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/of_device.h>
16 #include <linux/regmap.h>
17 #include <linux/regulator/consumer.h>
18 #include <linux/spi/spi.h>
19
20 #include <drm/drm_modes.h>
21 #include <drm/drm_panel.h>
22
23 enum nt39016_regs {
24 NT39016_REG_SYSTEM,
25 NT39016_REG_TIMING,
26 NT39016_REG_OP,
27 NT39016_REG_DATA_IN,
28 NT39016_REG_SRC_TIMING_DELAY,
29 NT39016_REG_GATE_TIMING_DELAY,
30 NT39016_REG_RESERVED,
31 NT39016_REG_INITIAL_FUNC,
32 NT39016_REG_CONTRAST,
33 NT39016_REG_BRIGHTNESS,
34 NT39016_REG_HUE_SATURATION,
35 NT39016_REG_RB_SUBCONTRAST,
36 NT39016_REG_R_SUBBRIGHTNESS,
37 NT39016_REG_B_SUBBRIGHTNESS,
38 NT39016_REG_VCOMDC,
39 NT39016_REG_VCOMAC,
40 NT39016_REG_VGAM2,
41 NT39016_REG_VGAM34,
42 NT39016_REG_VGAM56,
43 NT39016_REG_VCOMDC_TRIM = 0x1e,
44 NT39016_REG_DISPLAY_MODE = 0x20,
45 };
46
47 #define NT39016_SYSTEM_RESET_N BIT(0)
48 #define NT39016_SYSTEM_STANDBY BIT(1)
49
50 struct nt39016_panel_info {
51 const struct drm_display_mode *display_modes;
52 unsigned int num_modes;
53 u16 width_mm, height_mm;
54 u32 bus_format, bus_flags;
55 };
56
57 struct nt39016 {
58 struct drm_panel drm_panel;
59 struct regmap *map;
60 struct regulator *supply;
61 const struct nt39016_panel_info *panel_info;
62
63 struct gpio_desc *reset_gpio;
64 };
65
to_nt39016(struct drm_panel * panel)66 static inline struct nt39016 *to_nt39016(struct drm_panel *panel)
67 {
68 return container_of(panel, struct nt39016, drm_panel);
69 }
70
71 #define RV(REG, VAL) { .reg = (REG), .def = (VAL), .delay_us = 2 }
72 static const struct reg_sequence nt39016_panel_regs[] = {
73 RV(NT39016_REG_SYSTEM, 0x00),
74 RV(NT39016_REG_TIMING, 0x00),
75 RV(NT39016_REG_OP, 0x03),
76 RV(NT39016_REG_DATA_IN, 0xCC),
77 RV(NT39016_REG_SRC_TIMING_DELAY, 0x46),
78 RV(NT39016_REG_GATE_TIMING_DELAY, 0x05),
79 RV(NT39016_REG_RESERVED, 0x00),
80 RV(NT39016_REG_INITIAL_FUNC, 0x00),
81 RV(NT39016_REG_CONTRAST, 0x08),
82 RV(NT39016_REG_BRIGHTNESS, 0x40),
83 RV(NT39016_REG_HUE_SATURATION, 0x88),
84 RV(NT39016_REG_RB_SUBCONTRAST, 0x88),
85 RV(NT39016_REG_R_SUBBRIGHTNESS, 0x20),
86 RV(NT39016_REG_B_SUBBRIGHTNESS, 0x20),
87 RV(NT39016_REG_VCOMDC, 0x67),
88 RV(NT39016_REG_VCOMAC, 0xA4),
89 RV(NT39016_REG_VGAM2, 0x04),
90 RV(NT39016_REG_VGAM34, 0x24),
91 RV(NT39016_REG_VGAM56, 0x24),
92 RV(NT39016_REG_DISPLAY_MODE, 0x00),
93 };
94
95 #undef RV
96
97 static const struct regmap_range nt39016_regmap_no_ranges[] = {
98 regmap_reg_range(0x13, 0x1D),
99 regmap_reg_range(0x1F, 0x1F),
100 };
101
102 static const struct regmap_access_table nt39016_regmap_access_table = {
103 .no_ranges = nt39016_regmap_no_ranges,
104 .n_no_ranges = ARRAY_SIZE(nt39016_regmap_no_ranges),
105 };
106
107 static const struct regmap_config nt39016_regmap_config = {
108 .reg_bits = 6,
109 .pad_bits = 2,
110 .val_bits = 8,
111
112 .max_register = NT39016_REG_DISPLAY_MODE,
113 .wr_table = &nt39016_regmap_access_table,
114 .write_flag_mask = 0x02,
115
116 .cache_type = REGCACHE_FLAT,
117 };
118
nt39016_prepare(struct drm_panel * drm_panel)119 static int nt39016_prepare(struct drm_panel *drm_panel)
120 {
121 struct nt39016 *panel = to_nt39016(drm_panel);
122 int err;
123
124 err = regulator_enable(panel->supply);
125 if (err) {
126 dev_err(drm_panel->dev, "Failed to enable power supply: %d\n", err);
127 return err;
128 }
129
130 /*
131 * Reset the NT39016.
