[PATCH v1 0/3] STM32 DSI HOST

[PATCH v1 0/3] STM32 DSI HOST

[Philippe CORNU]

The purpose of this set of patches is to add the mipi dsi host driver
to the stm32 family.

This mipi dsi host driver is based on the Rockchip version of the
Synopsys Designware mipi dsi driver (rockchip/dw-mipi-dsi.c)
modified for the stm32 family:
    - replace Rockchip digital & phy specific extensions with stm32's ones.
    - add a bridge

Philippe CORNU (3):
  drm/stm: ltdc: Add bridge support
  dt-bindings: display: Add STM32 DSI host driver
  drm/stm: Add STM32 DSI host driver

 .../devicetree/bindings/display/st,stm32-ltdc.txt  |   92 +-
 drivers/gpu/drm/stm/Kconfig                        |    7 +
 drivers/gpu/drm/stm/Makefile                       |    2 +
 drivers/gpu/drm/stm/dw-mipi-dsi.c                  | 1197 ++++++++++++++++++++
 drivers/gpu/drm/stm/ltdc.c                         |   82 +-
 drivers/gpu/drm/stm/ltdc.h                         |    1 +
 6 files changed, 1368 insertions(+), 13 deletions(-)
 create mode 100644 drivers/gpu/drm/stm/dw-mipi-dsi.c

-- 
1.9.1

[PATCH v1 1/3] drm/stm: ltdc: Add bridge support

[Philippe CORNU]

Add the bridge support, used by DSI host and HDMI/LVDS bridges.

Signed-off-by: Philippe CORNU <philippe.cornu@st.com>
---
 drivers/gpu/drm/stm/ltdc.c | 82 +++++++++++++++++++++++++++++++++++++++-------
 drivers/gpu/drm/stm/ltdc.h |  1 +
 2 files changed, 72 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index 7b2d63b..b0d1fba 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -858,6 +858,43 @@ static struct drm_encoder *ltdc_rgb_encoder_create(struct drm_device *ddev)
 	return encoder;
 }
 
+static const struct drm_encoder_funcs bridge_encoder_funcs = {
+	.destroy = drm_encoder_cleanup,
+};
+
+struct drm_encoder *bridge_encoder_create(struct drm_device *ddev,
+					  struct drm_bridge *bridge)
+{
+	struct drm_encoder *encoder;
+	int ret;
+
+	encoder = devm_kzalloc(ddev->dev, sizeof(*encoder), GFP_KERNEL);
+	if (!encoder)
+		return NULL;
+
+	encoder->possible_crtcs = CRTC_MASK;
+	encoder->possible_clones = 0; /* No cloning support */
+
+	drm_encoder_init(ddev, encoder, &bridge_encoder_funcs,
+			 DRM_MODE_ENCODER_TMDS, NULL);
+
+	drm_encoder_helper_add(encoder, NULL);
+
+	/* Link drm_bridge to encoder */
+	bridge->encoder = encoder;
+	encoder->bridge = bridge;
+
+	ret = drm_bridge_attach(encoder, bridge, NULL);
+	if (ret) {
+		drm_encoder_cleanup(encoder);
+		return NULL;
+	}
+
+	DRM_DEBUG_DRIVER("Bridge encoder:%d created\n", encoder->base.id);
+
+	return encoder;
+}
+
 /*
  * DRM_CONNECTOR
  */
@@ -967,12 +1004,12 @@ static int ltdc_get_caps(struct drm_device *ddev)
 	return 0;
 }
 
-static struct drm_panel *ltdc_get_panel(struct drm_device *ddev)
+static int ltdc_parse_dt(struct drm_device *ddev)
 {
+	struct ltdc_device *ldev = ddev->dev_private;
 	struct device *dev = ddev->dev;
 	struct device_node *np = dev->of_node;
 	struct device_node *entity, *port = NULL;
-	struct drm_panel *panel = NULL;
 
 	DRM_DEBUG_DRIVER("\n");
 
@@ -987,19 +1024,36 @@ static struct drm_panel *ltdc_get_panel(struct drm_device *ddev)
 
 		port = of_graph_get_remote_port_parent(entity);
 		if (port) {
+			struct drm_bridge *bridge;
+			struct drm_panel *panel;
+
+			bridge = of_drm_find_bridge(port);
 			panel = of_drm_find_panel(port);
-			of_node_put(port);
+			if (!bridge && !panel) {
+				of_node_put(entity);
+				return -EPROBE_DEFER;
+			}
+
+			if (bridge) {
+				if (!ldev->bridge) {
+					ldev->bridge = bridge;
+					DRM_INFO("remote bridge %s\n",
+						 port->full_name);
+				}
+			}
+
 			if (panel) {
-				DRM_DEBUG_DRIVER("remote panel %s\n",
+				if (!ldev->panel) {
+					ldev->panel = panel;
+					DRM_INFO("remote panel %s\n",
 						 port->full_name);
-			} else {
-				DRM_DEBUG_DRIVER("panel missing\n");
-				of_node_put(entity);
+				}
 			}
+			of_node_put(port);
 		}
 	}
 
-	return panel;
+	return 0;
 }
 
 int ltdc_load(struct drm_device *ddev)
@@ -1017,9 +1071,9 @@ int ltdc_load(struct drm_device *ddev)
 
 	DRM_DEBUG_DRIVER("\n");
 
-	ldev->panel = ltdc_get_panel(ddev);
-	if (!ldev->panel)
-		return -EPROBE_DEFER;
+	ret = ltdc_parse_dt(ddev);
+	if (ret)
+		return ret;
 
 	rstc = of_reset_control_get(np, NULL);
 
@@ -1077,6 +1131,12 @@ int ltdc_load(struct drm_device *ddev)
 
 	DRM_INFO("ltdc hw version 0x%08x - ready\n", ldev->caps.hw_version);
 
+	if (ldev->bridge) {
+		encoder = bridge_encoder_create(ddev, ldev->bridge);
+		if (!encoder)
+			return -EINVAL;
+	}
+
 	if (ldev->panel) {
 		encoder = ltdc_rgb_encoder_create(ddev);
 		if (!encoder) {
diff --git a/drivers/gpu/drm/stm/ltdc.h b/drivers/gpu/drm/stm/ltdc.h
index 5427ef4..0083cad 100644
--- a/drivers/gpu/drm/stm/ltdc.h
+++ b/drivers/gpu/drm/stm/ltdc.h
@@ -25,6 +25,7 @@ struct ltdc_device {
 	void __iomem *regs;
 	struct clk *pixel_clk;	/* lcd pixel clock */
 	struct drm_panel *panel;
+	struct drm_bridge *bridge;
 	struct spinlock lock;	/* protecting irq status register */
 	struct ltdc_caps caps;
 	u32 clut[256];		/* color look up table */
-- 
1.9.1

Re: [PATCH v1 1/3] drm/stm: ltdc: Add bridge support

[Eric Anholt]

[-- Attachment #1: Type: text/plain, Size: 1335 bytes --]

Philippe CORNU <philippe.cornu-qxv4g6HH51o@public.gmane.org> writes:

> Add the bridge support, used by DSI host and HDMI/LVDS bridges.
>
> Signed-off-by: Philippe CORNU <philippe.cornu-qxv4g6HH51o@public.gmane.org>

> @@ -987,19 +1024,36 @@ static struct drm_panel *ltdc_get_panel(struct drm_device *ddev)
>  
>  		port = of_graph_get_remote_port_parent(entity);
>  		if (port) {
> +			struct drm_bridge *bridge;
> +			struct drm_panel *panel;
> +
> +			bridge = of_drm_find_bridge(port);
>  			panel = of_drm_find_panel(port);
> -			of_node_put(port);
> +			if (!bridge && !panel) {
> +				of_node_put(entity);
> +				return -EPROBE_DEFER;
> +			}
> +
> +			if (bridge) {
> +				if (!ldev->bridge) {
> +					ldev->bridge = bridge;
> +					DRM_INFO("remote bridge %s\n",
> +						 port->full_name);
> +				}
> +			}
> +
>  			if (panel) {
> -				DRM_DEBUG_DRIVER("remote panel %s\n",
> +				if (!ldev->panel) {
> +					ldev->panel = panel;
> +					DRM_INFO("remote panel %s\n",
>  						 port->full_name);
> -			} else {
> -				DRM_DEBUG_DRIVER("panel missing\n");
> -				of_node_put(entity);
> +				}
>  			}
> +			of_node_put(port);

Is it possible to use drm_of_find_panel_or_bridge() instead?  I don't
think it makes sense to have both a bridge and a panel for the same
node, does it?

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[PATCH v1 2/3] dt-bindings: display: Add STM32 DSI host driver

[Philippe CORNU]

This patch adds documentation of device tree bindings for the STM32
DSI host driver based on the Synopsys DW MIPI DSI driver from Rockchip.

Signed-off-by: Philippe CORNU <philippe.cornu@st.com>
---
 .../devicetree/bindings/display/st,stm32-ltdc.txt  | 92 +++++++++++++++++++++-
 1 file changed, 90 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt b/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt
index 8e14769..a61381b 100644
--- a/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt
+++ b/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt
@@ -1,7 +1,6 @@
 * STMicroelectronics STM32 lcd-tft display controller
 
 - ltdc: lcd-tft display controller host
-  must be a sub-node of st-display-subsystem
   Required properties:
   - compatible: "st,stm32-ltdc"
   - reg: Physical base address of the IP registers and length of memory mapped region.
@@ -13,8 +12,25 @@
   Required nodes:
     - Video port for RGB output.
 
