[PATCH 2/2] drm/panel: Add Truly NT35521 panel driver

[Shawn Guo <shawn.guo@linaro.org>]

It adds a drm driver for Truly NT35521 5.24" 1280x720 DSI panel, which
can be found on Sony Xperia M4 Aqua phone.  The panel backlight is
managed through DSI link.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
---
 drivers/gpu/drm/panel/Kconfig               |   9 +
 drivers/gpu/drm/panel/Makefile              |   1 +
 drivers/gpu/drm/panel/panel-truly-nt35521.c | 491 ++++++++++++++++++++
 3 files changed, 501 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-truly-nt35521.c

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index ef87d92cdf49..cdc4abd5c40c 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -537,6 +537,15 @@ config DRM_PANEL_TPO_TPG110
 	  400CH LTPS TFT LCD Single Chip Digital Driver for up to
 	  800x400 LCD panels.
 
+config DRM_PANEL_TRULY_NT35521
+	tristate "Truly NT35521 panel"
+	depends on OF
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	help
+	  Say Y here if you want to enable support for Truly NT35521
+	  1280x720 DSI panel.
+
 config DRM_PANEL_TRULY_NT35597_WQXGA
 	tristate "Truly WQXGA"
 	depends on OF
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index cae4d976c069..3d3c98cb7a7b 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_DRM_PANEL_TDO_TL070WSH30) += panel-tdo-tl070wsh30.o
 obj-$(CONFIG_DRM_PANEL_TPO_TD028TTEC1) += panel-tpo-td028ttec1.o
 obj-$(CONFIG_DRM_PANEL_TPO_TD043MTEA1) += panel-tpo-td043mtea1.o
 obj-$(CONFIG_DRM_PANEL_TPO_TPG110) += panel-tpo-tpg110.o
+obj-$(CONFIG_DRM_PANEL_TRULY_NT35521) += panel-truly-nt35521.o
 obj-$(CONFIG_DRM_PANEL_TRULY_NT35597_WQXGA) += panel-truly-nt35597.o
 obj-$(CONFIG_DRM_PANEL_VISIONOX_RM69299) += panel-visionox-rm69299.o
 obj-$(CONFIG_DRM_PANEL_XINPENG_XPP055C272) += panel-xinpeng-xpp055c272.o
diff --git a/drivers/gpu/drm/panel/panel-truly-nt35521.c b/drivers/gpu/drm/panel/panel-truly-nt35521.c
new file mode 100644
index 000000000000..ea3cfb46be7e
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-truly-nt35521.c
@@ -0,0 +1,491 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021, Linaro Limited
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+
+#include <video/mipi_display.h>
+
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+#include <drm/drm_print.h>
+
+struct nt35521_panel {
+	struct drm_panel panel;
+	struct device *dev;
+	struct gpio_desc *rst_gpio;
+	struct gpio_desc *pwrp5_gpio;
+	struct gpio_desc *pwrn5_gpio;
+	struct gpio_desc *en_gpio;
+	bool prepared;
+	bool enabled;
+};
+
+static inline struct nt35521_panel *panel_to_nt35521(struct drm_panel *panel)
+{
+	return container_of(panel, struct nt35521_panel, panel);
+}
+
+#define nt_dcs_write(seq...)						\
+({									\
