1 /*
2  * Copyright © 2016-2017 Broadcom
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  *
8  * Portions of this file (derived from panel-simple.c) are:
9  *
10  * Copyright (C) 2013, NVIDIA Corporation.  All rights reserved.
11  *
12  * Permission is hereby granted, free of charge, to any person obtaining a
13  * copy of this software and associated documentation files (the "Software"),
14  * to deal in the Software without restriction, including without limitation
15  * the rights to use, copy, modify, merge, publish, distribute, sub license,
16  * and/or sell copies of the Software, and to permit persons to whom the
17  * Software is furnished to do so, subject to the following conditions:
18  *
19  * The above copyright notice and this permission notice (including the
20  * next paragraph) shall be included in all copies or substantial portions
21  * of the Software.
22  *
23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
24  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
25  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
26  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
27  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
28  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
29  * DEALINGS IN THE SOFTWARE.
30  */
31 
32 /*
33  * Raspberry Pi 7" touchscreen panel driver.
34  *
35  * The 7" touchscreen consists of a DPI LCD panel, a Toshiba
36  * TC358762XBG DSI-DPI bridge, and an I2C-connected Atmel ATTINY88-MUR
37  * controlling power management, the LCD PWM, and initial register
38  * setup of the Tohsiba.
39  *
40  * This driver controls the TC358762 and ATTINY88, presenting a DSI
41  * device with a drm_panel.
42  */
43 
44 #include <linux/delay.h>
45 #include <linux/err.h>
46 #include <linux/i2c.h>
47 #include <linux/media-bus-format.h>
48 #include <linux/module.h>
49 #include <linux/of.h>
50 #include <linux/of_graph.h>
51 #include <linux/pm.h>
52 
53 #include <drm/drm_crtc.h>
54 #include <drm/drm_device.h>
55 #include <drm/drm_mipi_dsi.h>
56 #include <drm/drm_panel.h>
57 
58 #define RPI_DSI_DRIVER_NAME "rpi-ts-dsi"
59 
60 /* I2C registers of the Atmel microcontroller. */
61 enum REG_ADDR {
62 	REG_ID = 0x80,
63 	REG_PORTA, /* BIT(2) for horizontal flip, BIT(3) for vertical flip */
64 	REG_PORTB,
65 	REG_PORTC,
66 	REG_PORTD,
67 	REG_POWERON,
68 	REG_PWM,
69 	REG_DDRA,
70 	REG_DDRB,
71 	REG_DDRC,
72 	REG_DDRD,
73 	REG_TEST,
74 	REG_WR_ADDRL,
75 	REG_WR_ADDRH,
76 	REG_READH,
77 	REG_READL,
78 	REG_WRITEH,
79 	REG_WRITEL,
80 	REG_ID2,
81 };
82 
83 /* DSI D-PHY Layer Registers */
84 #define D0W_DPHYCONTTX		0x0004
85 #define CLW_DPHYCONTRX		0x0020
86 #define D0W_DPHYCONTRX		0x0024
87 #define D1W_DPHYCONTRX		0x0028
88 #define COM_DPHYCONTRX		0x0038
89 #define CLW_CNTRL		0x0040
90 #define D0W_CNTRL		0x0044
91 #define D1W_CNTRL		0x0048
92 #define DFTMODE_CNTRL		0x0054
93 
94 /* DSI PPI Layer Registers */
95 #define PPI_STARTPPI		0x0104
