect at least data-lanes, and clock-lanes as well if
> > > > > the hardware supports lane mapping.
> > > >
> > > > I enquired about that too. As far as I understand, CSI0 isn't supported yet in
> > > > the driver due to lack of documentation and lack of open-source vendor-
> > > > provided source code. While DT bindings are not tied to driver
> > > > implementations, it's not the best idea to design DT bindings without at least
> > > > one working implementation to test them. I thus proposed just listing CSI0 as
> > > > being unsupported for now.
> > >
> > > Ack.
> > >
> > > We should still define which receiver corresponds to a given port. Probably
> > > 1 for CSI1 would make sense, in order to avoid changing the order the
> > > hardware already uses. 0 doesn't need to be documented no IMO.
> > >
> > > What do you think?
> >
> > AFAICT it would be a completely seperate node, since they have different address
> > spaces, clocks and reset controls. So there's no possibility of confusion.
> >
> > According to Yong, CSI0 is tied internally to some unknown MIPI CSI2-receiver,
> > which is the undocumented part. CSI1 has its parallel data pins exposed to the
> > outside.
>
> Thanks for clearing up the confusion. If these are truly different kinds of
> devices, then don't they also deserve different compatible strings? And
> possibly also different DT binding documentation in a separate file.

Allwinner's documents aren't particularly clear about this. AFAICT it does not
say anything about them being different. The CSI section gives a register table
with two base addresses. The V3S SDK listed on linux-sunxi wiki also doesn't
differentiate between the two. What's more is there's actually code and register
addresses for the MIPI stuff [1], though the license is questionable,
as with most
BSPs. It indeed seems like a CSI controller, which basically just takes whatever
input it is configured for and sends it to either a downstream ISP or DRAM.
There are MIPI-CSI receiver and DPHY blocks in addresses following CSI0, but we
can treat them as separate hardware blocks.

