[PATCH 0/2] media: v4l: Add support for the Cadence MIPI-CSI2RX

[PATCH 0/2] media: v4l: Add support for the Cadence MIPI-CSI2RX

[Maxime Ripard]

Hi,

Here is an attempt at supporting the MIPI-CSI2 RX block from Cadence.

This IP block is able to receive CSI data over up to 4 lanes, and
split it to over 4 streams. Those streams are basically the interfaces
to the video grabbers that will perform the capture.

It is able to map streams to both CSI datatypes and virtual channels,
dynamically. This is unclear at this point what the right way to
support it would be, so the driver only uses a static mapping between
the virtual channels and streams, and ignores the data types.

This serie depends on the patch "v4l: async: add subnotifier
registration for subdevices" from Niklas Söderlund.

Let me know what you think!
Maxime

Maxime Ripard (2):
  dt-bindings: media: Add Cadence MIPI-CSI2RX Device Tree bindings
  v4l: cadence: Add Cadence MIPI-CSI2 RX driver

 .../devicetree/bindings/media/cdns-csi2rx.txt      |  87 ++++
 drivers/media/platform/Kconfig                     |   1 +
 drivers/media/platform/Makefile                    |   2 +
 drivers/media/platform/cadence/Kconfig             |  12 +
 drivers/media/platform/cadence/Makefile            |   1 +
 drivers/media/platform/cadence/cdns-csi2rx.c       | 440 +++++++++++++++++++++
 6 files changed, 543 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/cdns-csi2rx.txt
 create mode 100644 drivers/media/platform/cadence/Kconfig
 create mode 100644 drivers/media/platform/cadence/Makefile
 create mode 100644 drivers/media/platform/cadence/cdns-csi2rx.c

-- 
2.13.0

[PATCH 1/2] dt-bindings: media: Add Cadence MIPI-CSI2RX Device Tree bindings

[Maxime Ripard]

The Cadence MIPI-CSI2 RX controller is a CSI2RX bridge that supports up to
4 CSI-2 lanes, and can route the frames to up to 4 streams, depending on
the hardware implementation.

It can operate with an external D-PHY, an internal one or no D-PHY at all
in some configurations.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 .../devicetree/bindings/media/cdns-csi2rx.txt      | 87 ++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/cdns-csi2rx.txt

diff --git a/Documentation/devicetree/bindings/media/cdns-csi2rx.txt b/Documentation/devicetree/bindings/media/cdns-csi2rx.txt
new file mode 100644
index 000000000000..b5bcb6ad18fc
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/cdns-csi2rx.txt
@@ -0,0 +1,87 @@
+Cadence CSI2RX controller
+=========================
+
+The Cadence CSI2RX controller is a CSI-2 bridge supporting up to 4 CSI
+lanes in input, and 4 different pixel streams in output.
+
+Required properties:
+  - compatible: must be set to "cdns,csi2rx"
+  - reg: base address and size of the memory mapped region
+  - clocks: phandles to the clocks driving the controller
+  - clock-names: must contain:
+    * sys_clk: main clock
+    * p_clk: register bank clock
+    * p_free_clk: free running register bank clock
+    * pixel_ifX_clk: pixel stream output clock, one for each stream
+                     implemented in hardware, between 0 and 3
+    * dphy_rx_clk: D-PHY byte clock, if implemented in hardware
+  - phys: phandle to the external D-PHY
+  - phy-names: must contain dphy, if the implementation uses an
+               external D-PHY
+
+Required subnodes:
+  - ports: A ports node with endpoint definitions as defined in
+           Documentation/devicetree/bindings/media/video-interfaces.txt. The
+           first port subnode should be the input endpoint, the second one the
+           outputs
+
+  The output port should have as many endpoints as stream supported by
+  the hardware implementation, between 1 and 4, their ID being the
+  stream output number used in the implementation.
+
+Example:
+
+csi2rx: csi-bridge@0d060000 {
+	compatible = "cdns,csi2rx";
+	reg = <0x0d060000 0x1000>;
+	clocks = <&byteclock>, <&byteclock>, <&byteclock>,
+		 <&coreclock>, <&coreclock>,
+		 <&coreclock>, <&coreclock>;
+	clock-names = "sys_clk", "p_clk", "p_free_clk",
+		      "pixel_if0_clk", "pixel_if1_clk",
+		      "pixel_if2_clk", "pixel_if3_clk";
+
+	ports {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		port@0 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			reg = <0>;
+
+			csi2rx_in_sensor: endpoint@0 {
+				reg = <0>;
+				remote-endpoint = <&sensor_out_csi2rx>;
+				clock-lanes = <0>;
+				data-lanes = <1 2>;
+			};
+		};
+
+		port@1 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			reg = <1>;
+
+			csi2rx_out_grabber0: endpoint@0 {
+				reg = <0>;
+				remote-endpoint = <&grabber0_in_csi2rx>;
+			};
+
+			csi2rx_out_grabber1: endpoint@1 {
+				reg = <1>;
+				remote-endpoint = <&grabber1_in_csi2rx>;
+			};
+
+			csi2rx_out_grabber2: endpoint@2 {
+				reg = <2>;
+				remote-endpoint = <&grabber2_in_csi2rx>;
+			};
+
+			csi2rx_out_grabber3: endpoint@3 {
+				reg = <3>;
+				remote-endpoint = <&grabber3_in_csi2rx>;
+			};
+		};
+	};
+};
-- 
2.13.0

