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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/backlight.h>
10#include <linux/delay.h>
11#include <linux/device.h>
12#include <linux/gpio/consumer.h>
13#include <linux/media-bus-format.h>
14#include <linux/module.h>
15#include <linux/of.h>
16#include <linux/of_device.h>
17#include <linux/regmap.h>
18#include <linux/regulator/consumer.h>
19#include <linux/spi/spi.h>
20
21#include <drm/drm_modes.h>
22#include <drm/drm_panel.h>
23
24enum nt39016_regs {
25 NT39016_REG_SYSTEM,
26 NT39016_REG_TIMING,
27 NT39016_REG_OP,
28 NT39016_REG_DATA_IN,
29 NT39016_REG_SRC_TIMING_DELAY,
30 NT39016_REG_GATE_TIMING_DELAY,
31 NT39016_REG_RESERVED,
32 NT39016_REG_INITIAL_FUNC,
33 NT39016_REG_CONTRAST,
34 NT39016_REG_BRIGHTNESS,
35 NT39016_REG_HUE_SATURATION,
36 NT39016_REG_RB_SUBCONTRAST,
37 NT39016_REG_R_SUBBRIGHTNESS,
38 NT39016_REG_B_SUBBRIGHTNESS,
39 NT39016_REG_VCOMDC,
40 NT39016_REG_VCOMAC,
41 NT39016_REG_VGAM2,
42 NT39016_REG_VGAM34,
43 NT39016_REG_VGAM56,
44 NT39016_REG_VCOMDC_TRIM = 0x1e,
45 NT39016_REG_DISPLAY_MODE = 0x20,
46};
47
48#define NT39016_SYSTEM_RESET_N BIT(0)
49#define NT39016_SYSTEM_STANDBY BIT(1)
50
51struct nt39016_panel_info {
52 const struct drm_display_mode *display_modes;
53 unsigned int num_modes;
54 u16 width_mm, height_mm;
55 u32 bus_format, bus_flags;
56};
57
58struct nt39016 {
59 struct drm_panel drm_panel;
60 struct device *dev;
61 struct regmap *map;
62 struct regulator *supply;
63 const struct nt39016_panel_info *panel_info;
64
65 struct gpio_desc *reset_gpio;
66
67 struct backlight_device *backlight;
68};
69
70static inline struct nt39016 *to_nt39016(struct drm_panel *panel)
71{
72 return container_of(panel, struct nt39016, drm_panel);
73}
74
75#define RV(REG, VAL) { .reg = (REG), .def = (VAL), .delay_us = 2 }
76static const struct reg_sequence nt39016_panel_regs[] = {
77 RV(NT39016_REG_SYSTEM, 0x00),
78 RV(NT39016_REG_TIMING, 0x00),
79 RV(NT39016_REG_OP, 0x03),
80 RV(NT39016_REG_DATA_IN, 0xCC),
81 RV(NT39016_REG_SRC_TIMING_DELAY, 0x46),
82 RV(NT39016_REG_GATE_TIMING_DELAY, 0x05),
83 RV(NT39016_REG_RESERVED, 0x00),
84 RV(NT39016_REG_INITIAL_FUNC, 0x00),
85 RV(NT39016_REG_CONTRAST, 0x08),
86 RV(NT39016_REG_BRIGHTNESS, 0x40),
87 RV(NT39016_REG_HUE_SATURATION, 0x88),
88 RV(NT39016_REG_RB_SUBCONTRAST, 0x88),
89 RV(NT39016_REG_R_SUBBRIGHTNESS, 0x20),
90 RV(NT39016_REG_B_SUBBRIGHTNESS, 0x20),
91 RV(NT39016_REG_VCOMDC, 0x67),
92 RV(NT39016_REG_VCOMAC, 0xA4),
93 RV(NT39016_REG_VGAM2, 0x04),
94 RV(NT39016_REG_VGAM34, 0x24),
95 RV(NT39016_REG_VGAM56, 0x24),
96 RV(NT39016_REG_DISPLAY_MODE, 0x00),
97};
98
99#undef RV
100
101static const struct regmap_range nt39016_regmap_no_ranges[] = {
102 regmap_reg_range(0x13, 0x1D),
103 regmap_reg_range(0x1F, 0x1F),
104};
105
106static const struct regmap_access_table nt39016_regmap_access_table = {
107 .no_ranges = nt39016_regmap_no_ranges,
108 .n_no_ranges = ARRAY_SIZE(nt39016_regmap_no_ranges),
109};
110
111static const struct regmap_config nt39016_regmap_config = {
112 .reg_bits = 6,
113 .pad_bits = 2,
114 .val_bits = 8,
115
116 .max_register = NT39016_REG_DISPLAY_MODE,
117 .wr_table = &nt39016_regmap_access_table,
118 .write_flag_mask = 0x02,
119
120 .cache_type = REGCACHE_FLAT,
121};
122
123static int nt39016_prepare(struct drm_panel *drm_panel)
124{
125 struct nt39016 *panel = to_nt39016(drm_panel);
126 int err;
127
128 err = regulator_enable(panel->supply);
129 if (err) {
130 dev_err(panel->dev, "Failed to enable power supply: %d", err);
131 return err;
132 }
133
134 /*
135 * Reset the NT39016.
