[PATCH v6 0/2] *** IT6505 driver read dt properties ***

[PATCH v6 0/2] *** IT6505 driver read dt properties ***

[allen]

This series let driver can read properties from dt to restrict dp output
bandwidth.

Changes in v3:
-Rename property name.

Changes in v4:
-Use data-lanes and link-frequencies instead of "ite,dp-output-data-lane-count" and "ite,dp-output-max-pixel-clock-mhz".

Changes in v5:
-Add a port and a endpoint.
-Move data-lanes property to the output endpoint.

Changes in v6:
-Modified data-lanes description by suggestion.

allen chen (2):
  dt-bindings: it6505: add properties to restrict output bandwidth
  drm/bridge: add it6505 driver to read data-lanes and link-frequencies
    from dt

 .../bindings/display/bridge/ite,it6505.yaml   | 68 ++++++++++++++--
 drivers/gpu/drm/bridge/ite-it6505.c           | 80 ++++++++++++++++++-
 2 files changed, 139 insertions(+), 9 deletions(-)

-- 
2.25.1

[PATCH v6 1/2] dt-bindings: it6505: add properties to restrict output bandwidth

[allen]

From: allen chen <allen.chen@ite.com.tw>

Add properties to restrict dp output data-lanes and clock.

Signed-off-by: Pin-Yen Lin <treapking@chromium.org>
Signed-off-by: Allen Chen <allen.chen@ite.com.tw>
---
 .../bindings/display/bridge/ite,it6505.yaml   | 68 +++++++++++++++++--
 1 file changed, 62 insertions(+), 6 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml b/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
index 833d11b2303a7..b16a9d9127ddb 100644
--- a/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
+++ b/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
@@ -52,9 +52,49 @@ properties:
     maxItems: 1
     description: extcon specifier for the Power Delivery
 
-  port:
-    $ref: /schemas/graph.yaml#/properties/port
-    description: A port node pointing to DPI host port node
+  ports:
+    $ref: /schemas/graph.yaml#/properties/ports
+
+    properties:
+      port@0:
+        $ref: /schemas/graph.yaml#/$defs/port-base
+        unevaluatedProperties: false
+        description: A port node pointing to DPI host port node
+
+        properties:
+          endpoint:
+            $ref: /schemas/graph.yaml#/$defs/endpoint-base
+            unevaluatedProperties: false
+
+            properties:
+              link-frequencies:
+                minItems: 1
+                maxItems: 1
+                description: Allowed max link frequencies in Hz
+
+      port@1:
+        $ref: /schemas/graph.yaml#/$defs/port-base
+        unevaluatedProperties: false
+        description: Video port for DP output
+
+        properties:
+          endpoint:
+            $ref: /schemas/graph.yaml#/$defs/endpoint-base
+            unevaluatedProperties: false
+
+            properties:
+              data-lanes:
+                minItems: 1
+                uniqueItems: true
+                items:
+                  - enum: [ 0, 1 ]
+                  - const: 1
+                  - const: 2
+                  - const: 3
+
+    required:
+      - port@0
+      - port@1
 
 required:
   - compatible
@@ -63,6 +103,7 @@ required:
   - interrupts
   - reset-gpios
   - extcon
+  - ports
 
 additionalProperties: false
 
@@ -85,9 +126,24 @@ examples:
             reset-gpios = <&pio 179 1>;
             extcon = <&usbc_extcon>;
 
-            port {
-                it6505_in: endpoint {
-                    remote-endpoint = <&dpi_out>;
+            ports {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                port@0 {
+                    reg = <0>;
+                    it6505_in: endpoint {
+                        remote-endpoint = <&dpi_out>;
+                        link-frequencies = /bits/ 64 <150000000>;
+                    };
+                };
+
+                port@1 {
+                    reg = <1>;
+                    it6505_out: endpoint {
+                        remote-endpoint = <&dp_in>;
+                        data-lanes = <0 1>;
+                    };
                 };
             };
         };
-- 
2.25.1

[PATCH v6 2/2] drm/bridge: add it6505 driver to read data-lanes and link-frequencies from dt

[allen]

From: allen chen <allen.chen@ite.com.tw>

Add driver to read data-lanes and link-frequencies from dt property to
restrict output bandwidth.