+	const u8 d[] = { seq };						\
+	if (mipi_dsi_dcs_write_buffer(dsi, d, ARRAY_SIZE(d)) < 0)	\
+		DRM_DEV_ERROR(dev, "dcs write buffer failed\n");	\
+})
+
+#define nt_gen_write(seq...)						\
+({									\
+	const u8 d[] = { seq };						\
+	if (mipi_dsi_generic_write(dsi, d, ARRAY_SIZE(d)) < 0)		\
+		DRM_DEV_ERROR(dev, "generic write buffer failed\n");	\
+})
+
+static void nt35521_panel_on(struct nt35521_panel *nt)
+{
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(nt->dev);
+	struct device *dev = nt->dev;
+
+	/* Transmit data in low power mode */
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	nt_dcs_write(0xf0, 0x55, 0xaa, 0x52, 0x08, 0x00);
+	nt_dcs_write(0xff, 0xaa, 0x55, 0xa5, 0x80);
+	nt_dcs_write(0x6f, 0x11, 0x00);
+	nt_dcs_write(0xf7, 0x20, 0x00);
+	nt_dcs_write(0x6f, 0x01);
+	nt_dcs_write(0xb1, 0x21);
+	nt_dcs_write(0xbd, 0x01, 0xa0, 0x10, 0x08, 0x01);
+	nt_dcs_write(0xb8, 0x01, 0x02, 0x0c, 0x02);
+	nt_dcs_write(0xbb, 0x11, 0x11);
+	nt_dcs_write(0xbc, 0x00, 0x00);
+	nt_dcs_write(0xb6, 0x02);
+	nt_dcs_write(0xf0, 0x55, 0xaa, 0x52, 0x08, 0x01);
+	nt_dcs_write(0xb0, 0x09, 0x09);
+	nt_dcs_write(0xb1, 0x09, 0x09);
+	nt_dcs_write(0xbc, 0x8c, 0x00);
+	nt_dcs_write(0xbd, 0x8c, 0x00);
+	nt_dcs_write(0xca, 0x00);
+	nt_dcs_write(0xc0, 0x04);
+	nt_dcs_write(0xbe, 0xb5);
+	nt_dcs_write(0xb3, 0x35, 0x35);
+	nt_dcs_write(0xb4, 0x25, 0x25);
+	nt_dcs_write(0xb9, 0x43, 0x43);
+	nt_dcs_write(0xba, 0x24, 0x24);
+	nt_dcs_write(0xf0, 0x55, 0xaa, 0x52, 0x08, 0x02);
+	nt_dcs_write(0xee, 0x03);
+	nt_dcs_write(0xb0, 0x00, 0xb2, 0x00, 0xb3, 0x00, 0xb6, 0x00,
+		     0xc3, 0x00, 0xce, 0x00, 0xe1, 0x00, 0xf3, 0x01,
+		     0x11);
+	nt_dcs_write(0xb1, 0x01, 0x2e, 0x01, 0x5c, 0x01, 0x82, 0x01,
+		     0xc3, 0x01, 0xfe, 0x02, 0x00, 0x02, 0x37, 0x02,
+		     0x77);
+	nt_dcs_write(0xb2, 0x02, 0xa1, 0x02, 0xd7, 0x02, 0xfe, 0x03,
+		     0x2c, 0x03, 0x4b, 0x03, 0x63, 0x03, 0x8f, 0x03,
+		     0x90);
+	nt_dcs_write(0xb3, 0x03, 0x96, 0x03, 0x98);
+	nt_dcs_write(0xb4, 0x00, 0x81, 0x00, 0x8b, 0x00, 0x9c, 0x00,
+		     0xa9, 0x00, 0xb5, 0x00, 0xcb, 0x00, 0xdf, 0x01,
+		     0x02);
+	nt_dcs_write(0xb5, 0x01, 0x1f, 0x01, 0x51, 0x01, 0x7a, 0x01,
+		     0xbf, 0x01, 0xfa, 0x01, 0xfc, 0x02, 0x34, 0x02, 0x76);
+	nt_dcs_write(0xb6, 0x02, 0x9f, 0x02, 0xd7, 0x02, 0xfc, 0x03, 0x2c,
+		     0x03, 0x4a, 0x03, 0x63, 0x03, 0x8f, 0x03, 0xa2);
+	nt_dcs_write(0xb7, 0x03, 0xb8, 0x03, 0xba);
+	nt_dcs_write(0xb8, 0x00, 0x01, 0x00, 0x02, 0x00, 0x0e, 0x00, 0x2a,
+		     0x00, 0x41, 0x00, 0x67, 0x00, 0x87, 0x00, 0xb9);
+	nt_dcs_write(0xb9, 0x00, 0xe2, 0x01, 0x22, 0x01, 0x54, 0x01, 0xa3,
+		     0x01, 0xe6, 0x01, 0xe7, 0x02, 0x24, 0x02, 0x67);
+	nt_dcs_write(0xba, 0x02, 0x93, 0x02, 0xcd, 0x02, 0xf6, 0x03, 0x31,
+		     0x03, 0x6c, 0x03, 0xe9, 0x03, 0xef, 0x03, 0xf4);