ChenYu

[1] https://github.com/yeashen/v3s-linux-sdk/blob/master/linux-3.4/drivers/media/video/sunxi-vfe/platform/sun8iw8p1_vfe_cfg.h#L27
Sakari Ailus Sept. 28, 2018, 2:47 p.m. UTC | #14
On Fri, Sep 28, 2018 at 09:42:50PM +0800, Chen-Yu Tsai wrote:
> Hi,
> 
> On Fri, Sep 28, 2018 at 8:56 PM Sakari Ailus
> <sakari.ailus@linux.intel.com> wrote:
> >
> > Hi Chen-Yu,
> >
> > On Fri, Sep 28, 2018 at 07:10:58PM +0800, Chen-Yu Tsai wrote:
> > > On Fri, Sep 28, 2018 at 6:23 PM Sakari Ailus
> > > <sakari.ailus@linux.intel.com> wrote:
> > > >
> > > > Hi Laurent,
> > > >
> > > > On Fri, Sep 28, 2018 at 12:45:12PM +0300, Laurent Pinchart wrote:
> > > > > Hi Sakari,
> > > > >
> > > > > On Friday, 28 September 2018 12:38:33 EEST Sakari Ailus wrote:
> > > > > > On Wed, Sep 26, 2018 at 04:40:04PM +0800, Yong Deng wrote:
> > > > > > > Add binding documentation for Allwinner V3s CSI.
> > > > > > >
> > > > > > > Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
> > > > > > > Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > > > >
> > > > > > I know... but I have a few more comments.
> > > > > >
> > > > > > > Reviewed-by: Rob Herring <robh@kernel.org>
> > > > > > > Signed-off-by: Yong Deng <yong.deng@magewell.com>
> > > > > > > ---
> > > > > > >
> > > > > > >  .../devicetree/bindings/media/sun6i-csi.txt        | 59 +++++++++++++++++
> > > > > > >  1 file changed, 59 insertions(+)
> > > > > > >  create mode 100644 Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > > > >
> > > > > > > diff --git a/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > > > > b/Documentation/devicetree/bindings/media/sun6i-csi.txt new file mode
> > > > > > > 100644
> > > > > > > index 000000000000..2ff47a9507a6
> > > > > > > --- /dev/null
> > > > > > > +++ b/Documentation/devicetree/bindings/media/sun6i-csi.txt
> > > > > > > @@ -0,0 +1,59 @@
> > > > > > > +Allwinner V3s Camera Sensor Interface
> > > > > > > +-------------------------------------
> > > > > > > +
> > > > > > > +Allwinner V3s SoC features two CSI module. CSI0 is used for MIPI CSI-2
> > > > > > > +interface and CSI1 is used for parallel interface.
> > > > > > > +
> > > > > > > +Required properties:
> > > > > > > +  - compatible: value must be "allwinner,sun8i-v3s-csi"
> > > > > > > +  - reg: base address and size of the memory-mapped region.
> > > > > > > +  - interrupts: interrupt associated to this IP
> > > > > > > +  - clocks: phandles to the clocks feeding the CSI
> > > > > > > +    * bus: the CSI interface clock
> > > > > > > +    * mod: the CSI module clock
> > > > > > > +    * ram: the CSI DRAM clock
> > > > > > > +  - clock-names: the clock names mentioned above
> > > > > > > +  - resets: phandles to the reset line driving the CSI
> > > > > > > +
> > > > > > > +Each CSI node should contain one 'port' child node with one child
> > > > > > > 'endpoint' +node, according to the bindings defined in
> > > > > > > +Documentation/devicetree/bindings/media/video-interfaces.txt. As
> > > > > > > mentioned
> > > > > > > +above, the endpoint's bus type should be MIPI CSI-2 for CSI0 and parallel
> > > > > > > or +Bt656 for CSI1.
> > > > > >
> > > > > > Which port represents CSI0 and which one is CSI1? That needs to be
> > > > > > documented.
> > > > >
> > > > > There are two CSI devices, named CSI0 and CSI1, with one port each. The CSI0
> > > > > device supports CSI-2 only, and the CSI1 device parallel (BT.601 or BT.656)
> > > > > only.
> > > > >
> > > > > > > +
> > > > > > > +Endpoint node properties for CSI1
> > > > > >
> > > > > > How about CSI0? I'd expect at least data-lanes, and clock-lanes as well if
> > > > > > the hardware supports lane mapping.
> > > > >
> > > > > I enquired about that too. As far as I understand, CSI0 isn't supported yet in
> > > > > the driver due to lack of documentation and lack of open-source vendor-
> > > > > provided source code. While DT bindings are not tied to driver
> > > > > implementations, it's not the best idea to design DT bindings without at least
> > > > > one working implementation to test them. I thus proposed just listing CSI0 as
> > > > > being unsupported for now.
> > > >
> > > > Ack.
> > > >
> > > > We should still define which receiver corresponds to a given port. Probably
> > > > 1 for CSI1 would make sense, in order to avoid changing the order the
> > > > hardware already uses. 0 doesn't need to be documented no IMO.
> > > >
> > > > What do you think?
> > >
> > > AFAICT it would be a completely seperate node, since they have different address
> > > spaces, clocks and reset controls. So there's no possibility of confusion.
> > >
> > > According to Yong, CSI0 is tied internally to some unknown MIPI CSI2-receiver,
> > > which is the undocumented part. CSI1 has its parallel data pins exposed to the
> > > outside.
> >
> > Thanks for clearing up the confusion. If these are truly different kinds of
> > devices, then don't they also deserve different compatible strings? And
> > possibly also different DT binding documentation in a separate file.
> 
> Allwinner's documents aren't particularly clear about this. AFAICT it does not
> say anything about them being different. The CSI section gives a register table
> with two base addresses. The V3S SDK listed on linux-sunxi wiki also doesn't
> differentiate between the two. What's more is there's actually code and register
> addresses for the MIPI stuff [1], though the license is questionable,
> as with most
> BSPs. It indeed seems like a CSI controller, which basically just takes whatever
> input it is configured for and sends it to either a downstream ISP or DRAM.
> There are MIPI-CSI receiver and DPHY blocks in addresses following CSI0, but we
> can treat them as separate hardware blocks.

