1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Panel driver for the Samsung LMS397KF04 480x800 DPI RGB panel.
4  * According to the data sheet the display controller is called DB7430.
5  * Found in the Samsung Galaxy Beam GT-I8350 mobile phone.
6  * Linus Walleij <linus.walleij@linaro.org>
7  */
8 #include <drm/drm_mipi_dbi.h>
9 #include <drm/drm_modes.h>
10 #include <drm/drm_panel.h>
11 
12 #include <linux/delay.h>
13 #include <linux/gpio/consumer.h>
14 #include <linux/init.h>
15 #include <linux/kernel.h>
16 #include <linux/media-bus-format.h>
17 #include <linux/module.h>
18 #include <linux/of.h>
19 #include <linux/regulator/consumer.h>
20 #include <linux/spi/spi.h>
21 
22 #include <video/mipi_display.h>
23 
24 #define DB7430_ACCESS_PROT_OFF		0xb0
25 #define DB7430_UNKNOWN_B4		0xb4
26 #define DB7430_USER_SELECT		0xb5
27 #define DB7430_UNKNOWN_B7		0xb7
28 #define DB7430_UNKNOWN_B8		0xb8
29 #define DB7430_PANEL_DRIVING		0xc0
30 #define DB7430_SOURCE_CONTROL		0xc1
31 #define DB7430_GATE_INTERFACE		0xc4
32 #define DB7430_DISPLAY_H_TIMING		0xc5
33 #define DB7430_RGB_SYNC_OPTION		0xc6
34 #define DB7430_GAMMA_SET_RED		0xc8
35 #define DB7430_GAMMA_SET_GREEN		0xc9
36 #define DB7430_GAMMA_SET_BLUE		0xca
37 #define DB7430_BIAS_CURRENT_CTRL	0xd1
38 #define DB7430_DDV_CTRL			0xd2
39 #define DB7430_GAMMA_CTRL_REF		0xd3
40 #define DB7430_UNKNOWN_D4		0xd4
41 #define DB7430_DCDC_CTRL		0xd5
42 #define DB7430_VCL_CTRL			0xd6
43 #define DB7430_UNKNOWN_F8		0xf8
44 #define DB7430_UNKNOWN_FC		0xfc
45 
46 #define DATA_MASK	0x100
47 
48 /**
49  * struct db7430 - state container for a panel controlled by the DB7430
50  * controller
51  */
52 struct db7430 {
53 	/** @dev: the container device */
54 	struct device *dev;
55 	/** @dbi: the DBI bus abstraction handle */
56 	struct mipi_dbi dbi;
57 	/** @panel: the DRM panel instance for this device */
58 	struct drm_panel panel;
59 	/** @width: the width of this panel in mm */
60 	u32 width;
61 	/** @height: the height of this panel in mm */
62 	u32 height;
63 	/** @reset: reset GPIO line */
64 	struct gpio_desc *reset;
65 	/** @regulators: VCCIO and VIO supply regulators */
66 	struct regulator_bulk_data regulators[2];
67 };
68 
69 static const struct drm_display_mode db7430_480_800_mode = {
70 	/*
71 	 * 31 ns period min (htotal*vtotal*vrefresh)/1000
72 	 * gives a Vrefresh of ~71 Hz.