96 #define PPI_BUSYPPI		0x0108
97 #define PPI_LINEINITCNT		0x0110
98 #define PPI_LPTXTIMECNT		0x0114
99 #define PPI_CLS_ATMR		0x0140
100 #define PPI_D0S_ATMR		0x0144
101 #define PPI_D1S_ATMR		0x0148
102 #define PPI_D0S_CLRSIPOCOUNT	0x0164
103 #define PPI_D1S_CLRSIPOCOUNT	0x0168
104 #define CLS_PRE			0x0180
105 #define D0S_PRE			0x0184
106 #define D1S_PRE			0x0188
107 #define CLS_PREP		0x01A0
108 #define D0S_PREP		0x01A4
109 #define D1S_PREP		0x01A8
110 #define CLS_ZERO		0x01C0
111 #define D0S_ZERO		0x01C4
112 #define D1S_ZERO		0x01C8
113 #define PPI_CLRFLG		0x01E0
114 #define PPI_CLRSIPO		0x01E4
115 #define HSTIMEOUT		0x01F0
116 #define HSTIMEOUTENABLE		0x01F4
117 
118 /* DSI Protocol Layer Registers */
119 #define DSI_STARTDSI		0x0204
120 #define DSI_BUSYDSI		0x0208
121 #define DSI_LANEENABLE		0x0210
122 # define DSI_LANEENABLE_CLOCK		BIT(0)
123 # define DSI_LANEENABLE_D0		BIT(1)
124 # define DSI_LANEENABLE_D1		BIT(2)
125 
126 #define DSI_LANESTATUS0		0x0214
127 #define DSI_LANESTATUS1		0x0218
128 #define DSI_INTSTATUS		0x0220
129 #define DSI_INTMASK		0x0224
130 #define DSI_INTCLR		0x0228
131 #define DSI_LPTXTO		0x0230
132 #define DSI_MODE		0x0260
133 #define DSI_PAYLOAD0		0x0268
134 #define DSI_PAYLOAD1		0x026C
135 #define DSI_SHORTPKTDAT		0x0270
136 #define DSI_SHORTPKTREQ		0x0274
137 #define DSI_BTASTA		0x0278
138 #define DSI_BTACLR		0x027C
139 
140 /* DSI General Registers */
141 #define DSIERRCNT		0x0300
142 #define DSISIGMOD		0x0304
143 
144 /* DSI Application Layer Registers */
145 #define APLCTRL			0x0400
146 #define APLSTAT			0x0404
147 #define APLERR			0x0408
148 #define PWRMOD			0x040C
149 #define RDPKTLN			0x0410
150 #define PXLFMT			0x0414
151 #define MEMWRCMD		0x0418
152 
153 /* LCDC/DPI Host Registers */
154 #define LCDCTRL			0x0420
155 #define HSR			0x0424
156 #define HDISPR			0x0428
157 #define VSR			0x042C
158 #define VDISPR			0x0430
159 #define VFUEN			0x0434
160 
161 /* DBI-B Host Registers */
162 #define DBIBCTRL		0x0440
163 
164 /* SPI Master Registers */
165 #define SPICMR			0x0450
166 #define SPITCR			0x0454
167 
168 /* System Controller Registers */
169 #define SYSSTAT			0x0460
170 #define SYSCTRL			0x0464
171 #define SYSPLL1			0x0468
172 #define SYSPLL2			0x046C
173 #define SYSPLL3			0x0470
174 #define SYSPMCTRL		0x047C
175 
176 /* GPIO Registers */
177 #define GPIOC			0x0480
178 #define GPIOO			0x0484
179 #define GPIOI			0x0488
180 
181 /* I2C Registers */
182 #define I2CCLKCTRL		0x0490
183 
184 /* Chip/Rev Registers */
185 #define IDREG			0x04A0
186 
187 /* Debug Registers */
188 #define WCMDQUEUE		0x0500
189 #define RCMDQUEUE		0x0504
190 
191 struct rpi_touchscreen {
192 	struct drm_panel base;
193 	struct mipi_dsi_device *dsi;
194 	struct i2c_client *i2c;
195 };
196 
197 static const struct drm_display_mode rpi_touchscreen_modes[] = {
198 	{
199 		/* Modeline comes from the Raspberry Pi firmware, with HFP=1
200 		 * plugged in and clock re-computed from that.