Re: [PATCH 1/2] dt-bindings: media: Add Cadence MIPI-CSI2RX Device Tree bindings

[Rob Herring]

On Mon, Jul 03, 2017 at 02:40:22PM +0200, Maxime Ripard wrote:
> The Cadence MIPI-CSI2 RX controller is a CSI2RX bridge that supports up to
> 4 CSI-2 lanes, and can route the frames to up to 4 streams, depending on
> the hardware implementation.

Streams and lanes are separate, right? Do you need to know how many 
lanes are configured/connected?

> 
> It can operate with an external D-PHY, an internal one or no D-PHY at all
> in some configurations.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
> ---
>  .../devicetree/bindings/media/cdns-csi2rx.txt      | 87 ++++++++++++++++++++++
>  1 file changed, 87 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/cdns-csi2rx.txt
> 
> diff --git a/Documentation/devicetree/bindings/media/cdns-csi2rx.txt b/Documentation/devicetree/bindings/media/cdns-csi2rx.txt
> new file mode 100644
> index 000000000000..b5bcb6ad18fc
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/cdns-csi2rx.txt
> @@ -0,0 +1,87 @@
> +Cadence CSI2RX controller
> +=========================
> +
> +The Cadence CSI2RX controller is a CSI-2 bridge supporting up to 4 CSI
> +lanes in input, and 4 different pixel streams in output.
> +
> +Required properties:
> +  - compatible: must be set to "cdns,csi2rx"

Should have a "and an SoC specific compatible string" statement.

> +  - reg: base address and size of the memory mapped region
> +  - clocks: phandles to the clocks driving the controller
> +  - clock-names: must contain:
> +    * sys_clk: main clock
> +    * p_clk: register bank clock
> +    * p_free_clk: free running register bank clock
> +    * pixel_ifX_clk: pixel stream output clock, one for each stream
> +                     implemented in hardware, between 0 and 3
> +    * dphy_rx_clk: D-PHY byte clock, if implemented in hardware

"if implemented in hardare" means internal D-PHY?

> +  - phys: phandle to the external D-PHY
> +  - phy-names: must contain dphy, if the implementation uses an
> +               external D-PHY

If? Should phys/phy-names be optional?