73 	 */
74 	.clock = 32258,
75 	.hdisplay = 480,
76 	.hsync_start = 480 + 10,
77 	.hsync_end = 480 + 10 + 4,
78 	.htotal = 480 + 10 + 4 + 40,
79 	.vdisplay = 800,
80 	.vsync_start = 800 + 6,
81 	.vsync_end = 800 + 6 + 1,
82 	.vtotal = 800 + 6 + 1 + 7,
83 	.width_mm = 53,
84 	.height_mm = 87,
85 	.flags = DRM_MODE_FLAG_NVSYNC | DRM_MODE_FLAG_NHSYNC,
86 };
87 
88 static inline struct db7430 *to_db7430(struct drm_panel *panel)
89 {
90 	return container_of(panel, struct db7430, panel);
91 }
92 
93 static int db7430_power_on(struct db7430 *db)
94 {
95 	struct mipi_dbi *dbi = &db->dbi;
96 	int ret;
97 
98 	/* Power up */
99 	ret = regulator_bulk_enable(ARRAY_SIZE(db->regulators),
100 				    db->regulators);
101 	if (ret) {
102 		dev_err(db->dev, "failed to enable regulators: %d\n", ret);
103 		return ret;
104 	}
105 	msleep(50);
106 
107 	/* Assert reset >=1 ms */
108 	gpiod_set_value_cansleep(db->reset, 1);
109 	usleep_range(1000, 5000);
110 	/* De-assert reset */
111 	gpiod_set_value_cansleep(db->reset, 0);
112 	/* Wait >= 10 ms */
113 	msleep(10);
114 	dev_dbg(db->dev, "de-asserted RESET\n");
115 
116 	/*
117 	 * This is set to 0x0a (RGB/BGR order + horizontal flip) in order
118 	 * to make the display behave normally. If this is not set the displays
119 	 * normal output behaviour is horizontally flipped and BGR ordered. Do
120 	 * it twice because the first message doesn't always "take".
121 	 */
122 	mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, 0x0a);
123 	mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, 0x0a);
124 	mipi_dbi_command(dbi, DB7430_ACCESS_PROT_OFF, 0x00);
125 	mipi_dbi_command(dbi, DB7430_PANEL_DRIVING, 0x28, 0x08);
126 	mipi_dbi_command(dbi, DB7430_SOURCE_CONTROL,
127 			 0x01, 0x30, 0x15, 0x05, 0x22);
128 	mipi_dbi_command(dbi, DB7430_GATE_INTERFACE,
129 			 0x10, 0x01, 0x00);
130 	mipi_dbi_command(dbi, DB7430_DISPLAY_H_TIMING,
131 			 0x06, 0x55, 0x03, 0x07, 0x0b,
132 			 0x33, 0x00, 0x01, 0x03);
133 	/*
134 	 * 0x00 in datasheet 0x01 in vendor code 0x00, it seems 0x01 means
135 	 * DE active high and 0x00 means DE active low.
136 	 */
137 	mipi_dbi_command(dbi, DB7430_RGB_SYNC_OPTION, 0x01);
138 	mipi_dbi_command(dbi, DB7430_GAMMA_SET_RED,
139 		/* R positive gamma */ 0x00,
140 		0x0A, 0x31, 0x3B, 0x4E, 0x58, 0x59, 0x5B, 0x58, 0x5E, 0x62,
141 		0x60, 0x61, 0x5E, 0x62, 0x55, 0x55, 0x7F, 0x08,
142 		/* R negative gamma */ 0x00,
143 		0x0A, 0x31, 0x3B, 0x4E, 0x58, 0x59, 0x5B, 0x58, 0x5E, 0x62,
144 		0x60, 0x61, 0x5E, 0x62, 0x55, 0x55, 0x7F, 0x08);
145 	mipi_dbi_command(dbi, DB7430_GAMMA_SET_GREEN,
146 		/* G positive gamma */ 0x00,
147 		0x25, 0x15, 0x28, 0x3D, 0x4A, 0x48, 0x4C, 0x4A, 0x52, 0x59,
148 		0x59, 0x5B, 0x56, 0x60, 0x5D, 0x55, 0x7F, 0x0A,
149 		/* G negative gamma */ 0x00,
150 		0x25, 0x15, 0x28, 0x3D, 0x4A, 0x48, 0x4C, 0x4A, 0x52, 0x59,
151 		0x59, 0x5B, 0x56, 0x60, 0x5D, 0x55, 0x7F, 0x0A);
152 	mipi_dbi_command(dbi, DB7430_GAMMA_SET_BLUE,
153 		/* B positive gamma */ 0x00,
154 		0x48, 0x10, 0x1F, 0x2F, 0x35, 0x38, 0x3D, 0x3C, 0x45, 0x4D,