What you could still do is to change the DT binding documentation to only
apply to the parallel receiver, not the CSI-2 receiver. That'd give you
more freedom going forward in case you'd later implement support for the
CSI-2 receiver, too. Up to you.
Jagan Teki Oct. 17, 2018, 7:33 a.m. UTC | #15
On Wed, Sep 26, 2018 at 2:11 PM Yong Deng <yong.deng@magewell.com> wrote:
>
> Add binding documentation for Allwinner V3s CSI.
>
> Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Reviewed-by: Rob Herring <robh@kernel.org>
> Signed-off-by: Yong Deng <yong.deng@magewell.com>
> ---
>  .../devicetree/bindings/media/sun6i-csi.txt        | 59 ++++++++++++++++++++++
>  1 file changed, 59 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/sun6i-csi.txt
>
> diff --git a/Documentation/devicetree/bindings/media/sun6i-csi.txt b/Documentation/devicetree/bindings/media/sun6i-csi.txt
> new file mode 100644
> index 000000000000..2ff47a9507a6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/sun6i-csi.txt
> @@ -0,0 +1,59 @@
> +Allwinner V3s Camera Sensor Interface
> +-------------------------------------
> +
> +Allwinner V3s SoC features two CSI module. CSI0 is used for MIPI CSI-2
> +interface and CSI1 is used for parallel interface.
> +
> +Required properties:
> +  - compatible: value must be "allwinner,sun8i-v3s-csi"
> +  - reg: base address and size of the memory-mapped region.
> +  - interrupts: interrupt associated to this IP
> +  - clocks: phandles to the clocks feeding the CSI
> +    * bus: the CSI interface clock
> +    * mod: the CSI module clock
> +    * ram: the CSI DRAM clock
> +  - clock-names: the clock names mentioned above
> +  - resets: phandles to the reset line driving the CSI
> +
> +Each CSI node should contain one 'port' child node with one child 'endpoint'
> +node, according to the bindings defined in
> +Documentation/devicetree/bindings/media/video-interfaces.txt. As mentioned
> +above, the endpoint's bus type should be MIPI CSI-2 for CSI0 and parallel or
> +Bt656 for CSI1.

But A64 manual claimed that CSI0 is parallel (ofcourse it has only one
controller). On the other-side the register space seems similar. and
also is Bt656 and CCIR656 are same types?
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/media/sun6i-csi.txt b/Documentation/devicetree/bindings/media/sun6i-csi.txt
new file mode 100644
index 000000000000..2ff47a9507a6
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/sun6i-csi.txt
@@ -0,0 +1,59 @@ 
+Allwinner V3s Camera Sensor Interface
+-------------------------------------
+
+Allwinner V3s SoC features two CSI module. CSI0 is used for MIPI CSI-2
+interface and CSI1 is used for parallel interface.
+
+Required properties:
+  - compatible: value must be "allwinner,sun8i-v3s-csi"
+  - reg: base address and size of the memory-mapped region.
+  - interrupts: interrupt associated to this IP
+  - clocks: phandles to the clocks feeding the CSI
+    * bus: the CSI interface clock
+    * mod: the CSI module clock
+    * ram: the CSI DRAM clock
+  - clock-names: the clock names mentioned above
+  - resets: phandles to the reset line driving the CSI
+
+Each CSI node should contain one 'port' child node with one child 'endpoint'
+node, according to the bindings defined in
+Documentation/devicetree/bindings/media/video-interfaces.txt. As mentioned
+above, the endpoint's bus type should be MIPI CSI-2 for CSI0 and parallel or
+Bt656 for CSI1.
+
+Endpoint node properties for CSI1
+---------------------------------
+
+- remote-endpoint	: (required) a phandle to the bus receiver's endpoint
+			   node
+- bus-width:		: (required) must be 8, 10, 12 or 16
+- pclk-sample		: (optional) (default: sample on falling edge)
+- hsync-active		: (only required for parallel)
+- vsync-active		: (only required for parallel)
+
+Example:
+
+csi1: csi@1cb4000 {
+	compatible = "allwinner,sun8i-v3s-csi";
+	reg = <0x01cb4000 0x1000>;
+	interrupts = <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>;
+	clocks = <&ccu CLK_BUS_CSI>,
+		 <&ccu CLK_CSI1_SCLK>,
+		 <&ccu CLK_DRAM_CSI>;
+	clock-names = "bus", "mod", "ram";
+	resets = <&ccu RST_BUS_CSI>;
+
+	port {
+		/* Parallel bus endpoint */
+		csi1_ep: endpoint {
+			remote-endpoint = <&adv7611_ep>;
+			bus-width = <16>;
+
+			/* If hsync-active/vsync-active are missing,
+			   embedded BT.656 sync is used */
+			hsync-active = <0>; /* Active low */
+			vsync-active = <0>; /* Active low */
+			pclk-sample = <1>;  /* Rising */
+		};
+	};
+};