[PATCH 2/2] drm/panel: Add Novatek NT39016 panel support

Paul Cercueil
2019-06-02T16:49:03Z

Add support for display panels built around the Novatek NT39016 display
controller, as found on e.g. the King Display KD035G6-54NT 24-bit
320x240 3.5" LCD panel which equips the GCW Zero open-source handheld
gaming console.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
drivers/gpu/drm/panel/Kconfig | 9 +
drivers/gpu/drm/panel/Makefile | 1 +
drivers/gpu/drm/panel/panel-novatek-nt39016.c | 368 ++++++++++++++++++
3 files changed, 378 insertions(+)
create mode 100644 drivers/gpu/drm/panel/panel-novatek-nt39016.c

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index e281fc544742..10b411b507cc 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -111,6 +111,15 @@ config DRM_PANEL_LG_LG4573
Say Y here if you want to enable support for LG4573 RGB panel.
To compile this driver as a module, choose M here.

+config DRM_PANEL_NOVATEK_NT39016
+ tristate "Novatek NT39016 RGB/SPI panel"
+ depends on OF && SPI
+ depends on BACKLIGHT_CLASS_DEVICE
+ select REGMAP_SPI
+ help
+ Say Y here if you want to enable support for the panels built
+ around the Novatek NT39016 display controller.
+
config DRM_PANEL_OLIMEX_LCD_OLINUXINO
tristate "Olimex LCD-OLinuXino panel"
depends on OF
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 78e3dc376bdd..c2c47fc99343 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_DRM_PANEL_INNOLUX_P079ZCA) += panel-innolux-p079zca.o
obj-$(CONFIG_DRM_PANEL_JDI_LT070ME05000) += panel-jdi-lt070me05000.o
obj-$(CONFIG_DRM_PANEL_KINGDISPLAY_KD097D04) += panel-kingdisplay-kd097d04.o
obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o
+obj-$(CONFIG_DRM_PANEL_NOVATEK_NT39016) += panel-novatek-nt39016.o
obj-$(CONFIG_DRM_PANEL_OLIMEX_LCD_OLINUXINO) += panel-olimex-lcd-olinuxino.o
obj-$(CONFIG_DRM_PANEL_ORISETECH_OTM8009A) += panel-orisetech-otm8009a.o
obj-$(CONFIG_DRM_PANEL_PANASONIC_VVX10F034N00) += panel-panasonic-vvx10f034n00.o
diff --git a/drivers/gpu/drm/panel/panel-novatek-nt39016.c b/drivers/gpu/drm/panel/panel-novatek-nt39016.c
new file mode 100644
index 000000000000..2738d145d452
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-novatek-nt39016.c
@@ -0,0 +1,368 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Novatek NT39016 TFT LCD panel driver
+ *
+ * Copyright (C) 2017, Maarten ter Huurne <maarten@treewalker.org>
+ * Copyright (C) 2019, Paul Cercueil <paul@crapouillou.net>
+ */
+
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+#include <uapi/linux/media-bus-format.h>
+
+
+enum nt39016_regs {
+ NT39016_REG_SYSTEM,
+ NT39016_REG_TIMING,
+ NT39016_REG_OP,
+ NT39016_REG_DATA_IN,
+ NT39016_REG_SRC_TIMING_DELAY,
+ NT39016_REG_GATE_TIMING_DELAY,
+ NT39016_REG_RESERVED,
+ NT39016_REG_INITIAL_FUNC,
+ NT39016_REG_CONTRAST,
