[PATCH v4 0/4] Add Novatek NT37705 panel driver for Fairphone (Gen. 6)

[PATCH v4 0/4] Add Novatek NT37705 panel driver for Fairphone (Gen. 6)

[Luca Weiss]

Add bindings and a panel driver for the NT37705, and then enable display
on the Fairphone (Gen. 6).

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
Changes in v4:
- Use MIPI_DCS_* for a few commands (Dmitry)
- Link to v3: https://patch.msgid.link/20261002-fp6-panel-v3-0-4b80f83bc936@fairphone.com

Changes in v3:
- dt-bindings: don't use 'contains' (Sashiko)
- driver: Use devm_drm_panel_add & devm_mipi_dsi_attach
- driver: Replace linux/mod_devicetable.h with linux/device-id/of.h
  (Uwe)
- Link to v2: https://patch.msgid.link/20260918-fp6-panel-v2-0-6695c4008920@fairphone.com

Changes in v2:
- Fix kconfig dependencies of panel driver
- Pick up tags
- Link to v1: https://patch.msgid.link/20260501-fp6-panel-v1-0-e09cb05651cc@fairphone.com

---
Luca Weiss (4):
      dt-bindings: display: panel: Add Novatek NT37705
      drm/panel: Add driver for Novatek NT37705 panel
      arm64: defconfig: Enable Novatek NT37705 panel
      arm64: dts: qcom: milos-fairphone-fp6: Enable display

 .../bindings/display/panel/novatek,nt37705.yaml    |  71 ++++
 arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts   |  64 ++++
 arch/arm64/configs/defconfig                       |   1 +
 drivers/gpu/drm/panel/Kconfig                      |  12 +
 drivers/gpu/drm/panel/Makefile                     |   1 +
 drivers/gpu/drm/panel/panel-novatek-nt37705.c      | 396 +++++++++++++++++++++
 6 files changed, 545 insertions(+)
---
base-commit: c2cd463d6ee7d55a3ec0719d93c49ff99022d58f
change-id: 20260501-fp6-panel-3d35c999d894

Best regards,
--  
Luca Weiss <luca.weiss@fairphone.com>

[PATCH v4 1/4] dt-bindings: display: panel: Add Novatek NT37705

[Luca Weiss]

Novatek NT37705 is a display driver IC used to drive AMOLED DSI panels.

Describe it and the panel in the Fairphone (Gen. 6) (BJ631JHM-T71-D900
from BOE) using it.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://lore.kernel.org/r/81a3c207-4d8f-490f-8e2a-6f3f4c2acd35@kernel.org/
Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
 .../bindings/display/panel/novatek,nt37705.yaml    | 71 ++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/novatek,nt37705.yaml b/Documentation/devicetree/bindings/display/panel/novatek,nt37705.yaml
new file mode 100644
index 000000000000..850d91e25af5
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/novatek,nt37705.yaml
@@ -0,0 +1,71 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/novatek,nt37705.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Novatek NT37705-based DSI display panels
+
+maintainers:
+  - Luca Weiss <luca.weiss@fairphone.com>
+
+description:
+  The Novatek NT37705 is a generic DSI Panel IC used to control AMOLED panels.
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    const: boe,bj631jhm-t71-d900
+
+  reg:
+    maxItems: 1
+
+  vddio-supply:
+    description: I/O voltage rail
+
+  dvdd-supply:
+    description: Digital voltage rail
+
+  vci-supply:
+    description: Analog voltage rail
+
+required:
+  - compatible
+  - reg
+  - reset-gpios
+  - vddio-supply
+  - dvdd-supply
+  - vci-supply
+  - port
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    dsi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        panel@0 {
+            compatible = "boe,bj631jhm-t71-d900";
+            reg = <0>;
+
+            reset-gpios = <&tlmm 12 GPIO_ACTIVE_LOW>;
+
+            vci-supply = <&vreg_l19b>;
+            vddio-supply = <&vreg_l9b>;
+            dvdd-supply = <&vreg_oled_dvdd_1p2>;
+
+            port {
+                panel_in_0: endpoint {
+                    remote-endpoint = <&dsi0_out>;
+                };
+            };
+        };
+    };
+
+...

