[PATCH RFC 04/10] drm/panel: novatek-nt36672a: add Tianma FHD+ video mode panel
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From: YİĞİTCAN KAVAKLI via B4 Relay <devnull+kavakliyigitcan.gmail.com@kernel.org>
Date: 2026-09-11 08:51:29
Also in:
b4-sent, dri-devel, linux-arm-msm, linux-devicetree, linux-input, linux-leds, lkml
Subsystem:
drm driver for novatek nt36672a panels, drm drivers, drm drivers and misc gpu patches, drm panel drivers, the rest · Maintainers:
Sumit Semwal, David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Neil Armstrong, Linus Torvalds
From: YİĞİTCAN KAVAKLI <redacted> Add support for the 1080x2340 Tianma video mode panel with Novatek NT36672A driver IC found in the Xiaomi Redmi Note 8 (ginkgo / SM6125). Changes: - Add 1080x2340 display mode timings (183.025 MHz pixel clock) - Add verified DCS initialization sequences for pages 0x25, 0x20, 0x24, 0x26, and user command page 0x10 - Add standard DRM panel .enable and .disable callbacks to coordinate display on/off commands with active DSI video stream - Set prepare_prev_first = true for host controller synchronization - Optimize power-on reset sequence to nominal 10ms timings Signed-off-by: YİĞİTCAN KAVAKLI <redacted> --- drivers/gpu/drm/panel/panel-novatek-nt36672a.c | 141 ++++++++++++++++++++----- 1 file changed, 117 insertions(+), 24 deletions(-)
diff --git a/drivers/gpu/drm/panel/panel-novatek-nt36672a.c b/drivers/gpu/drm/panel/panel-novatek-nt36672a.c
index 464d9ce47d87dc857c3a565a63156ac79ddeb30c..b69213790441f204016895a391b58f676762b1aa 100644
--- a/drivers/gpu/drm/panel/panel-novatek-nt36672a.c
+++ b/drivers/gpu/drm/panel/panel-novatek-nt36672a.c@@ -34,7 +34,7 @@ static const char * const nt36672a_regulator_names[] = { "vddneg", }; -static unsigned long const nt36672a_regulator_enable_loads[] = { +static const unsigned long nt36672a_regulator_enable_loads[] = { 62000, 100000, 100000
@@ -92,18 +92,12 @@ static int nt36672a_panel_unprepare(struct drm_panel *panel) if (pinfo->desc->send_deinit_cmds) pinfo->desc->send_deinit_cmds(&dsi_ctx); - /* Reset error to continue with display off even if send_cmds failed */ + /* Reset error to continue power-down even if send_cmds failed */ dsi_ctx.accum_err = 0; - mipi_dsi_dcs_set_display_off_multi(&dsi_ctx); - /* Reset error to continue power-down even if display off failed */ - dsi_ctx.accum_err = 0; - - /* 120ms delay required here as per DCS spec */ - msleep(120); mipi_dsi_dcs_enter_sleep_mode_multi(&dsi_ctx); - /* 0x3C = 60ms delay */ + /* 60ms delay as per DCS spec */ msleep(60); nt36672a_panel_power_off(panel);
@@ -120,15 +114,14 @@ static int nt36672a_panel_power_on(struct nt36672a_panel *pinfo) return ret; /* - * As per downstream kernel, Reset sequence of Tianma FHD panel requires the panel to - * be out of reset for 10ms, followed by being held in reset for 10ms. But for Android - * AOSP, we needed to bump it upto 200ms otherwise we get white screen sometimes. - * FIXME: Try to reduce this 200ms to a lesser value. + * Reset sequence: 10ms out of reset, 10ms held in reset, 10ms out of reset. */ - gpiod_set_value(pinfo->reset_gpio, 1); - msleep(200); - gpiod_set_value(pinfo->reset_gpio, 0); - msleep(200); + gpiod_set_value_cansleep(pinfo->reset_gpio, 0); + usleep_range(10000, 11000); + gpiod_set_value_cansleep(pinfo->reset_gpio, 1); + usleep_range(10000, 11000); + gpiod_set_value_cansleep(pinfo->reset_gpio, 0); + usleep_range(10000, 11000); return 0; }
@@ -146,19 +139,41 @@ static int nt36672a_panel_prepare(struct drm_panel *panel) mipi_dsi_dcs_exit_sleep_mode_multi(&dsi_ctx); - /* 0x46 = 70 ms delay */ - mipi_dsi_msleep(&dsi_ctx, 70); - - mipi_dsi_dcs_set_display_on_multi(&dsi_ctx); + /* 80 ms delay as per DCS spec / downstream timing */ + msleep(80); /* Send rest of the init cmds */ if (pinfo->desc->send_init_cmds_2) pinfo->desc->send_init_cmds_2(&dsi_ctx); - mipi_dsi_msleep(&dsi_ctx, 120); - if (dsi_ctx.accum_err < 0) - gpiod_set_value(pinfo->reset_gpio, 0); + gpiod_set_value_cansleep(pinfo->reset_gpio, 0); + + return dsi_ctx.accum_err; +} + +static int nt36672a_panel_enable(struct drm_panel *panel) +{ + struct nt36672a_panel *pinfo = to_nt36672a_panel(panel); + struct mipi_dsi_multi_context dsi_ctx = { .dsi = pinfo->link }; + + mipi_dsi_dcs_set_display_on_multi(&dsi_ctx); + + /* Frame settling delay */ + msleep(20); + + return dsi_ctx.accum_err; +} + +static int nt36672a_panel_disable(struct drm_panel *panel) +{ + struct nt36672a_panel *pinfo = to_nt36672a_panel(panel); + struct mipi_dsi_multi_context dsi_ctx = { .dsi = pinfo->link }; + + mipi_dsi_dcs_set_display_off_multi(&dsi_ctx); + + /* 120ms delay as per DCS spec */ + msleep(120); return dsi_ctx.accum_err; }