201 		 */
202 		.clock = 25979400 / 1000,
203 		.hdisplay = 800,
204 		.hsync_start = 800 + 1,
205 		.hsync_end = 800 + 1 + 2,
206 		.htotal = 800 + 1 + 2 + 46,
207 		.vdisplay = 480,
208 		.vsync_start = 480 + 7,
209 		.vsync_end = 480 + 7 + 2,
210 		.vtotal = 480 + 7 + 2 + 21,
211 	},
212 };
213 
214 static struct rpi_touchscreen *panel_to_ts(struct drm_panel *panel)
215 {
216 	return container_of(panel, struct rpi_touchscreen, base);
217 }
218 
219 static int rpi_touchscreen_i2c_read(struct rpi_touchscreen *ts, u8 reg)
220 {
221 	return i2c_smbus_read_byte_data(ts->i2c, reg);
222 }
223 
224 static void rpi_touchscreen_i2c_write(struct rpi_touchscreen *ts,
225 				      u8 reg, u8 val)
226 {
227 	int ret;
228 
229 	ret = i2c_smbus_write_byte_data(ts->i2c, reg, val);
230 	if (ret)
231 		dev_err(&ts->i2c->dev, "I2C write failed: %d\n", ret);
232 }
233 
234 static int rpi_touchscreen_write(struct rpi_touchscreen *ts, u16 reg, u32 val)
235 {
236 	u8 msg[] = {
237 		reg,
238 		reg >> 8,
239 		val,
240 		val >> 8,
241 		val >> 16,
242 		val >> 24,
243 	};
244 
245 	mipi_dsi_generic_write(ts->dsi, msg, sizeof(msg));
246 
247 	return 0;
248 }
249 
250 static int rpi_touchscreen_disable(struct drm_panel *panel)
251 {
252 	struct rpi_touchscreen *ts = panel_to_ts(panel);
253 
254 	rpi_touchscreen_i2c_write(ts, REG_PWM, 0);
255 
256 	rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);
257 	udelay(1);
258 
259 	return 0;
260 }
261 
262 static int rpi_touchscreen_noop(struct drm_panel *panel)
263 {
264 	return 0;
265 }
266 
267 static int rpi_touchscreen_prepare(struct drm_panel *panel)
268 {
269 	struct rpi_touchscreen *ts = panel_to_ts(panel);
270 	int i;
271 
272 	rpi_touchscreen_i2c_write(ts, REG_POWERON, 1);
273 	/* Wait for nPWRDWN to go low to indicate poweron is done. */
274 	for (i = 0; i < 100; i++) {
275 		if (rpi_touchscreen_i2c_read(ts, REG_PORTB) & 1)
276 			break;
277 	}
278 
279 	rpi_touchscreen_write(ts, DSI_LANEENABLE,
280 			      DSI_LANEENABLE_CLOCK |
281 			      DSI_LANEENABLE_D0);
282 	rpi_touchscreen_write(ts, PPI_D0S_CLRSIPOCOUNT, 0x05);
283 	rpi_touchscreen_write(ts, PPI_D1S_CLRSIPOCOUNT, 0x05);
284 	rpi_touchscreen_write(ts, PPI_D0S_ATMR, 0x00);
285 	rpi_touchscreen_write(ts, PPI_D1S_ATMR, 0x00);
286 	rpi_touchscreen_write(ts, PPI_LPTXTIMECNT, 0x03);
287 
288 	rpi_touchscreen_write(ts, SPICMR, 0x00);
289 	rpi_touchscreen_write(ts, LCDCTRL, 0x00100150);
290 	rpi_touchscreen_write(ts, SYSCTRL, 0x040f);
291 	msleep(100);
292 
293 	rpi_touchscreen_write(ts, PPI_STARTPPI, 0x01);
294 	rpi_touchscreen_write(ts, DSI_STARTDSI, 0x01);
295 	msleep(100);
296 
297 	return 0;
298 }
299 
300 static int rpi_touchscreen_enable(struct drm_panel *panel)
301 {
302 	struct rpi_touchscreen *ts = panel_to_ts(panel);
303 
304 	/* Turn on the backlight. */
305 	rpi_touchscreen_i2c_write(ts, REG_PWM, 255);
306 
307 	/* Default to the same orientation as the closed source
308 	 * firmware used for the panel.  Runtime rotation
309 	 * configuration will be supported using VC4's plane
310 	 * orientation bits.