-- 
2.56.0

[PATCH v4 2/4] drm/panel: Add driver for Novatek NT37705 panel

[Luca Weiss]

Add support for the 2484x1116 AMOLED panel from BOE (BJ631JHM-T71-D900)
bundled with a NT37705 driver IC, as found on the Fairphone (Gen. 6)
smartphone.

The panel can also be configured in 10-bit (RGB101010) mode, however
currently it's configured in 8-bit (RGB888) since there's some issues in
the Qualcomm DPU driver when driving this panel in 10-bit.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
 drivers/gpu/drm/panel/Kconfig                 |  12 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 drivers/gpu/drm/panel/panel-novatek-nt37705.c | 396 ++++++++++++++++++++++++++
 3 files changed, 409 insertions(+)

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index cbdf7b8f7f7a..be2f812bef76 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -706,6 +706,18 @@ config DRM_PANEL_NOVATEK_NT37700F
 	  Say Y here if you want to enable support for Novatek NT37700F DSI
 	  panel module. The panel has a resolution of 1080x2160.
 
+config DRM_PANEL_NOVATEK_NT37705
+	tristate "Novatek NT37705-based DSI panel"
+	depends on OF
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	select DRM_DISPLAY_DSC_HELPER
+	select DRM_DISPLAY_HELPER
+	help
+	  Say Y here if you want to enable support for Novatek NT37705-based
+	  display panels, such as the one found in the Fairphone (Gen. 6)
+	  smartphone.
+
 config DRM_PANEL_NOVATEK_NT37801
 	tristate "Novatek NT37801/NT37810 AMOLED DSI panel"
 	depends on OF
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 3b523cf37833..e1366b5e25fc 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36536) += panel-novatek-nt36536.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36672A) += panel-novatek-nt36672a.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36672E) += panel-novatek-nt36672e.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT37700F) += panel-novatek-nt37700f.o
+obj-$(CONFIG_DRM_PANEL_NOVATEK_NT37705) += panel-novatek-nt37705.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT37801) += panel-novatek-nt37801.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT39016) += panel-novatek-nt39016.o
 obj-$(CONFIG_DRM_PANEL_MANTIX_MLAF057WE51) += panel-mantix-mlaf057we51.o
diff --git a/drivers/gpu/drm/panel/panel-novatek-nt37705.c b/drivers/gpu/drm/panel/panel-novatek-nt37705.c
new file mode 100644
index 000000000000..342e58591bab
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-novatek-nt37705.c
@@ -0,0 +1,396 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generated with linux-mdss-dsi-panel-driver-generator from vendor device tree.
+ * Copyright (c) 2026 Luca Weiss <luca.weiss@fairphone.com>
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/device-id/of.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+
+#include <video/mipi_display.h>
+
+#include <drm/display/drm_dsc.h>
+#include <drm/display/drm_dsc_helper.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+#include <drm/drm_probe_helper.h>
+
+struct nt37705_panel {
+	struct drm_panel panel;
+	struct mipi_dsi_device *dsi;
+	struct drm_dsc_config dsc;
+	struct regulator_bulk_data *supplies;
+	struct gpio_desc *reset_gpio;
+};
+
+static const struct regulator_bulk_data nt37705_supplies[] = {
+	{ .supply = "vddio" },
+	{ .supply = "dvdd" },
+	{ .supply = "vci" },
+};
+
+static inline struct nt37705_panel *to_nt37705_panel(struct drm_panel *panel)
+{
+	return container_of_const(panel, struct nt37705_panel, panel);
+}
+
+static void nt37705_reset(struct nt37705_panel *ctx)
+{
+	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
+	usleep_range(10000, 11000);
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+	usleep_range(5000, 6000);
+	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
+	usleep_range(10000, 11000);
+}
+
+static int nt37705_on(struct nt37705_panel *ctx)
+{
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
+
+	ctx->dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0,