132 * The documentation says the reset pulse should be at least 40 us to
133 * pass the glitch filter, but when testing I see some resets fail and
134 * some succeed when using a 70 us delay, so we use 100 us instead.
135 */
136 gpiod_set_value_cansleep(panel->reset_gpio, 1);
137 usleep_range(100, 1000);
138 gpiod_set_value_cansleep(panel->reset_gpio, 0);
139 udelay(2);
140
141 /* Init all registers. */
142 err = regmap_multi_reg_write(panel->map, nt39016_panel_regs,
143 ARRAY_SIZE(nt39016_panel_regs));
144 if (err) {
145 dev_err(drm_panel->dev, "Failed to init registers: %d\n", err);
146 goto err_disable_regulator;
147 }
148
149 return 0;
150
151 err_disable_regulator:
152 regulator_disable(panel->supply);
153 return err;
154 }
155
nt39016_unprepare(struct drm_panel * drm_panel)156 static int nt39016_unprepare(struct drm_panel *drm_panel)
157 {
158 struct nt39016 *panel = to_nt39016(drm_panel);
159
160 gpiod_set_value_cansleep(panel->reset_gpio, 1);
161
162 regulator_disable(panel->supply);
163
164 return 0;
165 }
166
nt39016_enable(struct drm_panel * drm_panel)167 static int nt39016_enable(struct drm_panel *drm_panel)
168 {
169 struct nt39016 *panel = to_nt39016(drm_panel);
170 int ret;
171
172 ret = regmap_write(panel->map, NT39016_REG_SYSTEM,
173 NT39016_SYSTEM_RESET_N | NT39016_SYSTEM_STANDBY);
174 if (ret) {
175 dev_err(drm_panel->dev, "Unable to enable panel: %d\n", ret);
176 return ret;
177 }
178
179 if (drm_panel->backlight) {
180 /* Wait for the picture to be ready before enabling backlight */
181 msleep(150);
182 }
183
184 return 0;
185 }
186
nt39016_disable(struct drm_panel * drm_panel)187 static int nt39016_disable(struct drm_panel *drm_panel)
188 {
189 struct nt39016 *panel = to_nt39016(drm_panel);
190 int err;
191
192 err = regmap_write(panel->map, NT39016_REG_SYSTEM,
193 NT39016_SYSTEM_RESET_N);
194 if (err) {
195 dev_err(drm_panel->dev, "Unable to disable panel: %d\n", err);
196 return err;
197 }
198
199 return 0;
200 }
201
nt39016_get_modes(struct drm_panel * drm_panel,struct drm_connector * connector)202 static int nt39016_get_modes(struct drm_panel *drm_panel,
203 struct drm_connector *connector)
204 {
205 struct nt39016 *panel = to_nt39016(drm_panel);
206 const struct nt39016_panel_info *panel_info = panel->panel_info;
207 struct drm_display_mode *mode;
208 unsigned int i;
209
210 for (i = 0; i < panel_info->num_modes; i++) {
211 mode = drm_mode_duplicate(connector->dev,
212 &panel_info->display_modes[i]);
213 if (!mode)
214 return -ENOMEM;
215
216 drm_mode_set_name(mode);
217
218 mode->type = DRM_MODE_TYPE_DRIVER;
219 if (panel_info->num_modes == 1)
220 mode->type |= DRM_MODE_TYPE_PREFERRED;
221
222 drm_mode_probed_add(connector, mode);
223 }
224
225 connector->display_info.bpc = 8;
226 connector->display_info.width_mm = panel_info->width_mm;
227 connector->display_info.height_mm = panel_info->height_mm;
228
229 drm_display_info_set_bus_formats(&connector->display_info,
230 &panel_info->bus_format, 1);
231 connector->display_info.bus_flags = panel_info->bus_flags;
232
233 return panel_info->num_modes;
234 }
235
236 static const struct drm_panel_funcs nt39016_funcs = {
237 .prepare = nt39016_prepare,
238 .unprepare = nt39016_unprepare,
239 .enable = nt39016_enable,
240 .disable = nt39016_disable,
241 .get_modes = nt39016_get_modes,