Signed-off-by: Allen chen <allen.chen@ite.com.tw>
Signed-off-by: Pin-yen Lin <treapking@chromium.org>
---
 drivers/gpu/drm/bridge/ite-it6505.c | 80 +++++++++++++++++++++++++++--
 1 file changed, 77 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index a4302492cf8df..ed4536cde3140 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -437,6 +437,8 @@ struct it6505 {
 	bool powered;
 	bool hpd_state;
 	u32 afe_setting;
+	u32 max_dpi_pixel_clock;
+	u32 max_lane_count;
 	enum hdcp_state hdcp_status;
 	struct delayed_work hdcp_work;
 	struct work_struct hdcp_wait_ksv_list;
@@ -1476,7 +1478,8 @@ static void it6505_parse_link_capabilities(struct it6505 *it6505)
 	it6505->lane_count = link->num_lanes;
 	DRM_DEV_DEBUG_DRIVER(dev, "Sink support %d lanes training",
 			     it6505->lane_count);
-	it6505->lane_count = min_t(int, it6505->lane_count, MAX_LANE_COUNT);
+	it6505->lane_count = min_t(int, it6505->lane_count,
+				   it6505->max_lane_count);
 
 	it6505->branch_device = drm_dp_is_branch(it6505->dpcd);
 	DRM_DEV_DEBUG_DRIVER(dev, "Sink %sbranch device",
@@ -2912,7 +2915,7 @@ it6505_bridge_mode_valid(struct drm_bridge *bridge,
 	if (mode->flags & DRM_MODE_FLAG_INTERLACE)
 		return MODE_NO_INTERLACE;
 
-	if (mode->clock > DPI_PIXEL_CLK_MAX)
+	if (mode->clock > it6505->max_dpi_pixel_clock)
 		return MODE_CLOCK_HIGH;
 
 	it6505->video_info.clock = mode->clock;
@@ -3099,10 +3102,32 @@ static int it6505_init_pdata(struct it6505 *it6505)
 	return 0;
 }
 
+static int it6505_get_data_lanes_count(const struct device_node *endpoint,
+				       const unsigned int min,
+				       const unsigned int max)
+{
+	int ret;
+
+	ret = of_property_count_u32_elems(endpoint, "data-lanes");
+	if (ret < 0)
+		return ret;
+
+	if (ret < min || ret > max)
+		return -EINVAL;
+
+	return ret;
+}
+
 static void it6505_parse_dt(struct it6505 *it6505)
 {
 	struct device *dev = &it6505->client->dev;
+	struct device_node *np = dev->of_node, *ep = NULL;
+	int len;
+	u64 link_frequencies;
+	u32 data_lanes[4];
 	u32 *afe_setting = &it6505->afe_setting;
+	u32 *max_lane_count = &it6505->max_lane_count;
+	u32 *max_dpi_pixel_clock = &it6505->max_dpi_pixel_clock;
 
 	it6505->lane_swap_disabled =
 		device_property_read_bool(dev, "no-laneswap");
@@ -3118,7 +3143,56 @@ static void it6505_parse_dt(struct it6505 *it6505)
 	} else {
 		*afe_setting = 0;
 	}
-	DRM_DEV_DEBUG_DRIVER(dev, "using afe_setting: %d", *afe_setting);
+
+	ep = of_graph_get_endpoint_by_regs(np, 1, 0);
+	of_node_put(ep);
+
+	if (ep) {
+		len = it6505_get_data_lanes_count(ep, 1, 4);
+
+		if (len > 0 && len != 3) {
+			of_property_read_u32_array(ep, "data-lanes",
+						   data_lanes, len);
+			*max_lane_count = len;
+		} else {
+			*max_lane_count = MAX_LANE_COUNT;
+			dev_err(dev, "error data-lanes, use default");
+		}
+	} else {
+		*max_lane_count = MAX_LANE_COUNT;
+		dev_err(dev, "error endpoint, use default");
+	}
+
+	ep = of_graph_get_endpoint_by_regs(np, 0, 0);
+	of_node_put(ep);
+
+	if (ep) {
+		len = of_property_read_variable_u64_array(ep,
+							  "link-frequencies",
+							  &link_frequencies, 0,
+							  1);
+		if (len >= 0) {
+			do_div(link_frequencies, 1000);
+			if (link_frequencies > 297000) {
+				dev_err(dev,
+					"max pixel clock error, use default");
+				*max_dpi_pixel_clock = DPI_PIXEL_CLK_MAX;
+			} else {
+				*max_dpi_pixel_clock = link_frequencies;
+			}
+		} else {
+			dev_err(dev, "error link frequencies, use default");
+			*max_dpi_pixel_clock = DPI_PIXEL_CLK_MAX;
+		}
+	} else {
+		dev_err(dev, "error endpoint, use default");
+		*max_dpi_pixel_clock = DPI_PIXEL_CLK_MAX;
+	}
+
+	DRM_DEV_DEBUG_DRIVER(dev, "using afe_setting: %u, max_lane_count: %u",
+			     it6505->afe_setting, it6505->max_lane_count);
+	DRM_DEV_DEBUG_DRIVER(dev, "using max_dpi_pixel_clock: %u kHz",
+			     it6505->max_dpi_pixel_clock);
 }
 
 static ssize_t receive_timing_debugfs_show(struct file *file, char __user *buf,
-- 
2.25.1