> +
> +Required subnodes:
> +  - ports: A ports node with endpoint definitions as defined in
> +           Documentation/devicetree/bindings/media/video-interfaces.txt. The
> +           first port subnode should be the input endpoint, the second one the
> +           outputs
> +
> +  The output port should have as many endpoints as stream supported by
> +  the hardware implementation, between 1 and 4, their ID being the
> +  stream output number used in the implementation.
> +
> +Example:
> +
> +csi2rx: csi-bridge@0d060000 {
> +	compatible = "cdns,csi2rx";
> +	reg = <0x0d060000 0x1000>;
> +	clocks = <&byteclock>, <&byteclock>, <&byteclock>,
> +		 <&coreclock>, <&coreclock>,
> +		 <&coreclock>, <&coreclock>;
> +	clock-names = "sys_clk", "p_clk", "p_free_clk",
> +		      "pixel_if0_clk", "pixel_if1_clk",
> +		      "pixel_if2_clk", "pixel_if3_clk";
> +
> +	ports {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +
> +		port@0 {
> +			#address-cells = <1>;
> +			#size-cells = <0>;
> +			reg = <0>;
> +
> +			csi2rx_in_sensor: endpoint@0 {
> +				reg = <0>;
> +				remote-endpoint = <&sensor_out_csi2rx>;
> +				clock-lanes = <0>;
> +				data-lanes = <1 2>;
> +			};
> +		};
> +
> +		port@1 {
> +			#address-cells = <1>;
> +			#size-cells = <0>;
> +			reg = <1>;
> +
> +			csi2rx_out_grabber0: endpoint@0 {
> +				reg = <0>;
> +				remote-endpoint = <&grabber0_in_csi2rx>;
> +			};
> +
> +			csi2rx_out_grabber1: endpoint@1 {
> +				reg = <1>;
> +				remote-endpoint = <&grabber1_in_csi2rx>;
> +			};
> +
> +			csi2rx_out_grabber2: endpoint@2 {
> +				reg = <2>;
> +				remote-endpoint = <&grabber2_in_csi2rx>;
> +			};
> +
> +			csi2rx_out_grabber3: endpoint@3 {
> +				reg = <3>;
> +				remote-endpoint = <&grabber3_in_csi2rx>;
> +			};
> +		};
> +	};
> +};
> -- 
> 2.13.0
> 
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Re: [PATCH 1/2] dt-bindings: media: Add Cadence MIPI-CSI2RX Device Tree bindings

[Maxime Ripard]

[-- Attachment #1: Type: text/plain, Size: 3705 bytes --]

Hi Rob,

Sorry for the slow answer.

On Fri, Jul 07, 2017 at 11:21:05AM -0500, Rob Herring wrote:
> On Mon, Jul 03, 2017 at 02:40:22PM +0200, Maxime Ripard wrote:
> > The Cadence MIPI-CSI2 RX controller is a CSI2RX bridge that supports up to
> > 4 CSI-2 lanes, and can route the frames to up to 4 streams, depending on
> > the hardware implementation.
> 
> Streams and lanes are separate, right? Do you need to know how many 
> lanes are configured/connected?

Streams are the output interfaces, lanes are in input. The number of
lanes used is basically defined by the device attached to the other
side, and each device can use between 1 to 4 lanes, depending on the
device.

On those lanes, the CSI protocol defines virtual channels, usually to
support multiple devices on the same set of lanes. This device is then
able to route the virtual channels in input to any of its streams in
output.

It doesn't really matter how many lanes are configured or connected,
beside some basic setup, and this is already described through the
media additions to the OF-graph through a property of the link.

What matters is how many streams you have in output to know your
routing options, and the number of virtual channels you will have, but
that's dynamic iirc.

> > It can operate with an external D-PHY, an internal one or no D-PHY at all
> > in some configurations.
> > 
> > Signed-off-by: Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
> > ---
> >  .../devicetree/bindings/media/cdns-csi2rx.txt      | 87 ++++++++++++++++++++++
> >  1 file changed, 87 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/media/cdns-csi2rx.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/media/cdns-csi2rx.txt b/Documentation/devicetree/bindings/media/cdns-csi2rx.txt
> > new file mode 100644
> > index 000000000000..b5bcb6ad18fc
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/media/cdns-csi2rx.txt
> > @@ -0,0 +1,87 @@
> > +Cadence CSI2RX controller
> > +=========================
> > +
> > +The Cadence CSI2RX controller is a CSI-2 bridge supporting up to 4 CSI
> > +lanes in input, and 4 different pixel streams in output.
> > +
> > +Required properties:
> > +  - compatible: must be set to "cdns,csi2rx"
> 
> Should have a "and an SoC specific compatible string" statement.

Ok.

