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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/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
23enum 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
50struct 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
57struct 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
66static 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 }
72static 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
97static const struct regmap_range nt39016_regmap_no_ranges[] = {
98 regmap_reg_range(0x13, 0x1D),
99 regmap_reg_range(0x1F, 0x1F),
100};
101
102static 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
107static 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
119static 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
151err_disable_regulator:
152 regulator_disable(panel->supply);
153 return err;
154}
155
156static 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
167static 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
187static 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
202static 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
236static 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
244static 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 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 drm_panel_init(&panel->drm_panel, dev, &nt39016_funcs,
284 DRM_MODE_CONNECTOR_DPI);
285
286 err = drm_panel_of_backlight(&panel->drm_panel);
287 if (err)
288 return dev_err_probe(dev, err, "Failed to get backlight handle\n");
289
290 drm_panel_add(&panel->drm_panel);
291
292 return 0;
293}
294
295static void nt39016_remove(struct spi_device *spi)
296{
297 struct nt39016 *panel = spi_get_drvdata(spi);
298
299 drm_panel_remove(&panel->drm_panel);
300
301 nt39016_disable(&panel->drm_panel);
302 nt39016_unprepare(&panel->drm_panel);
303}
304
305static const struct drm_display_mode kd035g6_display_modes[] = {
306 { /* 60 Hz */
307 .clock = 6000,
308 .hdisplay = 320,
309 .hsync_start = 320 + 10,
310 .hsync_end = 320 + 10 + 50,
311 .htotal = 320 + 10 + 50 + 20,
312 .vdisplay = 240,
313 .vsync_start = 240 + 5,
314 .vsync_end = 240 + 5 + 1,
315 .vtotal = 240 + 5 + 1 + 4,
316 .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
317 },
318 { /* 50 Hz */
319 .clock = 5400,
320 .hdisplay = 320,
321 .hsync_start = 320 + 42,
322 .hsync_end = 320 + 42 + 50,
323 .htotal = 320 + 42 + 50 + 20,
324 .vdisplay = 240,
325 .vsync_start = 240 + 5,
326 .vsync_end = 240 + 5 + 1,
327 .vtotal = 240 + 5 + 1 + 4,
328 .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
329 },
330};
331
332static const struct nt39016_panel_info kd035g6_info = {
333 .display_modes = kd035g6_display_modes,
334 .num_modes = ARRAY_SIZE(kd035g6_display_modes),
335 .width_mm = 71,
336 .height_mm = 53,
337 .bus_format = MEDIA_BUS_FMT_RGB888_1X24,
338 .bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
339};
340
341static const struct of_device_id nt39016_of_match[] = {
342 { .compatible = "kingdisplay,kd035g6-54nt", .data = &kd035g6_info },
343 { /* sentinel */ }
344};
345MODULE_DEVICE_TABLE(of, nt39016_of_match);
346
347static struct spi_driver nt39016_driver = {
348 .driver = {
349 .name = "nt39016",
350 .of_match_table = nt39016_of_match,
351 },
352 .probe = nt39016_probe,
353 .remove = nt39016_remove,
354};
355
356module_spi_driver(nt39016_driver);
357
358MODULE_AUTHOR("Maarten ter Huurne <maarten@treewalker.org>");
359MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
360MODULE_LICENSE("GPL v2");