136 * The documentation says the reset pulse should be at least 40 us to
137 * pass the glitch filter, but when testing I see some resets fail and
138 * some succeed when using a 70 us delay, so we use 100 us instead.
139 */
140 gpiod_set_value_cansleep(panel->reset_gpio, 1);
141 usleep_range(100, 1000);
142 gpiod_set_value_cansleep(panel->reset_gpio, 0);
143 udelay(2);
144
145 /* Init all registers. */
146 err = regmap_multi_reg_write(panel->map, nt39016_panel_regs,
147 ARRAY_SIZE(nt39016_panel_regs));
148 if (err) {
149 dev_err(panel->dev, "Failed to init registers: %d", err);
150 goto err_disable_regulator;
151 }
152
153 return 0;
154
155err_disable_regulator:
156 regulator_disable(panel->supply);
157 return err;
158}
159
160static int nt39016_unprepare(struct drm_panel *drm_panel)
161{
162 struct nt39016 *panel = to_nt39016(drm_panel);
163
164 gpiod_set_value_cansleep(panel->reset_gpio, 1);
165
166 regulator_disable(panel->supply);
167
168 return 0;
169}
170
171static int nt39016_enable(struct drm_panel *drm_panel)
172{
173 struct nt39016 *panel = to_nt39016(drm_panel);
174 int ret;
175
176 ret = regmap_write(panel->map, NT39016_REG_SYSTEM,
177 NT39016_SYSTEM_RESET_N | NT39016_SYSTEM_STANDBY);
178 if (ret) {
179 dev_err(panel->dev, "Unable to enable panel: %d", ret);
180 return ret;
181 }
182
183 if (panel->backlight) {
184 /* Wait for the picture to be ready before enabling backlight */
185 msleep(150);
186
187 ret = backlight_enable(panel->backlight);
188 }
189
190 return ret;
191}
192
193static int nt39016_disable(struct drm_panel *drm_panel)
194{
195 struct nt39016 *panel = to_nt39016(drm_panel);
196 int err;
197
198 backlight_disable(panel->backlight);
199
200 err = regmap_write(panel->map, NT39016_REG_SYSTEM,
201 NT39016_SYSTEM_RESET_N);
202 if (err) {
203 dev_err(panel->dev, "Unable to disable panel: %d", err);
204 return err;
205 }
206
207 return 0;
208}
209
210static int nt39016_get_modes(struct drm_panel *drm_panel,
211 struct drm_connector *connector)
212{
213 struct nt39016 *panel = to_nt39016(drm_panel);
214 const struct nt39016_panel_info *panel_info = panel->panel_info;
215 struct drm_display_mode *mode;
216 unsigned int i;
217
218 for (i = 0; i < panel_info->num_modes; i++) {
219 mode = drm_mode_duplicate(connector->dev,
220 &panel_info->display_modes[i]);
221 if (!mode)
222 return -ENOMEM;
223
224 drm_mode_set_name(mode);
225
226 mode->type = DRM_MODE_TYPE_DRIVER;
227 if (panel_info->num_modes == 1)
228 mode->type |= DRM_MODE_TYPE_PREFERRED;
229
230 drm_mode_probed_add(connector, mode);
231 }
232
233 connector->display_info.bpc = 8;
234 connector->display_info.width_mm = panel_info->width_mm;
235 connector->display_info.height_mm = panel_info->height_mm;
236
237 drm_display_info_set_bus_formats(&connector->display_info,
238 &panel_info->bus_format, 1);
239 connector->display_info.bus_flags = panel_info->bus_flags;
240
241 return panel_info->num_modes;
242}
243
244static const struct drm_panel_funcs nt39016_funcs = {
245 .prepare = nt39016_prepare,
246 .unprepare = nt39016_unprepare,
247 .enable = nt39016_enable,
248 .disable = nt39016_disable,
249 .get_modes = nt39016_get_modes,
250};
251
252static int nt39016_probe(struct spi_device *spi)
253{
254 struct device *dev = &spi->dev;
255 struct nt39016 *panel;
256 int err;
257
258 panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