+ NT39016_REG_BRIGHTNESS,
+ NT39016_REG_HUE_SATURATION,
+ NT39016_REG_RB_SUBCONTRAST,
+ NT39016_REG_R_SUBBRIGHTNESS,
+ NT39016_REG_B_SUBBRIGHTNESS,
+ NT39016_REG_VCOMDC,
+ NT39016_REG_VCOMAC,
+ NT39016_REG_VGAM2,
+ NT39016_REG_VGAM34,
+ NT39016_REG_VGAM56,
+ NT39016_REG_VCOMDC_TRIM = 0x1e,
+ NT39016_REG_DISPLAY_MODE = 0x20,
+};
+
+struct nt39016_panel_info {
+ struct drm_display_mode display_mode;
+ u16 width_mm, height_mm;
+ u32 bus_format, bus_flags;
+};
+
+struct nt39016 {
+ struct drm_panel drm_panel;
+ struct device *dev;
+ struct regmap *map;
+ struct regulator *supply;
+ const struct nt39016_panel_info *panel_info;
+
+ struct gpio_desc *reset_gpio;
+
+ struct backlight_device *backlight;
+};
+
+static inline struct nt39016 *to_nt39016(struct drm_panel *panel)
+{
+ return container_of(panel, struct nt39016, drm_panel);
+}
+
+#define RV(REG, VAL) { .reg = (REG), .def = (VAL), .delay_us = 2 }
+static const struct reg_sequence nt39016_panel_regs[] = {
+ RV(NT39016_REG_SYSTEM, 0x04),
+ RV(NT39016_REG_TIMING, 0x00),
+ RV(NT39016_REG_OP, 0x03),
+ RV(NT39016_REG_DATA_IN, 0xCC),
+ RV(NT39016_REG_SRC_TIMING_DELAY, 0x46),
+ RV(NT39016_REG_GATE_TIMING_DELAY, 0x05),
+ RV(NT39016_REG_RESERVED, 0x00),
+ RV(NT39016_REG_INITIAL_FUNC, 0x00),
+ RV(NT39016_REG_CONTRAST, 0x08),
+ RV(NT39016_REG_BRIGHTNESS, 0x40),
+ RV(NT39016_REG_HUE_SATURATION, 0x88),
+ RV(NT39016_REG_RB_SUBCONTRAST, 0x88),
+ RV(NT39016_REG_R_SUBBRIGHTNESS, 0x20),
+ RV(NT39016_REG_B_SUBBRIGHTNESS, 0x20),
+ RV(NT39016_REG_VCOMDC, 0x67),
+ RV(NT39016_REG_VCOMAC, 0xA4),
+ RV(NT39016_REG_VGAM2, 0x04),
+ RV(NT39016_REG_VGAM34, 0x24),
+ RV(NT39016_REG_VGAM56, 0x24),
+ RV(NT39016_REG_DISPLAY_MODE, 0x00),
+};
+#undef RV
+
+static const struct regmap_range nt39016_regmap_no_ranges[] = {
+ regmap_reg_range(0x13, 0x1D),
+ regmap_reg_range(0x1F, 0x1F),
+};
+
+static const struct regmap_access_table nt39016_regmap_access_table = {
+ .no_ranges = nt39016_regmap_no_ranges,
+ .n_no_ranges = ARRAY_SIZE(nt39016_regmap_no_ranges),
+};
+
+static const struct regmap_config nt39016_regmap_config = {
+ .reg_bits = 6,
+ .pad_bits = 2,
+ .val_bits = 8,
+
+ .max_register = NT39016_REG_DISPLAY_MODE,
+ .wr_table = &nt39016_regmap_access_table,
+ .write_flag_mask = 0x02,
+
+ .cache_type = REGCACHE_FLAT,
+};
+
+static int nt39016_prepare(struct drm_panel *drm_panel)
+{
+ struct nt39016 *panel = to_nt39016(drm_panel);
+ int err;
+
+ err = regulator_enable(panel->supply);
+ if (err) {
+ dev_err(panel->dev, "Failed to enable power supply: %i", err);
+ return err;
+ }
+
+ /*
+ * Reset the NT39016.
+ * The documentation says the reset pulse should be at least 40 us to
+ * pass the glitch filter, but when testing I see some resets fail and
+ * some succeed when using a 70 us delay, so we use 100 us instead.