-Example:
+* STMicroelectronics STM32 specific extensions to Synopsys Designware MIPI DSI
+(similar to "rockchip/dw_mipi_dsi_rockchip.txt")
 
+Required properties:
+- #address-cells: Should be <1>.
+- #size-cells: Should be <0>.
+- compatible: "st,stm32-dsi_host".
+- reg: Represent the physical address range of the controller.
+- clocks, clock-names: Phandles to the controller's pll reference
+  clock(ref) and APB clock(pclk). As described in [1].
+- ports: contain a port node with endpoint definitions as defined in [2].
+- resets: list of phandle + reset specifier pairs, as described in [3].
+- reset-names: string reset name, must be "apb".
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+[2] Documentation/devicetree/bindings/media/video-interfaces.txt
+[3] Documentation/devicetree/bindings/reset/reset.txt
+
+Example 1: RGB panel
 / {
 	...
 	soc {
@@ -34,3 +50,75 @@ Example:
 		};
 	};
 };
+
+Example 2: DSI panel
+
+/ {
+	...
+	soc {
+	...
+		ltdc: display-controller@40016800 {
+			compatible = "st,stm32-ltdc";
+			reg = <0x40016800 0x200>;
+			interrupts = <88>, <89>;
+			resets = <&rcc STM32F4_APB2_RESET(LTDC)>;
+			clocks = <&rcc 1 CLK_LCD>;
+			clock-names = "lcd";
+
+			port {
+				ltdc_out_dsi_host: endpoint {
+					remote-endpoint = <&dsi_host_in>;
+				};
+			};
+		};
+
+
+		dsi_host: dsi_host@40016C00 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "st,stm32-dsi_host";
+			reg = <0x40016C00 0x800>;
+			clocks = <&rcc 1 CLK_F469_DSI>, <&clk_hse>;
+			clock-names = "ref", "pclk";
+			resets = <&rcc STM32F4_APB2_RESET(DSI)>;
+			reset-names = "apb";
+			status = "okay";
+
+			ports {
+				#address-cells = <1>;
+				#size-cells = <0>;
+
+				port@0 {
+					reg = <0>;
+					dsi_host_in: endpoint {
+						remote-endpoint = <&ltdc_out_dsi_host>;
+					};
+				};
+
+				port@1 {
+					reg = <1>;
+					dsi_host_out_panel: endpoint {
+						remote-endpoint = <&dsi_host_in_panel>;
+					};
+				};
+
+			};
+
+			panel-dsi@0 {
+				reg = <0>; /* dsi virtual channel (0..3) */
+				compatible = ...;
+				enable-gpios = ...;
+				status = "okay";
+
+				port {
+					dsi_host_in_panel: endpoint {
+						remote-endpoint = <&dsi_host_out_panel>;
+					};
+				};
+
+			};
+
+		};
+
+	};
+};
-- 
1.9.1

Re: [PATCH v1 2/3] dt-bindings: display: Add STM32 DSI host driver

[Rob Herring]

On Fri, May 12, 2017 at 04:56:28PM +0200, Philippe CORNU wrote:
> This patch adds documentation of device tree bindings for the STM32
> DSI host driver based on the Synopsys DW MIPI DSI driver from Rockchip.
> 
> Signed-off-by: Philippe CORNU <philippe.cornu-qxv4g6HH51o@public.gmane.org>
> ---
>  .../devicetree/bindings/display/st,stm32-ltdc.txt  | 92 +++++++++++++++++++++-
>  1 file changed, 90 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt b/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt
> index 8e14769..a61381b 100644
> --- a/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt
> +++ b/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt
> @@ -1,7 +1,6 @@
>  * STMicroelectronics STM32 lcd-tft display controller
>  
>  - ltdc: lcd-tft display controller host
> -  must be a sub-node of st-display-subsystem

Why is this removed? The "must" refers to the location, not whether 
present or not if that's what you were trying to change.

>    Required properties:
>    - compatible: "st,stm32-ltdc"
>    - reg: Physical base address of the IP registers and length of memory mapped region.
> @@ -13,8 +12,25 @@
>    Required nodes:
>      - Video port for RGB output.
>  
> -Example:
> +* STMicroelectronics STM32 specific extensions to Synopsys Designware MIPI DSI
> +(similar to "rockchip/dw_mipi_dsi_rockchip.txt")
>  
> +Required properties:
> +- #address-cells: Should be <1>.
> +- #size-cells: Should be <0>.
> +- compatible: "st,stm32-dsi_host".

Don't use '_' and this needs to be more specific than just "stm32".

> +- reg: Represent the physical address range of the controller.
> +- clocks, clock-names: Phandles to the controller's pll reference
> +  clock(ref) and APB clock(pclk). As described in [1].

Ideally these should be in a common binding (like the driver) as a given 
IP block doesn't have a varying number of clocks (typically).

> +- ports: contain a port node with endpoint definitions as defined in [2].

a single port? Need to be clear how many ports/endpoints and their 
function.

> +- resets: list of phandle + reset specifier pairs, as described in [3].
> +- reset-names: string reset name, must be "apb".
> +
> +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
> +[2] Documentation/devicetree/bindings/media/video-interfaces.txt
> +[3] Documentation/devicetree/bindings/reset/reset.txt
> +
> +Example 1: RGB panel
>  / {
>  	...
>  	soc {
> @@ -34,3 +50,75 @@ Example:
>  		};
>  	};
>  };
> +
> +Example 2: DSI panel
> +
> +/ {
> +	...
> +	soc {
> +	...
> +		ltdc: display-controller@40016800 {
> +			compatible = "st,stm32-ltdc";
> +			reg = <0x40016800 0x200>;
> +			interrupts = <88>, <89>;
> +			resets = <&rcc STM32F4_APB2_RESET(LTDC)>;
> +			clocks = <&rcc 1 CLK_LCD>;
> +			clock-names = "lcd";
> +
> +			port {
> +				ltdc_out_dsi_host: endpoint {
> +					remote-endpoint = <&dsi_host_in>;
> +				};
> +			};
> +		};
> +
> +
> +		dsi_host: dsi_host@40016C00 {

dsi@...

> +			#address-cells = <1>;
> +			#size-cells = <0>;
> +			compatible = "st,stm32-dsi_host";
> +			reg = <0x40016C00 0x800>;
> +			clocks = <&rcc 1 CLK_F469_DSI>, <&clk_hse>;
> +			clock-names = "ref", "pclk";
> +			resets = <&rcc STM32F4_APB2_RESET(DSI)>;
> +			reset-names = "apb";
> +			status = "okay";

Don't show status in examples.
> +
> +			ports {
> +				#address-cells = <1>;
> +				#size-cells = <0>;
> +
> +				port@0 {
> +					reg = <0>;
> +					dsi_host_in: endpoint {
> +						remote-endpoint = <&ltdc_out_dsi_host>;
> +					};
> +				};
> +
> +				port@1 {
> +					reg = <1>;
> +					dsi_host_out_panel: endpoint {
> +						remote-endpoint = <&dsi_host_in_panel>;
> +					};
> +				};
> +
> +			};
> +
> +			panel-dsi@0 {
> +				reg = <0>; /* dsi virtual channel (0..3) */
> +				compatible = ...;
> +				enable-gpios = ...;
> +				status = "okay";
> +
> +				port {
> +					dsi_host_in_panel: endpoint {
> +						remote-endpoint = <&dsi_host_out_panel>;
> +					};
> +				};
> +
> +			};
> +
> +		};
> +
> +	};
> +};
> -- 
> 1.9.1
> 
> 
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Re: [PATCH v1 2/3] dt-bindings: display: Add STM32 DSI host driver

[Philippe CORNU]

On 05/18/2017 11:42 PM, Rob Herring wrote:
> On Fri, May 12, 2017 at 04:56:28PM +0200, Philippe CORNU wrote:
>> This patch adds documentation of device tree bindings for the STM32
>> DSI host driver based on the Synopsys DW MIPI DSI driver from Rockchip.
>>
>> Signed-off-by: Philippe CORNU <philippe.cornu@st.com>
>> ---
>>   .../devicetree/bindings/display/st,stm32-ltdc.txt  | 92 +++++++++++++++++++++-
>>   1 file changed, 90 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt b/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt
>> index 8e14769..a61381b 100644
>> --- a/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt
>> +++ b/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt
>> @@ -1,7 +1,6 @@
>>   * STMicroelectronics STM32 lcd-tft display controller
>>   
>>   - ltdc: lcd-tft display controller host
>> -  must be a sub-node of st-display-subsystem
> 
> Why is this removed? The "must" refers to the location, not whether
> present or not if that's what you were trying to change.
> 
Dear Rob,
Many thanks for your comments.

There is no need anymore to have a st-display-subsystem parent node in 
the device tree for the ltdc, that is why I removed this "must" information.

>>     Required properties:
>>     - compatible: "st,stm32-ltdc"
>>     - reg: Physical base address of the IP registers and length of memory mapped region.
>> @@ -13,8 +12,25 @@
>>     Required nodes:
>>       - Video port for RGB output.
>>   
>> -Example:
>> +* STMicroelectronics STM32 specific extensions to Synopsys Designware MIPI DSI
>> +(similar to "rockchip/dw_mipi_dsi_rockchip.txt")
>>   
>> +Required properties:
>> +- #address-cells: Should be <1>.
>> +- #size-cells: Should be <0>.
>> +- compatible: "st,stm32-dsi_host".
> 
> Don't use '_' and this needs to be more specific than just "stm32".
> 
Fixed in v2 patchset.

>> +- reg: Represent the physical address range of the controller.
>> +- clocks, clock-names: Phandles to the controller's pll reference
>> +  clock(ref) and APB clock(pclk). As described in [1].
> 
> Ideally these should be in a common binding (like the driver) as a given
> IP block doesn't have a varying number of clocks (typically).
> 
Updated in v2 patchset.

>> +- ports: contain a port node with endpoint definitions as defined in [2].
> 
> a single port? Need to be clear how many ports/endpoints and their
> function.
> 
Updated in v2 patchset.

>> +- resets: list of phandle + reset specifier pairs, as described in [3].
>> +- reset-names: string reset name, must be "apb".
>> +
>> +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
>> +[2] Documentation/devicetree/bindings/media/video-interfaces.txt
>> +[3] Documentation/devicetree/bindings/reset/reset.txt
>> +
>> +Example 1: RGB panel
>>   / {
>>   	...
>>   	soc {
>> @@ -34,3 +50,75 @@ Example:
>>   		};
>>   	};
>>   };
>> +
>> +Example 2: DSI panel
>> +
>> +/ {
>> +	...
>> +	soc {
>> +	...
>> +		ltdc: display-controller@40016800 {
>> +			compatible = "st,stm32-ltdc";
>> +			reg = <0x40016800 0x200>;
>> +			interrupts = <88>, <89>;
>> +			resets = <&rcc STM32F4_APB2_RESET(LTDC)>;
>> +			clocks = <&rcc 1 CLK_LCD>;
>> +			clock-names = "lcd";
>> +
>> +			port {
>> +				ltdc_out_dsi_host: endpoint {
>> +					remote-endpoint = <&dsi_host_in>;
>> +				};
>> +			};
>> +		};
>> +
>> +
>> +		dsi_host: dsi_host@40016C00 {
> 
> dsi@...
> 
Fixed in v2 patchset.

>> +			#address-cells = <1>;
>> +			#size-cells = <0>;
>> +			compatible = "st,stm32-dsi_host";
>> +			reg = <0x40016C00 0x800>;
>> +			clocks = <&rcc 1 CLK_F469_DSI>, <&clk_hse>;
>> +			clock-names = "ref", "pclk";
>> +			resets = <&rcc STM32F4_APB2_RESET(DSI)>;
>> +			reset-names = "apb";
>> +			status = "okay";
> 
> Don't show status in examples.
Fixed in v2 patchset.