155 		0x4E, 0x52, 0x51, 0x60, 0x7F, 0x7E, 0x7F, 0x0C,
156 		/* B negative gamma */ 0x00,
157 		0x48, 0x10, 0x1F, 0x2F, 0x35, 0x38, 0x3D, 0x3C, 0x45, 0x4D,
158 		0x4E, 0x52, 0x51, 0x60, 0x7F, 0x7E, 0x7F, 0x0C);
159 	mipi_dbi_command(dbi, DB7430_BIAS_CURRENT_CTRL, 0x33, 0x13);
160 	mipi_dbi_command(dbi, DB7430_DDV_CTRL, 0x11, 0x00, 0x00);
161 	mipi_dbi_command(dbi, DB7430_GAMMA_CTRL_REF, 0x50, 0x50);
162 	mipi_dbi_command(dbi, DB7430_DCDC_CTRL, 0x2f, 0x11, 0x1e, 0x46);
163 	mipi_dbi_command(dbi, DB7430_VCL_CTRL, 0x11, 0x0a);
164 
165 	return 0;
166 }
167 
168 static int db7430_power_off(struct db7430 *db)
169 {
170 	/* Go into RESET and disable regulators */
171 	gpiod_set_value_cansleep(db->reset, 1);
172 	return regulator_bulk_disable(ARRAY_SIZE(db->regulators),
173 				      db->regulators);
174 }
175 
176 static int db7430_unprepare(struct drm_panel *panel)
177 {
178 	return db7430_power_off(to_db7430(panel));
179 }
180 
181 static int db7430_disable(struct drm_panel *panel)
182 {
183 	struct db7430 *db = to_db7430(panel);
184 	struct mipi_dbi *dbi = &db->dbi;
185 
186 	mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
187 	msleep(25);
188 	mipi_dbi_command(dbi, MIPI_DCS_ENTER_SLEEP_MODE);
189 	msleep(120);
190 
191 	return 0;
192 }
193 
194 static int db7430_prepare(struct drm_panel *panel)
195 {
196 	return db7430_power_on(to_db7430(panel));
197 }
198 
199 static int db7430_enable(struct drm_panel *panel)
200 {
201 	struct db7430 *db = to_db7430(panel);
202 	struct mipi_dbi *dbi = &db->dbi;
203 
204 	/* Exit sleep mode */
205 	mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
206 	msleep(20);
207 
208 	/* NVM (non-volatile memory) load sequence */
209 	mipi_dbi_command(dbi, DB7430_UNKNOWN_D4, 0x52, 0x5e);
210 	mipi_dbi_command(dbi, DB7430_UNKNOWN_F8, 0x01, 0xf5, 0xf2, 0x71, 0x44);
211 	mipi_dbi_command(dbi, DB7430_UNKNOWN_FC, 0x00, 0x08);
212 	msleep(150);
213 
214 	/* CABC turn on sequence (BC = backlight control) */
215 	mipi_dbi_command(dbi, DB7430_UNKNOWN_B4, 0x0f, 0x00, 0x50);
216 	mipi_dbi_command(dbi, DB7430_USER_SELECT, 0x80);
217 	mipi_dbi_command(dbi, DB7430_UNKNOWN_B7, 0x24);
218 	mipi_dbi_command(dbi, DB7430_UNKNOWN_B8, 0x01);
219 
220 	/* Turn on display */
221 	mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
222 
223 	return 0;
224 }
225 
226 /**
227  * db7430_get_modes() - return the mode
228  * @panel: the panel to get the mode for
229  * @connector: reference to the central DRM connector control structure
230  */
231 static int db7430_get_modes(struct drm_panel *panel,
232 			    struct drm_connector *connector)
233 {
234 	struct db7430 *db = to_db7430(panel);
235 	struct drm_display_mode *mode;
236 	static const u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
237 
238 	mode = drm_mode_duplicate(connector->dev, &db7430_480_800_mode);
239 	if (!mode) {
240 		dev_err(db->dev, "failed to add mode\n");
241 		return -ENOMEM;
242 	}
243 
244 	connector->display_info.bpc = 8;