+ */
+ gpiod_set_value_cansleep(panel->reset_gpio, 1);
+ usleep_range(100, 1000);
+ gpiod_set_value_cansleep(panel->reset_gpio, 0);
+ udelay(2);
+
+ /* Init all registers. */
+ err = regmap_multi_reg_write(panel->map, nt39016_panel_regs,
+ ARRAY_SIZE(nt39016_panel_regs));
+ if (err) {
+ dev_err(panel->dev, "Failed to init registers: %i", err);
+ goto err_disable_regulator;
+ }
+
+ return 0;
+
+err_disable_regulator:
+ regulator_disable(panel->supply);
+ return err;
+}
+
+static int nt39016_unprepare(struct drm_panel *drm_panel)
+{
+ struct nt39016 *panel = to_nt39016(drm_panel);
+
+ gpiod_set_value_cansleep(panel->reset_gpio, 1);
+
+ regulator_disable(panel->supply);
+
+ return 0;
+}
+
+static int nt39016_enable(struct drm_panel *drm_panel)
+{
+ struct nt39016 *panel = to_nt39016(drm_panel);
+ int err;
+
+ err = regmap_write(panel->map, NT39016_REG_SYSTEM, 0x07);
+ if (err) {
+ dev_err(panel->dev, "Unable to enable panel: %i", err);
+ return err;
+ }
+
+ /* Wait for the picture to be ready before enabling backlight */
+ msleep(150);
+
+ if (panel->backlight) {
+ panel->backlight->props.state &= ~BL_CORE_FBBLANK;
+ panel->backlight->props.power = FB_BLANK_UNBLANK;
+ backlight_update_status(panel->backlight);
+ }
+
+ return 0;
+}
+
+static int nt39016_disable(struct drm_panel *drm_panel)
+{
+ struct nt39016 *panel = to_nt39016(drm_panel);
+ int err;
+
+ if (panel->backlight) {
+ panel->backlight->props.power = FB_BLANK_POWERDOWN;
+ panel->backlight->props.state |= BL_CORE_FBBLANK;
+ backlight_update_status(panel->backlight);
+ }
+
+ err = regmap_write(panel->map, NT39016_REG_SYSTEM, 0x05);
+ if (err) {
+ dev_err(panel->dev, "Unable to disable panel: %i", err);
+ return err;
+ }
+
+ return 0;
+}
+
+static int nt39016_get_modes(struct drm_panel *drm_panel)
+{
+ struct nt39016 *panel = to_nt39016(drm_panel);
+ const struct nt39016_panel_info *panel_info = panel->panel_info;
+ struct drm_connector *connector = drm_panel->connector;
+ struct drm_display_mode *mode;
+
+ mode = drm_mode_duplicate(drm_panel->drm, &panel_info->display_mode);
+ if (!mode)
+ return -ENOMEM;
+
+ drm_mode_set_name(mode);
+
+ mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
+ drm_mode_probed_add(connector, mode);
+
+ connector->display_info.bpc = 8;
+ connector->display_info.width_mm = panel_info->width_mm;
+ connector->display_info.height_mm = panel_info->height_mm;
+
+ drm_display_info_set_bus_formats(&connector->display_info,
+ &panel_info->bus_format, 1);
+ connector->display_info.bus_flags = panel_info->bus_flags;
+
+ return 1;
+}
+
+static const struct drm_panel_funcs nt39016_funcs = {
+ .prepare = nt39016_prepare,
+ .unprepare = nt39016_unprepare,
+ .enable = nt39016_enable,
+ .disable = nt39016_disable,
+ .get_modes = nt39016_get_modes,
+};
+
+static int nt39016_probe(struct spi_device *spi)
+{
+ struct device *dev = &spi->dev;
+ struct nt39016 *panel;
+ int err;
+
+ panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
+ if (!panel)
+ return -ENOMEM;
+
+ panel->dev = dev;
+ spi_set_drvdata(spi, panel);
+
+ panel->panel_info = of_device_get_match_data(dev);
+ if (!panel->panel_info)
+ return -EINVAL;
+
+ panel->supply = devm_regulator_get(dev, "power");
+ if (IS_ERR(panel->supply)) {
+ dev_err(dev, "Failed to get power supply");
+ return PTR_ERR(panel->supply);
+ }
+
+ panel->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+ if (IS_ERR(panel->reset_gpio)) {
+ dev_err(dev, "Failed to get reset GPIO");
+ return PTR_ERR(panel->reset_gpio);
+ }
+
+ spi->bits_per_word = 8;
+ spi->mode = SPI_MODE_3 | SPI_3WIRE;
+ err = spi_setup(spi);
+ if (err) {
+ dev_err(dev, "Failed to setup SPI");
+ return err;
+ }
+
+ panel->map = devm_regmap_init_spi(spi, &nt39016_regmap_config);
+ if (IS_ERR(panel->map)) {
+ dev_err(dev, "Failed to init regmap");
+ return PTR_ERR(panel->map);
+ }
+
+ panel->backlight = devm_of_find_backlight(dev);
+ if (IS_ERR(panel->backlight)) {
+ err = PTR_ERR(panel->backlight);
+ if (err != -EPROBE_DEFER)
+ dev_err(dev, "Failed to get backlight handle");
+ return err;
+ }
+
+ drm_panel_init(&panel->drm_panel);
+ panel->drm_panel.dev = dev;
+ panel->drm_panel.funcs = &nt39016_funcs;
+
+ err = drm_panel_add(&panel->drm_panel);
+ if (err < 0) {
+ dev_err(dev, "Failed to register panel");
+ goto err_free_backlight;
+ }
+
+ return 0;
+
+err_free_backlight:
+ if (panel->backlight)
+ put_device(&panel->backlight->dev);
+
+ return err;
+}
+
+static int nt39016_remove(struct spi_device *spi)
+{
+ struct nt39016 *panel = spi_get_drvdata(spi);
+
+ drm_panel_remove(&panel->drm_panel);
+
+ nt39016_disable(&panel->drm_panel);
+ nt39016_unprepare(&panel->drm_panel);
+
+ if (panel->backlight)
+ put_device(&panel->backlight->dev);
+
+ return 0;
+}
+
+static const struct nt39016_panel_info kd035g6_info = {
+ .display_mode = {
+ .clock = 6000,
+ .hdisplay = 320,
+ .hsync_start = 320 + 10,
+ .hsync_end = 320 + 10 + 50,
+ .htotal = 320 + 10 + 50 + 20,
+ .vdisplay = 240,
+ .vsync_start = 240 + 5,
+ .vsync_end = 240 + 5 + 1,
+ .vtotal = 240 + 5 + 1 + 4,
+ .vrefresh = 60,
+ .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
+ },
+ .width_mm = 71,
+ .height_mm = 53,
+ .bus_format = MEDIA_BUS_FMT_RGB888_1X24,
+ .bus_flags = DRM_BUS_FLAG_PIXDATA_NEGEDGE,
+};
+
+static const struct of_device_id nt39016_of_match[] = {
+ { .compatible = "kingdisplay,kd035g6-54nt", .data = &kd035g6_info },
+ {},
+};
+MODULE_DEVICE_TABLE(of, nt39016_of_match);
+
+static struct spi_driver nt39016_driver = {
+ .driver = {
+ .name = "nt39016",
+ .of_match_table = nt39016_of_match,
+ },
+ .probe = nt39016_probe,
+ .remove = nt39016_remove,
+};
+
+module_spi_driver(nt39016_driver);
+
+MODULE_AUTHOR("Maarten ter Huurne <maarten@treewalker.org>");
+MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
+MODULE_LICENSE("GPL v2");
--
2.21.0.593.g511ec345e18