>> +
>> +			ports {
>> +				#address-cells = <1>;
>> +				#size-cells = <0>;
>> +
>> +				port@0 {
>> +					reg = <0>;
>> +					dsi_host_in: endpoint {
>> +						remote-endpoint = <&ltdc_out_dsi_host>;
>> +					};
>> +				};
>> +
>> +				port@1 {
>> +					reg = <1>;
>> +					dsi_host_out_panel: endpoint {
>> +						remote-endpoint = <&dsi_host_in_panel>;
>> +					};
>> +				};
>> +
>> +			};
>> +
>> +			panel-dsi@0 {
>> +				reg = <0>; /* dsi virtual channel (0..3) */
>> +				compatible = ...;
>> +				enable-gpios = ...;
>> +				status = "okay";
>> +
>> +				port {
>> +					dsi_host_in_panel: endpoint {
>> +						remote-endpoint = <&dsi_host_out_panel>;
>> +					};
>> +				};
>> +
>> +			};
>> +
>> +		};
>> +
>> +	};
>> +};
>> -- 
>> 1.9.1
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v1 2/3] dt-bindings: display: Add STM32 DSI host driver

[Rob Herring]

On Fri, May 19, 2017 at 11:25 AM, Philippe CORNU <philippe.cornu@st.com> wrote:
>
>
> On 05/18/2017 11:42 PM, Rob Herring wrote:
>> On Fri, May 12, 2017 at 04:56:28PM +0200, Philippe CORNU wrote:
>>> This patch adds documentation of device tree bindings for the STM32
>>> DSI host driver based on the Synopsys DW MIPI DSI driver from Rockchip.
>>>
>>> Signed-off-by: Philippe CORNU <philippe.cornu@st.com>
>>> ---
>>>   .../devicetree/bindings/display/st,stm32-ltdc.txt  | 92 +++++++++++++++++++++-
>>>   1 file changed, 90 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt b/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt
>>> index 8e14769..a61381b 100644
>>> --- a/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt
>>> +++ b/Documentation/devicetree/bindings/display/st,stm32-ltdc.txt
>>> @@ -1,7 +1,6 @@
>>>   * STMicroelectronics STM32 lcd-tft display controller
>>>
>>>   - ltdc: lcd-tft display controller host
>>> -  must be a sub-node of st-display-subsystem
>>
>> Why is this removed? The "must" refers to the location, not whether
>> present or not if that's what you were trying to change.
>>
> Dear Rob,
> Many thanks for your comments.
>
> There is no need anymore to have a st-display-subsystem parent node in
> the device tree for the ltdc, that is why I removed this "must" information.

Okay, that's good because I'm not a fan of them. That seems like an
unrelated change though.

Rob
_______________________________________________
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dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[PATCH v1 3/3] drm/stm: Add STM32 DSI host driver

[Philippe CORNU]

This mipi dsi host driver is based on the Rockchip version of the
Synopsys Designware mipi dsi driver (rockchip/dw-mipi-dsi.c)
modified for the stm32 family:
- replace Rockchip digital & phy specific extensions with stm32's ones.
- add a bridge

Signed-off-by: Philippe CORNU <philippe.cornu@st.com>
---
 drivers/gpu/drm/stm/Kconfig       |    7 +
 drivers/gpu/drm/stm/Makefile      |    2 +
 drivers/gpu/drm/stm/dw-mipi-dsi.c | 1197 +++++++++++++++++++++++++++++++++++++
 3 files changed, 1206 insertions(+)
 create mode 100644 drivers/gpu/drm/stm/dw-mipi-dsi.c

diff --git a/drivers/gpu/drm/stm/Kconfig b/drivers/gpu/drm/stm/Kconfig
index 2c4817f..0007789 100644
--- a/drivers/gpu/drm/stm/Kconfig
+++ b/drivers/gpu/drm/stm/Kconfig
@@ -14,3 +14,10 @@ config DRM_STM
 	  STMicroelectronics STM32 MCUs.
 	  To compile this driver as a module, choose M here: the module
 	  will be called stm-drm.
+
+config DRM_STM_DSI
+	tristate "MIPI DSI support for STMicroelectronics SoC"
+	depends on DRM_STM
+	select DRM_MIPI_DSI
+	help
+	  Choose this option for MIPI DSI support on STMicroelectronics SoC.
diff --git a/drivers/gpu/drm/stm/Makefile b/drivers/gpu/drm/stm/Makefile
index e114d45..e448a93 100644
--- a/drivers/gpu/drm/stm/Makefile
+++ b/drivers/gpu/drm/stm/Makefile
@@ -4,4 +4,6 @@ stm-drm-y := \
 	drv.o \
 	ltdc.o
 