+	nt_dcs_write(0xbb, 0x03, 0xf6, 0x03, 0xf7);
+	nt_dcs_write(0xf0, 0x55, 0xaa, 0x52, 0x08, 0x03);
+	nt_dcs_write(0xb0, 0x22, 0x00);
+	nt_dcs_write(0xb1, 0x22, 0x00);
+	nt_dcs_write(0xb2, 0x05, 0x00, 0x60, 0x00, 0x00);
+	nt_dcs_write(0xb3, 0x05, 0x00, 0x60, 0x00, 0x00);
+	nt_dcs_write(0xb4, 0x05, 0x00, 0x60, 0x00, 0x00);
+	nt_dcs_write(0xb5, 0x05, 0x00, 0x60, 0x00, 0x00);
+	nt_dcs_write(0xba, 0x53, 0x00, 0x60, 0x00, 0x00);
+	nt_dcs_write(0xbb, 0x53, 0x00, 0x60, 0x00, 0x00);
+	nt_dcs_write(0xbc, 0x53, 0x00, 0x60, 0x00, 0x00);
+	nt_dcs_write(0xbd, 0x53, 0x00, 0x60, 0x00, 0x00);
+	nt_dcs_write(0xc0, 0x00, 0x34, 0x00, 0x00);
+	nt_dcs_write(0xc1, 0x00, 0x00, 0x34, 0x00);
+	nt_dcs_write(0xc2, 0x00, 0x00, 0x34, 0x00);
+	nt_dcs_write(0xc3, 0x00, 0x00, 0x34, 0x00);
+	nt_dcs_write(0xc4, 0x60);
+	nt_dcs_write(0xc5, 0xc0);
+	nt_dcs_write(0xc6, 0x00);
+	nt_dcs_write(0xc7, 0x00);
+	nt_dcs_write(0xf0, 0x55, 0xaa, 0x52, 0x08, 0x05);
+	nt_dcs_write(0xb0, 0x17, 0x06);
+	nt_dcs_write(0xb1, 0x17, 0x06);
+	nt_dcs_write(0xb2, 0x17, 0x06);
+	nt_dcs_write(0xb3, 0x17, 0x06);
+	nt_dcs_write(0xb4, 0x17, 0x06);
+	nt_dcs_write(0xb5, 0x17, 0x06);
+	nt_dcs_write(0xb6, 0x17, 0x06);
+	nt_dcs_write(0xb7, 0x17, 0x06);
+	nt_dcs_write(0xb8, 0x00);
+	nt_dcs_write(0xb9, 0x00, 0x03);
+	nt_dcs_write(0xba, 0x00, 0x00);
+	nt_dcs_write(0xbb, 0x02, 0x03);
+	nt_dcs_write(0xbc, 0x02, 0x03);
+	nt_dcs_write(0xbd, 0x03, 0x03, 0x00, 0x03, 0x03);
+	nt_dcs_write(0xc0, 0x0b);
+	nt_dcs_write(0xc1, 0x09);
+	nt_dcs_write(0xc2, 0xa6);
+	nt_dcs_write(0xc3, 0x05);
+	nt_dcs_write(0xc4, 0x00);
+	nt_dcs_write(0xc5, 0x02);
+	nt_dcs_write(0xc6, 0x22);
+	nt_dcs_write(0xc7, 0x03);
+	nt_dcs_write(0xc8, 0x07, 0x20);
+	nt_dcs_write(0xc9, 0x03, 0x20);
+	nt_dcs_write(0xca, 0x01, 0x60);
+	nt_dcs_write(0xcb, 0x01, 0x60);
+	nt_dcs_write(0xcc, 0x00, 0x00, 0x02);
+	nt_dcs_write(0xcd, 0x00, 0x00, 0x02);
+	nt_dcs_write(0xce, 0x00, 0x00, 0x02);
+	nt_dcs_write(0xcf, 0x00, 0x00, 0x02);
+	nt_dcs_write(0xd1, 0x00, 0x05, 0x01, 0x07, 0x10);
+	nt_dcs_write(0xd2, 0x10, 0x05, 0x05, 0x03, 0x10);
+	nt_dcs_write(0xd3, 0x20, 0x00, 0x43, 0x07, 0x10);
+	nt_dcs_write(0xd4, 0x30, 0x00, 0x43, 0x07, 0x10);
+	nt_dcs_write(0xd0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00);
+	nt_dcs_write(0xd5, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		     0x00, 0x00, 0x00, 0x00);
+	nt_dcs_write(0xd6, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		     0x00, 0x00, 0x00, 0x00);
+	nt_dcs_write(0xd7, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		     0x00, 0x00, 0x00, 0x00);
+	nt_dcs_write(0xd8, 0x00, 0x00, 0x00, 0x00, 0x00);
+	nt_dcs_write(0xe5, 0x06);
+	nt_dcs_write(0xe6, 0x06);
+	nt_dcs_write(0xe7, 0x00);
+	nt_dcs_write(0xe8, 0x06);
+	nt_dcs_write(0xe9, 0x06);