259 if (!panel)
260 return -ENOMEM;
261
262 panel->dev = dev;
263 spi_set_drvdata(spi, panel);
264
265 panel->panel_info = of_device_get_match_data(dev);
266 if (!panel->panel_info)
267 return -EINVAL;
268
269 panel->supply = devm_regulator_get(dev, "power");
270 if (IS_ERR(panel->supply)) {
271 dev_err(dev, "Failed to get power supply");
272 return PTR_ERR(panel->supply);
273 }
274
275 panel->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
276 if (IS_ERR(panel->reset_gpio)) {
277 dev_err(dev, "Failed to get reset GPIO");
278 return PTR_ERR(panel->reset_gpio);
279 }
280
281 spi->bits_per_word = 8;
282 spi->mode = SPI_MODE_3 | SPI_3WIRE;
283 err = spi_setup(spi);
284 if (err) {
285 dev_err(dev, "Failed to setup SPI");
286 return err;
287 }
288
289 panel->map = devm_regmap_init_spi(spi, &nt39016_regmap_config);
290 if (IS_ERR(panel->map)) {
291 dev_err(dev, "Failed to init regmap");
292 return PTR_ERR(panel->map);
293 }
294
295 panel->backlight = devm_of_find_backlight(dev);
296 if (IS_ERR(panel->backlight)) {
297 err = PTR_ERR(panel->backlight);
298 if (err != -EPROBE_DEFER)
299 dev_err(dev, "Failed to get backlight handle");
300 return err;
301 }
302
303 drm_panel_init(&panel->drm_panel, dev, &nt39016_funcs,
304 DRM_MODE_CONNECTOR_DPI);
305
306 err = drm_panel_add(&panel->drm_panel);
307 if (err < 0) {
308 dev_err(dev, "Failed to register panel");
309 return err;
310 }
311
312 return 0;
313}
314
315static int nt39016_remove(struct spi_device *spi)
316{
317 struct nt39016 *panel = spi_get_drvdata(spi);
318
319 drm_panel_remove(&panel->drm_panel);
320
321 nt39016_disable(&panel->drm_panel);
322 nt39016_unprepare(&panel->drm_panel);
323
324 return 0;
325}
326
327static const struct drm_display_mode kd035g6_display_modes[] = {
328 { /* 60 Hz */
329 .clock = 6000,
330 .hdisplay = 320,
331 .hsync_start = 320 + 10,
332 .hsync_end = 320 + 10 + 50,
333 .htotal = 320 + 10 + 50 + 20,
334 .vdisplay = 240,
335 .vsync_start = 240 + 5,
336 .vsync_end = 240 + 5 + 1,
337 .vtotal = 240 + 5 + 1 + 4,
338 .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
339 },
340 { /* 50 Hz */
341 .clock = 5400,
342 .hdisplay = 320,
343 .hsync_start = 320 + 42,
344 .hsync_end = 320 + 42 + 50,
345 .htotal = 320 + 42 + 50 + 20,
346 .vdisplay = 240,
347 .vsync_start = 240 + 5,
348 .vsync_end = 240 + 5 + 1,
349 .vtotal = 240 + 5 + 1 + 4,
350 .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
351 },
352};
353
354static const struct nt39016_panel_info kd035g6_info = {
355 .display_modes = kd035g6_display_modes,
356 .num_modes = ARRAY_SIZE(kd035g6_display_modes),
357 .width_mm = 71,
358 .height_mm = 53,
359 .bus_format = MEDIA_BUS_FMT_RGB888_1X24,
360 .bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
361};
362
363static const struct of_device_id nt39016_of_match[] = {
364 { .compatible = "kingdisplay,kd035g6-54nt", .data = &kd035g6_info },
365 { /* sentinel */ }
366};
367MODULE_DEVICE_TABLE(of, nt39016_of_match);
368
369static struct spi_driver nt39016_driver = {
370 .driver = {
371 .name = "nt39016",
372 .of_match_table = nt39016_of_match,
373 },
374 .probe = nt39016_probe,
375 .remove = nt39016_remove,
376};
377
378module_spi_driver(nt39016_driver);
379
380MODULE_AUTHOR("Maarten ter Huurne <maarten@treewalker.org>");
381MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
382MODULE_LICENSE("GPL v2");