panel-novatek-nt39016.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Novatek NT39016 TFT LCD panel driver
  4 *
  5 * Copyright (C) 2017, Maarten ter Huurne <maarten@treewalker.org>
  6 * Copyright (C) 2019, Paul Cercueil <paul@crapouillou.net>
  7 */
  8
  9#include <linux/delay.h>
 10#include <linux/device.h>
 11#include <linux/gpio/consumer.h>
 12#include <linux/media-bus-format.h>
 13#include <linux/module.h>
 14#include <linux/of.h>
 15#include <linux/regmap.h>
 16#include <linux/regulator/consumer.h>
 17#include <linux/spi/spi.h>
 18
 19#include <drm/drm_modes.h>
 20#include <drm/drm_panel.h>
 21
 22enum nt39016_regs {
 23	NT39016_REG_SYSTEM,
 24	NT39016_REG_TIMING,
 25	NT39016_REG_OP,
 26	NT39016_REG_DATA_IN,
 27	NT39016_REG_SRC_TIMING_DELAY,
 28	NT39016_REG_GATE_TIMING_DELAY,
 29	NT39016_REG_RESERVED,
 30	NT39016_REG_INITIAL_FUNC,
 31	NT39016_REG_CONTRAST,
 32	NT39016_REG_BRIGHTNESS,
 33	NT39016_REG_HUE_SATURATION,
 34	NT39016_REG_RB_SUBCONTRAST,
 35	NT39016_REG_R_SUBBRIGHTNESS,
 36	NT39016_REG_B_SUBBRIGHTNESS,
 37	NT39016_REG_VCOMDC,
 38	NT39016_REG_VCOMAC,
 39	NT39016_REG_VGAM2,
 40	NT39016_REG_VGAM34,
 41	NT39016_REG_VGAM56,
 42	NT39016_REG_VCOMDC_TRIM = 0x1e,
 43	NT39016_REG_DISPLAY_MODE = 0x20,
 44};
 45
 46#define NT39016_SYSTEM_RESET_N	BIT(0)
 47#define NT39016_SYSTEM_STANDBY	BIT(1)
 48
 49struct nt39016_panel_info {
 50	const struct drm_display_mode *display_modes;
 51	unsigned int num_modes;
 52	u16 width_mm, height_mm;
 53	u32 bus_format, bus_flags;
 54};
 55
 56struct nt39016 {
 57	struct drm_panel drm_panel;
 58	struct regmap *map;
 59	struct regulator *supply;
 60	const struct nt39016_panel_info *panel_info;
 61
 62	struct gpio_desc *reset_gpio;
 63};
 64
 65static inline struct nt39016 *to_nt39016(struct drm_panel *panel)
 66{
 67	return container_of(panel, struct nt39016, drm_panel);
 68}
 69
 70#define RV(REG, VAL) { .reg = (REG), .def = (VAL), .delay_us = 2 }
 71static const struct reg_sequence nt39016_panel_regs[] = {
 72	RV(NT39016_REG_SYSTEM, 0x00),
 73	RV(NT39016_REG_TIMING, 0x00),
 74	RV(NT39016_REG_OP, 0x03),
 75	RV(NT39016_REG_DATA_IN, 0xCC),
 76	RV(NT39016_REG_SRC_TIMING_DELAY, 0x46),
 77	RV(NT39016_REG_GATE_TIMING_DELAY, 0x05),
 78	RV(NT39016_REG_RESERVED, 0x00),
 79	RV(NT39016_REG_INITIAL_FUNC, 0x00),
 80	RV(NT39016_REG_CONTRAST, 0x08),
 81	RV(NT39016_REG_BRIGHTNESS, 0x40),
 82	RV(NT39016_REG_HUE_SATURATION, 0x88),
 83	RV(NT39016_REG_RB_SUBCONTRAST, 0x88),
 84	RV(NT39016_REG_R_SUBBRIGHTNESS, 0x20),
 85	RV(NT39016_REG_B_SUBBRIGHTNESS, 0x20),
 86	RV(NT39016_REG_VCOMDC, 0x67),
 87	RV(NT39016_REG_VCOMAC, 0xA4),
 88	RV(NT39016_REG_VGAM2, 0x04),
 89	RV(NT39016_REG_VGAM34, 0x24),
 90	RV(NT39016_REG_VGAM56, 0x24),
 91	RV(NT39016_REG_DISPLAY_MODE, 0x00),
 92};
 93
 94#undef RV
 95
 96static const struct regmap_range nt39016_regmap_no_ranges[] = {
 97	regmap_reg_range(0x13, 0x1D),
 98	regmap_reg_range(0x1F, 0x1F),
 99};
100
101static const struct regmap_access_table nt39016_regmap_access_table = {
102	.no_ranges = nt39016_regmap_no_ranges,
103	.n_no_ranges = ARRAY_SIZE(nt39016_regmap_no_ranges),
104};
105
106static const struct regmap_config nt39016_regmap_config = {
107	.reg_bits = 6,
108	.pad_bits = 2,
109	.val_bits = 8,
110
111	.max_register = NT39016_REG_DISPLAY_MODE,
112	.wr_table = &nt39016_regmap_access_table,
113	.write_flag_mask = 0x02,
114
115	.cache_type = REGCACHE_FLAT,
116};
117
118static int nt39016_prepare(struct drm_panel *drm_panel)
119{
120	struct nt39016 *panel = to_nt39016(drm_panel);
121	int err;
122
123	err = regulator_enable(panel->supply);
124	if (err) {
125		dev_err(drm_panel->dev, "Failed to enable power supply: %d\n", err);
126		return err;
127	}
128
129	/*
130	 * Reset the NT39016.
