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

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

[Steffen Trumtrar]

Add support for the above mentioned LCD panel from NEC.

---
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               | 28 ++++++++++++++++++++++
 2 files changed, 30 insertions(+)
---
base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731
change-id: 20260513-v7-1-topic-panel-simple-nl6448bc33-c36e33b18ab1

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

[PATCH 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 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 | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index 236bd56208ccf..bbbbdd399d1c3 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -3659,6 +3659,31 @@ 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 = 243,
+		.height = 185,
+	},
+	.bus_format = MEDIA_BUS_FMT_RGB666_1X18,
+	.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
+};
+
 static const struct drm_display_mode netron_dy_e231732_mode = {
 	.clock = 66000,
 	.hdisplay = 1024,
@@ -5520,6 +5545,9 @@ 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

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: 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: 3
Reviewed: 2026-05-16T11:43:36.601099

---

This is a straightforward 2-patch series adding support for the NEC NL6448BC33-70C 10.4" 640x480 LCD panel to the `panel-simple` driver. The series follows the standard pattern well: patch 1 adds the DT binding compatible string, patch 2 adds the driver entry. The code structure is clean and follows existing conventions in the file. However, there is one likely error in the physical dimensions that should be corrected before merging, and one timing value worth verifying against the datasheet.

---
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

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

[Claude Code Review Bot]

Patch Review

This patch adds the mode definition, panel descriptor, and OF match table entry.

**Issue 1 (likely bug): Physical size uses module outline dimensions, not active area.**

The `panel_desc` struct documents `size.width` and `size.height` as "Width/Height (in mm) of the **active display area**" (panel-simple.c lines 79-86). The patch uses:

```c
.size = {
    .width = 243,
    .height = 185,
},
```

These values (243 x 185 mm) correspond to the **module outline dimensions** of the NL6448BC33-70C, not the active display area. The active area for this panel is 211.2 x 158.4 mm. Using the outline dimensions inflates the reported physical size, leading to incorrect DPI calculations (and undersized rendering on any compositor that uses this information). This should be:

```c
.size = {
    .width = 211,
    .height = 158,
},
```

**Item 2 (worth verifying): Vertical sync pulse width of 31 lines is unusual.**

```c
.vsync_start = 480 + 2,
.vsync_end = 480 + 2 + 31,
.vtotal = 480 + 2 + 31 + 31,
```

This gives VFP=2, VSW=31, VBP=31, vtotal=544. The NL6448BC33 family datasheets I'm aware of typically specify VSW=2 (not 31), VFP=10, VBP=33, for vtotal=525 and ~60 Hz refresh. With vtotal=544, the refresh rate works out to approximately 57.8 Hz (25175000 / (800 * 544)). The submitter should confirm these vertical timing values against the actual -70C variant datasheet. A 31-line sync pulse is very atypical for this class of panel.

**Item 3 (minor, worth confirming): Sync polarity.**

```c
.flags = DRM_MODE_FLAG_PVSYNC | DRM_MODE_FLAG_PHSYNC,
```

Standard 640x480@60Hz VGA uses negative sync (NVSYNC | NHSYNC). Some NL6448BC33 variants accept either polarity, so positive may be valid for the -70C, but the submitter should confirm this matches the datasheet.

**Everything else looks correct:**
- The pixel clock of 25175 kHz matches the standard VGA dot clock.
- Horizontal timings (HFP=16, HSW=48, HBP=96, htotal=800) match standard VGA horizontal timing.
- `bpc = 6` with `bus_format = MEDIA_BUS_FMT_RGB666_1X18` is consistent (6 bits x 3 channels = 18 bits).
- `bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE` follows the same pattern as the existing `nec_nl4827hc19_05b` entry.
- The OF match table entry is correctly placed in alphabetical order.

---
Generated by Claude Code Patch Reviewer