+				     0x55, 0xaa, 0x52, 0x08, 0x00);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x1b);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba, 0x18);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x1c);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
+				     0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00,
+				     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+				     0x00, 0x00);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x2c);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
+				     0x00, 0x01, 0x01, 0x01, 0x00, 0x05, 0x05,
+				     0x05, 0x00, 0x05, 0x05, 0x05, 0x00, 0x00,
+				     0x00, 0x00);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x3c);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
+				     0x00, 0x00, 0x01, 0x01, 0x00, 0x00, 0x0b,
+				     0x0b, 0x00, 0x00, 0x0b, 0x0b, 0x00, 0x00,
+				     0x00, 0x00);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x4c);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
+				     0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
+				     0x1d, 0x00, 0x00, 0x00, 0x1d, 0x00, 0x00,
+				     0x00, 0x00);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x5c);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
+				     0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+				     0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+				     0x01, 0x01);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x6c);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
+				     0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x0b,
+				     0x77, 0x77, 0x00, 0x00, 0x0b, 0x00, 0x1d,
+				     0x00, 0x1d);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x7c);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
+				     0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x0b,
+				     0x77, 0x77, 0x00, 0x00, 0x0b, 0x00, 0x1d,
+				     0x00, 0x1d);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x8c);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
+				     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+				     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+				     0x00, 0x00);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x9c);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
+				     0x11, 0x11, 0x20, 0x02, 0x00, 0x03, 0x00,
+				     0x00);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0xa4);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba, 0x00, 0xc0, 0x40, 0x08);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0xa8);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
+				     0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,
+				     0x22);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0xb0);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xba,
+				     0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,
+				     0x22);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0,
+				     0x55, 0xaa, 0x52, 0x08, 0x01);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x05);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xc5, 0x15, 0x15, 0x15, 0xdd);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0,
+				     0x55, 0xaa, 0x52, 0x08, 0x00);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x0e);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb5, 0x32);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0,
+				     0x55, 0xaa, 0x52, 0x00, 0x00);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xff, 0xaa, 0x55, 0xa5, 0x80);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x19);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf2, 0x00);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x1a);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf4, 0x55);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x11);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf8, 0x01, 0x7f);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x2d);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf8, 0x01, 0x20);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xff, 0xaa, 0x55, 0xa5, 0x81);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x05);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfe, 