Re: [PATCH v6 1/2] dt-bindings: it6505: add properties to restrict output bandwidth

[Krzysztof Kozlowski]

On 26/10/2022 23:01, allen wrote:
> From: allen chen <allen.chen@ite.com.tw>
> 
> Add properties to restrict dp output data-lanes and clock.

This is a friendly reminder during the review process.

It seems my previous comments were not fully addressed. Maybe my
feedback got lost between the quotes, maybe you just forgot to apply it.
Please go back to the previous discussion and either implement all
requested changes or keep discussing them.

Thank you.

Rob asked - Commit msg should explain reason for breaking users.

> 
> Signed-off-by: Pin-Yen Lin <treapking@chromium.org>
> Signed-off-by: Allen Chen <allen.chen@ite.com.tw>
> ---
>  .../bindings/display/bridge/ite,it6505.yaml   | 68 +++++++++++++++++--
>  1 file changed, 62 insertions(+), 6 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml b/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> index 833d11b2303a7..b16a9d9127ddb 100644
> --- a/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> +++ b/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> @@ -52,9 +52,49 @@ properties:
>      maxItems: 1
>      description: extcon specifier for the Power Delivery
>  
> -  port:
> -    $ref: /schemas/graph.yaml#/properties/port
> -    description: A port node pointing to DPI host port node
> +  ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port@0:
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        unevaluatedProperties: false
> +        description: A port node pointing to DPI host port node
> +
> +        properties:
> +          endpoint:
> +            $ref: /schemas/graph.yaml#/$defs/endpoint-base
> +            unevaluatedProperties: false
> +
> +            properties:
> +              link-frequencies:
> +                minItems: 1
> +                maxItems: 1
> +                description: Allowed max link frequencies in Hz
> +
> +      port@1:
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        unevaluatedProperties: false
> +        description: Video port for DP output
> +
> +        properties:
> +          endpoint:
> +            $ref: /schemas/graph.yaml#/$defs/endpoint-base
> +            unevaluatedProperties: false
> +
> +            properties:
> +              data-lanes:
> +                minItems: 1
> +                uniqueItems: true
> +                items:
> +                  - enum: [ 0, 1 ]
> +                  - const: 1
> +                  - const: 2
> +                  - const: 3
> +

This looks ok.

Best regards,
Krzysztof

RE: [PATCH v6 1/2] dt-bindings: it6505: add properties to restrict output bandwidth

[allen.chen]

hi

-----Original Message-----
From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> 
Sent: Friday, October 28, 2022 9:59 AM
To: Allen Chen (陳柏宇) <allen.chen@ite.com.tw>
Cc: Pin-Yen Lin <treapking@chromium.org>; Jau-Chih Tseng (曾昭智) <Jau-Chih.Tseng@ite.com.tw>; Hermes Wu (吳佳宏) <Hermes.Wu@ite.com.tw>; Kenneth Hung (洪家倫) <Kenneth.Hung@ite.com.tw>; Andrzej Hajda <andrzej.hajda@intel.com>; Neil Armstrong <narmstrong@baylibre.com>; Robert Foss <robert.foss@linaro.org>; Laurent Pinchart <Laurent.pinchart@ideasonboard.com>; Jonas Karlman <jonas@kwiboo.se>; Jernej Skrabec <jernej.skrabec@gmail.com>; David Airlie <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; Rob Herring <robh+dt@kernel.org>; Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>; open list:DRM DRIVERS <dri-devel@lists.freedesktop.org>; open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS <devicetree@vger.kernel.org>; open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v6 1/2] dt-bindings: it6505: add properties to restrict output bandwidth

On 26/10/2022 23:01, allen wrote:
> From: allen chen <allen.chen@ite.com.tw>
> 
> Add properties to restrict dp output data-lanes and clock.

This is a friendly reminder during the review process.

It seems my previous comments were not fully addressed. Maybe my feedback got lost between the quotes, maybe you just forgot to apply it.
Please go back to the previous discussion and either implement all requested changes or keep discussing them.

Thank you.

==> I am sorry I didn't find the missing advice you said. Could you explain it again?

Rob asked - Commit msg should explain reason for breaking users.

