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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_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
250 if (!panel)
251 return -ENOMEM;
252
253 spi_set_drvdata(spi, panel);
254
255 panel->panel_info = of_device_get_match_data(dev);
256 if (!panel->panel_info)
257 return -EINVAL;
258
259 panel->supply = devm_regulator_get(dev, "power");
260 if (IS_ERR(panel->supply))
261 return dev_err_probe(dev, PTR_ERR(panel->supply),
262 "Failed to get power supply\n");
263
264 panel->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
265 if (IS_ERR(panel->reset_gpio))
266 return dev_err_probe(dev, PTR_ERR(panel->reset_gpio), "Failed to get reset GPIO\n");
267
268 spi->bits_per_word = 8;
269 spi->mode = SPI_MODE_3 | SPI_3WIRE;
270 err = spi_setup(spi);
271 if (err) {
272 dev_err(dev, "Failed to setup SPI\n");
273 return err;
274 }
275
276 panel->map = devm_regmap_init_spi(spi, &nt39016_regmap_config);
277 if (IS_ERR(panel->map)) {
278 dev_err(dev, "Failed to init regmap\n");
279 return PTR_ERR(panel->map);
280 }
281
282 drm_panel_init(&panel->drm_panel, dev, &nt39016_funcs,
283 DRM_MODE_CONNECTOR_DPI);
284
285 err = drm_panel_of_backlight(&panel->drm_panel);
286 if (err)
287 return dev_err_probe(dev, err, "Failed to get backlight handle\n");
288
289 drm_panel_add(&panel->drm_panel);
290
291 return 0;
292}
293
294static void nt39016_remove(struct spi_device *spi)
295{
296 struct nt39016 *panel = spi_get_drvdata(spi);
297
298 drm_panel_remove(&panel->drm_panel);
299
300 nt39016_disable(&panel->drm_panel);
301 nt39016_unprepare(&panel->drm_panel);
302}
303
304static const struct drm_display_mode kd035g6_display_modes[] = {
305 { /* 60 Hz */
306 .clock = 6000,
307 .hdisplay = 320,
308 .hsync_start = 320 + 10,
309 .hsync_end = 320 + 10 + 50,
310 .htotal = 320 + 10 + 50 + 20,
311 .vdisplay = 240,
312 .vsync_start = 240 + 5,
313 .vsync_end = 240 + 5 + 1,
314 .vtotal = 240 + 5 + 1 + 4,
315 .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
316 },
317 { /* 50 Hz */
318 .clock = 5400,
319 .hdisplay = 320,
320 .hsync_start = 320 + 42,
321 .hsync_end = 320 + 42 + 50,
322 .htotal = 320 + 42 + 50 + 20,
323 .vdisplay = 240,
324 .vsync_start = 240 + 5,
325 .vsync_end = 240 + 5 + 1,
326 .vtotal = 240 + 5 + 1 + 4,
327 .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
328 },
329};
330
331static const struct nt39016_panel_info kd035g6_info = {
332 .display_modes = kd035g6_display_modes,
333 .num_modes = ARRAY_SIZE(kd035g6_display_modes),
334 .width_mm = 71,
335 .height_mm = 53,
336 .bus_format = MEDIA_BUS_FMT_RGB888_1X24,
337 .bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
338};
339
340static const struct of_device_id nt39016_of_match[] = {
341 { .compatible = "kingdisplay,kd035g6-54nt", .data = &kd035g6_info },
342 { /* sentinel */ }
343};
344MODULE_DEVICE_TABLE(of, nt39016_of_match);
345
346static struct spi_driver nt39016_driver = {
347 .driver = {
348 .name = "nt39016",
349 .of_match_table = nt39016_of_match,
350 },
351 .probe = nt39016_probe,
352 .remove = nt39016_remove,
353};
354
355module_spi_driver(nt39016_driver);
356
357MODULE_AUTHOR("Maarten ter Huurne <maarten@treewalker.org>");
358MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
359MODULE_DESCRIPTION("Novatek NT39016 TFT LCD panel driver");
360MODULE_LICENSE("GPL v2");