0x3c);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x02);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf9, 0x04);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x1e);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfb, 0x0f);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x0f);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf5, 0x20);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x0d);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfb, 0x80);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xff, 0xaa, 0x55, 0xa5, 0x83);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x12);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfe, 0x41);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x13);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfd, 0x21);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xff, 0xaa, 0x55, 0xa5, 0x00);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_SET_TEAR_ON);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY,
+				     0x20);
+	mipi_dsi_dcs_set_column_address_multi(&dsi_ctx, 0x0000, 0x045b);
+	mipi_dsi_dcs_set_page_address_multi(&dsi_ctx, 0x0000, 0x09b3);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_SET_GAMMA_CURVE, 0x00);
+	mipi_dsi_dcs_set_display_brightness_multi(&dsi_ctx, 0xbb0d);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x04);
+	mipi_dsi_dcs_set_display_brightness_multi(&dsi_ctx, 0xfe0f);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x81, 0x01, 0x19);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x03, 0x01);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x90, 0x03, 0x03);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x91,
+				     0x89, 0x28, 0x00, 0x0c, 0xd2, 0x00, 0x02,
+				     0x2f, 0x01, 0x18, 0x00, 0x07, 0x09, 0x75,
+				     0x08, 0x34, 0x10, 0xf0);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x2f, 0x02);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x5a, 0x01);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x2f, 0x30);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6d, 0x00);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_EXIT_SLEEP_MODE, 0x00);
+	mipi_dsi_msleep(&dsi_ctx, 120);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_SET_DISPLAY_ON, 0x00);
+	mipi_dsi_msleep(&dsi_ctx, 22);
+
+	return dsi_ctx.accum_err;
+}
+
+static int nt37705_off(struct nt37705_panel *ctx)
+{
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
+
+	ctx->dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_SET_DISPLAY_OFF, 0x00);
+	mipi_dsi_msleep(&dsi_ctx, 20);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_ENTER_SLEEP_MODE, 0x00);
+	mipi_dsi_msleep(&dsi_ctx, 120);
+
+	return dsi_ctx.accum_err;
+}
+
+static int nt37705_prepare(struct drm_panel *panel)
+{
+	struct nt37705_panel *ctx = to_nt37705_panel(panel);
+	struct device *dev = &ctx->dsi->dev;
+	struct drm_dsc_picture_parameter_set pps;
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(nt37705_supplies), ctx->supplies);
+	if (ret < 0) {
+		dev_err(dev, "Failed to enable regulators: %d\n", ret);
+		return ret;
+	}
+
+	nt37705_reset(ctx);
+
+	ret = nt37705_on(ctx);
+	if (ret < 0) {
+		dev_err(dev, "Failed to initialize panel: %d\n", ret);
+		gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+		regulator_bulk_disable(ARRAY_SIZE(nt37705_supplies), ctx->supplies);
+		return ret;
+	}
+
+	drm_dsc_pps_payload_pack(&pps, &ctx->dsc);
+
+	ret = mipi_dsi_picture_parameter_set(ctx->dsi, &pps);
+	if (ret < 0) {
+		dev_err(panel->dev, "failed to transmit PPS: %d\n", ret);
+		return ret;
+	}
+
+	ret = mipi_dsi_compression_mode(ctx->dsi, true);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable compression mode: %d\n", ret);
+		return ret;
+	}
+
+	msleep(28); /* TODO: Is this panel-dependent? */
+
+	return 0;
+}
+
+static int nt37705_unprepare(struct drm_panel *panel)
+{
+	struct nt37705_panel *ctx = to_nt37705_panel(panel);
+	struct device *dev = &ctx->dsi->dev;
+	int ret;
+
+	ret = nt37705_off(ctx);
+	if (ret < 0)
+		dev_err(dev, "Failed to un-initialize panel: %d\n", ret);
+
