| // 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 <linux/delay.h> | 
 | #include <linux/device.h> | 
 | #include <linux/gpio/consumer.h> | 
 | #include <linux/media-bus-format.h> | 
 | #include <linux/module.h> | 
 | #include <linux/of.h> | 
 | #include <linux/regmap.h> | 
 | #include <linux/regulator/consumer.h> | 
 | #include <linux/spi/spi.h> | 
 |  | 
 | #include <drm/drm_modes.h> | 
 | #include <drm/drm_panel.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, | 
 | }; | 
 |  | 
 | #define NT39016_SYSTEM_RESET_N	BIT(0) | 
 | #define NT39016_SYSTEM_STANDBY	BIT(1) | 
 |  | 
 | struct nt39016_panel_info { | 
 | 	const struct drm_display_mode *display_modes; | 
 | 	unsigned int num_modes; | 
 | 	u16 width_mm, height_mm; | 
 | 	u32 bus_format, bus_flags; | 
 | }; | 
 |  | 
 | struct nt39016 { | 
 | 	struct drm_panel drm_panel; | 
 | 	struct regmap *map; | 
 | 	struct regulator *supply; | 
 | 	const struct nt39016_panel_info *panel_info; | 
 |  | 
 | 	struct gpio_desc *reset_gpio; | 
 | }; | 
 |  | 
 | 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, 0x00), | 
 | 	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(drm_panel->dev, "Failed to enable power supply: %d\n", 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(drm_panel->dev, "Failed to init registers: %d\n", 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 ret; | 
 |  | 
 | 	ret = regmap_write(panel->map, NT39016_REG_SYSTEM, | 
 | 			   NT39016_SYSTEM_RESET_N | NT39016_SYSTEM_STANDBY); | 
 | 	if (ret) { | 
 | 		dev_err(drm_panel->dev, "Unable to enable panel: %d\n", ret); | 
 | 		return ret; | 
 | 	} | 
 |  | 
 | 	if (drm_panel->backlight) { | 
 | 		/* Wait for the picture to be ready before enabling backlight */ | 
 | 		msleep(150); | 
 | 	} | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | static int nt39016_disable(struct drm_panel *drm_panel) | 
 | { | 
 | 	struct nt39016 *panel = to_nt39016(drm_panel); | 
 | 	int err; | 
 |  | 
 | 	err = regmap_write(panel->map, NT39016_REG_SYSTEM, | 
 | 			   NT39016_SYSTEM_RESET_N); | 
 | 	if (err) { | 
 | 		dev_err(drm_panel->dev, "Unable to disable panel: %d\n", err); | 
 | 		return err; | 
 | 	} | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | static int nt39016_get_modes(struct drm_panel *drm_panel, | 
 | 			     struct drm_connector *connector) | 
 | { | 
 | 	struct nt39016 *panel = to_nt39016(drm_panel); | 
 | 	const struct nt39016_panel_info *panel_info = panel->panel_info; | 
 | 	struct drm_display_mode *mode; | 
 | 	unsigned int i; | 
 |  | 
 | 	for (i = 0; i < panel_info->num_modes; i++) { | 
 | 		mode = drm_mode_duplicate(connector->dev, | 
 | 					  &panel_info->display_modes[i]); | 
 | 		if (!mode) | 
 | 			return -ENOMEM; | 
 |  | 
 | 		drm_mode_set_name(mode); | 
 |  | 
 | 		mode->type = DRM_MODE_TYPE_DRIVER; | 
 | 		if (panel_info->num_modes == 1) | 
 | 			mode->type |= 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 panel_info->num_modes; | 
 | } | 
 |  | 
 | 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; | 
 |  | 
 | 	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)) | 
 | 		return dev_err_probe(dev, PTR_ERR(panel->supply), | 
 | 				     "Failed to get power supply\n"); | 
 |  | 
 | 	panel->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH); | 
 | 	if (IS_ERR(panel->reset_gpio)) | 
 | 		return dev_err_probe(dev, PTR_ERR(panel->reset_gpio), "Failed to get reset GPIO\n"); | 
 |  | 
 | 	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\n"); | 
 | 		return err; | 
 | 	} | 
 |  | 
 | 	panel->map = devm_regmap_init_spi(spi, &nt39016_regmap_config); | 
 | 	if (IS_ERR(panel->map)) { | 
 | 		dev_err(dev, "Failed to init regmap\n"); | 
 | 		return PTR_ERR(panel->map); | 
 | 	} | 
 |  | 
 | 	drm_panel_init(&panel->drm_panel, dev, &nt39016_funcs, | 
 | 		       DRM_MODE_CONNECTOR_DPI); | 
 |  | 
 | 	err = drm_panel_of_backlight(&panel->drm_panel); | 
 | 	if (err) | 
 | 		return dev_err_probe(dev, err, "Failed to get backlight handle\n"); | 
 |  | 
 | 	drm_panel_add(&panel->drm_panel); | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | static void 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); | 
 | } | 
 |  | 
 | static const struct drm_display_mode kd035g6_display_modes[] = { | 
 | 	{	/* 60 Hz */ | 
 | 		.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, | 
 | 		.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC, | 
 | 	}, | 
 | 	{	/* 50 Hz */ | 
 | 		.clock = 5400, | 
 | 		.hdisplay = 320, | 
 | 		.hsync_start = 320 + 42, | 
 | 		.hsync_end = 320 + 42 + 50, | 
 | 		.htotal = 320 + 42 + 50 + 20, | 
 | 		.vdisplay = 240, | 
 | 		.vsync_start = 240 + 5, | 
 | 		.vsync_end = 240 + 5 + 1, | 
 | 		.vtotal = 240 + 5 + 1 + 4, | 
 | 		.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC, | 
 | 	}, | 
 | }; | 
 |  | 
 | static const struct nt39016_panel_info kd035g6_info = { | 
 | 	.display_modes = kd035g6_display_modes, | 
 | 	.num_modes = ARRAY_SIZE(kd035g6_display_modes), | 
 | 	.width_mm = 71, | 
 | 	.height_mm = 53, | 
 | 	.bus_format = MEDIA_BUS_FMT_RGB888_1X24, | 
 | 	.bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, | 
 | }; | 
 |  | 
 | static const struct of_device_id nt39016_of_match[] = { | 
 | 	{ .compatible = "kingdisplay,kd035g6-54nt", .data = &kd035g6_info }, | 
 | 	{ /* sentinel */ } | 
 | }; | 
 | 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"); |