245 	connector->display_info.width_mm = mode->width_mm;
246 	connector->display_info.height_mm = mode->height_mm;
247 	connector->display_info.bus_flags =
248 		DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE;
249 	drm_display_info_set_bus_formats(&connector->display_info,
250 					 &bus_format, 1);
251 
252 	drm_mode_set_name(mode);
253 	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
254 
255 	drm_mode_probed_add(connector, mode);
256 
257 	return 1;
258 }
259 
260 static const struct drm_panel_funcs db7430_drm_funcs = {
261 	.disable = db7430_disable,
262 	.unprepare = db7430_unprepare,
263 	.prepare = db7430_prepare,
264 	.enable = db7430_enable,
265 	.get_modes = db7430_get_modes,
266 };
267 
268 static int db7430_probe(struct spi_device *spi)
269 {
270 	struct device *dev = &spi->dev;
271 	struct db7430 *db;
272 	int ret;
273 
274 	db = devm_kzalloc(dev, sizeof(*db), GFP_KERNEL);
275 	if (!db)
276 		return -ENOMEM;
277 	db->dev = dev;
278 
279 	/*
280 	 * VCI   is the analog voltage supply
281 	 * VCCIO is the digital I/O voltage supply
282 	 */
283 	db->regulators[0].supply = "vci";
284 	db->regulators[1].supply = "vccio";
285 	ret = devm_regulator_bulk_get(dev,
286 				      ARRAY_SIZE(db->regulators),
287 				      db->regulators);
288 	if (ret)
289 		return dev_err_probe(dev, ret, "failed to get regulators\n");
290 
291 	db->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
292 	if (IS_ERR(db->reset)) {
293 		ret = PTR_ERR(db->reset);
294 		return dev_err_probe(dev, ret, "no RESET GPIO\n");
295 	}
296 
297 	ret = mipi_dbi_spi_init(spi, &db->dbi, NULL);
298 	if (ret)
299 		return dev_err_probe(dev, ret, "MIPI DBI init failed\n");
300 
301 	drm_panel_init(&db->panel, dev, &db7430_drm_funcs,
302 		       DRM_MODE_CONNECTOR_DPI);
303 
304 	/* FIXME: if no external backlight, use internal backlight */
305 	ret = drm_panel_of_backlight(&db->panel);
306 	if (ret)
307 		return dev_err_probe(dev, ret, "failed to add backlight\n");
308 
309 	spi_set_drvdata(spi, db);
310 
311 	drm_panel_add(&db->panel);
312 	dev_dbg(dev, "added panel\n");
313 
314 	return 0;
315 }
316 
317 static void db7430_remove(struct spi_device *spi)
318 {
319 	struct db7430 *db = spi_get_drvdata(spi);
320 
321 	drm_panel_remove(&db->panel);
322 }
323 
324 /*
325  * The DB7430 display controller may be used in several display products,
326  * so list the different variants here and add per-variant data if needed.
327  */
328 static const struct of_device_id db7430_match[] = {
329 	{ .compatible = "samsung,lms397kf04", },
330 	{},
331 };
332 MODULE_DEVICE_TABLE(of, db7430_match);
333 
334 static struct spi_driver db7430_driver = {
335 	.probe		= db7430_probe,
336 	.remove		= db7430_remove,
337 	.driver		= {
338 		.name	= "db7430-panel",
339 		.of_match_table = db7430_match,
340 	},
341 };
342 module_spi_driver(db7430_driver);
343 
344 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
345 MODULE_DESCRIPTION("Samsung DB7430 panel driver");
346 MODULE_LICENSE("GPL v2");
347