[PATCH v3 2/2] drm/panel: Add panel driver for ChipWealth CH13726A based panels

Aaron Kling
2026-03-23T17:08:33Z

From: Teguh Sobirin <teguh@sobir.in>

This is used by the AYN Thor for the bottom panel.

Signed-off-by: Teguh Sobirin <teguh@sobir.in>
Co-developed-by: Aaron Kling <webgeek1234@gmail.com>
Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
---
drivers/gpu/drm/panel/Kconfig | 11 +
drivers/gpu/drm/panel/Makefile | 1 +
drivers/gpu/drm/panel/panel-chipwealth-ch13726a.c | 339 ++++++++++++++++++++++
3 files changed, 351 insertions(+)

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index a99f2e2a49fe66a09c6f2d503f570b05a5e228b1..e953b61a819082866b93d0a453ee750a76d70c18 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -105,6 +105,17 @@ config DRM_PANEL_BOE_TV101WUM_LL2
Say Y here if you want to support for BOE TV101WUM-LL2
WUXGA PANEL DSI Video Mode panel

+config DRM_PANEL_CHIPWEALTH_CH13726A
+ tristate "CHIPWEALTH CH13726A-based DSI panel"
+ depends on OF
+ depends on DRM_MIPI_DSI
+ depends on BACKLIGHT_CLASS_DEVICE
+ select DRM_DISPLAY_DP_HELPER
+ select DRM_DISPLAY_HELPER
+ help
+ Say Y here if you want to enable support for ChipWealth
+ CH13726A-based display panels.
+
config DRM_PANEL_EBBG_FT8719
tristate "EBBG FT8719 panel driver"
depends on OF
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 3336a2c0cd86419b6a22f74dcde6df966a311da9..85da2eb5a5c664d4302837f52e7e10ec11da8966 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_DRM_PANEL_BOE_TD4320) += panel-boe-td4320.o
obj-$(CONFIG_DRM_PANEL_BOE_TH101MB31UIG002_28A) += panel-boe-th101mb31ig002-28a.o
obj-$(CONFIG_DRM_PANEL_BOE_TV101WUM_LL2) += panel-boe-tv101wum-ll2.o
obj-$(CONFIG_DRM_PANEL_BOE_TV101WUM_NL6) += panel-boe-tv101wum-nl6.o
+obj-$(CONFIG_DRM_PANEL_CHIPWEALTH_CH13726A) += panel-chipwealth-ch13726a.o
obj-$(CONFIG_DRM_PANEL_DSI_CM) += panel-dsi-cm.o
obj-$(CONFIG_DRM_PANEL_LVDS) += panel-lvds.o
obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
diff --git a/drivers/gpu/drm/panel/panel-chipwealth-ch13726a.c b/drivers/gpu/drm/panel/panel-chipwealth-ch13726a.c
new file mode 100644
index 0000000000000000000000000000000000000000..48a5e20e07c48748e073f8bb9147036c18c51caa
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-chipwealth-ch13726a.c
@@ -0,0 +1,339 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ChipWealth CH13726A MIPI-DSI panel driver
+ * Copyright (c) 2024, Teguh Sobirin <teguh@sobir.in>.
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regulator/consumer.h>
+
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+
+#include <video/mipi_display.h>
+
+struct ch13726a_panel {
+ struct drm_panel panel;
+ struct mipi_dsi_device *dsi;
+ struct regulator_bulk_data supplies[4];
+ struct gpio_desc *reset_gpio;
+ struct ch13726a_desc *desc;
+ enum drm_panel_orientation orientation;
+ bool prepared;
+};
+
+struct ch13726a_desc {
+ unsigned int width_mm;
+ unsigned int height_mm;
+ unsigned int bpc;
+
+ const struct drm_display_mode *modes;
+ unsigned int num_modes;
+};
+
+static inline struct ch13726a_panel *to_ch13726a_panel(struct drm_panel *panel)
+{
+ return container_of(panel, struct ch13726a_panel, panel);
+}
+
+static void ch13726a_reset(struct ch13726a_panel *ctx)
+{
+ gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+ usleep_range(10000, 11000);
+ gpiod_set_value_cansleep(ctx->reset_gpio, 0);
+ usleep_range(10000, 11000);
+ gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+ usleep_range(10000, 11000);
+}
+
+static int ch13726a_on(struct ch13726a_panel *ctx)
+{
+ struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
+
+ ctx->dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+ mipi_dsi_generic_write_seq_multi(&dsi_ctx, 0xf0, 0x50);
+ mipi_dsi_generic_write_seq_multi(&dsi_ctx, 0xb9, 0x00);
+
+ mipi_dsi_dcs_exit_sleep_mode_multi(&dsi_ctx);
+
+ mipi_dsi_dcs_set_display_on_multi(&dsi_ctx);
+
+ return dsi_ctx.accum_err;
+}
+
+static int ch13726a_disable(struct drm_panel *panel)
+{
+ struct ch13726a_panel *ctx = to_ch13726a_panel(panel);
+ struct mipi_dsi_multi_context dsi_ctx = { .dsi = ctx->dsi };
+
+ ctx->dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+ mipi_dsi_dcs_set_display_off_multi(&dsi_ctx);
+ mipi_dsi_msleep(&dsi_ctx, 50);
+ mipi_dsi_dcs_enter_sleep_mode_multi(&dsi_ctx);
+
+ return dsi_ctx.accum_err;
+}
+
+static int ch13726a_prepare(struct drm_panel *panel)
+{
+ struct ch13726a_panel *ctx = to_ch13726a_panel(panel);
+ struct device *dev = &ctx->dsi->dev;
+ int ret;
+
+ if (ctx->prepared)
+ return 0;
+
+ ret = regulator_bulk_enable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
+ if (ret < 0) {
+ dev_err(dev, "Failed to enable regulators: %d\n", ret);
+ return ret;
+ }
+
+ ch13726a_reset(ctx);
+
+ ret = ch13726a_on(ctx);
+ if (ret < 0) {
+ dev_err(dev, "Failed to initialize panel: %d\n", ret);
+ gpiod_set_value_cansleep(ctx->reset_gpio, 0);
+ regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
+ return ret;
+ }
+
+ msleep(28);
+
+ ctx->prepared = true;
+
+ return 0;
+}
+
+static int ch13726a_unprepare(struct drm_panel *panel)
+{
+ struct ch13726a_panel *ctx = to_ch13726a_panel(panel);
+
+ if (!ctx->prepared)
+ return 0;
+
+ gpiod_set_value_cansleep(ctx->reset_gpio, 0);
+ regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
+
+ ctx->prepared = false;
+ return 0;
+}
+
+static const struct drm_display_mode thor_bottom_modes[] = {
+ {
+ /* 120Hz */
+ .clock = (1080 + 28 + 4 + 36) * (1240 + 16 + 4 + 8) * 120 / 1000,
+ .hdisplay = 1080,
+ .hsync_start = 1080 + 28,
+ .hsync_end = 1080 + 28 + 4,
+ .htotal = 1080 + 28 + 4 + 36,
+ .vdisplay = 1240,
+ .vsync_start = 1240 + 16,
+ .vsync_end = 1240 + 16 + 4,
+ .vtotal = 1240 + 16 + 4 + 8,
+ },
+ {
+ /* 60Hz */
+ .clock = (1080 + 28 + 4 + 36) * (1240 + 16 + 4 + 8) * 60 / 1000,
+ .hdisplay = 1080,
+ .hsync_start = 1080 + 28,
+ .hsync_end = 1080 + 28 + 4,
+ .htotal = 1080 + 28 + 4 + 36,
+ .vdisplay = 1240,
+ .vsync_start = 1240 + 16,
+ .vsync_end = 1240 + 16 + 4,
+ .vtotal = 1240 + 16 + 4 + 8,
+ }
+};
+
+static struct ch13726a_desc thor_bottom_desc = {
+ .modes = thor_bottom_modes,
+ .num_modes = ARRAY_SIZE(thor_bottom_modes),
+ .width_mm = 65,
+ .height_mm = 75,
+ .bpc = 8,
+};
+
+static int ch13726a_get_modes(struct drm_panel *panel,
+ struct drm_connector *connector)
+{
+ struct ch13726a_panel *ctx = to_ch13726a_panel(panel);
+
+ for (uint8_t i = 0; i < ctx->desc->num_modes; i++) {
+ const struct drm_display_mode *m = &ctx->desc->modes[i];
+ struct drm_display_mode *mode;
+
+ mode = drm_mode_duplicate(connector->dev, m);
+ if (!mode) {
+ dev_err(&ctx->dsi->dev, "failed to add mode %ux%u@%u\n",
+ m->hdisplay, m->vdisplay, drm_mode_vrefresh(m));
+ return -ENOMEM;
+ }
+
+ mode->type = DRM_MODE_TYPE_DRIVER;
+ if (i == 0)
+ mode->type |= DRM_MODE_TYPE_PREFERRED;
+
+ drm_mode_set_name(mode);
+ drm_mode_probed_add(connector, mode);
+ }
+
+ connector->display_info.width_mm = ctx->desc->width_mm;
+ connector->display_info.height_mm = ctx->desc->height_mm;
+ connector->display_info.bpc = ctx->desc->bpc;
+
+ return ctx->desc->num_modes;
+}
+
+static enum drm_panel_orientation ch13726a_get_orientation(struct drm_panel *panel)