> > +  - reg: base address and size of the memory mapped region
> > +  - clocks: phandles to the clocks driving the controller
> > +  - clock-names: must contain:
> > +    * sys_clk: main clock
> > +    * p_clk: register bank clock
> > +    * p_free_clk: free running register bank clock
> > +    * pixel_ifX_clk: pixel stream output clock, one for each stream
> > +                     implemented in hardware, between 0 and 3
> > +    * dphy_rx_clk: D-PHY byte clock, if implemented in hardware
> 
> "if implemented in hardare" means internal D-PHY?

It means if we have a D-PHY, either internal or external. In the case
where we don't have any D-PHY, then we'll obviously won't have that
clock.

> > +  - phys: phandle to the external D-PHY
> > +  - phy-names: must contain dphy, if the implementation uses an
> > +               external D-PHY
> 
> If? Should phys/phy-names be optional?

Yes and no, and I don't really know how it's usually handled in the
documentation. The property is mandatory if the hardware uses a
D-PHY. But it shouldn't be there if it doesn't. So it's not really
optional, it's mandatory in one case, and useless in the other.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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[PATCH 2/2] v4l: cadence: Add Cadence MIPI-CSI2 RX driver

[Maxime Ripard]

The Cadence CSI-2 RX Controller is an hardware block meant to be used as a
bridge between a CSI-2 bus and pixel grabbers.

It supports operating with internal or external D-PHY, with up to 4 lanes,
or without any D-PHY. The current code only supports the former case.

It also support dynamic mapping of the CSI-2 virtual channels to the
associated pixel grabbers, but that isn't allowed at the moment either.

Signed-off-by: Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
---
 drivers/media/platform/Kconfig               |   1 +
 drivers/media/platform/Makefile              |   2 +
 drivers/media/platform/cadence/Kconfig       |  12 +
 drivers/media/platform/cadence/Makefile      |   1 +
 drivers/media/platform/cadence/cdns-csi2rx.c | 440 +++++++++++++++++++++++++++
 5 files changed, 456 insertions(+)
 create mode 100644 drivers/media/platform/cadence/Kconfig
 create mode 100644 drivers/media/platform/cadence/Makefile
 create mode 100644 drivers/media/platform/cadence/cdns-csi2rx.c

diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
index 1313cd533436..a79d96e9b723 100644
--- a/drivers/media/platform/Kconfig
+++ b/drivers/media/platform/Kconfig
@@ -26,6 +26,7 @@ config VIDEO_VIA_CAMERA
 #
 # Platform multimedia device configuration
 #
+source "drivers/media/platform/cadence/Kconfig"
 
 source "drivers/media/platform/davinci/Kconfig"
 
diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
index 9beadc760467..1d31eb51e9bb 100644
--- a/drivers/media/platform/Makefile
+++ b/drivers/media/platform/Makefile
@@ -2,6 +2,8 @@
 # Makefile for the video capture/playback device drivers.
 #
 
+obj-$(CONFIG_VIDEO_CADENCE)		+= cadence/
+
 obj-$(CONFIG_VIDEO_M32R_AR_M64278) += arv.o
 