@@ -189,6 +204,8 @@ static int nt36672a_panel_get_modes(struct drm_panel *panel, static const struct drm_panel_funcs panel_funcs = { .unprepare = nt36672a_panel_unprepare, .prepare = nt36672a_panel_prepare, + .enable = nt36672a_panel_enable, + .disable = nt36672a_panel_disable, .get_modes = nt36672a_panel_get_modes, };
@@ -404,6 +421,79 @@ static const struct nt36672a_panel_desc tianma_fhd_video_panel_desc = { .send_deinit_cmds = tianma_fhd_video_send_deinit_cmds, }; +static void tianma_ginkgo_send_init_cmds(struct mipi_dsi_multi_context *dsi_ctx) +{ + /* Page 0x25 init */ + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0x25); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xfb, 0x01); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x18, 0x96); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x05, 0x04); + + /* Page 0x20 init */ + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0x20); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xfb, 0x01); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x78, 0x01); + + /* Page 0x24 init */ + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0x24); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xfb, 0x01); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x82, 0x13); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x84, 0x31); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x88, 0x13); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x8a, 0x31); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x8e, 0xe4); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x8f, 0x01); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x90, 0x80); + + /* Page 0x26 init */ + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0x26); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xfb, 0x01); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xa9, 0x12); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xaa, 0x10); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xae, 0x8a); + + /* Page 0x10 (User command page) */ + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xff, 0x10); +} + +static void tianma_ginkgo_send_post_on_cmds(struct mipi_dsi_multi_context *dsi_ctx) +{ + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0xb0, 0x01); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x35, 0x00); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x68, 0x04, 0x03); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x51, 0xb8); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x53, 0x2c); + mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x55, 0x00); +} + +static const struct drm_display_mode tianma_ginkgo_fhd_video_mode = { + .clock = 183025, + + .hdisplay = 1080, + .hsync_start = 1080 + 90, + .hsync_end = 1080 + 90 + 2, + .htotal = 1080 + 90 + 2 + 120, + + .vdisplay = 2340, + .vsync_start = 2340 + 10, + .vsync_end = 2340 + 10 + 3, + .vtotal = 2340 + 10 + 3 + 8, + + .type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED, +}; + +static const struct nt36672a_panel_desc tianma_ginkgo_fhd_video_panel_desc = { + .display_mode = &tianma_ginkgo_fhd_video_mode, + .panel_name = "tianma-ginkgo-fhd-video", + .width_mm = 67, + .height_mm = 145, + .mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_LPM, + .format = MIPI_DSI_FMT_RGB888, + .lanes = 4, + .send_init_cmds_1 = tianma_ginkgo_send_init_cmds, + .send_init_cmds_2 = tianma_ginkgo_send_post_on_cmds, +}; + static int nt36672a_panel_add(struct nt36672a_panel *pinfo) { struct device *dev = &pinfo->link->dev;
@@ -428,6 +518,8 @@ static int nt36672a_panel_add(struct nt36672a_panel *pinfo) if (ret) return dev_err_probe(dev, ret, "Failed to get backlight\n"); + pinfo->base.prepare_prev_first = true; + drm_panel_add(&pinfo->base); return 0;
@@ -481,6 +573,7 @@ static void nt36672a_panel_remove(struct mipi_dsi_device *dsi) static const struct of_device_id tianma_fhd_video_of_match[] = { { .compatible = "tianma,fhd-video", .data = &tianma_fhd_video_panel_desc }, + { .compatible = "tianma,fhd-video-ginkgo", .data = &tianma_ginkgo_fhd_video_panel_desc }, { }, }; MODULE_DEVICE_TABLE(of, tianma_fhd_video_of_match);
--
2.47.3