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/fb.h>
47 #include <linux/gpio.h>
48 #include <linux/gpio/consumer.h>
49 #include <linux/i2c.h>
50 #include <linux/module.h>
51 #include <linux/of.h>
52 #include <linux/of_device.h>
53 #include <linux/of_graph.h>
54 #include <linux/pm.h>
55 
56 #include <drm/drm_crtc.h>
57 #include <drm/drm_device.h>
58 #include <drm/drm_mipi_dsi.h>
59 #include <drm/drm_panel.h>
60 
61 #define RPI_DSI_DRIVER_NAME "rpi-ts-dsi"
62 
63 /* I2C registers of the Atmel microcontroller. */
64 enum REG_ADDR {
65 	REG_ID = 0x80,
66 	REG_PORTA, /* BIT(2) for horizontal flip, BIT(3) for vertical flip */
67 	REG_PORTB,
68 	REG_PORTC,
69 	REG_PORTD,
70 	REG_POWERON,
71 	REG_PWM,
72 	REG_DDRA,
73 	REG_DDRB,
74 	REG_DDRC,
75 	REG_DDRD,
76 	REG_TEST,
77 	REG_WR_ADDRL,
78 	REG_WR_ADDRH,
79 	REG_READH,
80 	REG_READL,
81 	REG_WRITEH,
82 	REG_WRITEL,
83 	REG_ID2,
84 };
85 
86 /* DSI D-PHY Layer Registers */
87 #define D0W_DPHYCONTTX		0x0004
88 #define CLW_DPHYCONTRX		0x0020
89 #define D0W_DPHYCONTRX		0x0024
90 #define D1W_DPHYCONTRX		0x0028
91 #define COM_DPHYCONTRX		0x0038
92 #define CLW_CNTRL		0x0040
93 #define D0W_CNTRL		0x0044
94 #define D1W_CNTRL		0x0048
95 #define DFTMODE_CNTRL		0x0054
96 
97 /* DSI PPI Layer Registers */
98 #define PPI_STARTPPI		0x0104
99 #define PPI_BUSYPPI		0x0108
100 #define PPI_LINEINITCNT		0x0110
101 #define PPI_LPTXTIMECNT		0x0114
102 #define PPI_CLS_ATMR		0x0140
103 #define PPI_D0S_ATMR		0x0144
104 #define PPI_D1S_ATMR		0x0148
105 #define PPI_D0S_CLRSIPOCOUNT	0x0164
106 #define PPI_D1S_CLRSIPOCOUNT	0x0168
107 #define CLS_PRE			0x0180
108 #define D0S_PRE			0x0184
109 #define D1S_PRE			0x0188
110 #define CLS_PREP		0x01A0
111 #define D0S_PREP		0x01A4
112 #define D1S_PREP		0x01A8
113 #define CLS_ZERO		0x01C0
114 #define D0S_ZERO		0x01C4
115 #define D1S_ZERO		0x01C8
116 #define PPI_CLRFLG		0x01E0
117 #define PPI_CLRSIPO		0x01E4
118 #define HSTIMEOUT		0x01F0
119 #define HSTIMEOUTENABLE		0x01F4
120 
121 /* DSI Protocol Layer Registers */
122 #define DSI_STARTDSI		0x0204
123 #define DSI_BUSYDSI		0x0208
124 #define DSI_LANEENABLE		0x0210
125 # define DSI_LANEENABLE_CLOCK		BIT(0)
126 # define DSI_LANEENABLE_D0		BIT(1)
127 # define DSI_LANEENABLE_D1		BIT(2)
128 
129 #define DSI_LANESTATUS0		0x0214
130 #define DSI_LANESTATUS1		0x0218
131 #define DSI_INTSTATUS		0x0220
132 #define DSI_INTMASK		0x0224
133 #define DSI_INTCLR		0x0228
134 #define DSI_LPTXTO		0x0230
135 #define DSI_MODE		0x0260
136 #define DSI_PAYLOAD0		0x0268
137 #define DSI_PAYLOAD1		0x026C
138 #define DSI_SHORTPKTDAT		0x0270
139 #define DSI_SHORTPKTREQ		0x0274
140 #define DSI_BTASTA		0x0278
141 #define DSI_BTACLR		0x027C
142 
143 /* DSI General Registers */
144 #define DSIERRCNT		0x0300
145 #define DSISIGMOD		0x0304
146 
147 /* DSI Application Layer Registers */
148 #define APLCTRL			0x0400
149 #define APLSTAT			0x0404
150 #define APLERR			0x0408
151 #define PWRMOD			0x040C
152 #define RDPKTLN			0x0410
153 #define PXLFMT			0x0414
154 #define MEMWRCMD		0x0418
155 
156 /* LCDC/DPI Host Registers */
157 #define LCDCTRL			0x0420
158 #define HSR			0x0424
159 #define HDISPR			0x0428
160 #define VSR			0x042C
161 #define VDISPR			0x0430