311 	 */
312 	rpi_touchscreen_i2c_write(ts, REG_PORTA, BIT(2));
313 
314 	return 0;
315 }
316 
317 static int rpi_touchscreen_get_modes(struct drm_panel *panel,
318 				     struct drm_connector *connector)
319 {
320 	unsigned int i, num = 0;
321 	static const u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
322 
323 	for (i = 0; i < ARRAY_SIZE(rpi_touchscreen_modes); i++) {
324 		const struct drm_display_mode *m = &rpi_touchscreen_modes[i];
325 		struct drm_display_mode *mode;
326 
327 		mode = drm_mode_duplicate(connector->dev, m);
328 		if (!mode) {
329 			dev_err(panel->dev, "failed to add mode %ux%u@%u\n",
330 				m->hdisplay, m->vdisplay,
331 				drm_mode_vrefresh(m));
332 			continue;
333 		}
334 
335 		mode->type |= DRM_MODE_TYPE_DRIVER;
336 
337 		if (i == 0)
338 			mode->type |= DRM_MODE_TYPE_PREFERRED;
339 
340 		drm_mode_set_name(mode);
341 
342 		drm_mode_probed_add(connector, mode);
343 		num++;
344 	}
345 
346 	connector->display_info.bpc = 8;
347 	connector->display_info.width_mm = 154;
348 	connector->display_info.height_mm = 86;
349 	drm_display_info_set_bus_formats(&connector->display_info,
350 					 &bus_format, 1);
351 
352 	return num;
353 }
354 
355 static const struct drm_panel_funcs rpi_touchscreen_funcs = {
356 	.disable = rpi_touchscreen_disable,
357 	.unprepare = rpi_touchscreen_noop,
358 	.prepare = rpi_touchscreen_prepare,
359 	.enable = rpi_touchscreen_enable,
360 	.get_modes = rpi_touchscreen_get_modes,
361 };
362 
363 static int rpi_touchscreen_probe(struct i2c_client *i2c)
364 {
365 	struct device *dev = &i2c->dev;
366 	struct rpi_touchscreen *ts;
367 	struct device_node *endpoint, *dsi_host_node;
368 	struct mipi_dsi_host *host;
369 	int ver;
370 	struct mipi_dsi_device_info info = {
371 		.type = RPI_DSI_DRIVER_NAME,
372 		.channel = 0,
373 		.node = NULL,
374 	};
375 
376 	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
377 	if (!ts)
378 		return -ENOMEM;
379 
380 	i2c_set_clientdata(i2c, ts);
381 
382 	ts->i2c = i2c;
383 
384 	ver = rpi_touchscreen_i2c_read(ts, REG_ID);
385 	if (ver < 0) {
386 		dev_err(dev, "Atmel I2C read failed: %d\n", ver);
387 		return -ENODEV;
388 	}
389 
390 	switch (ver) {
391 	case 0xde: /* ver 1 */
392 	case 0xc3: /* ver 2 */
393 		break;
394 	default:
395 		dev_err(dev, "Unknown Atmel firmware revision: 0x%02x\n", ver);
396 		return -ENODEV;
397 	}
398 
399 	/* Turn off at boot, so we can cleanly sequence powering on. */
400 	rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);
401 
402 	/* Look up the DSI host.  It needs to probe before we do. */
403 	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
404 	if (!endpoint)
405 		return -ENODEV;
406 
407 	dsi_host_node = of_graph_get_remote_port_parent(endpoint);
408 	if (!dsi_host_node)
409 		goto error;
410 
411 	host = of_find_mipi_dsi_host_by_node(dsi_host_node);
412 	of_node_put(dsi_host_node);
413 	if (!host) {
414 		of_node_put(endpoint);
415 		return -EPROBE_DEFER;
416 	}
417 
418 	info.node = of_graph_get_remote_port(endpoint);
419 	if (!info.node)
420 		goto error;
421 
422 	of_node_put(endpoint);
423 
424 	ts->dsi = mipi_dsi_device_register_full(host, &info);
425 	if (IS_ERR(ts->dsi)) {
426 		dev_err(dev, "DSI device registration failed: %ld\n",
427 			PTR_ERR(ts->dsi));
428 		return PTR_ERR(ts->dsi);
429 	}
430 
431 	drm_panel_init(&ts->base, dev, &rpi_touchscreen_funcs,
432 		       DRM_MODE_CONNECTOR_DSI);
433 
434 	/* This appears last, as it's what will unblock the DSI host
435 	 * driver's component bind function.