242 };
243
nt39016_probe(struct spi_device * spi)244 static int nt39016_probe(struct spi_device *spi)
245 {
246 struct device *dev = &spi->dev;
247 struct nt39016 *panel;
248 int err;
249
250 panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
251 if (!panel)
252 return -ENOMEM;
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 dev_err(dev, "Failed to get power supply\n");
263 return PTR_ERR(panel->supply);
264 }
265
266 panel->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
267 if (IS_ERR(panel->reset_gpio)) {
268 dev_err(dev, "Failed to get reset GPIO\n");
269 return PTR_ERR(panel->reset_gpio);
270 }
271
272 spi->bits_per_word = 8;
273 spi->mode = SPI_MODE_3 | SPI_3WIRE;
274 err = spi_setup(spi);
275 if (err) {
276 dev_err(dev, "Failed to setup SPI\n");
277 return err;
278 }
279
280 panel->map = devm_regmap_init_spi(spi, &nt39016_regmap_config);
281 if (IS_ERR(panel->map)) {
282 dev_err(dev, "Failed to init regmap\n");
283 return PTR_ERR(panel->map);
284 }
285
286 drm_panel_init(&panel->drm_panel, dev, &nt39016_funcs,
287 DRM_MODE_CONNECTOR_DPI);
288
289 err = drm_panel_of_backlight(&panel->drm_panel);
290 if (err) {
291 if (err != -EPROBE_DEFER)
292 dev_err(dev, "Failed to get backlight handle\n");
293 return err;
294 }
295
296 drm_panel_add(&panel->drm_panel);
297
298 return 0;
299 }
300
nt39016_remove(struct spi_device * spi)301 static int nt39016_remove(struct spi_device *spi)
302 {
303 struct nt39016 *panel = spi_get_drvdata(spi);
304
305 drm_panel_remove(&panel->drm_panel);
306
307 nt39016_disable(&panel->drm_panel);
308 nt39016_unprepare(&panel->drm_panel);
309
310 return 0;
311 }
312
313 static const struct drm_display_mode kd035g6_display_modes[] = {
314 { /* 60 Hz */
315 .clock = 6000,
316 .hdisplay = 320,
317 .hsync_start = 320 + 10,
318 .hsync_end = 320 + 10 + 50,
319 .htotal = 320 + 10 + 50 + 20,
320 .vdisplay = 240,
321 .vsync_start = 240 + 5,
322 .vsync_end = 240 + 5 + 1,
323 .vtotal = 240 + 5 + 1 + 4,
324 .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
325 },
326 { /* 50 Hz */
327 .clock = 5400,
328 .hdisplay = 320,
329 .hsync_start = 320 + 42,
330 .hsync_end = 320 + 42 + 50,
331 .htotal = 320 + 42 + 50 + 20,
332 .vdisplay = 240,
333 .vsync_start = 240 + 5,
334 .vsync_end = 240 + 5 + 1,
335 .vtotal = 240 + 5 + 1 + 4,
336 .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
337 },
338 };
339
340 static const struct nt39016_panel_info kd035g6_info = {
341 .display_modes = kd035g6_display_modes,
342 .num_modes = ARRAY_SIZE(kd035g6_display_modes),
343 .width_mm = 71,
344 .height_mm = 53,
345 .bus_format = MEDIA_BUS_FMT_RGB888_1X24,
346 .bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
347 };
348
349 static const struct of_device_id nt39016_of_match[] = {
350 { .compatible = "kingdisplay,kd035g6-54nt", .data = &kd035g6_info },
351 { /* sentinel */ }
352 };
353 MODULE_DEVICE_TABLE(of, nt39016_of_match);
354
355 static struct spi_driver nt39016_driver = {
356 .driver = {
357 .name = "nt39016",
358 .of_match_table = nt39016_of_match,
359 },
360 .probe = nt39016_probe,
361 .remove = nt39016_remove,
362 };
363
364 module_spi_driver(nt39016_driver);
365
366 MODULE_AUTHOR("Maarten ter Huurne <maarten@treewalker.org>");
367 MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
368 MODULE_LICENSE("GPL v2");
369