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+	regulator_bulk_disable(ARRAY_SIZE(nt37705_supplies), ctx->supplies);
+
+	return 0;
+}
+
+static const struct drm_display_mode nt37705_mode = {
+	.clock = (1116 + 100 + 30 + 100) * (2484 + 70 + 48 + 70) * 120 / 1000,
+	.hdisplay = 1116,
+	.hsync_start = 1116 + 100,
+	.hsync_end = 1116 + 100 + 30,
+	.htotal = 1116 + 100 + 30 + 100,
+	.vdisplay = 2484,
+	.vsync_start = 2484 + 70,
+	.vsync_end = 2484 + 70 + 48,
+	.vtotal = 2484 + 70 + 48 + 70,
+	.width_mm = 66,
+	.height_mm = 146,
+	.type = DRM_MODE_TYPE_DRIVER,
+};
+
+static int nt37705_get_modes(struct drm_panel *panel,
+			     struct drm_connector *connector)
+{
+	return drm_connector_helper_get_modes_fixed(connector, &nt37705_mode);
+}
+
+static const struct drm_panel_funcs nt37705_panel_funcs = {
+	.prepare = nt37705_prepare,
+	.unprepare = nt37705_unprepare,
+	.get_modes = nt37705_get_modes,
+};
+
+static int nt37705_bl_update_status(struct backlight_device *bl)
+{
+	struct mipi_dsi_device *dsi = bl_get_data(bl);
+	u16 brightness = backlight_get_brightness(bl);
+	int ret;
+
+	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+	ret = mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);
+	if (ret < 0)
+		return ret;
+
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	return 0;
+}
+
+static const struct backlight_ops nt37705_bl_ops = {
+	.update_status = nt37705_bl_update_status,
+};
+
+static struct backlight_device *
+nt37705_create_backlight(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	const struct backlight_properties props = {
+		.type = BACKLIGHT_RAW,
+		.scale = BACKLIGHT_SCALE_NON_LINEAR,
+		.brightness = 4095,
+		.max_brightness = 4095,
+	};
+
+	return devm_backlight_device_register(dev, dev_name(dev), dev, dsi,
+					      &nt37705_bl_ops, &props);
+}
+
+static int nt37705_probe(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	struct nt37705_panel *ctx;
+	int ret;
+
+	ctx = devm_drm_panel_alloc(dev, struct nt37705_panel, panel,
+				   &nt37705_panel_funcs,
+				   DRM_MODE_CONNECTOR_DSI);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	ret = devm_regulator_bulk_get_const(dev,
+					    ARRAY_SIZE(nt37705_supplies),
+					    nt37705_supplies,
+					    &ctx->supplies);
+	if (ret < 0)
+		return ret;
+
+	ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(ctx->reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(ctx->reset_gpio),
+				     "Failed to get reset-gpios\n");
+
+	ctx->dsi = dsi;
+	mipi_dsi_set_drvdata(dsi, ctx);
+
+	dsi->lanes = 4;
+	dsi->format = MIPI_DSI_FMT_RGB888;
+	dsi->mode_flags = MIPI_DSI_MODE_NO_EOT_PACKET |
+			  MIPI_DSI_CLOCK_NON_CONTINUOUS;
+
+	ctx->panel.prepare_prev_first = true;
+
+	ctx->panel.backlight = nt37705_create_backlight(dsi);
+	if (IS_ERR(ctx->panel.backlight))
+		return dev_err_probe(dev, PTR_ERR(ctx->panel.backlight),
+				     "Failed to create backlight\n");
+
+	ret = devm_drm_panel_add(dev, &ctx->panel);
+	if (ret)
+		return ret;
+
+	/* This panel only supports DSC; unconditionally enable it */
+	dsi->dsc = &ctx->dsc;
+
+	ctx->dsc.dsc_version_major = 1;
+	ctx->dsc.dsc_version_minor = 1;
+
+	/* TODO: Pass slice_per_pkt = 2 */
+	ctx->dsc.slice_height = 12;
+	ctx->dsc.slice_width = 558;
+	/*
+	 * TODO: hdisplay should be read from the selected mode once
+	 * it is passed back to drm_panel (in prepare?)
+	 */
+	WARN_ON(1116 % ctx->dsc.slice_width);
+	ctx->dsc.slice_count = 1116 / ctx->dsc.slice_width;
+	ctx->dsc.bits_per_component = 8;
+	ctx->dsc.bits_per_pixel = 8 << 4; /* 4 fractional bits */
+	ctx->dsc.block_pred_enable = true;
+
+	return devm_mipi_dsi_attach(dev, dsi);
+}
+
+static const struct of_device_id nt37705_of_match[] = {
+	{ .compatible = "boe,bj631jhm-t71-d900" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, nt37705_of_match);
+
+static struct mipi_dsi_driver nt37705_driver = {
+	.probe = nt37705_probe,
+	.driver = {
+		.name = "panel-novatek-nt37705",
+		.of_match_table = nt37705_of_match,
+	},
+};
+module_mipi_dsi_driver(nt37705_driver);
+
+MODULE_DESCRIPTION("DRM driver for NT37705-equipped DSI panels");
+MODULE_LICENSE("GPL");