 obj-$(CONFIG_VIDEO_VIA_CAMERA) += via-camera.o
diff --git a/drivers/media/platform/cadence/Kconfig b/drivers/media/platform/cadence/Kconfig
new file mode 100644
index 000000000000..d1b6bbb6a0eb
--- /dev/null
+++ b/drivers/media/platform/cadence/Kconfig
@@ -0,0 +1,12 @@
+config VIDEO_CADENCE
+	bool "Cadence Video Devices"
+
+if VIDEO_CADENCE
+
+config VIDEO_CADENCE_CSI2RX
+	tristate "Cadence MIPI-CSI2 RX Controller v1.3"
+	depends on MEDIA_CONTROLLER
+	depends on VIDEO_V4L2_SUBDEV_API
+	select V4L2_FWNODE
+
+endif
diff --git a/drivers/media/platform/cadence/Makefile b/drivers/media/platform/cadence/Makefile
new file mode 100644
index 000000000000..99a4086b7448
--- /dev/null
+++ b/drivers/media/platform/cadence/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_VIDEO_CADENCE_CSI2RX)	+= cdns-csi2rx.o
diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
new file mode 100644
index 000000000000..40bf063bd44f
--- /dev/null
+++ b/drivers/media/platform/cadence/cdns-csi2rx.c
@@ -0,0 +1,440 @@
+/*
+ * Driver for Cadence MIPI-CSI2 RX Controller v1.3
+ *
+ * Copyright (C) 2017 Cadence Design Systems Inc.
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-fwnode.h>
+#include <media/v4l2-subdev.h>
+
+#define CSI2RX_DEVICE_CFG_REG			0x000
+
+#define CSI2RX_SOFT_RESET_REG			0x004
+#define CSI2RX_SOFT_RESET_PROTOCOL			BIT(1)
+#define CSI2RX_SOFT_RESET_FRONT				BIT(0)
+
+#define CSI2RX_STATIC_CFG_REG			0x008
+
+#define CSI2RX_STREAM_BASE(n)		(((n) + 1) * 0x100)
+
+#define CSI2RX_STREAM_CTRL_REG(n)		(CSI2RX_STREAM_BASE(n) + 0x000)
+#define CSI2RX_STREAM_CTRL_START			BIT(0)
+
+#define CSI2RX_STREAM_DATA_CFG_REG(n)		(CSI2RX_STREAM_BASE(n) + 0x008)
+#define CSI2RX_STREAM_DATA_CFG_EN_VC_SELECT		BIT(31)
+#define CSI2RX_STREAM_DATA_CFG_VC_SELECT(n)		BIT((n) + 16)
+
+#define CSI2RX_STREAM_CFG_REG(n)		(CSI2RX_STREAM_BASE(n) + 0x00c)
+#define CSI2RX_STREAM_CFG_FIFO_MODE_LARGE_BUF		(1 << 8)
+
+#define CSI2RX_STREAMS_MAX	4
+
+enum csi2rx_pads {
+	CSI2RX_PAD_SINK,
+	CSI2RX_PAD_SOURCE_VC0,
+	CSI2RX_PAD_SOURCE_VC1,
+	CSI2RX_PAD_SOURCE_VC2,
+	CSI2RX_PAD_SOURCE_VC3,
+	CSI2RX_PAD_MAX,
+};
+
+struct csi2rx_priv {
+	struct device		*dev;
+
+	void __iomem		*base;
+	struct clk		*sys_clk;
+	struct clk		*p_clk;
+	struct clk		*p_free_clk;
+	struct clk		*pixel_clk[CSI2RX_STREAMS_MAX];
+	struct clk		*dphy_rx_clk;
+
+	u8			lanes;
+	u8			max_lanes;
+	u8			max_streams;
+	bool			cdns_dphy;
+
+	struct v4l2_subdev	subdev;
+	struct media_pad	pads[CSI2RX_PAD_MAX];
+
+	/* Remote sensor */
+	struct v4l2_async_notifier	notifier;
+	struct v4l2_async_subdev	asd;
+	struct device_node		*sensor_node;
+	struct v4l2_subdev		*sensor_subdev;
+	unsigned int			sensor_pad;
+};
+
+static inline
+struct csi2rx_priv *v4l2_subdev_to_csi2rx(struct v4l2_subdev *subdev)
+{
+	return container_of(subdev, struct csi2rx_priv, subdev);
+}
+
+static inline
+struct csi2rx_priv *v4l2_notifier_to_csi2rx(struct v4l2_async_notifier *notifier)
+{
+	return container_of(notifier, struct csi2rx_priv, notifier);
+}
+
+static void csi2rx_reset(struct csi2rx_priv *csi2rx)
+{