+obj-$(CONFIG_DRM_STM_DSI) += dw-mipi-dsi.o
+
 obj-$(CONFIG_DRM_STM) += stm-drm.o
diff --git a/drivers/gpu/drm/stm/dw-mipi-dsi.c b/drivers/gpu/drm/stm/dw-mipi-dsi.c
new file mode 100644
index 0000000..4b7f7b9
--- /dev/null
+++ b/drivers/gpu/drm/stm/dw-mipi-dsi.c
@@ -0,0 +1,1197 @@
+/*
+ * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
+ *
+ * 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.
+ *
+ * Modified by Philippe Cornu <philippe.cornu@st.com> for the stm32 family.
+ */
+#include <linux/clk.h>
+#include <linux/component.h>
+#include <linux/iopoll.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/mfd/syscon.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_of.h>
+#include <drm/drm_panel.h>
+#include <drm/drmP.h>
+#include <video/mipi_display.h>
+
+#define DRIVER_NAME    "dw-mipi-dsi"
+
+#define DSI_VERSION			0x00
+#define DSI_PWR_UP			0x04
+#define RESET				0
+#define POWERUP				BIT(0)
+
+#define DSI_CLKMGR_CFG			0x08
+#define TO_CLK_DIVIDSION(div)		(((div) & 0xff) << 8)
+#define TX_ESC_CLK_DIVIDSION(div)	(((div) & 0xff) << 0)
+
+#define DSI_DPI_VCID			0x0c
+#define DPI_VID(vid)			(((vid) & 0x3) << 0)
+
+#define DSI_DPI_COLOR_CODING		0x10
+#define EN18_LOOSELY			BIT(8)
+#define DPI_COLOR_CODING_16BIT_1	0x0
+#define DPI_COLOR_CODING_16BIT_2	0x1
+#define DPI_COLOR_CODING_16BIT_3	0x2
+#define DPI_COLOR_CODING_18BIT_1	0x3
+#define DPI_COLOR_CODING_18BIT_2	0x4
+#define DPI_COLOR_CODING_24BIT		0x5
+
+#define DSI_DPI_CFG_POL			0x14
+#define COLORM_ACTIVE_LOW		BIT(4)
+#define SHUTD_ACTIVE_LOW		BIT(3)
+#define HSYNC_ACTIVE_LOW		BIT(2)
+#define VSYNC_ACTIVE_LOW		BIT(1)
+#define DATAEN_ACTIVE_LOW		BIT(0)
+
+#define DSI_DPI_LP_CMD_TIM		0x18
+#define OUTVACT_LPCMD_TIME(p)		(((p) & 0xff) << 16)
+#define INVACT_LPCMD_TIME(p)		((p) & 0xff)
+
+#define DSI_DBI_CFG			0x20
+#define DSI_DBI_CMDSIZE			0x28
+
+#define DSI_PCKHDL_CFG			0x2c
+#define EN_CRC_RX			BIT(4)
+#define EN_ECC_RX			BIT(3)
+#define EN_BTA				BIT(2)
+#define EN_EOTP_RX			BIT(1)
+#define EN_EOTP_TX			BIT(0)
+
+#define DSI_MODE_CFG			0x34
+#define ENABLE_VIDEO_MODE		0
+#define ENABLE_CMD_MODE			BIT(0)
+
+#define DSI_VID_MODE_CFG		0x38
+#define FRAME_BTA_ACK			BIT(14)
+#define ENABLE_LOW_POWER		(0x3f << 8)
+#define ENABLE_LOW_POWER_MASK		(0x3f << 8)
+#define VID_MODE_TYPE_NON_BURST_SYNC_PULSES	0x0
+#define VID_MODE_TYPE_NON_BURST_SYNC_EVENTS	0x1
+#define VID_MODE_TYPE_BURST			0x2
+#define VID_MODE_TYPE_MASK			0x3
+
+#define DSI_VID_PKT_SIZE		0x3c
+#define VID_PKT_SIZE(p)			(((p) & 0x3fff) << 0)
+#define VID_PKT_MAX_SIZE		0x3fff
+
+#define DSI_VID_HSA_TIME		0x48
+#define DSI_VID_HBP_TIME		0x4c
+#define DSI_VID_HLINE_TIME		0x50
+#define DSI_VID_VSA_LINES		0x54
+#define DSI_VID_VBP_LINES		0x58
+#define DSI_VID_VFP_LINES		0x5c
+#define DSI_VID_VACTIVE_LINES		0x60
+#define DSI_CMD_MODE_CFG		0x68
+#define MAX_RD_PKT_SIZE_LP		BIT(24)
+#define DCS_LW_TX_LP			BIT(19)
+#define DCS_SR_0P_TX_LP			BIT(18)
+#define DCS_SW_1P_TX_LP			BIT(17)
+#define DCS_SW_0P_TX_LP			BIT(16)
+#define GEN_LW_TX_LP			BIT(14)
+#define GEN_SR_2P_TX_LP			BIT(13)
+#define GEN_SR_1P_TX_LP			BIT(12)
+#define GEN_SR_0P_TX_LP			BIT(11)
+#define GEN_SW_2P_TX_LP			BIT(10)
+#define GEN_SW_1P_TX_LP			BIT(9)
+#define GEN_SW_0P_TX_LP			BIT(8)
+#define EN_ACK_RQST			BIT(1)
+#define EN_TEAR_FX			BIT(0)
+
+#define CMD_MODE_ALL_LP			(MAX_RD_PKT_SIZE_LP | \
+					 DCS_LW_TX_LP | \
+					 DCS_SR_0P_TX_LP | \
+					 DCS_SW_1P_TX_LP | \
+					 DCS_SW_0P_TX_LP | \
+					 GEN_LW_TX_LP | \
+					 GEN_SR_2P_TX_LP | \
+					 GEN_SR_1P_TX_LP | \
+					 GEN_SR_0P_TX_LP | \
+					 GEN_SW_2P_TX_LP | \
+					 GEN_SW_1P_TX_LP | \
+					 GEN_SW_0P_TX_LP)
+
+#define DSI_GEN_HDR			0x6c
+#define GEN_HDATA(data)			(((data) & 0xffff) << 8)
+#define GEN_HDATA_MASK			(0xffff << 8)
+#define GEN_HTYPE(type)			(((type) & 0xff) << 0)
+#define GEN_HTYPE_MASK			0xff
+
+#define DSI_GEN_PLD_DATA		0x70
+
+#define DSI_CMD_PKT_STATUS		0x74
+#define GEN_CMD_EMPTY			BIT(0)
+#define GEN_CMD_FULL			BIT(1)
+#define GEN_PLD_W_EMPTY			BIT(2)
+#define GEN_PLD_W_FULL			BIT(3)
+#define GEN_PLD_R_EMPTY			BIT(4)
+#define GEN_PLD_R_FULL			BIT(5)
+#define GEN_RD_CMD_BUSY			BIT(6)
+
+#define DSI_TO_CNT_CFG			0x78
+#define HSTX_TO_CNT(p)			(((p) & 0xffff) << 16)
+#define LPRX_TO_CNT(p)			((p) & 0xffff)
+
+#define DSI_BTA_TO_CNT			0x8c
+#define DSI_LPCLK_CTRL			0x94
+#define AUTO_CLKLANE_CTRL		BIT(1)
+#define PHY_TXREQUESTCLKHS		BIT(0)
+
+#define DSI_PHY_TMR_LPCLK_CFG		0x98
+#define PHY_CLKHS2LP_TIME(lbcc)		(((lbcc) & 0x3ff) << 16)
+#define PHY_CLKLP2HS_TIME(lbcc)		((lbcc) & 0x3ff)
+
+#define DSI_PHY_TMR_CFG			0x9c
+#define PHY_HS2LP_TIME(lbcc)		(((lbcc) & 0xff) << 24)
+#define PHY_LP2HS_TIME(lbcc)		(((lbcc) & 0xff) << 16)
+#define MAX_RD_TIME(lbcc)		((lbcc) & 0x7fff)
+
+#define DSI_PHY_RSTZ			0xa0
+#define PHY_DISFORCEPLL			0
+#define PHY_ENFORCEPLL			BIT(3)
+#define PHY_DISABLECLK			0
+#define PHY_ENABLECLK			BIT(2)
+#define PHY_RSTZ			0
+#define PHY_UNRSTZ			BIT(1)
+#define PHY_SHUTDOWNZ			0
+#define PHY_UNSHUTDOWNZ			BIT(0)
+
+#define DSI_PHY_IF_CFG			0xa4
+#define N_LANES(n)			((((n) - 1) & 0x3) << 0)
+#define PHY_STOP_WAIT_TIME(cycle)	(((cycle) & 0xff) << 8)
+
+#define DSI_PHY_STATUS			0xb0
+#define LOCK				BIT(0)
+#define STOP_STATE_CLK_LANE		BIT(2)
+
+#define DSI_PHY_TST_CTRL0		0xb4
+#define PHY_TESTCLK			BIT(1)
+#define PHY_UNTESTCLK			0
+#define PHY_TESTCLR			BIT(0)
+#define PHY_UNTESTCLR			0
+
+#define DSI_PHY_TST_CTRL1		0xb8
+#define PHY_TESTEN			BIT(16)
+#define PHY_UNTESTEN			0
+#define PHY_TESTDOUT(n)			(((n) & 0xff) << 8)
+#define PHY_TESTDIN(n)			(((n) & 0xff) << 0)
+
+#define DSI_INT_ST0			0xbc
+#define DSI_INT_ST1			0xc0
+#define DSI_INT_MSK0			0xc4
+#define DSI_INT_MSK1			0xc8
+
+#define PHY_STATUS_TIMEOUT_US		10000
+#define CMD_PKT_STATUS_TIMEOUT_US	20000
+
+/* DSI wrapper register & bit definitions */
+/* Note: registers are named as in the Reference Manual */
+#define DSI_WCFGR	0x0400		/* Wrapper ConFiGuration Reg */
+#define WCFGR_DSIM	BIT(0)		/* DSI Mode */
+#define WCFGR_COLMUX	GENMASK(3, 1)	/* COLor MUltipleXing */
+
+#define DSI_WCR		0x0404		/* Wrapper Control Reg */
+#define WCR_DSIEN	BIT(3)		/* DSI ENable */
+
+#define DSI_WISR	0x040C		/* Wrapper Interrupt and Status Reg */
+#define WISR_PLLLS	BIT(8)		/* PLL Lock Status */
+#define WISR_RRS	BIT(12)		/* Regulator Ready Status */
+
+#define DSI_WPCR0	0x0418		/* Wrapper Phy Conf Reg 0 */
+#define WPCR0_UIX4	GENMASK(5, 0)	/* Unit Interval X 4 */
+#define WPCR0_TDDL	BIT(16)		/* Turn Disable Data Lanes */
+
+#define DSI_WRPCR	0x0430		/* Wrapper Regulator & Pll Ctrl Reg */
+#define WRPCR_PLLEN	BIT(0)		/* PLL ENable */
+#define WRPCR_NDIV	GENMASK(8, 2)	/* pll loop DIVision Factor */
+#define WRPCR_IDF	GENMASK(14, 11)	/* pll Input Division Factor */
+#define WRPCR_ODF	GENMASK(17, 16)	/* pll Output Division Factor */
+#define WRPCR_REGEN	BIT(24)		/* REGulator ENable */
+#define WRPCR_BGREN	BIT(28)		/* BandGap Reference ENable */
+#define IDF_MIN		1
+#define IDF_MAX		7
+#define NDIV_MIN	10
+#define NDIV_MAX	125
+#define ODF_MIN		1
+#define ODF_MAX		8
+
+/* dsi color format coding according to the datasheet */
+enum dsi_color {
+	DSI_RGB565_CONF1, DSI_RGB565_CONF2, DSI_RGB565_CONF3,
+	DSI_RGB666_CONF1, DSI_RGB666_CONF2,
+	DSI_RGB888,
+};
+
+#define LANE_MIN_KBPS	31250
+#define LANE_MAX_KBPS	500000
+
+/* Sleep & timeout for regulator on/off, pll lock/unlock & fifo empty */
+#define SLEEP_US	1000
+#define TIMEOUT_US	200000
+
+struct dw_mipi_dsi_plat_data {
+	unsigned int max_data_lanes;
+};
+
+struct dw_mipi_dsi {
+	struct drm_bridge bridge;
+	struct drm_connector connector;
+	struct mipi_dsi_host dsi_host;
+	struct drm_panel *panel;
+	struct device *dev;
+	struct regmap *grf_regmap;
+	void __iomem *base;
+
+	struct clk *pllref_clk;
+	struct clk *pclk;
+
+	int dpms_mode;
+	unsigned int lane_mbps; /* per lane */
+	u32 channel;
+	u32 lanes;
+	u32 format;
+	unsigned long mode_flags;
+
+	const struct dw_mipi_dsi_plat_data *pdata;
+};
+
+enum dw_mipi_dsi_mode {
+	DW_MIPI_DSI_CMD_MODE,
+	DW_MIPI_DSI_VID_MODE,
+};
+
+/*
+ * The controller should generate 2 frames before
+ * preparing the peripheral.
+ */
+static void dw_mipi_dsi_wait_for_two_frames(struct drm_display_mode *mode)
+{
+	int refresh, two_frames;
+
+	refresh = drm_mode_vrefresh(mode);
+	two_frames = DIV_ROUND_UP(MSEC_PER_SEC, refresh) * 2;
+	msleep(two_frames);
+}
+
+static inline struct dw_mipi_dsi *host_to_dsi(struct mipi_dsi_host *host)
+{
+	return container_of(host, struct dw_mipi_dsi, dsi_host);
+}
+
+static inline struct dw_mipi_dsi *con_to_dsi(struct drm_connector *con)
+{
+	return container_of(con, struct dw_mipi_dsi, connector);
+}
+
+static inline struct dw_mipi_dsi *bridge_to_dsi(struct drm_bridge *bridge)
+{
+	return container_of(bridge, struct dw_mipi_dsi, bridge);
+}
+
+static inline void dsi_write(struct dw_mipi_dsi *dsi, u32 reg, u32 val)
+{
+	writel_relaxed(val, dsi->base + reg);
+}
+
+static inline u32 dsi_read(struct dw_mipi_dsi *dsi, u32 reg)
+{
+	return readl_relaxed(dsi->base + reg);
+}
+
+static inline void dsi_set(struct dw_mipi_dsi *dsi, u32 reg, u32 mask)
+{
+	dsi_write(dsi, reg, dsi_read(dsi, reg) | mask);
+}
+
+static inline void dsi_clear(struct dw_mipi_dsi *dsi, u32 reg, u32 mask)
+{
+	dsi_write(dsi, reg, dsi_read(dsi, reg) & ~mask);
+}
+
+static inline void dsi_update_bits(struct dw_mipi_dsi *dsi, u32 reg, u32 mask,
+				   u32 val)
+{
+	dsi_write(dsi, reg, (dsi_read(dsi, reg) & ~mask) | val);
+}
+
+/*
+ * DSI HOST PHY
+ */
+
+/* todo remove me (used only once) */
+static enum dsi_color dsi_color_from_mipi(enum mipi_dsi_pixel_format fmt)
+{
+	switch (fmt) {
+	case MIPI_DSI_FMT_RGB888:
+		return DSI_RGB888;
+	case MIPI_DSI_FMT_RGB666:
+		return DSI_RGB666_CONF2;
+	case MIPI_DSI_FMT_RGB666_PACKED:
+		return DSI_RGB666_CONF1;
+	case MIPI_DSI_FMT_RGB565:
+		return DSI_RGB565_CONF1;
+	default:
+		DRM_DEBUG_DRIVER("MIPI color invalid, so we use rgb888\n");
+	}
+	return DSI_RGB888;
+}
+
+static int dsi_pll_get_clkout_khz(int clkin_khz, int idf, int ndiv, int odf)
+{
+	/* prevent from division by 0 */
+	if (idf * odf)
+		return DIV_ROUND_CLOSEST(clkin_khz * ndiv, idf * odf);
+	else
+		return 0;
+}
+
+static int dsi_pll_get_params(int clkin_khz, int clkout_khz,
+			      int *idf, int *ndiv, int *odf)
+{
+	int i, o, n, n_min, n_max;
+	int fvco_min, fvco_max, delta, best_delta; /* all in khz */
+
+	/* Early checks preventing division by 0 & odd results */
+	if ((clkin_khz <= 0) || (clkout_khz <= 0))
+		return 0;
+
+	fvco_min = LANE_MIN_KBPS * 2 * ODF_MAX;
+	fvco_max = LANE_MAX_KBPS * 2 * ODF_MIN;
+
+	best_delta = 1000000; /* big started value (1000000khz) */
+
+	for (i = IDF_MIN; i <= IDF_MAX; i++) {
+		/* Compute ndiv range according to Fvco */
+		n_min = ((fvco_min * i) / (2 * clkin_khz)) + 1;
+		n_max = (fvco_max * i) / (2 * clkin_khz);
+
+		/* No need to continue idf loop if we reach ndiv max */
+		if (n_min >= NDIV_MAX)
+			break;
+
+		/* Clamp ndiv to valid values */
+		if (n_min < NDIV_MIN)
+			n_min = NDIV_MIN;
+		if (n_max > NDIV_MAX)
+			n_max = NDIV_MAX;
+
+		for (o = ODF_MIN; o <= ODF_MAX; o *= 2) {