> 
> Signed-off-by: Pin-Yen Lin <treapking@chromium.org>
> Signed-off-by: Allen Chen <allen.chen@ite.com.tw>
> ---
>  .../bindings/display/bridge/ite,it6505.yaml   | 68 +++++++++++++++++--
>  1 file changed, 62 insertions(+), 6 deletions(-)
> 
> diff --git 
> a/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml 
> b/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> index 833d11b2303a7..b16a9d9127ddb 100644
> --- a/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> +++ b/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> @@ -52,9 +52,49 @@ properties:
>      maxItems: 1
>      description: extcon specifier for the Power Delivery
>  
> -  port:
> -    $ref: /schemas/graph.yaml#/properties/port
> -    description: A port node pointing to DPI host port node
> +  ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port@0:
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        unevaluatedProperties: false
> +        description: A port node pointing to DPI host port node
> +
> +        properties:
> +          endpoint:
> +            $ref: /schemas/graph.yaml#/$defs/endpoint-base
> +            unevaluatedProperties: false
> +
> +            properties:
> +              link-frequencies:
> +                minItems: 1
> +                maxItems: 1
> +                description: Allowed max link frequencies in Hz
> +
> +      port@1:
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        unevaluatedProperties: false
> +        description: Video port for DP output
> +
> +        properties:
> +          endpoint:
> +            $ref: /schemas/graph.yaml#/$defs/endpoint-base
> +            unevaluatedProperties: false
> +
> +            properties:
> +              data-lanes:
> +                minItems: 1
> +                uniqueItems: true
> +                items:
> +                  - enum: [ 0, 1 ]
> +                  - const: 1
> +                  - const: 2
> +                  - const: 3
> +

This looks ok.

Best regards,
Krzysztof

Re: [PATCH v6 1/2] dt-bindings: it6505: add properties to restrict output bandwidth

[Krzysztof Kozlowski]

On 02/11/2022 02:54, allen.chen@ite.com.tw wrote:
> On 26/10/2022 23:01, allen wrote:
>> From: allen chen <allen.chen@ite.com.tw>
>>
>> Add properties to restrict dp output data-lanes and clock.
> 
> This is a friendly reminder during the review process.
> 
> It seems my previous comments were not fully addressed. Maybe my feedback got lost between the quotes, maybe you just forgot to apply it.
> Please go back to the previous discussion and either implement all requested changes or keep discussing them.
> 
> Thank you.
> 
> ==> I am sorry I didn't find the missing advice you said. Could you explain it again?
> 
> Rob asked - Commit msg should explain reason for breaking users.

And where is the reason? I saw only one sentence "Add properties to
restrict dp output data-lanes and clock."

Best regards,
Krzysztof

RE: [PATCH v6 1/2] dt-bindings: it6505: add properties to restrict output bandwidth

[allen.chen]

hi

-----Original Message-----
From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> 
Sent: Thursday, November 3, 2022 12:34 AM
To: Allen Chen (陳柏宇) <allen.chen@ite.com.tw>
Cc: treapking@chromium.org; Jau-Chih Tseng (曾昭智) <Jau-Chih.Tseng@ite.com.tw>; Hermes Wu (吳佳宏) <Hermes.Wu@ite.com.tw>; Kenneth Hung (洪家倫) <Kenneth.Hung@ite.com.tw>; andrzej.hajda@intel.com; narmstrong@baylibre.com; robert.foss@linaro.org; Laurent.pinchart@ideasonboard.com; jonas@kwiboo.se; jernej.skrabec@gmail.com; airlied@linux.ie; daniel@ffwll.ch; robh+dt@kernel.org; krzysztof.kozlowski+dt@linaro.org; dri-devel@lists.freedesktop.org; devicetree@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 1/2] dt-bindings: it6505: add properties to restrict output bandwidth

On 02/11/2022 02:54, allen.chen@ite.com.tw wrote:
> On 26/10/2022 23:01, allen wrote:
>> From: allen chen <allen.chen@ite.com.tw>
>>
>> Add properties to restrict dp output data-lanes and clock.
> 
> This is a friendly reminder during the review process.
> 
> It seems my previous comments were not fully addressed. Maybe my feedback got lost between the quotes, maybe you just forgot to apply it.
> Please go back to the previous discussion and either implement all requested changes or keep discussing them.
> 
> Thank you.
> 
> ==> I am sorry I didn't find the missing advice you said. Could you explain it again?
> 
> Rob asked - Commit msg should explain reason for breaking users.

And where is the reason? I saw only one sentence "Add properties to restrict dp output data-lanes and clock."
==> I will add the commit msg in v7. Thanks for the suggestion.

Best regards,
Krzysztof