+	nt_dcs_write(0xea, 0x06);
+	nt_dcs_write(0xeb, 0x00);
+	nt_dcs_write(0xec, 0x00);
+	nt_dcs_write(0xed, 0x30);
+	nt_dcs_write(0xf0, 0x55, 0xaa, 0x52, 0x08, 0x06);
+	nt_dcs_write(0xb0, 0x31, 0x31);
+	nt_dcs_write(0xb1, 0x31, 0x31);
+	nt_dcs_write(0xb2, 0x2d, 0x2e);
+	nt_dcs_write(0xb3, 0x31, 0x34);
+	nt_dcs_write(0xb4, 0x29, 0x2a);
+	nt_dcs_write(0xb5, 0x12, 0x10);
+	nt_dcs_write(0xb6, 0x18, 0x16);
+	nt_dcs_write(0xb7, 0x00, 0x02);
+	nt_dcs_write(0xb8, 0x08, 0x31);
+	nt_dcs_write(0xb9, 0x31, 0x31);
+	nt_dcs_write(0xba, 0x31, 0x31);
+	nt_dcs_write(0xbb, 0x31, 0x08);
+	nt_dcs_write(0xbc, 0x03, 0x01);
+	nt_dcs_write(0xbd, 0x17, 0x19);
+	nt_dcs_write(0xbe, 0x11, 0x13);
+	nt_dcs_write(0xbf, 0x2a, 0x29);
+	nt_dcs_write(0xc0, 0x34, 0x31);
+	nt_dcs_write(0xc1, 0x2e, 0x2d);
+	nt_dcs_write(0xc2, 0x31, 0x31);
+	nt_dcs_write(0xc3, 0x31, 0x31);
+	nt_dcs_write(0xc4, 0x31, 0x31);
+	nt_dcs_write(0xc5, 0x31, 0x31);
+	nt_dcs_write(0xc6, 0x2e, 0x2d);
+	nt_dcs_write(0xc7, 0x31, 0x34);
+	nt_dcs_write(0xc8, 0x29, 0x2a);
+	nt_dcs_write(0xc9, 0x17, 0x19);
+	nt_dcs_write(0xca, 0x11, 0x13);
+	nt_dcs_write(0xcb, 0x03, 0x01);
+	nt_dcs_write(0xcc, 0x08, 0x31);
+	nt_dcs_write(0xcd, 0x31, 0x31);
+	nt_dcs_write(0xce, 0x31, 0x31);
+	nt_dcs_write(0xcf, 0x31, 0x08);
+	nt_dcs_write(0xd0, 0x00, 0x02);
+	nt_dcs_write(0xd1, 0x12, 0x10);
+	nt_dcs_write(0xd2, 0x18, 0x16);
+	nt_dcs_write(0xd3, 0x2a, 0x29);
+	nt_dcs_write(0xd4, 0x34, 0x31);
+	nt_dcs_write(0xd5, 0x2d, 0x2e);
+	nt_dcs_write(0xd6, 0x31, 0x31);
+	nt_dcs_write(0xd7, 0x31, 0x31);
+	nt_dcs_write(0xe5, 0x31, 0x31);
+	nt_dcs_write(0xe6, 0x31, 0x31);
+	nt_dcs_write(0xd8, 0x00, 0x00, 0x00, 0x00, 0x00);
+	nt_dcs_write(0xd9, 0x00, 0x00, 0x00, 0x00, 0x00);
+	nt_dcs_write(0xe7, 0x00);
+	nt_dcs_write(0x6f, 0x02);
+	nt_dcs_write(0xf7, 0x47);
+	nt_dcs_write(0x6f, 0x0a);
+	nt_dcs_write(0xf7, 0x02);
+	nt_dcs_write(0x6f, 0x17);
+	nt_dcs_write(0xf4, 0x60);
+	nt_dcs_write(0x6f, 0x01);
+	nt_dcs_write(0xf9, 0x46);
+	nt_dcs_write(0x6f, 0x11);
+	nt_dcs_write(0xf3, 0x01);
+	nt_dcs_write(0x35, 0x00);
+	nt_dcs_write(0xf0, 0x55, 0xaa, 0x52, 0x08, 0x00);
+	nt_dcs_write(0xd9, 0x02, 0x03, 0x00);
+	nt_dcs_write(0xf0, 0x55, 0xaa, 0x52, 0x00, 0x00);
+	nt_dcs_write(0xf0, 0x55, 0xaa, 0x52, 0x08, 0x00);
+	nt_dcs_write(0xb1, 0x6c, 0x21);
+	nt_dcs_write(0xf0, 0x55, 0xaa, 0x52, 0x00, 0x00);
+	nt_dcs_write(0x35, 0x00);
+	nt_gen_write(0x11, 0x00);
+	msleep(120);
+	nt_gen_write(0x29, 0x00);
+	usleep_range(1000, 1500);
+	nt_dcs_write(0x53, 0x24);
+}
+
+static void nt35521_panel_off(struct nt35521_panel *nt)
+{
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(nt->dev);
+	struct device *dev = nt->dev;
+
+	/* Transmit data in high speed mode */
+	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+	nt_dcs_write(0x28, 0x00);