-- 
2.56.0

Re: [PATCH v4 2/4] drm/panel: Add driver for Novatek NT37705 panel

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 5 potential issue(s) to consider:
- [High] drm/panel: missing error cleanup in nt37705_prepare() leaks regulators
- [High] drm/panel: nt37705: data race and DSI timeout in backlight sysfs
- [Medium] drm/panel: dsi->mode_flags mutated and not restored on error in nt37705_bl_update_status()
- [Medium] drm/panel: invalid payload for 0-parameter DCS commands
- [Medium] drm/panel: nt37705: missing panel.prepared check in backlight update_status
--

commit a437b7eca971b2adefff7488ccaf50028c00b068
Author: Luca Weiss <luca.weiss@fairphone.com>
drm/panel: Add driver for Novatek NT37705 panel

This commit adds support for the 2484x1116 AMOLED panel from BOE
(BJ631JHM-T71-D900) bundled with a NT37705 driver IC, as found on the
Fairphone 6 smartphone.

> diff --git a/drivers/gpu/drm/panel/panel-novatek-nt37705.c b/drivers/gpu/drm/panel/panel-novatek-nt37705.c
> new file mode 100644
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-novatek-nt37705.c
> @@ -0,0 +1,396 @@
[ ... ]
> +static int nt37705_on(struct nt37705_panel *ctx)
> +{
> +	struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
[ ... ]
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_SET_TEAR_ON);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_WRITE_CONTROL_DISPLAY,
> +				     0x20);
> +	mipi_dsi_dcs_set_column_address_multi(&dsi_ctx, 0x0000, 0x045b);
> +	mipi_dsi_dcs_set_page_address_multi(&dsi_ctx, 0x0000, 0x09b3);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_SET_GAMMA_CURVE, 0x00);
> +	mipi_dsi_dcs_set_display_brightness_multi(&dsi_ctx, 0xbb0d);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6f, 0x04);
> +	mipi_dsi_dcs_set_display_brightness_multi(&dsi_ctx, 0xfe0f);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x81, 0x01, 0x19);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x03, 0x01);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x90, 0x03, 0x03);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x91,
> +				     0x89, 0x28, 0x00, 0x0c, 0xd2, 0x00, 0x02,
> +				     0x2f, 0x01, 0x18, 0x00, 0x07, 0x09, 0x75,
> +				     0x08, 0x34, 0x10, 0xf0);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x2f, 0x02);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x5a, 0x01);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x2f, 0x30);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x6d, 0x00);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_EXIT_SLEEP_MODE, 0x00);
> +	mipi_dsi_msleep(&dsi_ctx, 120);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_SET_DISPLAY_ON, 0x00);
> +	mipi_dsi_msleep(&dsi_ctx, 22);

[Severity: Medium]
The driver issues several MIPI DCS commands that require zero parameters,
such as MIPI_DCS_EXIT_SLEEP_MODE (0x11) and MIPI_DCS_SET_DISPLAY_ON (0x29).
However, passing 0x00 as an argument to mipi_dsi_dcs_write_seq_multi()
creates a 2-byte array ({ cmd, 0x00 }). This triggers a DCS Short Write
with 1 parameter (Data Type 0x15) instead of a 0-parameter write (Data Type
0x05). 

Similarly, earlier in this sequence, MIPI_DCS_SET_TEAR_ON takes 1 parameter 
but is called with no parameters.

Could this cause strict DSI sinks to reject these malformed packets and fail
panel initialization?

> +	return dsi_ctx.accum_err;
> +}
> +
> +static int nt37705_off(struct nt37705_panel *ctx)
> +{
> +	struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
> +
> +	ctx->dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_SET_DISPLAY_OFF, 0x00);
> +	mipi_dsi_msleep(&dsi_ctx, 20);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, MIPI_DCS_ENTER_SLEEP_MODE, 0x00);
> +	mipi_dsi_msleep(&dsi_ctx, 120);

[Severity: Medium]
As mentioned above, MIPI_DCS_SET_DISPLAY_OFF and MIPI_DCS_ENTER_SLEEP_MODE
are also 0-parameter commands being given a 0x00 payload, creating an
incorrect DCS short write length.