+	writel(CSI2RX_SOFT_RESET_PROTOCOL | CSI2RX_SOFT_RESET_FRONT,
+	       csi2rx->base + CSI2RX_SOFT_RESET_REG);
+
+	udelay(10);
+
+	writel(0, csi2rx->base + CSI2RX_SOFT_RESET_REG);
+}
+
+static int csi2rx_start(struct csi2rx_priv *csi2rx)
+{
+	u32 reg;
+	int i;
+
+	csi2rx_reset(csi2rx);
+
+	// TODO: modify the mapping of the DPHY lanes?
+	reg = readl(csi2rx->base + CSI2RX_STATIC_CFG_REG);
+	reg &= ~GENMASK(11, 8);
+	writel(reg | (csi2rx->lanes << 8),
+	       csi2rx->base + CSI2RX_STATIC_CFG_REG);
+
+	/*
+	 * Create a static mapping between the CSI virtual channels
+	 * and the output stream.
+	 *
+	 * This should be enhanced, but v4l2 lacks the support for
+	 * changing that mapping dynamically.
+	 */
+	for (i = 0; i < csi2rx->max_streams; i++) {
+		writel(CSI2RX_STREAM_CFG_FIFO_MODE_LARGE_BUF,
+		       csi2rx->base + CSI2RX_STREAM_CFG_REG(i));
+
+		writel(CSI2RX_STREAM_DATA_CFG_EN_VC_SELECT |
+		       CSI2RX_STREAM_DATA_CFG_VC_SELECT(i),
+		       csi2rx->base + CSI2RX_STREAM_DATA_CFG_REG(i));
+
+		writel(CSI2RX_STREAM_CTRL_START,
+		       csi2rx->base + CSI2RX_STREAM_CTRL_REG(i));
+	}
+
+	return 0;
+}
+
+static int csi2rx_stop(struct csi2rx_priv *csi2rx)
+{
+	int i;
+
+	for (i = 0; i < csi2rx->max_streams; i++)
+		writel(0, csi2rx->base + CSI2RX_STREAM_CTRL_REG(i));
+
+	return 0;
+}
+
+static int csi2rx_s_stream(struct v4l2_subdev *sd, int enable)
+{
+	struct csi2rx_priv *csi2rx = v4l2_subdev_to_csi2rx(sd);
+
+	v4l2_subdev_call(csi2rx->sensor_subdev, video, s_stream,
+			 enable);
+
+	if (enable)
+		csi2rx_start(csi2rx);
+	else
+		csi2rx_stop(csi2rx);
+
+	return 0;
+}
+
+static const struct v4l2_subdev_video_ops csi2rx_video_ops = {
+	.s_stream	= csi2rx_s_stream,
+};
+
+static struct v4l2_subdev_ops csi2rx_subdev_ops = {
+	.video		= &csi2rx_video_ops,
+};
+
+static int csi2rx_async_complete(struct v4l2_async_notifier *notifier)
+{
+	struct csi2rx_priv *csi2rx = v4l2_notifier_to_csi2rx(notifier);
+	int ret;
+
+	ret = v4l2_device_register_subdev_nodes(csi2rx->subdev.v4l2_dev);
+	if (ret) {
+		dev_err(csi2rx->dev, "Couldn't register our subdev nodes\n");
+		return ret;
+	}
+
+	return media_create_pad_link(&csi2rx->sensor_subdev->entity,
+				     csi2rx->sensor_pad,
+				     &csi2rx->subdev.entity, 0,
+				     MEDIA_LNK_FL_ENABLED |
+				     MEDIA_LNK_FL_IMMUTABLE);
+}
+
+static int csi2rx_async_bound(struct v4l2_async_notifier *notifier,
+			      struct v4l2_subdev *subdev,
+			      struct v4l2_async_subdev *asd)
+{
+	struct csi2rx_priv *csi2rx = v4l2_notifier_to_csi2rx(notifier);
+
+	csi2rx->sensor_pad = media_entity_get_fwnode_pad(&subdev->entity,
+							 &csi2rx->sensor_node->fwnode,
+							 MEDIA_PAD_FL_SOURCE);
+	if (csi2rx->sensor_pad < 0) {
+		dev_err(csi2rx->dev, "Couldn't find output pad for subdev %s\n",
+			subdev->name);
+		return csi2rx->sensor_pad;
+	}
+
+	csi2rx->sensor_subdev = subdev;
+
+	dev_dbg(csi2rx->dev, "Bound %s pad: %d\n", subdev->name,
+		csi2rx->sensor_pad);
+
+	return 0;
+}
+
+static int csi2rx_registered(struct v4l2_subdev *sd)
+{
+	struct csi2rx_priv *csi2rx = container_of(sd, struct csi2rx_priv,