+	msleep(50);
+	nt_dcs_write(0x10, 0x00);
+	msleep(150);
+}
+
+static int nt35521_prepare(struct drm_panel *panel)
+{
+	struct nt35521_panel *nt = panel_to_nt35521(panel);
+
+	if (nt->prepared)
+		return 0;
+
+	gpiod_set_value_cansleep(nt->pwrp5_gpio, 1);
+	usleep_range(1000, 1500);
+	gpiod_set_value_cansleep(nt->pwrn5_gpio, 1);
+	usleep_range(10000, 15000);
+	gpiod_set_value_cansleep(nt->rst_gpio, 0);
+	msleep(150);
+
+	nt35521_panel_on(nt);
+
+	nt->prepared = true;
+
+	return 0;
+}
+
+static int nt35521_unprepare(struct drm_panel *panel)
+{
+	struct nt35521_panel *nt = panel_to_nt35521(panel);
+
+	if (!nt->prepared)
+		return 0;
+
+	nt35521_panel_off(nt);
+
+	gpiod_set_value_cansleep(nt->rst_gpio, 1);
+
+	nt->prepared = false;
+
+	return 0;
+}
+
+static int nt35521_enable(struct drm_panel *panel)
+{
+	struct nt35521_panel *nt = panel_to_nt35521(panel);
+
+	if (nt->enabled)
+		return 0;
+
+	gpiod_set_value_cansleep(nt->en_gpio, 1);
+
+	nt->enabled = true;
+
+	return 0;
+}
+
+static int nt35521_disable(struct drm_panel *panel)
+{
+	struct nt35521_panel *nt = panel_to_nt35521(panel);
+
+	if (!nt->enabled)
+		return 0;
+
+	gpiod_set_value_cansleep(nt->en_gpio, 0);
+
+	nt->enabled = false;
+
+	return 0;
+}
+
+static const struct drm_display_mode nt35521_modes = {
+	.clock = 133306,
+	.hdisplay = 720,
+	.hsync_start = 720 + 632,
+	.hsync_end = 720 + 632 + 40,
+	.htotal = 720 + 632 + 40 + 295,
+	.vdisplay = 1280,
+	.vsync_start = 1280 + 18,
+	.vsync_end = 1280 + 18 + 1,
+	.vtotal = 1280 + 18 + 1 + 18,
+};
+
+static int nt35521_get_modes(struct drm_panel *panel,
+			      struct drm_connector *connector)
+{
+	struct nt35521_panel *nt = panel_to_nt35521(panel);
+	struct drm_display_mode *mode;
+
+	mode = drm_mode_duplicate(connector->dev, &nt35521_modes);
+	if (!mode) {
+		DRM_DEV_ERROR(nt->dev, "failed to add display mode\n");
+		return -ENOMEM;
+	}
+
+	drm_mode_set_name(mode);
+	drm_mode_probed_add(connector, mode);
+
+	connector->display_info.width_mm = 65;
+	connector->display_info.height_mm = 116;
+
+	return 1;
+}
+
+static const struct drm_panel_funcs nt35521_drm_funcs = {
+	.prepare = nt35521_prepare,
+	.unprepare = nt35521_unprepare,
+	.enable = nt35521_enable,
+	.disable = nt35521_disable,
+	.get_modes = nt35521_get_modes,
+};
+
+static int nt35521_backlight_update_status(struct backlight_device *bd)
+{
+	struct nt35521_panel *nt = bl_get_data(bd);
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(nt->dev);
+	u8 brightness = bd->props.brightness;
+	int ret;
+
+	ret = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
+				 &brightness,
+				 sizeof(brightness));
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static const struct backlight_ops nt35521_backlight_ops = {
+	.update_status = nt35521_backlight_update_status,