+			n = DIV_ROUND_CLOSEST(i * o * clkout_khz, clkin_khz);
+			/* Check ndiv according to vco range */
+			if ((n < n_min) || (n > n_max))
+				continue;
+			/* Check if new delta is better & saves parameters */
+			delta = dsi_pll_get_clkout_khz(clkin_khz, i, n, o) -
+				clkout_khz;
+			if (delta < 0)
+				delta = -delta;
+			if (delta < best_delta) {
+				*idf = i;
+				*ndiv = n;
+				*odf = o;
+				best_delta = delta;
+			}
+			/* fast return in case of "perfect result" */
+			if (!delta)
+				return 1;
+		}
+	}
+
+	return 1;
+}
+
+static int dw_mipi_dsi_phy_init(struct dw_mipi_dsi *dsi)
+{
+	u32 val;
+	int ret;
+
+	/* Enable the regulator */
+	dsi_set(dsi, DSI_WRPCR, WRPCR_REGEN | WRPCR_BGREN);
+	ret = readl_poll_timeout(dsi->base + DSI_WISR, val, val & WISR_RRS,
+				 SLEEP_US, TIMEOUT_US);
+	if (ret)
+		DRM_DEBUG_DRIVER("!TIMEOUT! waiting REGU, let's continue\n");
+
+	/* Enable the DSI PLL & wait for its lock */
+	dsi_set(dsi, DSI_WRPCR, WRPCR_PLLEN);
+	ret = readl_poll_timeout(dsi->base + DSI_WISR, val, val & WISR_PLLLS,
+				 SLEEP_US, TIMEOUT_US);
+	if (ret)
+		DRM_DEBUG_DRIVER("!TIMEOUT! waiting PLL, let's continue\n");
+
+	/* Enable the DSI wrapper */
+	dsi_set(dsi, DSI_WCR, WCR_DSIEN);
+
+	return 0;
+}
+
+static int dw_mipi_dsi_get_lane_bps(struct dw_mipi_dsi *dsi,
+				    struct drm_display_mode *mode)
+{
+	unsigned int idf, ndiv, odf, pll_in_khz, pll_out_khz;
+	u32 val;
+	int bpp;
+
+	pll_in_khz = (unsigned int)(clk_get_rate(dsi->pllref_clk) / 1000);
+
+	/* Compute requested pll out */
+	bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
+	pll_out_khz = mode->clock * bpp / dsi->lanes;
+	/* Add 20% to pll out to be higher than pixel bw (burst mode only) */
+	pll_out_khz = (pll_out_khz * 12) / 10;
+	if (pll_out_khz > LANE_MAX_KBPS) {
+		pll_out_khz = LANE_MAX_KBPS;
+		DRM_DEBUG_DRIVER("Warning max phy mbps is used\n");
+	} else if (pll_out_khz < LANE_MIN_KBPS) {
+		pll_out_khz = LANE_MIN_KBPS;
+		DRM_DEBUG_DRIVER("Warning min phy mbps is used\n");
+	}
+
+	/* Compute best pll parameters */
+	dsi_pll_get_params(pll_in_khz, pll_out_khz, &idf, &ndiv, &odf);
+
+	/* Get the adjusted pll out value */
+	pll_out_khz = dsi_pll_get_clkout_khz(pll_in_khz, idf, ndiv, odf);
+
+	clk_enable(dsi->pclk);
+
+	/* Set the PLL division factors */
+	dsi_update_bits(dsi, DSI_WRPCR,	WRPCR_NDIV | WRPCR_IDF | WRPCR_ODF,
+			(ndiv << 2) | (idf << 11) | ((ffs(odf) - 1) << 16));
+
+	/* Compute uix4 & set the bit period in high-speed mode */
+	val = 4000000 / pll_out_khz;
+	dsi_update_bits(dsi, DSI_WPCR0, WPCR0_UIX4, val);
+
+	/* Select video mode by resetting DSIM bit */
+	dsi_clear(dsi, DSI_WCFGR, WCFGR_DSIM);
+
+	/* Select the color coding for host & wrapper (same value) */
+	dsi_update_bits(dsi, DSI_WCFGR, WCFGR_COLMUX,
+			dsi_color_from_mipi(dsi->format) << 1);
+
+	clk_disable(dsi->pclk);
+
+	dsi->lane_mbps = pll_out_khz / 1000;
+
+	return 0;
+}
+
+/*
+ * DSI HOST DIGITAL
+ */
+
+static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
+				   struct mipi_dsi_device *device)
+{
+	struct dw_mipi_dsi *dsi = host_to_dsi(host);
+
+	if (device->lanes > dsi->pdata->max_data_lanes) {
+		dev_err(dsi->dev, "the number of data lanes(%u) is too many\n",
+			device->lanes);
+		return -EINVAL;
+	}
+
+	dsi->lanes = device->lanes;
+	dsi->channel = device->channel;
+	dsi->format = device->format;
+	dsi->mode_flags = device->mode_flags;
+	dsi->panel = of_drm_find_panel(device->dev.of_node);
+	if (dsi->panel)
+		return drm_panel_attach(dsi->panel, &dsi->connector);
+
+	return -EINVAL;
+}
+
+static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host,
+				   struct mipi_dsi_device *device)
+{
+	struct dw_mipi_dsi *dsi = host_to_dsi(host);
+
+	drm_panel_detach(dsi->panel);
+
+	return 0;
+}
+
+static void dw_mipi_message_config(struct dw_mipi_dsi *dsi,
+				   const struct mipi_dsi_msg *msg)
+{
+	bool lpm = msg->flags & MIPI_DSI_MSG_USE_LPM;
+	u32 val = 0;
+
+	if (msg->flags & MIPI_DSI_MSG_REQ_ACK)
+		val |= EN_ACK_RQST;
+	if (lpm)
+		val |= CMD_MODE_ALL_LP;
+
+	dsi_write(dsi, DSI_LPCLK_CTRL, lpm ? 0 : PHY_TXREQUESTCLKHS);
+
+	/* todo debug force the PHY_TXREQUESTCLKHS, to be improved... */
+	dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
+
+	dsi_write(dsi, DSI_CMD_MODE_CFG, val);
+}
+
+static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32 hdr_val)
+{
+	int ret;
+	u32 val, mask;
+
+	ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
+				 val, !(val & GEN_CMD_FULL), 1000,
+				 CMD_PKT_STATUS_TIMEOUT_US);
+	if (ret < 0) {
+		dev_err(dsi->dev, "failed to get available command FIFO\n");
+		return ret;
+	}
+
+	dsi_write(dsi, DSI_GEN_HDR, hdr_val);
+
+	mask = GEN_CMD_EMPTY | GEN_PLD_W_EMPTY;
+	ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
+				 val, (val & mask) == mask,
+				 1000, CMD_PKT_STATUS_TIMEOUT_US);
+	if (ret < 0) {
+		dev_err(dsi->dev, "failed to write command FIFO\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int dw_mipi_dsi_dcs_short_write(struct dw_mipi_dsi *dsi,
+				       const struct mipi_dsi_msg *msg)
+{
+	const u8 *tx_buf = msg->tx_buf;
+	u16 data = 0;
+	u32 val;
+
+	if (msg->tx_len > 0)
+		data |= tx_buf[0];
+	if (msg->tx_len > 1)
+		data |= tx_buf[1] << 8;
+
+	if (msg->tx_len > 2) {
+		dev_err(dsi->dev, "too long tx buf length %zu for short write\n",
+			msg->tx_len);
+		return -EINVAL;
+	}
+
+	val = GEN_HDATA(data) | GEN_HTYPE(msg->type);
+	return dw_mipi_dsi_gen_pkt_hdr_write(dsi, val);
+}
+
+static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
+				      const struct mipi_dsi_msg *msg)
+{
+	const u8 *tx_buf = msg->tx_buf;
+	int len = msg->tx_len, pld_data_bytes = sizeof(u32), ret;
+	u32 hdr_val = GEN_HDATA(msg->tx_len) | GEN_HTYPE(msg->type);
+	u32 remainder;
+	u32 val;
+
+	if (msg->tx_len < 3) {
+		dev_err(dsi->dev, "wrong tx buf length %zu for long write\n",
+			msg->tx_len);
+		return -EINVAL;
+	}
+
+	while (DIV_ROUND_UP(len, pld_data_bytes)) {
+		if (len < pld_data_bytes) {
+			remainder = 0;
+			memcpy(&remainder, tx_buf, len);
+			dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
+			len = 0;
+		} else {
+			memcpy(&remainder, tx_buf, pld_data_bytes);
+			dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
+			tx_buf += pld_data_bytes;
+			len -= pld_data_bytes;
+		}
+
+		ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
+					 val, !(val & GEN_PLD_W_FULL), 1000,
+					 CMD_PKT_STATUS_TIMEOUT_US);
+		if (ret < 0) {
+			dev_err(dsi->dev,
+				"failed to get available write payload FIFO\n");
+			return ret;
+		}
+	}
+
+	return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val);
+}
+
+static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
+					 const struct mipi_dsi_msg *msg)
+{
+	struct dw_mipi_dsi *dsi = host_to_dsi(host);
+	int ret;
+
+	/*
+	 * todo dw drv improvements
+	 * use mipi_dsi_create_packet() instead of all following
+	 * functions and code (no switch cases, no
+	 * dw_mipi_dsi_dcs_short_write(), only the loop in long_write...)
+	 * and use packet.header...
+	 */
+	dw_mipi_message_config(dsi, msg);
+
+	switch (msg->type) {
+	case MIPI_DSI_DCS_SHORT_WRITE:
+	case MIPI_DSI_DCS_SHORT_WRITE_PARAM:
+	case MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE:
+		ret = dw_mipi_dsi_dcs_short_write(dsi, msg);
+		break;
+	case MIPI_DSI_DCS_LONG_WRITE:
+		ret = dw_mipi_dsi_dcs_long_write(dsi, msg);
+		break;
+	default:
+		dev_err(dsi->dev, "unsupported message type 0x%02x\n",
+			msg->type);
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
+	.attach = dw_mipi_dsi_host_attach,
+	.detach = dw_mipi_dsi_host_detach,
+	.transfer = dw_mipi_dsi_host_transfer,
+};
+
+static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
+{
+	u32 val;
+
+	/*
+	 * todo dw drv improvements
+	 * enabling low power is panel-dependent, we should use the
+	 * panel configuration here...
+	 */
+	val = ENABLE_LOW_POWER;
+
+	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
+		val |= VID_MODE_TYPE_BURST;
+	else if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
+		val |= VID_MODE_TYPE_NON_BURST_SYNC_PULSES;
+	else
+		val |= VID_MODE_TYPE_NON_BURST_SYNC_EVENTS;
+
+	dsi_write(dsi, DSI_VID_MODE_CFG, val);
+}
+
+static void dw_mipi_dsi_set_mode(struct dw_mipi_dsi *dsi,
+				 enum dw_mipi_dsi_mode mode)
+{
+	if (mode == DW_MIPI_DSI_CMD_MODE) {
+		dsi_write(dsi, DSI_PWR_UP, RESET);
+		dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
+		dsi_write(dsi, DSI_PWR_UP, POWERUP);
+	} else {
+		dsi_write(dsi, DSI_PWR_UP, RESET);
+		dsi_write(dsi, DSI_MODE_CFG, ENABLE_VIDEO_MODE);
+		dw_mipi_dsi_video_mode_config(dsi);
+		dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
+		dsi_write(dsi, DSI_PWR_UP, POWERUP);
+	}
+}
+
+static void dw_mipi_dsi_disable(struct dw_mipi_dsi *dsi)
+{
+	dsi_write(dsi, DSI_PWR_UP, RESET);
+	dsi_write(dsi, DSI_PHY_RSTZ, PHY_RSTZ);
+}
+
+static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi)
+{
+	/*
+	 * The maximum permitted escape clock is 20MHz and it is derived from
+	 * lanebyteclk, which is running at "lane_mbps / 8".  Thus we want:
+	 *
+	 *     (lane_mbps >> 3) / esc_clk_division < 20
+	 * which is:
+	 *     (lane_mbps >> 3) / 20 > esc_clk_division
+	 */
+	u32 esc_clk_division = (dsi->lane_mbps >> 3) / 20 + 1;
+
+	dsi_write(dsi, DSI_PWR_UP, RESET);
+	dsi_write(dsi, DSI_PHY_RSTZ, PHY_DISFORCEPLL | PHY_DISABLECLK
+		  | PHY_RSTZ | PHY_SHUTDOWNZ);
+	/*
+	 * todo dw drv improvements
+	 * timeout clock division should be computed with the
+	 * high speed transmission counter timeout and byte lane...
+	 */
+	dsi_write(dsi, DSI_CLKMGR_CFG, TO_CLK_DIVIDSION(10) |
+		  TX_ESC_CLK_DIVIDSION(esc_clk_division));
+}
+
+static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,
+				   struct drm_display_mode *mode)
+{
+	u32 val = 0, color = 0;
+
+	switch (dsi->format) {
+	case MIPI_DSI_FMT_RGB888:
+		color = DPI_COLOR_CODING_24BIT;
+		break;
+	case MIPI_DSI_FMT_RGB666:
+		color = DPI_COLOR_CODING_18BIT_2 | EN18_LOOSELY;
+		break;
+	case MIPI_DSI_FMT_RGB666_PACKED:
+		color = DPI_COLOR_CODING_18BIT_1;
+		break;
+	case MIPI_DSI_FMT_RGB565:
+		color = DPI_COLOR_CODING_16BIT_1;
+		break;
+	}
+
+	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
+		val |= VSYNC_ACTIVE_LOW;
+	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
+		val |= HSYNC_ACTIVE_LOW;
+
+	dsi_write(dsi, DSI_DPI_VCID, DPI_VID(dsi->channel));
+	dsi_write(dsi, DSI_DPI_COLOR_CODING, color);
+	dsi_write(dsi, DSI_DPI_CFG_POL, val);
+	/*
+	 * todo dw drv improvements
+	 * largest packet sizes during hfp or during vsa/vpb/vfp
+	 * should be computed according to byte lane, lane number and only
+	 * if sending lp cmds in high speed is enable (PHY_TXREQUESTCLKHS)
+	 */
+	dsi_write(dsi, DSI_DPI_LP_CMD_TIM, OUTVACT_LPCMD_TIME(4)
+		  | INVACT_LPCMD_TIME(4));
+}
+
+static void dw_mipi_dsi_packet_handler_config(struct dw_mipi_dsi *dsi)
+{
+	dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA);
+}
+
+static void dw_mipi_dsi_video_packet_config(struct dw_mipi_dsi *dsi,
+					    struct drm_display_mode *mode)
+{
+	/*
+	 * todo dw drv improvements
+	 * only burst mode is supported here. For non-burst video modes,