131	 * The documentation says the reset pulse should be at least 40 us to
132	 * pass the glitch filter, but when testing I see some resets fail and
133	 * some succeed when using a 70 us delay, so we use 100 us instead.
134	 */
135	gpiod_set_value_cansleep(panel->reset_gpio, 1);
136	usleep_range(100, 1000);
137	gpiod_set_value_cansleep(panel->reset_gpio, 0);
138	udelay(2);
139
140	/* Init all registers. */
141	err = regmap_multi_reg_write(panel->map, nt39016_panel_regs,
142				     ARRAY_SIZE(nt39016_panel_regs));
143	if (err) {
144		dev_err(drm_panel->dev, "Failed to init registers: %d\n", err);
145		goto err_disable_regulator;
146	}
147
148	return 0;
149
150err_disable_regulator:
151	regulator_disable(panel->supply);
152	return err;
153}
154
155static int nt39016_unprepare(struct drm_panel *drm_panel)
156{
157	struct nt39016 *panel = to_nt39016(drm_panel);
158
159	gpiod_set_value_cansleep(panel->reset_gpio, 1);
160
161	regulator_disable(panel->supply);
162
163	return 0;
164}
165
166static int nt39016_enable(struct drm_panel *drm_panel)
167{
168	struct nt39016 *panel = to_nt39016(drm_panel);
169	int ret;
170
171	ret = regmap_write(panel->map, NT39016_REG_SYSTEM,
172			   NT39016_SYSTEM_RESET_N | NT39016_SYSTEM_STANDBY);
173	if (ret) {
174		dev_err(drm_panel->dev, "Unable to enable panel: %d\n", ret);
175		return ret;
176	}
177
178	if (drm_panel->backlight) {
179		/* Wait for the picture to be ready before enabling backlight */
180		msleep(150);
181	}
182
183	return 0;
184}
185
186static int nt39016_disable(struct drm_panel *drm_panel)
187{
188	struct nt39016 *panel = to_nt39016(drm_panel);
189	int err;
190
191	err = regmap_write(panel->map, NT39016_REG_SYSTEM,
192			   NT39016_SYSTEM_RESET_N);
193	if (err) {
194		dev_err(drm_panel->dev, "Unable to disable panel: %d\n", err);
195		return err;
196	}
197
198	return 0;
199}
200
201static int nt39016_get_modes(struct drm_panel *drm_panel,
202			     struct drm_connector *connector)
203{
204	struct nt39016 *panel = to_nt39016(drm_panel);
205	const struct nt39016_panel_info *panel_info = panel->panel_info;
206	struct drm_display_mode *mode;
207	unsigned int i;
208
209	for (i = 0; i < panel_info->num_modes; i++) {
210		mode = drm_mode_duplicate(connector->dev,
211					  &panel_info->display_modes[i]);
212		if (!mode)
213			return -ENOMEM;
214
215		drm_mode_set_name(mode);
216
217		mode->type = DRM_MODE_TYPE_DRIVER;
218		if (panel_info->num_modes == 1)
219			mode->type |= DRM_MODE_TYPE_PREFERRED;
220
221		drm_mode_probed_add(connector, mode);
222	}
223
224	connector->display_info.bpc = 8;
225	connector->display_info.width_mm = panel_info->width_mm;
226	connector->display_info.height_mm = panel_info->height_mm;
227
228	drm_display_info_set_bus_formats(&connector->display_info,
229					 &panel_info->bus_format, 1);
230	connector->display_info.bus_flags = panel_info->bus_flags;
231
232	return panel_info->num_modes;
233}
234
235static const struct drm_panel_funcs nt39016_funcs = {
236	.prepare	= nt39016_prepare,
237	.unprepare	= nt39016_unprepare,
238	.enable		= nt39016_enable,
239	.disable	= nt39016_disable,
240	.get_modes	= nt39016_get_modes,
241};
242
243static int nt39016_probe(struct spi_device *spi)
244{
245	struct device *dev = &spi->dev;
246	struct nt39016 *panel;