+						  subdev);
+	struct v4l2_async_subdev **subdevs;
+	int ret;
+
+	subdevs = devm_kzalloc(csi2rx->dev, sizeof(*subdevs), GFP_KERNEL);
+	if (subdevs == NULL)
+		return -ENOMEM;
+
+	subdevs[0] = &csi2rx->asd;
+
+	csi2rx->notifier.num_subdevs = 1;
+	csi2rx->notifier.subdevs = subdevs;
+	csi2rx->notifier.bound = csi2rx_async_bound;
+	csi2rx->notifier.complete = csi2rx_async_complete;
+
+	ret = v4l2_async_subnotifier_register(&csi2rx->subdev,
+					      &csi2rx->notifier);
+	if (ret < 0) {
+		dev_err(csi2rx->dev, "Failed to register our notifier\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static void csi2rx_unregistered(struct v4l2_subdev *sd)
+{
+	struct csi2rx_priv *csi2rx = container_of(sd, struct csi2rx_priv,
+						  subdev);
+
+	v4l2_async_subnotifier_unregister(&csi2rx->notifier);
+}
+
+static const struct v4l2_subdev_internal_ops csi2rx_internal_ops = {
+	.registered	= csi2rx_registered,
+	.unregistered	= csi2rx_unregistered,
+};
+
+static int csi2rx_get_resources(struct csi2rx_priv *csi2rx,
+				struct platform_device *pdev)
+{
+	struct resource *res;
+	u32 reg;
+	int i;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	csi2rx->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(csi2rx->base)) {
+		dev_err(&pdev->dev, "Couldn't map our registers\n");
+		return PTR_ERR(csi2rx->base);
+	}
+
+	reg = readl(csi2rx->base + CSI2RX_DEVICE_CFG_REG);
+	csi2rx->max_lanes = (reg & 7) + 1;
+	csi2rx->max_streams = ((reg >> 4) & 7);
+	csi2rx->cdns_dphy = reg & BIT(3);
+
+	csi2rx->sys_clk = devm_clk_get(&pdev->dev, "sys_clk");
+	if (IS_ERR(csi2rx->sys_clk)) {
+		dev_err(&pdev->dev, "Couldn't get sys clock\n");
+		return PTR_ERR(csi2rx->sys_clk);
+	}
+
+	csi2rx->p_clk = devm_clk_get(&pdev->dev, "p_clk");
+	if (IS_ERR(csi2rx->p_clk)) {
+		dev_err(&pdev->dev, "Couldn't get P clock\n");
+		return PTR_ERR(csi2rx->p_clk);
+	}
+
+	csi2rx->p_free_clk = devm_clk_get(&pdev->dev, "p_free_clk");
+	if (IS_ERR(csi2rx->p_free_clk)) {
+		dev_err(&pdev->dev, "Couldn't get free running P clock\n");
+		return PTR_ERR(csi2rx->p_free_clk);
+	}
+
+	for (i = 0; i < csi2rx->max_streams; i++) {
+		char clk_name[16];
+
+		snprintf(clk_name, sizeof(clk_name), "pixel_if%u_clk", i);
+		csi2rx->pixel_clk[i] = devm_clk_get(&pdev->dev, clk_name);
+		if (IS_ERR(csi2rx->pixel_clk[i])) {
+			dev_err(&pdev->dev, "Couldn't get clock %s\n", clk_name);
+			return PTR_ERR(csi2rx->pixel_clk[i]);
+		}
+	}
+
+	if (csi2rx->cdns_dphy) {
+		csi2rx->dphy_rx_clk = devm_clk_get(&pdev->dev, "dphy_rx_clk");
+		if (IS_ERR(csi2rx->dphy_rx_clk)) {
+			dev_err(&pdev->dev, "Couldn't get D-PHY RX clock\n");
+			return PTR_ERR(csi2rx->dphy_rx_clk);
+		}
+	}
+
+	return 0;
+}
+
+static int csi2rx_parse_dt(struct csi2rx_priv *csi2rx)
+{
+	struct v4l2_fwnode_endpoint v4l2_ep;
+	struct device_node *ep, *remote;
+	int ret = 0;
+
+	ep = of_graph_get_endpoint_by_regs(csi2rx->dev->of_node, 0, 0);
+	if (!ep)
+		return -EINVAL;
+
+	ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(ep), &v4l2_ep);
+	if (ret) {
+		dev_err(csi2rx->dev, "Could not parse v4l2 endpoint\n");
+		goto out;