162 #define VFUEN			0x0434
163 
164 /* DBI-B Host Registers */
165 #define DBIBCTRL		0x0440
166 
167 /* SPI Master Registers */
168 #define SPICMR			0x0450
169 #define SPITCR			0x0454
170 
171 /* System Controller Registers */
172 #define SYSSTAT			0x0460
173 #define SYSCTRL			0x0464
174 #define SYSPLL1			0x0468
175 #define SYSPLL2			0x046C
176 #define SYSPLL3			0x0470
177 #define SYSPMCTRL		0x047C
178 
179 /* GPIO Registers */
180 #define GPIOC			0x0480
181 #define GPIOO			0x0484
182 #define GPIOI			0x0488
183 
184 /* I2C Registers */
185 #define I2CCLKCTRL		0x0490
186 
187 /* Chip/Rev Registers */
188 #define IDREG			0x04A0
189 
190 /* Debug Registers */
191 #define WCMDQUEUE		0x0500
192 #define RCMDQUEUE		0x0504
193 
194 struct rpi_touchscreen {
195 	struct drm_panel base;
196 	struct mipi_dsi_device *dsi;
197 	struct i2c_client *i2c;
198 };
199 
200 static const struct drm_display_mode rpi_touchscreen_modes[] = {
201 	{
202 		/* Modeline comes from the Raspberry Pi firmware, with HFP=1
203 		 * plugged in and clock re-computed from that.
204 		 */
205 		.clock = 25979400 / 1000,
206 		.hdisplay = 800,
207 		.hsync_start = 800 + 1,
208 		.hsync_end = 800 + 1 + 2,
209 		.htotal = 800 + 1 + 2 + 46,
210 		.vdisplay = 480,
211 		.vsync_start = 480 + 7,
212 		.vsync_end = 480 + 7 + 2,
213 		.vtotal = 480 + 7 + 2 + 21,
214 		.vrefresh = 60,
215 	},
216 };
217 
218 static struct rpi_touchscreen *panel_to_ts(struct drm_panel *panel)
219 {
220 	return container_of(panel, struct rpi_touchscreen, base);
221 }
222 
223 static int rpi_touchscreen_i2c_read(struct rpi_touchscreen *ts, u8 reg)
224 {
225 	return i2c_smbus_read_byte_data(ts->i2c, reg);
226 }
227 
228 static void rpi_touchscreen_i2c_write(struct rpi_touchscreen *ts,
229 				      u8 reg, u8 val)
230 {
231 	int ret;
232 
233 	ret = i2c_smbus_write_byte_data(ts->i2c, reg, val);
234 	if (ret)
235 		dev_err(&ts->dsi->dev, "I2C write failed: %d\n", ret);
236 }
237 
238 static int rpi_touchscreen_write(struct rpi_touchscreen *ts, u16 reg, u32 val)
239 {
240 	u8 msg[] = {
241 		reg,
242 		reg >> 8,
243 		val,
244 		val >> 8,
245 		val >> 16,
246 		val >> 24,
247 	};
248 
249 	mipi_dsi_generic_write(ts->dsi, msg, sizeof(msg));
250 
251 	return 0;
252 }
253 
254 static int rpi_touchscreen_disable(struct drm_panel *panel)
255 {
256 	struct rpi_touchscreen *ts = panel_to_ts(panel);
257 
258 	rpi_touchscreen_i2c_write(ts, REG_PWM, 0);
259 
260 	rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);
261 	udelay(1);
262 
263 	return 0;
264 }
265 
266 static int rpi_touchscreen_noop(struct drm_panel *panel)
267 {
268 	return 0;
269 }
270 
271 static int rpi_touchscreen_enable(struct drm_panel *panel)
272 {
273 	struct rpi_touchscreen *ts = panel_to_ts(panel);
274 	int i;
275 
276 	rpi_touchscreen_i2c_write(ts, REG_POWERON, 1);
277 	/* Wait for nPWRDWN to go low to indicate poweron is done. */
278 	for (i = 0; i < 100; i++) {
279 		if (rpi_touchscreen_i2c_read(ts, REG_PORTB) & 1)
280 			break;
281 	}
282 
283 	rpi_touchscreen_write(ts, DSI_LANEENABLE,
284 			      DSI_LANEENABLE_CLOCK |
285 			      DSI_LANEENABLE_D0);
286 	rpi_touchscreen_write(ts, PPI_D0S_CLRSIPOCOUNT, 0x05);
