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_panel.h>
57 #include <drm/drmP.h>
58 #include <drm/drm_crtc.h>
59 #include <drm/drm_mipi_dsi.h>
60 #include <drm/drm_panel.h>
61 
62 #define RPI_DSI_DRIVER_NAME "rpi-ts-dsi"
63 
64 /* I2C registers of the Atmel microcontroller. */
65 enum REG_ADDR {
66 	REG_ID = 0x80,
67 	REG_PORTA, /* BIT(2) for horizontal flip, BIT(3) for vertical flip */
68 	REG_PORTB,
69 	REG_PORTC,
70 	REG_PORTD,
71 	REG_POWERON,
72 	REG_PWM,
73 	REG_DDRA,
74 	REG_DDRB,
75 	REG_DDRC,
76 	REG_DDRD,
77 	REG_TEST,
78 	REG_WR_ADDRL,
79 	REG_WR_ADDRH,
80 	REG_READH,
81 	REG_READL,
82 	REG_WRITEH,
83 	REG_WRITEL,
84 	REG_ID2,
85 };
86 
87 /* DSI D-PHY Layer Registers */
88 #define D0W_DPHYCONTTX		0x0004
89 #define CLW_DPHYCONTRX		0x0020
90 #define D0W_DPHYCONTRX		0x0024
91 #define D1W_DPHYCONTRX		0x0028
92 #define COM_DPHYCONTRX		0x0038
93 #define CLW_CNTRL		0x0040
94 #define D0W_CNTRL		0x0044
95 #define D1W_CNTRL		0x0048
96 #define DFTMODE_CNTRL		0x0054
97 
98 /* DSI PPI Layer Registers */
99 #define PPI_STARTPPI		0x0104
100 #define PPI_BUSYPPI		0x0108
101 #define PPI_LINEINITCNT		0x0110
102 #define PPI_LPTXTIMECNT		0x0114
103 #define PPI_CLS_ATMR		0x0140
104 #define PPI_D0S_ATMR		0x0144
105 #define PPI_D1S_ATMR		0x0148
106 #define PPI_D0S_CLRSIPOCOUNT	0x0164
107 #define PPI_D1S_CLRSIPOCOUNT	0x0168
108 #define CLS_PRE			0x0180
109 #define D0S_PRE			0x0184
110 #define D1S_PRE			0x0188
111 #define CLS_PREP		0x01A0
112 #define D0S_PREP		0x01A4
113 #define D1S_PREP		0x01A8
114 #define CLS_ZERO		0x01C0
115 #define D0S_ZERO		0x01C4
116 #define D1S_ZERO		0x01C8
117 #define PPI_CLRFLG		0x01E0
118 #define PPI_CLRSIPO		0x01E4
119 #define HSTIMEOUT		0x01F0
120 #define HSTIMEOUTENABLE		0x01F4
121 
122 /* DSI Protocol Layer Registers */
123 #define DSI_STARTDSI		0x0204
124 #define DSI_BUSYDSI		0x0208
125 #define DSI_LANEENABLE		0x0210
126 # define DSI_LANEENABLE_CLOCK		BIT(0)
127 # define DSI_LANEENABLE_D0		BIT(1)
128 # define DSI_LANEENABLE_D1		BIT(2)
129 
130 #define DSI_LANESTATUS0		0x0214
131 #define DSI_LANESTATUS1		0x0218
132 #define DSI_INTSTATUS		0x0220
133 #define DSI_INTMASK		0x0224
134 #define DSI_INTCLR		0x0228
135 #define DSI_LPTXTO		0x0230
136 #define DSI_MODE		0x0260
137 #define DSI_PAYLOAD0		0x0268
138 #define DSI_PAYLOAD1		0x026C
139 #define DSI_SHORTPKTDAT		0x0270
140 #define DSI_SHORTPKTREQ		0x0274
141 #define DSI_BTASTA		0x0278
142 #define DSI_BTACLR		0x027C
143 
144 /* DSI General Registers */
145 #define DSIERRCNT		0x0300
146 #define DSISIGMOD		0x0304
147 
148 /* DSI Application Layer Registers */
149 #define APLCTRL			0x0400
150 #define APLSTAT			0x0404
151 #define APLERR			0x0408
152 #define PWRMOD			0x040C
153 #define RDPKTLN			0x0410
154 #define PXLFMT			0x0414
155 #define MEMWRCMD		0x0418
156 
157 /* LCDC/DPI Host Registers */
158 #define LCDCTRL			0x0420
159 #define HSR			0x0424
160 #define HDISPR			0x0428
161 #define VSR			0x042C
162 #define VDISPR			0x0430
163 #define VFUEN			0x0434
164 
165 /* DBI-B Host Registers */
166 #define DBIBCTRL		0x0440
167 
168 /* SPI Master Registers */
169 #define SPICMR			0x0450
170 #define SPITCR			0x0454
171 
172 /* System Controller Registers */
173 #define SYSSTAT			0x0460
174 #define SYSCTRL			0x0464
175 #define SYSPLL1			0x0468
176 #define SYSPLL2			0x046C
177 #define SYSPLL3			0x0470
178 #define SYSPMCTRL		0x047C
179 
180 /* GPIO Registers */
181 #define GPIOC			0x0480
182 #define GPIOO			0x0484
183 #define GPIOI			0x0488
184 
185 /* I2C Registers */
186 #define I2CCLKCTRL		0x0490
187 
188 /* Chip/Rev Registers */
189 #define IDREG			0x04A0
190 
191 /* Debug Registers */
192 #define WCMDQUEUE		0x0500
193 #define RCMDQUEUE		0x0504
194 
195 struct rpi_touchscreen {
196 	struct drm_panel base;
197 	struct mipi_dsi_device *dsi;
198 	struct i2c_client *i2c;
199 };
200 
201 static const struct drm_display_mode rpi_touchscreen_modes[] = {
202 	{
203 		/* Modeline comes from the Raspberry Pi firmware, with HFP=1
204 		 * plugged in and clock re-computed from that.
