[PATCH v2 0/2] Add NEC LCD Technologies NL6448BC33-70C Panel Support

[PATCH v2 0/2] Add NEC LCD Technologies NL6448BC33-70C Panel Support

[Steffen Trumtrar]

Add support for the above mentioned LCD panel from NEC.

---
Changes in v2:
- fix .size settings
- set connector_type
- Include feedback from Sashiko AI review: https://sashiko.dev/#/patchset/20260513-v7-1-topic-panel-simple-nl6448bc33-v1-0-9bd4b7d0eac0@pengutronix.de?part=2
- Link to v1: https://patch.msgid.link/20260513-v7-1-topic-panel-simple-nl6448bc33-v1-0-9bd4b7d0eac0@pengutronix.de

To: Neil Armstrong <neil.armstrong@linaro.org>
To: Jessica Zhang <jesszhan0024@gmail.com>
To: David Airlie <airlied@gmail.com>
To: Simona Vetter <simona@ffwll.ch>
To: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
To: Maxime Ripard <mripard@kernel.org>
To: Thomas Zimmermann <tzimmermann@suse.de>
To: Rob Herring <robh@kernel.org>
To: Krzysztof Kozlowski <krzk+dt@kernel.org>
To: Conor Dooley <conor+dt@kernel.org>
To: Thierry Reding <thierry.reding@gmail.com>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: dri-devel@lists.freedesktop.org
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

---
Steffen Trumtrar (2):
      dt-bindings: display: simple: Add NEC NL6448BC33-70C panel
      drm/panel: simple: add NEC NL6448BC33-70C

 .../bindings/display/panel/panel-simple.yaml       |  2 ++
 drivers/gpu/drm/panel/panel-simple.c               | 29 ++++++++++++++++++++++
 2 files changed, 31 insertions(+)
---
base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731
change-id: 20260513-v7-1-topic-panel-simple-nl6448bc33-c36e33b18ab1

Best regards,
--  
Steffen Trumtrar <s.trumtrar@pengutronix.de>

[PATCH v2 1/2] dt-bindings: display: simple: Add NEC NL6448BC33-70C panel

[Steffen Trumtrar]

Add the NEC LCD Technologies,Ltd. NL6448BC33-70C 10.4" 640x480 LCD panel.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
---
 Documentation/devicetree/bindings/display/panel/panel-simple.yaml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/panel-simple.yaml b/Documentation/devicetree/bindings/display/panel/panel-simple.yaml
index 3e41ed0ef5d51..96d218f78b0be 100644
--- a/Documentation/devicetree/bindings/display/panel/panel-simple.yaml
+++ b/Documentation/devicetree/bindings/display/panel/panel-simple.yaml
@@ -232,6 +232,8 @@ properties:
       - nec,nl12880bc20-05
         # NEC LCD Technologies,Ltd. WQVGA TFT LCD panel
       - nec,nl4827hc19-05b
+        # NEC LCD Technologies,Ltd. VGA TFT LCD panel
+      - nec,nl6448bc33-70c
         # Netron-DY E231732 7.0" WSVGA TFT LCD panel
       - netron-dy,e231732
         # Newhaven Display International 480 x 272 TFT LCD panel

-- 
2.53.0

[PATCH v2 2/2] drm/panel: simple: add NEC NL6448BC33-70C

[Steffen Trumtrar]

Add NEC NL6448BC33-70C 10.4" 640x480 LCD module support.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
---
 drivers/gpu/drm/panel/panel-simple.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index 236bd56208ccf..dca6cbc41bd9f 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -3659,6 +3659,32 @@ static const struct panel_desc nec_nl4827hc19_05b = {
 	.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
 };
 
+static const struct drm_display_mode nec_nl6448bc33_70c_mode = {
+	.clock = 25175,
+	.hdisplay = 640,
+	.hsync_start = 640 + 16,
+	.hsync_end = 640 + 16 + 48,
+	.htotal = 640 + 16 + 48 + 96,
+	.vdisplay = 480,
+	.vsync_start = 480 + 2,
+	.vsync_end = 480 + 2 + 31,
+	.vtotal = 480 + 2 + 31 + 31,
+	.flags = DRM_MODE_FLAG_PVSYNC | DRM_MODE_FLAG_PHSYNC,
+};
+
+static const struct panel_desc nec_nl6448bc33_70c = {
+	.modes = &nec_nl6448bc33_70c_mode,
+	.num_modes = 1,
+	.bpc = 6,
+	.size = {
+		.width = 211,
+		.height = 158,
+	},
+	.bus_format = MEDIA_BUS_FMT_RGB666_1X18,
+	.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
+	.connector_type = DRM_MODE_CONNECTOR_LVDS,
+};
+
 static const struct drm_display_mode netron_dy_e231732_mode = {
 	.clock = 66000,
 	.hdisplay = 1024,
@@ -5520,6 +5546,9 @@ static const struct of_device_id platform_of_match[] = {
 	}, {
 		.compatible = "nec,nl4827hc19-05b",
 		.data = &nec_nl4827hc19_05b,
+	}, {
+		.compatible = "nec,nl6448bc33-70c",
+		.data = &nec_nl6448bc33_70c,
 	}, {
 		.compatible = "netron-dy,e231732",
 		.data = &netron_dy_e231732,

-- 
2.53.0

Re: [PATCH v2 1/2] dt-bindings: display: simple: Add NEC NL6448BC33-70C panel

[Conor Dooley]