+	 * we should compute DSI_VID_PKT_SIZE, DSI_VCCR.NUMC &
+	 * DSI_VNPCR.NPSIZE... especially because this driver supports
+	 * non-burst video modes, see dw_mipi_dsi_video_mode_config()...
+	 */
+	dsi_write(dsi, DSI_VID_PKT_SIZE, VID_PKT_SIZE(mode->hdisplay));
+}
+
+static void dw_mipi_dsi_command_mode_config(struct dw_mipi_dsi *dsi)
+{
+	/*
+	 * todo dw drv improvements
+	 * compute high speed transmission counter timeout according
+	 * to the timeout clock division (TO_CLK_DIVIDSION) and byte lane...
+	 */
+	dsi_write(dsi, DSI_TO_CNT_CFG, HSTX_TO_CNT(1000) | LPRX_TO_CNT(1000));
+	/*
+	 * todo dw drv improvements
+	 * the Bus-Turn-Around Timeout Counter should be computed
+	 * according to byte lane...
+	 */
+	dsi_write(dsi, DSI_BTA_TO_CNT, 0xd00);
+	dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
+}
+
+/* Get lane byte clock cycles. */
+static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct dw_mipi_dsi *dsi,
+					   struct drm_display_mode *mode,
+					   u32 hcomponent)
+{
+	u32 frac, lbcc;
+
+	lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8;
+
+	frac = lbcc % mode->clock;
+	lbcc = lbcc / mode->clock;
+	if (frac)
+		lbcc++;
+
+	return lbcc;
+}
+
+static void dw_mipi_dsi_line_timer_config(struct dw_mipi_dsi *dsi,
+					  struct drm_display_mode *mode)
+{
+	u32 htotal, hsa, hbp, lbcc;
+
+	htotal = mode->htotal;
+	hsa = mode->hsync_end - mode->hsync_start;
+	hbp = mode->htotal - mode->hsync_end;
+
+	/*
+	 * todo dw drv improvements
+	 * computations below may be improved...
+	 */
+	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, htotal);
+	dsi_write(dsi, DSI_VID_HLINE_TIME, lbcc);
+
+	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hsa);
+	dsi_write(dsi, DSI_VID_HSA_TIME, lbcc);
+
+	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hbp);
+	dsi_write(dsi, DSI_VID_HBP_TIME, lbcc);
+}
+
+static void dw_mipi_dsi_vertical_timing_config(struct dw_mipi_dsi *dsi,
+					       struct drm_display_mode *mode)
+{
+	u32 vactive, vsa, vfp, vbp;
+
+	vactive = mode->vdisplay;
+	vsa = mode->vsync_end - mode->vsync_start;
+	vfp = mode->vsync_start - mode->vdisplay;
+	vbp = mode->vtotal - mode->vsync_end;
+
+	dsi_write(dsi, DSI_VID_VACTIVE_LINES, vactive);
+	dsi_write(dsi, DSI_VID_VSA_LINES, vsa);
+	dsi_write(dsi, DSI_VID_VFP_LINES, vfp);
+	dsi_write(dsi, DSI_VID_VBP_LINES, vbp);
+}
+
+static void dw_mipi_dsi_dphy_timing_config(struct dw_mipi_dsi *dsi)
+{
+	/*
+	 * todo dw drv improvements
+	 * data & clock lane timers should be computed according to panel
+	 * blankings and to the automatic clock lane control mode...
+	 * note: DSI_PHY_TMR_CFG.MAX_RD_TIME should be in line with
+	 * DSI_CMD_MODE_CFG.MAX_RD_PKT_SIZE_LP (see CMD_MODE_ALL_LP)
+	 */
+	dsi_write(dsi, DSI_PHY_TMR_CFG, PHY_HS2LP_TIME(0x40)
+		  | PHY_LP2HS_TIME(0x40) | MAX_RD_TIME(10000));
+
+	dsi_write(dsi, DSI_PHY_TMR_LPCLK_CFG, PHY_CLKHS2LP_TIME(0x40)
+		  | PHY_CLKLP2HS_TIME(0x40));
+}
+
+static void dw_mipi_dsi_dphy_interface_config(struct dw_mipi_dsi *dsi)
+{
+	/*
+	 * todo dw drv improvements
+	 * stop wait time should be the maximum between host dsi
+	 * and panel stop wait times
+	 */
+	dsi_write(dsi, DSI_PHY_IF_CFG, PHY_STOP_WAIT_TIME(0x20) |
+		  N_LANES(dsi->lanes));
+}
+
+static void dw_mipi_dsi_clear_err(struct dw_mipi_dsi *dsi)
+{
+	dsi_read(dsi, DSI_INT_ST0);
+	dsi_read(dsi, DSI_INT_ST1);
+	dsi_write(dsi, DSI_INT_MSK0, 0);
+	dsi_write(dsi, DSI_INT_MSK1, 0);
+}
+
+static void dw_mipi_dsi_bridge_disable(struct drm_bridge *bridge)
+{
+	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
+
+	if (dsi->dpms_mode != DRM_MODE_DPMS_ON)
+		return;
+
+	if (clk_enable(dsi->pclk)) {
+		dev_err(dsi->dev, "%s: Failed to enable pclk\n", __func__);
+		return;
+	}
+
+	drm_panel_disable(dsi->panel);
+
+	dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_CMD_MODE);
+	drm_panel_unprepare(dsi->panel);
+
+	dw_mipi_dsi_disable(dsi);
+	pm_runtime_put(dsi->dev);
+	clk_disable(dsi->pclk);
+	dsi->dpms_mode = DRM_MODE_DPMS_OFF;
+}
+
+static void dw_mipi_dsi_bridge_enable(struct drm_bridge *bridge)
+{
+	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
+	struct drm_encoder *encoder = bridge->encoder;
+	struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
+	int ret;
+
+	ret = dw_mipi_dsi_get_lane_bps(dsi, mode);
+	if (ret < 0)
+		return;
+
+	if (dsi->dpms_mode == DRM_MODE_DPMS_ON)
+		return;
+
+	if (clk_enable(dsi->pclk)) {
+		dev_err(dsi->dev, "%s: Failed to enable pclk\n", __func__);
+		return;
+	}
+
+	pm_runtime_get_sync(dsi->dev);
+	dw_mipi_dsi_init(dsi);
+	dw_mipi_dsi_dpi_config(dsi, mode);
+	dw_mipi_dsi_packet_handler_config(dsi);
+	dw_mipi_dsi_video_mode_config(dsi);
+	dw_mipi_dsi_video_packet_config(dsi, mode);
+	dw_mipi_dsi_command_mode_config(dsi);
+	dw_mipi_dsi_line_timer_config(dsi, mode);
+	dw_mipi_dsi_vertical_timing_config(dsi, mode);
+	dw_mipi_dsi_dphy_timing_config(dsi);
+	dw_mipi_dsi_dphy_interface_config(dsi);
+	dw_mipi_dsi_clear_err(dsi);
+
+	/*
+	 * todo dw drv improvements
+	 * following command is inside dw_mipi_dsi_phy_init()
+	 * but this function is also required here. We way move it in the
+	 * phy but here we are using dsi regs...
+	 * maybe add the waiting loop here too...
+	 */
+	dsi_write(dsi, DSI_PHY_RSTZ, PHY_ENFORCEPLL | PHY_ENABLECLK |
+				     PHY_UNRSTZ | PHY_UNSHUTDOWNZ);
+
+	dw_mipi_dsi_phy_init(dsi);
+	dw_mipi_dsi_wait_for_two_frames(mode);
+
+	dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_CMD_MODE);
+	if (drm_panel_prepare(dsi->panel))
+		dev_err(dsi->dev, "failed to prepare panel\n");
+
+	dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_VID_MODE);
+	drm_panel_enable(dsi->panel);
+
+	clk_disable(dsi->pclk);
+
+	dsi->dpms_mode = DRM_MODE_DPMS_ON;
+}
+
+static int dw_mipi_dsi_connector_get_modes(struct drm_connector *connector)
+{
+	struct dw_mipi_dsi *dsi = con_to_dsi(connector);
+
+	return drm_panel_get_modes(dsi->panel);
+}
+
+static struct drm_connector_helper_funcs dw_mipi_dsi_connector_helper_funcs = {
+	.get_modes = dw_mipi_dsi_connector_get_modes,
+};
+
+static void dw_mipi_dsi_drm_connector_destroy(struct drm_connector *connector)
+{
+	drm_connector_unregister(connector);
+	drm_connector_cleanup(connector);
+}
+
+static const struct drm_connector_funcs dw_mipi_dsi_atomic_connector_funcs = {
+	.dpms = drm_atomic_helper_connector_dpms,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.destroy = dw_mipi_dsi_drm_connector_destroy,
+	.reset = drm_atomic_helper_connector_reset,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge)
+{
+	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
+	struct drm_connector *connector = &dsi->connector;
+
+	if (!bridge->encoder) {
+		DRM_ERROR("Parent encoder object not found");
+		return -ENODEV;
+	}
+
+	/* Set the encoder type as caller does not know it */
+	bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI;
+
+	connector->polled = DRM_CONNECTOR_POLL_HPD;
+
+	drm_connector_helper_add(connector,
+				 &dw_mipi_dsi_connector_helper_funcs);
+
+	drm_connector_init(bridge->dev, connector,
+			   &dw_mipi_dsi_atomic_connector_funcs,
+			   DRM_MODE_CONNECTOR_DSI);
+
+	drm_mode_connector_attach_encoder(connector, bridge->encoder);
+
+	return 0;
+}
+
+static struct drm_bridge_funcs dw_mipi_dsi_bridge_funcs = {
+	.enable = dw_mipi_dsi_bridge_enable,
+	.disable = dw_mipi_dsi_bridge_disable,
+	.attach = dw_mipi_dsi_bridge_attach,
+};
+
+static struct dw_mipi_dsi_plat_data stm_mipi_dsi_drv_data = {
+	.max_data_lanes = 2,
+};
+
+static const struct of_device_id dw_mipi_dsi_dt_ids[] = {
+	{
+	 .compatible = "st,stm32-dsi_host",
+	 .data = &stm_mipi_dsi_drv_data,
+	},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, dw_mipi_dsi_dt_ids);
+
+static int dw_mipi_dsi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct of_device_id *of_id =
+			of_match_device(dw_mipi_dsi_dt_ids, dev);
+	const struct dw_mipi_dsi_plat_data *pdata = of_id->data;
+	struct reset_control *apb_rst;
+	struct dw_mipi_dsi *dsi;
+	struct resource *res;
+	int ret;
+
+	dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
+	if (!dsi)
+		return -ENOMEM;
+
+	dsi->dev = dev;
+	dsi->pdata = pdata;
+	dsi->dpms_mode = DRM_MODE_DPMS_OFF;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	dsi->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(dsi->base))
+		return PTR_ERR(dsi->base);
+
+	dsi->pllref_clk = devm_clk_get(dev, "ref");
+	if (IS_ERR(dsi->pllref_clk)) {
+		ret = PTR_ERR(dsi->pllref_clk);
+		dev_err(dev, "Unable to get pll reference clock: %d\n", ret);
+		return ret;
+	}
+
+	dsi->pclk = devm_clk_get(dev, "pclk");
+	if (IS_ERR(dsi->pclk)) {
+		ret = PTR_ERR(dsi->pclk);
+		dev_err(dev, "Unable to get pclk: %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * Note that the reset was not defined in the initial device tree, so
+	 * we have to be prepared for it not being found.
+	 */
+	apb_rst = devm_reset_control_get(dev, "apb");
+	if (IS_ERR(apb_rst)) {
+		ret = PTR_ERR(apb_rst);
+		if (ret == -ENOENT) {
+			apb_rst = NULL;
+		} else {
+			dev_err(dev, "Unable to get reset control: %d\n", ret);
+			return ret;
+		}
+	}
+
+	if (apb_rst) {
+		ret = clk_prepare_enable(dsi->pclk);
+		if (ret) {
+			dev_err(dev, "%s: Failed to enable pclk\n", __func__);
+			return ret;
+		}
+
+		reset_control_assert(apb_rst);
+		usleep_range(10, 20);
+		reset_control_deassert(apb_rst);
+
+		clk_disable(dsi->pclk);
+	}
+
+	ret = clk_prepare_enable(dsi->pllref_clk);
+	if (ret) {
+		dev_err(dev, "%s: Failed to enable pllref_clk\n", __func__);
+		return ret;
+	}
+
+	pm_runtime_enable(dev);
+
+	dsi->dsi_host.ops = &dw_mipi_dsi_host_ops;
+	dsi->dsi_host.dev = dev;
+	ret = mipi_dsi_host_register(&dsi->dsi_host);
+	if (ret) {
+		dev_err(dev, "Failed to register MIPI host: %d\n", ret);
+		goto err_cleanup;
+	}
+
+	dsi->bridge.driver_private = dsi;
+	dsi->bridge.funcs = &dw_mipi_dsi_bridge_funcs;
+#ifdef CONFIG_OF
+	dsi->bridge.of_node = pdev->dev.of_node;
+#endif
+	ret = drm_bridge_add(&dsi->bridge);
+	if (ret) {
+		dev_err(dev, "Failed to add bridge: %d\n", ret);
+		goto err_mipi_dsi_host;
+	}
+
+	clk_enable(dsi->pclk);
+
+	dev_set_drvdata(dev, dsi);
+	return 0;
+
+err_mipi_dsi_host:
+	mipi_dsi_host_unregister(&dsi->dsi_host);
+err_cleanup:
+	clk_disable_unprepare(dsi->pllref_clk);
+	return ret;
+}
+
+static int dw_mipi_dsi_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct dw_mipi_dsi *dsi = dev_get_drvdata(dev);
+
+	drm_bridge_remove(&dsi->bridge);
+	mipi_dsi_host_unregister(&dsi->dsi_host);
+	pm_runtime_disable(dev);
+	clk_disable_unprepare(dsi->pllref_clk);
+
+	return 0;
+}
+
+static struct platform_driver dw_mipi_dsi_driver = {
+	.probe		= dw_mipi_dsi_probe,
+	.remove		= dw_mipi_dsi_remove,
+	.driver		= {
+		.of_match_table = dw_mipi_dsi_dt_ids,
+		.name	= DRIVER_NAME,
+	},
+};
+
+module_platform_driver(dw_mipi_dsi_driver);
+
+MODULE_DESCRIPTION("ROCKCHIP MIPI DSI host controller driver");
+MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>");
+MODULE_AUTHOR("Philippe Cornu <philippe.cornu@st.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);
-- 
1.9.1