+};
+
+static int nt35521_probe(struct mipi_dsi_device *dsi)
+{
+	struct backlight_properties props;
+	struct device *dev = &dsi->dev;
+	struct nt35521_panel *nt;
+	int ret;
+
+	nt = devm_kzalloc(dev, sizeof(*nt), GFP_KERNEL);
+	if (!nt)
+		return -ENOMEM;
+
+	nt->rst_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(nt->rst_gpio)) {
+		ret = PTR_ERR(nt->rst_gpio);
+		DRM_DEV_ERROR(dev, "failed to get reset GPIO: %d\n", ret);
+		return ret;
+	}
+
+	nt->pwrp5_gpio = devm_gpiod_get(dev, "pwr-positive5", GPIOD_OUT_LOW);
+	if (IS_ERR(nt->pwrp5_gpio)) {
+		ret = PTR_ERR(nt->pwrp5_gpio);
+		DRM_DEV_ERROR(dev, "failed to get positive5 GPIO: %d\n", ret);
+		return ret;
+	}
+
+	nt->pwrn5_gpio = devm_gpiod_get(dev, "pwr-negative5", GPIOD_OUT_LOW);
+	if (IS_ERR(nt->pwrn5_gpio)) {
+		ret = PTR_ERR(nt->pwrn5_gpio);
+		DRM_DEV_ERROR(dev, "failed to get negative5 GPIO: %d\n", ret);
+		return ret;
+	}
+
+	nt->en_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
+	if (IS_ERR(nt->en_gpio)) {
+		ret = PTR_ERR(nt->en_gpio);
+		DRM_DEV_ERROR(dev, "failed to get enable GPIO: %d\n", ret);
+		return ret;
+	}
+
+	nt->dev = dev;
+
+	drm_panel_init(&nt->panel, dev, &nt35521_drm_funcs,
+		       DRM_MODE_CONNECTOR_DSI);
+
+	props.max_brightness = 255;
+	props.brightness = 240;
+	props.type = BACKLIGHT_RAW;
+
+	nt->panel.backlight = devm_backlight_device_register(dev, dev_name(dev),
+						dev, nt, &nt35521_backlight_ops,
+						&props);
+	if (IS_ERR(nt->panel.backlight)) {
+		ret = PTR_ERR(nt->panel.backlight);
+		DRM_DEV_ERROR(dev, "failed to register backlight: %d\n", ret);
+		return ret;
+	}
+
+	drm_panel_add(&nt->panel);
+
+	dsi->lanes = 4;
+	dsi->format = MIPI_DSI_FMT_RGB888;
+	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
+			  MIPI_DSI_CLOCK_NON_CONTINUOUS;
+
+	ret = mipi_dsi_attach(dsi);
+	if (ret < 0) {
+		DRM_DEV_ERROR(dev, "failed to attach DSI device: %d\n", ret);
+		drm_panel_remove(&nt->panel);
+		return ret;
+	}
+
+	mipi_dsi_set_drvdata(dsi, nt);
+
+	return 0;
+}
+
+static int nt35521_remove(struct mipi_dsi_device *dsi)
+{
+	struct nt35521_panel *nt = mipi_dsi_get_drvdata(dsi);
+
+	mipi_dsi_detach(dsi);
+	drm_panel_remove(&nt->panel);
+
+	return 0;
+}
+
+static const struct of_device_id truly_nt35521_of_match[] = {
+	{ .compatible = "truly,nt35521" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, truly_nt35521_of_match);
+
+static struct mipi_dsi_driver truly_nt35521_driver = {
+	.driver = {
+		.name = "panel-truly-nt35521",
+		.of_match_table = truly_nt35521_of_match,
+	},
+	.probe  = nt35521_probe,
+	.remove = nt35521_remove,
+};
+module_mipi_dsi_driver(truly_nt35521_driver);
+
+MODULE_DESCRIPTION("Truly NT35521 DSI panel driver");
+MODULE_LICENSE("GPL v2");
-- 
2.17.1