> +	return dsi_ctx.accum_err;
> +}
> +
> +static int nt37705_prepare(struct drm_panel *panel)
> +{
> +	struct nt37705_panel *ctx = to_nt37705_panel(panel);
> +	struct device *dev = &ctx->dsi->dev;
> +	struct drm_dsc_picture_parameter_set pps;
> +	int ret;
> +
> +	ret = regulator_bulk_enable(ARRAY_SIZE(nt37705_supplies), ctx->supplies);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to enable regulators: %d\n", ret);
> +		return ret;
> +	}
> +
> +	nt37705_reset(ctx);
> +
> +	ret = nt37705_on(ctx);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to initialize panel: %d\n", ret);
> +		gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +		regulator_bulk_disable(ARRAY_SIZE(nt37705_supplies), ctx->supplies);
> +		return ret;
> +	}
> +
> +	drm_dsc_pps_payload_pack(&pps, &ctx->dsc);
> +
> +	ret = mipi_dsi_picture_parameter_set(ctx->dsi, &pps);
> +	if (ret < 0) {
> +		dev_err(panel->dev, "failed to transmit PPS: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = mipi_dsi_compression_mode(ctx->dsi, true);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to enable compression mode: %d\n", ret);
> +		return ret;
> +	}

[Severity: High]
If mipi_dsi_picture_parameter_set() or mipi_dsi_compression_mode() fails
here, the function returns immediately. Earlier in this function, the
regulators are enabled and the reset GPIO is toggled. Should these error
paths also assert the reset GPIO and call regulator_bulk_disable() like
the error path for nt37705_on() does?

Since the prepare callback failed, the DRM core will not call
drm_panel_unprepare(), which leaves a permanent regulator imbalance and the
panel powered on in an inconsistent state.

> +	msleep(28); /* TODO: Is this panel-dependent? */
> +
> +	return 0;
> +}
[ ... ]
> +static int nt37705_bl_update_status(struct backlight_device *bl)
> +{
> +	struct mipi_dsi_device *dsi = bl_get_data(bl);
> +	u16 brightness = backlight_get_brightness(bl);
> +	int ret;
> +
> +	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +
> +	ret = mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);
> +	if (ret < 0)
> +		return ret;
> +
> +	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
> +
> +	return 0;
> +}

[Severity: High]
This function modifies dsi->mode_flags using non-atomic bitwise operations
without taking a lock. Since userspace can write to the sysfs brightness
node at any time, could this race with a DRM modeset where nt37705_on() or
nt37705_off() also modify the panel state? Concurrent execution could
corrupt dsi->mode_flags and lose flags like MIPI_DSI_MODE_NO_EOT_PACKET set
during probe.

[Severity: Medium]
When the panel is disabled and unprepared, its regulators are turned off.
If a write occurs to the sysfs backlight node while the panel is unprepared,
is it safe to unconditionally issue a DSI transmission via
mipi_dsi_dcs_set_display_brightness_large()?

Sending DSI DCS commands to a powered-off panel usually causes the DSI bus
to hang or timeout. Should this function check if ctx->panel.prepared is
true before attempting to communicate with the panel?

[Severity: Medium]
If mipi_dsi_dcs_set_display_brightness_large() fails, the function
returns early. Doesn't this leave the MIPI_DSI_MODE_LPM flag permanently
cleared? 

Also, on success, it unconditionally forces the MIPI_DSI_MODE_LPM flag on,
even if it wasn't originally set. This might corrupt the panel's mode flags
and cause subsequent commands to incorrectly use or omit Low Power Mode.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261009-fp6-panel-v4-0-7c3819664778@fairphone.com?part=2

Re: [PATCH v4 2/4] drm/panel: Add driver for Novatek NT37705 panel

[Dmitry Baryshkov]

On Fri, Oct 09, 2026 at 01:25:01PM +0200, Luca Weiss wrote:
> Add support for the 2484x1116 AMOLED panel from BOE (BJ631JHM-T71-D900)
> bundled with a NT37705 driver IC, as found on the Fairphone (Gen. 6)
> smartphone.
> 
> The panel can also be configured in 10-bit (RGB101010) mode, however
> currently it's configured in 8-bit (RGB888) since there's some issues in
> the Qualcomm DPU driver when driving this panel in 10-bit.

I hoped that fixed all of them...

> 
> Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
> ---
>  drivers/gpu/drm/panel/Kconfig                 |  12 +
>  drivers/gpu/drm/panel/Makefile                |   1 +
>  drivers/gpu/drm/panel/panel-novatek-nt37705.c | 396 ++++++++++++++++++++++++++
>  3 files changed, 409 insertions(+)

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

I went through Sashiko comments, I don't think that this driver diverges
from any other panel driver.