+	}
+
+	if (v4l2_ep.bus_type != V4L2_MBUS_CSI2) {
+		dev_err(csi2rx->dev, "Unsupported media bus type: 0x%x\n",
+			v4l2_ep.bus_type);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	csi2rx->lanes = v4l2_ep.bus.mipi_csi2.num_data_lanes;
+	if (csi2rx->lanes > csi2rx->max_lanes) {
+		dev_err(csi2rx->dev, "Unsupported number of data-lanes: %d\n",
+			csi2rx->lanes);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	remote = of_graph_get_remote_port_parent(ep);
+	if (!remote) {
+		dev_err(csi2rx->dev, "No device found for endpoint %s\n",
+			of_node_full_name(ep));
+		ret = -EINVAL;
+		goto out;
+	}
+
+	dev_dbg(csi2rx->dev, "Found remote device %s\n",
+		of_node_full_name(remote));
+
+	csi2rx->sensor_node = remote;
+	csi2rx->asd.match.fwnode.fwnode = &remote->fwnode;
+	csi2rx->asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
+
+out:
+	of_node_put(ep);
+	return ret;
+}
+
+static int csi2rx_probe(struct platform_device *pdev)
+{
+	struct csi2rx_priv *csi2rx;
+	int i, ret;
+
+	csi2rx = devm_kzalloc(&pdev->dev, sizeof(*csi2rx), GFP_KERNEL);
+	if (!csi2rx)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, csi2rx);
+	csi2rx->dev = &pdev->dev;
+
+	ret = csi2rx_get_resources(csi2rx, pdev);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to get our resources\n");
+		return ret;
+	}
+
+	ret = csi2rx_parse_dt(csi2rx);
+	if (ret)
+		return ret;
+
+	csi2rx->subdev.owner = THIS_MODULE;
+	csi2rx->subdev.dev = &pdev->dev;
+	v4l2_subdev_init(&csi2rx->subdev, &csi2rx_subdev_ops);
+	v4l2_set_subdevdata(&csi2rx->subdev, &pdev->dev);
+	snprintf(csi2rx->subdev.name, V4L2_SUBDEV_NAME_SIZE, "%s.%s",
+		 KBUILD_MODNAME, dev_name(&pdev->dev));
+	csi2rx->subdev.internal_ops = &csi2rx_internal_ops;
+
+	/* Create our media pads */
+	csi2rx->subdev.entity.function = MEDIA_ENT_F_PROC_VIDEO_PIXEL_FORMATTER;
+	csi2rx->pads[CSI2RX_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
+	for (i = CSI2RX_PAD_SOURCE_VC0; i < CSI2RX_PAD_MAX; i++)
+		csi2rx->pads[i].flags = MEDIA_PAD_FL_SOURCE;
+
+	ret = media_entity_pads_init(&csi2rx->subdev.entity, CSI2RX_PAD_MAX,
+				     csi2rx->pads);
+	if (ret)
+		return ret;
+
+	ret = v4l2_async_register_subdev(&csi2rx->subdev);
+	if (ret < 0)
+		return ret;
+
+	dev_info(&pdev->dev,
+		 "Probed CSI2RX with %d/%d lanes, %d streams, %s D-PHY\n",
+		 csi2rx->lanes, csi2rx->max_lanes, csi2rx->max_streams,
+		 csi2rx->cdns_dphy ? "Cadence" : "no");
+
+	return 0;
+}
+
+static int csi2rx_remove(struct platform_device *pdev)
+{
+	struct csi2rx_priv *csi2rx = platform_get_drvdata(pdev);
+
+	v4l2_async_unregister_subdev(&csi2rx->subdev);
+
+	return 0;
+}
+
+static const struct of_device_id csi2rx_of_table[] = {
+	{ .compatible = "cdns,csi2rx" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, csi2rx_of_table);
+
+static struct platform_driver csi2rx_driver = {
+	.probe	= csi2rx_probe,
+	.remove	= csi2rx_remove,
+
+	.driver	= {
+		.name		= "cdns-csi2rx",
+		.of_match_table	= csi2rx_of_table,
+	},
+};
+module_platform_driver(csi2rx_driver);
-- 
2.13.0

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