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Acked-by: Conor Dooley <conor.dooley@microchip.com>
pw-bot: not-applicable

[-- Attachment #2: signature.asc --]
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Claude review: Add NEC LCD Technologies NL6448BC33-70C Panel Support

[Claude Code Review Bot]

Overall Series Review

Subject: Add NEC LCD Technologies NL6448BC33-70C Panel Support
Author: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Patches: 4
Reviewed: 2026-05-16T09:23:01.700385

---

This is a clean, well-structured 2-patch series adding support for the NEC NL6448BC33-70C 10.4" 640x480 LVDS panel to `panel-simple`. The code follows existing conventions, alphabetical ordering is correct in both the DT binding and the driver, and `connector_type` is properly set. The physical dimensions (211x158 mm) are consistent with a 10.4" 4:3 panel.

The only area worth scrutiny is the display timing — the horizontal sync width and back porch appear swapped relative to standard VGA, and the vertical timing produces a vtotal of 544 (vs. the standard 525), yielding a ~57.85 Hz refresh rate. These could be correct per the panel's datasheet, but the submitter should confirm.

**Verdict: Looks good with one timing question to resolve.**

---

---
Generated by Claude Code Patch Reviewer

Claude review: dt-bindings: display: simple: Add NEC NL6448BC33-70C panel

[Claude Code Review Bot]

Patch Review

**Status: No issues.**

The binding addition is correct:

```yaml
        # NEC LCD Technologies,Ltd. VGA TFT LCD panel
      - nec,nl6448bc33-70c
```

- Alphabetical placement between `nec,nl4827hc19-05b` and `netron-dy,e231732` is correct.
- Comment follows the existing pattern (comment line above the compatible string).
- The description "VGA TFT LCD panel" is accurate for 640x480. It could optionally include the size ("10.4\"") to match the more detailed style of some neighboring entries (e.g., `nec,nl12880bc20-05` uses "12.1\" WXGA (1280x800) LVDS TFT LCD panel"), but this is a style nit and not a blocking issue.

---

---
Generated by Claude Code Patch Reviewer

Claude review: drm/panel: simple: add NEC NL6448BC33-70C

[Claude Code Review Bot]

Patch Review

**Status: One question on timing values.**

The `panel_desc` structure is well-formed and follows conventions:

```c
static const struct panel_desc nec_nl6448bc33_70c = {
	.modes = &nec_nl6448bc33_70c_mode,
	.num_modes = 1,
	.bpc = 6,
	.size = {
		.width = 211,
		.height = 158,
	},
	.bus_format = MEDIA_BUS_FMT_RGB666_1X18,
	.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
	.connector_type = DRM_MODE_CONNECTOR_LVDS,
};
```

- `.bpc = 6` with `MEDIA_BUS_FMT_RGB666_1X18` — consistent (6 bits × 3 channels = 18 bits).
- `.connector_type = DRM_MODE_CONNECTOR_LVDS` — correctly set (the neighboring `nec_nl4827hc19_05b` omits this and would hit the "Specify missing connector_type" warning at runtime).
- `.size` = 211×158 mm — correct for a 10.4" panel with 4:3 aspect (10.4" × 4/5 ≈ 211 mm, 10.4" × 3/5 ≈ 158 mm).
- OF match table entry is in correct alphabetical position.

**Timing concern:**

```c
static const struct drm_display_mode nec_nl6448bc33_70c_mode = {
	.clock = 25175,
	.hdisplay = 640,
	.hsync_start = 640 + 16,      /* HFP = 16 */
	.hsync_end = 640 + 16 + 48,   /* HSW = 48 */
	.htotal = 640 + 16 + 48 + 96, /* HBP = 96 */
	.vdisplay = 480,
	.vsync_start = 480 + 2,       /* VFP = 2  */
	.vsync_end = 480 + 2 + 31,    /* VSW = 31 */
	.vtotal = 480 + 2 + 31 + 31,  /* VBP = 31 */
	.flags = DRM_MODE_FLAG_PVSYNC | DRM_MODE_FLAG_PHSYNC,
};
```

The htotal (800) is standard for 640×480, but:

1. **HSW and HBP appear swapped vs. standard VGA** — standard 640×480@60 has HSW=96 and HBP=48, i.e. the reverse of what's here. If these values come from the datasheet they may be correct, but it's worth double-checking.

2. **vtotal = 544 instead of 525** — this yields a refresh rate of 25175000 / (800 × 544) ≈ **57.85 Hz**, which is below the typical 59.94 Hz. The vertical sync width of 31 lines and back porch of 31 lines are quite different from standard VGA (VSW=2, VBP=33). Again, this may be correct per the panel's specifications, but the submitter should confirm these are from the NL6448BC33-70C datasheet and not a transcription error.

Everything else — code structure, naming, placement — looks correct and ready to merge pending timing confirmation.

---
Generated by Claude Code Patch Reviewer

Claude review: dt-bindings: display: simple: Add NEC NL6448BC33-70C panel

[Claude Code Review Bot]

Patch Review

This patch adds the compatible string `nec,nl6448bc33-70c` to the panel-simple bindings YAML.

**No issues found.** The entry is correctly placed in alphabetical order after `nec,nl4827hc19-05b` and before `netron-dy,e231732`. The comment "NEC LCD Technologies,Ltd. VGA TFT LCD panel" is accurate for a 640x480 panel.

---
Generated by Claude Code Patch Reviewer