+{
+ struct ch13726a_panel *ctx = to_ch13726a_panel(panel);
+
+ return ctx->orientation;
+}
+
+static const struct drm_panel_funcs ch13726a_panel_funcs = {
+ .prepare = ch13726a_prepare,
+ .unprepare = ch13726a_unprepare,
+ .disable = ch13726a_disable,
+ .get_modes = ch13726a_get_modes,
+ .get_orientation = ch13726a_get_orientation,
+};
+
+static int ch13726a_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(dsi, brightness);
+ if (ret < 0)
+ return ret;
+
+ dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+ return 0;
+}
+
+static const struct backlight_ops ch13726a_bl_ops = {
+ .update_status = ch13726a_bl_update_status,
+};
+
+static struct backlight_device *
+ch13726a_create_backlight(struct mipi_dsi_device *dsi)
+{
+ struct device *dev = &dsi->dev;
+ const struct backlight_properties props = {
+ .type = BACKLIGHT_RAW,
+ .brightness = 255,
+ .max_brightness = 255,
+ };
+
+ return devm_backlight_device_register(dev, dev_name(dev), dev, dsi,
+ &ch13726a_bl_ops, &props);
+}
+
+static int ch13726a_probe(struct mipi_dsi_device *dsi)
+{
+ struct device *dev = &dsi->dev;
+ struct ch13726a_panel *ctx;
+ int ret;
+
+ ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ ctx->desc = (struct ch13726a_desc *)of_device_get_match_data(dev);
+ if (!ctx->desc)
+ return -ENODEV;
+
+ ctx->supplies[0].supply = "vdd1v2";
+ ctx->supplies[1].supply = "vddio";
+ ctx->supplies[2].supply = "vdd";
+ ctx->supplies[3].supply = "avdd";
+
+ ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ctx->supplies),
+ ctx->supplies);
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "Failed to get regulators\n");
+
+ ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+ if (IS_ERR(ctx->reset_gpio))
+ return dev_err_probe(dev, PTR_ERR(ctx->reset_gpio),
+ "Failed to get reset-gpios\n");
+
+ ret = of_drm_get_panel_orientation(dev->of_node, &ctx->orientation);
+ if (ret < 0) {
+ dev_err(dev, "%pOF: failed to get orientation %d\n", dev->of_node, ret);
+ return ret;
+ }
+
+ ctx->dsi = dsi;
+ mipi_dsi_set_drvdata(dsi, ctx);
+
+ dsi->lanes = 4;
+ dsi->format = MIPI_DSI_FMT_RGB888;
+ dsi->mode_flags = MIPI_DSI_MODE_VIDEO |
+ MIPI_DSI_CLOCK_NON_CONTINUOUS;
+
+ drm_panel_init(&ctx->panel, dev, &ch13726a_panel_funcs,
+ DRM_MODE_CONNECTOR_DSI);
+ ctx->panel.prepare_prev_first = true;
+
+ ctx->panel.backlight = ch13726a_create_backlight(dsi);
+ if (IS_ERR(ctx->panel.backlight))
+ return dev_err_probe(dev, PTR_ERR(ctx->panel.backlight),
+ "Failed to create backlight\n");
+
+ drm_panel_add(&ctx->panel);
+
+ ret = mipi_dsi_attach(dsi);
+ if (ret < 0) {
+ dev_err(dev, "Failed to attach to DSI host: %d\n", ret);
+ drm_panel_remove(&ctx->panel);
+ return ret;
+ }
+
+ return 0;
+}
+
+static void ch13726a_remove(struct mipi_dsi_device *dsi)
+{
+ struct ch13726a_panel *ctx = mipi_dsi_get_drvdata(dsi);
+ int ret;
+
+ ret = mipi_dsi_detach(dsi);
+ if (ret < 0)
+ dev_err(&dsi->dev, "Failed to detach from DSI host: %d\n", ret);
+
+ drm_panel_remove(&ctx->panel);
+}
+
+static const struct of_device_id ch13726a_of_match[] = {
+ { .compatible = "ayntec,thor-panel-bottom", .data = &thor_bottom_desc },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ch13726a_of_match);
+
+static struct mipi_dsi_driver ch13726a_driver = {
+ .probe = ch13726a_probe,
+ .remove = ch13726a_remove,
+ .driver = {
+ .name = "panel-ch13726a-amoled",
+ .of_match_table = ch13726a_of_match,
+ },
+};
+module_mipi_dsi_driver(ch13726a_driver);
+
+MODULE_DESCRIPTION("DRM driver for CH13726A DSI panels");
+MODULE_LICENSE("GPL");

--
2.53.0