Re: [PATCH v1 3/3] drm/stm: Add STM32 DSI host driver

[Neil Armstrong]

On 05/12/2017 04:56 PM, Philippe CORNU wrote:
> This mipi dsi host driver is based on the Rockchip version of the
> Synopsys Designware mipi dsi driver (rockchip/dw-mipi-dsi.c)
> modified for the stm32 family:
> - replace Rockchip digital & phy specific extensions with stm32's ones.
> - add a bridge
> 
> Signed-off-by: Philippe CORNU <philippe.cornu@st.com>
> ---
>  drivers/gpu/drm/stm/Kconfig       |    7 +
>  drivers/gpu/drm/stm/Makefile      |    2 +
>  drivers/gpu/drm/stm/dw-mipi-dsi.c | 1197 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 1206 insertions(+)
>  create mode 100644 drivers/gpu/drm/stm/dw-mipi-dsi.c
> 
> diff --git a/drivers/gpu/drm/stm/Kconfig b/drivers/gpu/drm/stm/Kconfig
> index 2c4817f..0007789 100644
> --- a/drivers/gpu/drm/stm/Kconfig
> +++ b/drivers/gpu/drm/stm/Kconfig
> @@ -14,3 +14,10 @@ config DRM_STM
>  	  STMicroelectronics STM32 MCUs.
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called stm-drm.
> +
> +config DRM_STM_DSI
> +	tristate "MIPI DSI support for STMicroelectronics SoC"
> +	depends on DRM_STM
> +	select DRM_MIPI_DSI
> +	help
> +	  Choose this option for MIPI DSI support on STMicroelectronics SoC.
> diff --git a/drivers/gpu/drm/stm/Makefile b/drivers/gpu/drm/stm/Makefile
> index e114d45..e448a93 100644
> --- a/drivers/gpu/drm/stm/Makefile
> +++ b/drivers/gpu/drm/stm/Makefile
> @@ -4,4 +4,6 @@ stm-drm-y := \
>  	drv.o \
>  	ltdc.o
>  
> +obj-$(CONFIG_DRM_STM_DSI) += dw-mipi-dsi.o
> +
>  obj-$(CONFIG_DRM_STM) += stm-drm.o
> diff --git a/drivers/gpu/drm/stm/dw-mipi-dsi.c b/drivers/gpu/drm/stm/dw-mipi-dsi.c
> new file mode 100644
> index 0000000..4b7f7b9
> --- /dev/null
> +++ b/drivers/gpu/drm/stm/dw-mipi-dsi.c


Hi Philippe,

First question, why couldn't this be transformed as a bridge driver along the Synopsys DW-HDMI driver ?

Neil
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Re: [PATCH v1 3/3] drm/stm: Add STM32 DSI host driver

[Philippe CORNU]

Hi Neil,
Many thanks for your comments.

The PHY part of the MIPI DSI is the main difference between all chipsets 
based on the Synopsys DesignWare MIPI DSI.
There is no "generic DSI PHY interface" and that is probably why all soc 
vendors have implemented their own drivers (RockChip, NXP/Freescale, 
HiSilicon and now STM32).

Regarding creating a "generic dw MIPI DSI bridge" as the recent dw hdmi 
bridge, several attempts have been done in the past but without success:
* Liu Ying from Freescale in February 2015 
(https://lkml.org/lkml/2015/2/12/38).
* Chris Zhong from Rockchip in November 2015 
(http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1024586.html).

The Rockchip driver looks nice and is updated regularly.
So, instead of creating a new driver for the STM32 family, we decided to 
use Rockchip’s in our own drm/stm directory and replace the 
Rockchip-specific PHY by the STM32.