436 	 */
437 	drm_panel_add(&ts->base);
438 
439 	return 0;
440 
441 error:
442 	of_node_put(endpoint);
443 	return -ENODEV;
444 }
445 
446 static void rpi_touchscreen_remove(struct i2c_client *i2c)
447 {
448 	struct rpi_touchscreen *ts = i2c_get_clientdata(i2c);
449 
450 	mipi_dsi_detach(ts->dsi);
451 
452 	drm_panel_remove(&ts->base);
453 
454 	mipi_dsi_device_unregister(ts->dsi);
455 }
456 
457 static int rpi_touchscreen_dsi_probe(struct mipi_dsi_device *dsi)
458 {
459 	int ret;
460 
461 	dsi->mode_flags = (MIPI_DSI_MODE_VIDEO |
462 			   MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
463 			   MIPI_DSI_MODE_LPM);
464 	dsi->format = MIPI_DSI_FMT_RGB888;
465 	dsi->lanes = 1;
466 
467 	ret = mipi_dsi_attach(dsi);
468 
469 	if (ret)
470 		dev_err(&dsi->dev, "failed to attach dsi to host: %d\n", ret);
471 
472 	return ret;
473 }
474 
475 static struct mipi_dsi_driver rpi_touchscreen_dsi_driver = {
476 	.driver.name = RPI_DSI_DRIVER_NAME,
477 	.probe = rpi_touchscreen_dsi_probe,
478 };
479 
480 static const struct of_device_id rpi_touchscreen_of_ids[] = {
481 	{ .compatible = "raspberrypi,7inch-touchscreen-panel" },
482 	{ } /* sentinel */
483 };
484 MODULE_DEVICE_TABLE(of, rpi_touchscreen_of_ids);
485 
486 static struct i2c_driver rpi_touchscreen_driver = {
487 	.driver = {
488 		.name = "rpi_touchscreen",
489 		.of_match_table = rpi_touchscreen_of_ids,
490 	},
491 	.probe = rpi_touchscreen_probe,
492 	.remove = rpi_touchscreen_remove,
493 };
494 
495 static int __init rpi_touchscreen_init(void)
496 {
497 	mipi_dsi_driver_register(&rpi_touchscreen_dsi_driver);
498 	return i2c_add_driver(&rpi_touchscreen_driver);
499 }
500 module_init(rpi_touchscreen_init);
501 
502 static void __exit rpi_touchscreen_exit(void)
503 {
504 	i2c_del_driver(&rpi_touchscreen_driver);
505 	mipi_dsi_driver_unregister(&rpi_touchscreen_dsi_driver);
506 }
507 module_exit(rpi_touchscreen_exit);
508 
509 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
510 MODULE_DESCRIPTION("Raspberry Pi 7-inch touchscreen driver");
511 MODULE_LICENSE("GPL v2");
512