-- 
With best wishes
Dmitry

[PATCH v4 3/4] arm64: defconfig: Enable Novatek NT37705 panel

[Luca Weiss]

Enable the NT37705 panel driver which is used on Fairphone (Gen. 6).

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
 arch/arm64/configs/defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
index 6ec8d3a69c98..1d4afc733c8a 100644
--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig
@@ -1023,6 +1023,7 @@ CONFIG_DRM_PANEL_KHADAS_TS050=m
 CONFIG_DRM_PANEL_MANTIX_MLAF057WE51=m
 CONFIG_DRM_PANEL_NOVATEK_NT36672A=m
 CONFIG_DRM_PANEL_NOVATEK_NT36672E=m
+CONFIG_DRM_PANEL_NOVATEK_NT37705=m
 CONFIG_DRM_PANEL_NOVATEK_NT37801=m
 CONFIG_DRM_PANEL_RAYDIUM_RM67191=m
 CONFIG_DRM_PANEL_RAYDIUM_RM692E5=m

-- 
2.56.0

[PATCH v4 4/4] arm64: dts: qcom: milos-fairphone-fp6: Enable display

[Luca Weiss]

Configure the MDSS nodes for the phone and add the panel node.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
 arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts | 64 ++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts b/arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts
index 4e8777162b53..11015c3fa331 100644
--- a/arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts
+++ b/arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts
@@ -709,6 +709,49 @@ &ipa {
 	status = "okay";
 };
 
+&mdss {
+	status = "okay";
+};
+
+&mdss_dsi0 {
+	vdda-supply = <&vreg_l4b>;
+
+	status = "okay";
+
+	panel@0 {
+		compatible = "boe,bj631jhm-t71-d900";
+		reg = <0>;
+
+		reset-gpios = <&tlmm 12 GPIO_ACTIVE_LOW>;
+
+		vci-supply = <&vreg_l19b>;
+		vddio-supply = <&vreg_l9b>;
+		dvdd-supply = <&vreg_oled_dvdd_1p2>;
+
+		pinctrl-0 = <&disp_reset_n_active>, <&mdp_vsync>;
+		pinctrl-1 = <&disp_reset_n_suspend>, <&mdp_vsync>;
+		pinctrl-names = "default",
+				"sleep";
+
+		port {
+			panel_in: endpoint {
+				remote-endpoint = <&mdss_dsi0_out>;
+			};
+		};
+	};
+};
+
+&mdss_dsi0_out {
+	data-lanes = <0 1 2 3>;
+	remote-endpoint = <&panel_in>;
+};
+
+&mdss_dsi0_phy {
+	vdds-supply = <&vreg_l2b>;
+
+	status = "okay";
+};
+
 &pm8550vs_c {
 	status = "okay";
 };
@@ -872,6 +915,20 @@ &tlmm {
 			       <13 1>, /* NC */
 			       <63 2>; /* WLAN UART */
 
+	disp_reset_n_active: disp-reset-n-active-state {
+		pins = "gpio12";
+		function = "gpio";
+		drive-strength = <8>;
+		bias-disable;
+	};
+
+	disp_reset_n_suspend: disp-reset-n-suspend-state {
+		pins = "gpio12";
+		function = "gpio";
+		drive-strength = <2>;
+		bias-pull-down;
+	};
+
 	sdc2_card_det_n: sdc2-card-det-state {
 		pins = "gpio65";
 		function = "gpio";
@@ -906,6 +963,13 @@ pm8008_int_default: pm8008-int-default-state {
 		drive-strength = <2>;
 		bias-disable;
 	};
+
+	mdp_vsync: mdp-vsync-state {
+		pins = "gpio129";
+		function = "mdp_vsync";
+		drive-strength = <2>;
+		bias-pull-down;
+	};
 };
 
 &uart5 {

-- 
2.56.0