Comments are welcome :-)
Many thanks,
Philippe


On 05/15/2017 10:22 AM, Neil Armstrong wrote:
> On 05/12/2017 04:56 PM, Philippe CORNU wrote:
>> This mipi dsi host driver is based on the Rockchip version of the
>> Synopsys Designware mipi dsi driver (rockchip/dw-mipi-dsi.c)
>> modified for the stm32 family:
>> - replace Rockchip digital & phy specific extensions with stm32's ones.
>> - add a bridge
>>
>> Signed-off-by: Philippe CORNU <philippe.cornu@st.com>
>> ---
>>  drivers/gpu/drm/stm/Kconfig       |    7 +
>>  drivers/gpu/drm/stm/Makefile      |    2 +
>>  drivers/gpu/drm/stm/dw-mipi-dsi.c | 1197 +++++++++++++++++++++++++++++++++++++
>>  3 files changed, 1206 insertions(+)
>>  create mode 100644 drivers/gpu/drm/stm/dw-mipi-dsi.c
>>
>> diff --git a/drivers/gpu/drm/stm/Kconfig b/drivers/gpu/drm/stm/Kconfig
>> index 2c4817f..0007789 100644
>> --- a/drivers/gpu/drm/stm/Kconfig
>> +++ b/drivers/gpu/drm/stm/Kconfig
>> @@ -14,3 +14,10 @@ config DRM_STM
>>  	  STMicroelectronics STM32 MCUs.
>>  	  To compile this driver as a module, choose M here: the module
>>  	  will be called stm-drm.
>> +
>> +config DRM_STM_DSI
>> +	tristate "MIPI DSI support for STMicroelectronics SoC"
>> +	depends on DRM_STM
>> +	select DRM_MIPI_DSI
>> +	help
>> +	  Choose this option for MIPI DSI support on STMicroelectronics SoC.
>> diff --git a/drivers/gpu/drm/stm/Makefile b/drivers/gpu/drm/stm/Makefile
>> index e114d45..e448a93 100644
>> --- a/drivers/gpu/drm/stm/Makefile
>> +++ b/drivers/gpu/drm/stm/Makefile
>> @@ -4,4 +4,6 @@ stm-drm-y := \
>>  	drv.o \
>>  	ltdc.o
>>
>> +obj-$(CONFIG_DRM_STM_DSI) += dw-mipi-dsi.o
>> +
>>  obj-$(CONFIG_DRM_STM) += stm-drm.o
>> diff --git a/drivers/gpu/drm/stm/dw-mipi-dsi.c b/drivers/gpu/drm/stm/dw-mipi-dsi.c
>> new file mode 100644
>> index 0000000..4b7f7b9
>> --- /dev/null
>> +++ b/drivers/gpu/drm/stm/dw-mipi-dsi.c
>
>
> Hi Philippe,
>
> First question, why couldn't this be transformed as a bridge driver along the Synopsys DW-HDMI driver ?
>
> Neil
>

Re: [PATCH v1 3/3] drm/stm: Add STM32 DSI host driver

[Neil Armstrong]

Hi Philippe,

(please avoid top posting)

On 05/15/2017 12:33 PM, Philippe CORNU wrote:
> Hi Neil,
> Many thanks for your comments.
> 
> The PHY part of the MIPI DSI is the main difference between all chipsets 
> based on the Synopsys DesignWare MIPI DSI.
> There is no "generic DSI PHY interface" and that is probably why all soc 
> vendors have implemented their own drivers (RockChip, NXP/Freescale, 
> HiSilicon and now STM32).

Sure, this is the same with the DW-HDMI, there is a Synopsys PHY, but also
vendor PHYs.

> 
> Regarding creating a "generic dw MIPI DSI bridge" as the recent dw hdmi 
> bridge, several attempts have been done in the past but without success:
> * Liu Ying from Freescale in February 2015 
> (https://lkml.org/lkml/2015/2/12/38).
> * Chris Zhong from Rockchip in November 2015 
> (http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1024586.html).

"Impossible n'est pas français !"
(Georges Courteline, Le 51e Chasseurs, Marpon et Flammario, 1887, p. 23)

I think it's worth the try, and will avoid a lot of code duplication among these
drivers. And since it's a Synopsys IP, it will continue to appear in current
and future SoCs.

> 
> The Rockchip driver looks nice and is updated regularly.
> So, instead of creating a new driver for the STM32 family, we decided to 
> use Rockchip’s in our own drm/stm directory and replace the 
> Rockchip-specific PHY by the STM32.

Sure, it looks OK.

Archit, any advices here ?

> Comments are welcome :-)
> Many thanks,
> Philippe

Thanks,
Neil
> 
> On 05/15/2017 10:22 AM, Neil Armstrong wrote:
>> On 05/12/2017 04:56 PM, Philippe CORNU wrote:
>>> This mipi dsi host driver is based on the Rockchip version of the
>>> Synopsys Designware mipi dsi driver (rockchip/dw-mipi-dsi.c)
>>> modified for the stm32 family:
>>> - replace Rockchip digital & phy specific extensions with stm32's ones.
>>> - add a bridge
>>>
>>> Signed-off-by: Philippe CORNU <philippe.cornu@st.com>
>>> ---
>>>  drivers/gpu/drm/stm/Kconfig       |    7 +
>>>  drivers/gpu/drm/stm/Makefile      |    2 +
>>>  drivers/gpu/drm/stm/dw-mipi-dsi.c | 1197 +++++++++++++++++++++++++++++++++++++
>>>  3 files changed, 1206 insertions(+)
>>>  create mode 100644 drivers/gpu/drm/stm/dw-mipi-dsi.c
>>>
>>> diff --git a/drivers/gpu/drm/stm/Kconfig b/drivers/gpu/drm/stm/Kconfig
>>> index 2c4817f..0007789 100644
>>> --- a/drivers/gpu/drm/stm/Kconfig
>>> +++ b/drivers/gpu/drm/stm/Kconfig
>>> @@ -14,3 +14,10 @@ config DRM_STM
>>>  	  STMicroelectronics STM32 MCUs.
>>>  	  To compile this driver as a module, choose M here: the module
>>>  	  will be called stm-drm.
>>> +
>>> +config DRM_STM_DSI
>>> +	tristate "MIPI DSI support for STMicroelectronics SoC"
>>> +	depends on DRM_STM
>>> +	select DRM_MIPI_DSI
>>> +	help
>>> +	  Choose this option for MIPI DSI support on STMicroelectronics SoC.
>>> diff --git a/drivers/gpu/drm/stm/Makefile b/drivers/gpu/drm/stm/Makefile
>>> index e114d45..e448a93 100644
>>> --- a/drivers/gpu/drm/stm/Makefile
>>> +++ b/drivers/gpu/drm/stm/Makefile
>>> @@ -4,4 +4,6 @@ stm-drm-y := \
>>>  	drv.o \
>>>  	ltdc.o
>>>
>>> +obj-$(CONFIG_DRM_STM_DSI) += dw-mipi-dsi.o
>>> +
>>>  obj-$(CONFIG_DRM_STM) += stm-drm.o
>>> diff --git a/drivers/gpu/drm/stm/dw-mipi-dsi.c b/drivers/gpu/drm/stm/dw-mipi-dsi.c
>>> new file mode 100644
>>> index 0000000..4b7f7b9
>>> --- /dev/null
>>> +++ b/drivers/gpu/drm/stm/dw-mipi-dsi.c
>>
>>
>> Hi Philippe,
>>
>> First question, why couldn't this be transformed as a bridge driver along the Synopsys DW-HDMI driver ?
>>
>> Neil
>>
> 

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Re: [PATCH v1 3/3] drm/stm: Add STM32 DSI host driver

[Archit Taneja]

Hi,

On 05/15/2017 04:03 PM, Philippe CORNU wrote:
> Hi Neil,
> Many thanks for your comments.
>
> The PHY part of the MIPI DSI is the main difference between all chipsets
> based on the Synopsys DesignWare MIPI DSI.
> There is no "generic DSI PHY interface" and that is probably why all soc
> vendors have implemented their own drivers (RockChip, NXP/Freescale,
> HiSilicon and now STM32).

We don't really need a generic DSI PHY interface to ensure we use a common
bridge driver. We need to do what's been done in the DW HDMI bridge driver.
The dw_hdmi_plat_data struct contains phy ops, which can be used to abstract
vendor PHYs.

>
> Regarding creating a "generic dw MIPI DSI bridge" as the recent dw hdmi
> bridge, several attempts have been done in the past but without success:
> * Liu Ying from Freescale in February 2015
> (https://lkml.org/lkml/2015/2/12/38).
> * Chris Zhong from Rockchip in November 2015
> (http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1024586.html).

We can't have 3 almost identical DW MIPI DSI implementations in the kernel.
You'll need to separate out the vendor specific PHY pieces into ops (like
it's done in the DW HDMI) and post a bridge driver for this.

You don't need to convert the existing rockhip and hisilicon implementations
into bridge drivers. We can CC the authors of the rockchip and hisil so that
they can adapt to the bridge driver too.

Thanks,
Archit

>
> The Rockchip driver looks nice and is updated regularly.
> So, instead of creating a new driver for the STM32 family, we decided to
> use Rockchip’s in our own drm/stm directory and replace the
> Rockchip-specific PHY by the STM32.
>
> Comments are welcome :-)
> Many thanks,
> Philippe
>
>
> On 05/15/2017 10:22 AM, Neil Armstrong wrote:
>> On 05/12/2017 04:56 PM, Philippe CORNU wrote:
>>> This mipi dsi host driver is based on the Rockchip version of the
>>> Synopsys Designware mipi dsi driver (rockchip/dw-mipi-dsi.c)
>>> modified for the stm32 family:
>>> - replace Rockchip digital & phy specific extensions with stm32's ones.
>>> - add a bridge
>>>
>>> Signed-off-by: Philippe CORNU <philippe.cornu@st.com>
>>> ---
>>>  drivers/gpu/drm/stm/Kconfig       |    7 +
>>>  drivers/gpu/drm/stm/Makefile      |    2 +
>>>  drivers/gpu/drm/stm/dw-mipi-dsi.c | 1197 +++++++++++++++++++++++++++++++++++++
>>>  3 files changed, 1206 insertions(+)
>>>  create mode 100644 drivers/gpu/drm/stm/dw-mipi-dsi.c
>>>
>>> diff --git a/drivers/gpu/drm/stm/Kconfig b/drivers/gpu/drm/stm/Kconfig
>>> index 2c4817f..0007789 100644
>>> --- a/drivers/gpu/drm/stm/Kconfig
>>> +++ b/drivers/gpu/drm/stm/Kconfig
>>> @@ -14,3 +14,10 @@ config DRM_STM
>>>  	  STMicroelectronics STM32 MCUs.
>>>  	  To compile this driver as a module, choose M here: the module
>>>  	  will be called stm-drm.
>>> +
>>> +config DRM_STM_DSI
>>> +	tristate "MIPI DSI support for STMicroelectronics SoC"
>>> +	depends on DRM_STM
>>> +	select DRM_MIPI_DSI
>>> +	help
>>> +	  Choose this option for MIPI DSI support on STMicroelectronics SoC.
>>> diff --git a/drivers/gpu/drm/stm/Makefile b/drivers/gpu/drm/stm/Makefile
>>> index e114d45..e448a93 100644
>>> --- a/drivers/gpu/drm/stm/Makefile
>>> +++ b/drivers/gpu/drm/stm/Makefile
>>> @@ -4,4 +4,6 @@ stm-drm-y := \
>>>  	drv.o \
>>>  	ltdc.o
>>>
>>> +obj-$(CONFIG_DRM_STM_DSI) += dw-mipi-dsi.o
>>> +
>>>  obj-$(CONFIG_DRM_STM) += stm-drm.o
>>> diff --git a/drivers/gpu/drm/stm/dw-mipi-dsi.c b/drivers/gpu/drm/stm/dw-mipi-dsi.c
>>> new file mode 100644
>>> index 0000000..4b7f7b9
>>> --- /dev/null
>>> +++ b/drivers/gpu/drm/stm/dw-mipi-dsi.c
>>
>>
>> Hi Philippe,
>>
>> First question, why couldn't this be transformed as a bridge driver along the Synopsys DW-HDMI driver ?
>>
>> Neil
>>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>

-- 
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a Linux Foundation Collaborative Project
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