247	int err;
248
249	panel = devm_drm_panel_alloc(dev, struct nt39016, drm_panel, &nt39016_funcs,
250				     DRM_MODE_CONNECTOR_DPI);
251	if (IS_ERR(panel))
252		return PTR_ERR(panel);
253
254	spi_set_drvdata(spi, panel);
255
256	panel->panel_info = of_device_get_match_data(dev);
257	if (!panel->panel_info)
258		return -EINVAL;
259
260	panel->supply = devm_regulator_get(dev, "power");
261	if (IS_ERR(panel->supply))
262		return dev_err_probe(dev, PTR_ERR(panel->supply),
263				     "Failed to get power supply\n");
264
265	panel->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
266	if (IS_ERR(panel->reset_gpio))
267		return dev_err_probe(dev, PTR_ERR(panel->reset_gpio), "Failed to get reset GPIO\n");
268
269	spi->bits_per_word = 8;
270	spi->mode = SPI_MODE_3 | SPI_3WIRE;
271	err = spi_setup(spi);
272	if (err) {
273		dev_err(dev, "Failed to setup SPI\n");
274		return err;
275	}
276
277	panel->map = devm_regmap_init_spi(spi, &nt39016_regmap_config);
278	if (IS_ERR(panel->map)) {
279		dev_err(dev, "Failed to init regmap\n");
280		return PTR_ERR(panel->map);
281	}
282
283	err = drm_panel_of_backlight(&panel->drm_panel);
284	if (err)
285		return dev_err_probe(dev, err, "Failed to get backlight handle\n");
286
287	drm_panel_add(&panel->drm_panel);
288
289	return 0;
290}
291
292static void nt39016_remove(struct spi_device *spi)
293{
294	struct nt39016 *panel = spi_get_drvdata(spi);
295
296	drm_panel_remove(&panel->drm_panel);
297
298	nt39016_disable(&panel->drm_panel);
299	nt39016_unprepare(&panel->drm_panel);
300}
301
302static const struct drm_display_mode kd035g6_display_modes[] = {
303	{	/* 60 Hz */
304		.clock = 6000,
305		.hdisplay = 320,
306		.hsync_start = 320 + 10,
307		.hsync_end = 320 + 10 + 50,
308		.htotal = 320 + 10 + 50 + 20,
309		.vdisplay = 240,
310		.vsync_start = 240 + 5,
311		.vsync_end = 240 + 5 + 1,
312		.vtotal = 240 + 5 + 1 + 4,
313		.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
314	},
315	{	/* 50 Hz */
316		.clock = 5400,
317		.hdisplay = 320,
318		.hsync_start = 320 + 42,
319		.hsync_end = 320 + 42 + 50,
320		.htotal = 320 + 42 + 50 + 20,
321		.vdisplay = 240,
322		.vsync_start = 240 + 5,
323		.vsync_end = 240 + 5 + 1,
324		.vtotal = 240 + 5 + 1 + 4,
325		.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
326	},
327};
328
329static const struct nt39016_panel_info kd035g6_info = {
330	.display_modes = kd035g6_display_modes,
331	.num_modes = ARRAY_SIZE(kd035g6_display_modes),
332	.width_mm = 71,
333	.height_mm = 53,
334	.bus_format = MEDIA_BUS_FMT_RGB888_1X24,
335	.bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
336};
337
338static const struct of_device_id nt39016_of_match[] = {
339	{ .compatible = "kingdisplay,kd035g6-54nt", .data = &kd035g6_info },
340	{ /* sentinel */ }
341};
342MODULE_DEVICE_TABLE(of, nt39016_of_match);
343
344static struct spi_driver nt39016_driver = {
345	.driver = {
346		.name = "nt39016",
347		.of_match_table = nt39016_of_match,
348	},
349	.probe = nt39016_probe,
350	.remove = nt39016_remove,
351};
352
353module_spi_driver(nt39016_driver);
354
355MODULE_AUTHOR("Maarten ter Huurne <maarten@treewalker.org>");
356MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
357MODULE_DESCRIPTION("Novatek NT39016 TFT LCD panel driver");
358MODULE_LICENSE("GPL v2");