287 	rpi_touchscreen_write(ts, PPI_D1S_CLRSIPOCOUNT, 0x05);
288 	rpi_touchscreen_write(ts, PPI_D0S_ATMR, 0x00);
289 	rpi_touchscreen_write(ts, PPI_D1S_ATMR, 0x00);
290 	rpi_touchscreen_write(ts, PPI_LPTXTIMECNT, 0x03);
291 
292 	rpi_touchscreen_write(ts, SPICMR, 0x00);
293 	rpi_touchscreen_write(ts, LCDCTRL, 0x00100150);
294 	rpi_touchscreen_write(ts, SYSCTRL, 0x040f);
295 	msleep(100);
296 
297 	rpi_touchscreen_write(ts, PPI_STARTPPI, 0x01);
298 	rpi_touchscreen_write(ts, DSI_STARTDSI, 0x01);
299 	msleep(100);
300 
301 	/* Turn on the backlight. */
302 	rpi_touchscreen_i2c_write(ts, REG_PWM, 255);
303 
304 	/* Default to the same orientation as the closed source
305 	 * firmware used for the panel.  Runtime rotation
306 	 * configuration will be supported using VC4's plane
307 	 * orientation bits.
308 	 */
309 	rpi_touchscreen_i2c_write(ts, REG_PORTA, BIT(2));
310 
311 	return 0;
312 }
313 
314 static int rpi_touchscreen_get_modes(struct drm_panel *panel)
315 {
316 	struct drm_connector *connector = panel->connector;
317 	struct drm_device *drm = panel->drm;
318 	unsigned int i, num = 0;
319 	static const u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
320 
321 	for (i = 0; i < ARRAY_SIZE(rpi_touchscreen_modes); i++) {
322 		const struct drm_display_mode *m = &rpi_touchscreen_modes[i];
323 		struct drm_display_mode *mode;
324 
325 		mode = drm_mode_duplicate(drm, m);
326 		if (!mode) {
327 			dev_err(drm->dev, "failed to add mode %ux%u@%u\n",
328 				m->hdisplay, m->vdisplay, m->vrefresh);
329 			continue;
330 		}
331 
332 		mode->type |= DRM_MODE_TYPE_DRIVER;
333 
334 		if (i == 0)
335 			mode->type |= DRM_MODE_TYPE_PREFERRED;
336 
337 		drm_mode_set_name(mode);
338 
339 		drm_mode_probed_add(connector, mode);
340 		num++;
341 	}
342 
343 	connector->display_info.bpc = 8;
344 	connector->display_info.width_mm = 154;
345 	connector->display_info.height_mm = 86;
346 	drm_display_info_set_bus_formats(&connector->display_info,
347 					 &bus_format, 1);
348 
349 	return num;
350 }
351 
352 static const struct drm_panel_funcs rpi_touchscreen_funcs = {
353 	.disable = rpi_touchscreen_disable,
354 	.unprepare = rpi_touchscreen_noop,
355 	.prepare = rpi_touchscreen_noop,
356 	.enable = rpi_touchscreen_enable,
357 	.get_modes = rpi_touchscreen_get_modes,
358 };
359 
360 static int rpi_touchscreen_probe(struct i2c_client *i2c,
361 				 const struct i2c_device_id *id)
362 {
363 	struct device *dev = &i2c->dev;
364 	struct rpi_touchscreen *ts;
365 	struct device_node *endpoint, *dsi_host_node;
366 	struct mipi_dsi_host *host;
367 	int ret, ver;
368 	struct mipi_dsi_device_info info = {
369 		.type = RPI_DSI_DRIVER_NAME,
370 		.channel = 0,
371 		.node = NULL,
372 	};
373 
374 	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
375 	if (!ts)
376 		return -ENOMEM;
377 
378 	i2c_set_clientdata(i2c, ts);
379 
380 	ts->i2c = i2c;
381 
382 	ver = rpi_touchscreen_i2c_read(ts, REG_ID);
383 	if (ver < 0) {
384 		dev_err(dev, "Atmel I2C read failed: %d\n", ver);
385 		return -ENODEV;
386 	}
387 
388 	switch (ver) {
389 	case 0xde: /* ver 1 */
390 	case 0xc3: /* ver 2 */
391 		break;
392 	default:
393 		dev_err(dev, "Unknown Atmel firmware revision: 0x%02x\n", ver);
394 		return -ENODEV;
395 	}
396 
397 	/* Turn off at boot, so we can cleanly sequence powering on. */
398 	rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);
399 
400 	/* Look up the DSI host.  It needs to probe before we do. */
401 	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
402 	if (!endpoint)
403 		return -ENODEV;
404 
405 	dsi_host_node = of_graph_get_remote_port_parent(endpoint);
406 	if (!dsi_host_node)
407 		goto error;
408 
409 	host = of_find_mipi_dsi_host_by_node(dsi_host_node);
410 	of_node_put(dsi_host_node);
411 	if (!host) {
412 		of_node_put(endpoint);
413 		return -EPROBE_DEFER;
414 	}
415 
416 	info.node = of_graph_get_remote_port(endpoint);
417 	if (!info.node)
418 		goto error;
419 
420 	of_node_put(endpoint);
421 
422 	ts->dsi = mipi_dsi_device_register_full(host, &info);
423 	if (IS_ERR(ts->dsi)) {
424 		dev_err(dev, "DSI device registration failed: %ld\n",
425 			PTR_ERR(ts->dsi));
426 		return PTR_ERR(ts->dsi);
427 	}
428 
429 	ts->base.dev = dev;
430 	ts->base.funcs = &rpi_touchscreen_funcs;
431 
432 	/* This appears last, as it's what will unblock the DSI host
433 	 * driver's component bind function.
434 	 */
435 	ret = drm_panel_add(&ts->base);
436 	if (ret)
437 		return ret;
438 
439 	return 0;
440 
441 error:
442 	of_node_put(endpoint);
443 	return -ENODEV;
444 }
445 
446 static int 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 	kfree(ts->dsi);
456 
457 	return 0;
458 }
459 
460 static int rpi_touchscreen_dsi_probe(struct mipi_dsi_device *dsi)
461 {
462 	int ret;
463 
464 	dsi->mode_flags = (MIPI_DSI_MODE_VIDEO |
465 			   MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
466 			   MIPI_DSI_MODE_LPM);
467 	dsi->format = MIPI_DSI_FMT_RGB888;
468 	dsi->lanes = 1;
469 
470 	ret = mipi_dsi_attach(dsi);
471 
472 	if (ret)
473 		dev_err(&dsi->dev, "failed to attach dsi to host: %d\n", ret);
474 
475 	return ret;
476 }
477 
478 static struct mipi_dsi_driver rpi_touchscreen_dsi_driver = {
479 	.driver.name = RPI_DSI_DRIVER_NAME,
480 	.probe = rpi_touchscreen_dsi_probe,
481 };
482 
483 static const struct of_device_id rpi_touchscreen_of_ids[] = {
484 	{ .compatible = "raspberrypi,7inch-touchscreen-panel" },
485 	{ } /* sentinel */
486 };
487 MODULE_DEVICE_TABLE(of, rpi_touchscreen_of_ids);
488 
489 static struct i2c_driver rpi_touchscreen_driver = {
490 	.driver = {
491 		.name = "rpi_touchscreen",
492 		.of_match_table = rpi_touchscreen_of_ids,
493 	},
494 	.probe = rpi_touchscreen_probe,
495 	.remove = rpi_touchscreen_remove,
496 };
497 
498 static int __init rpi_touchscreen_init(void)
499 {
500 	mipi_dsi_driver_register(&rpi_touchscreen_dsi_driver);
501 	return i2c_add_driver(&rpi_touchscreen_driver);
502 }
503 module_init(rpi_touchscreen_init);
504 
505 static void __exit rpi_touchscreen_exit(void)
506 {
507 	i2c_del_driver(&rpi_touchscreen_driver);
508 	mipi_dsi_driver_unregister(&rpi_touchscreen_dsi_driver);
509 }
510 module_exit(rpi_touchscreen_exit);
511 
512 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
513 MODULE_DESCRIPTION("Raspberry Pi 7-inch touchscreen driver");
514 MODULE_LICENSE("GPL v2");
515