205 		 */
206 		.clock = 25979400 / 1000,
207 		.hdisplay = 800,
208 		.hsync_start = 800 + 1,
209 		.hsync_end = 800 + 1 + 2,
210 		.htotal = 800 + 1 + 2 + 46,
211 		.vdisplay = 480,
212 		.vsync_start = 480 + 7,
213 		.vsync_end = 480 + 7 + 2,
214 		.vtotal = 480 + 7 + 2 + 21,
215 		.vrefresh = 60,
216 	},
217 };
218 
219 static struct rpi_touchscreen *panel_to_ts(struct drm_panel *panel)
220 {
221 	return container_of(panel, struct rpi_touchscreen, base);
222 }
223 
224 static int rpi_touchscreen_i2c_read(struct rpi_touchscreen *ts, u8 reg)
225 {
226 	return i2c_smbus_read_byte_data(ts->i2c, reg);
227 }
228 
229 static void rpi_touchscreen_i2c_write(struct rpi_touchscreen *ts,
230 				      u8 reg, u8 val)
231 {
232 	int ret;
233 
234 	ret = i2c_smbus_write_byte_data(ts->i2c, reg, val);
235 	if (ret)
236 		dev_err(&ts->dsi->dev, "I2C write failed: %d\n", ret);
237 }
238 
239 static int rpi_touchscreen_write(struct rpi_touchscreen *ts, u16 reg, u32 val)
240 {
241 	u8 msg[] = {
242 		reg,
243 		reg >> 8,
244 		val,
245 		val >> 8,
246 		val >> 16,
247 		val >> 24,
248 	};
249 
250 	mipi_dsi_generic_write(ts->dsi, msg, sizeof(msg));
251 
252 	return 0;
253 }
254 
255 static int rpi_touchscreen_disable(struct drm_panel *panel)
256 {
257 	struct rpi_touchscreen *ts = panel_to_ts(panel);
258 
259 	rpi_touchscreen_i2c_write(ts, REG_PWM, 0);
260 
261 	rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);
262 	udelay(1);
263 
264 	return 0;
265 }
266 
267 static int rpi_touchscreen_noop(struct drm_panel *panel)
268 {
269 	return 0;
270 }
271 
272 static int rpi_touchscreen_enable(struct drm_panel *panel)
273 {
274 	struct rpi_touchscreen *ts = panel_to_ts(panel);
275 	int i;
276 
277 	rpi_touchscreen_i2c_write(ts, REG_POWERON, 1);
278 	/* Wait for nPWRDWN to go low to indicate poweron is done. */
279 	for (i = 0; i < 100; i++) {
280 		if (rpi_touchscreen_i2c_read(ts, REG_PORTB) & 1)
281 			break;
282 	}
283 
284 	rpi_touchscreen_write(ts, DSI_LANEENABLE,
285 			      DSI_LANEENABLE_CLOCK |
286 			      DSI_LANEENABLE_D0);
287 	rpi_touchscreen_write(ts, PPI_D0S_CLRSIPOCOUNT, 0x05);
288 	rpi_touchscreen_write(ts, PPI_D1S_CLRSIPOCOUNT, 0x05);
289 	rpi_touchscreen_write(ts, PPI_D0S_ATMR, 0x00);
290 	rpi_touchscreen_write(ts, PPI_D1S_ATMR, 0x00);
291 	rpi_touchscreen_write(ts, PPI_LPTXTIMECNT, 0x03);
292 
293 	rpi_touchscreen_write(ts, SPICMR, 0x00);
294 	rpi_touchscreen_write(ts, LCDCTRL, 0x00100150);
295 	rpi_touchscreen_write(ts, SYSCTRL, 0x040f);
296 	msleep(100);
297 
298 	rpi_touchscreen_write(ts, PPI_STARTPPI, 0x01);
299 	rpi_touchscreen_write(ts, DSI_STARTDSI, 0x01);
300 	msleep(100);
301 
302 	/* Turn on the backlight. */
303 	rpi_touchscreen_i2c_write(ts, REG_PWM, 255);
304 
305 	/* Default to the same orientation as the closed source
306 	 * firmware used for the panel.  Runtime rotation
307 	 * configuration will be supported using VC4's plane
308 	 * orientation bits.
309 	 */
310 	rpi_touchscreen_i2c_write(ts, REG_PORTA, BIT(2));
311 
312 	return 0;
313 }
314 
315 static int rpi_touchscreen_get_modes(struct drm_panel *panel)
316 {
317 	struct drm_connector *connector = panel->connector;
318 	struct drm_device *drm = panel->drm;
319 	unsigned int i, num = 0;
320 	static const u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
321 
322 	for (i = 0; i < ARRAY_SIZE(rpi_touchscreen_modes); i++) {
323 		const struct drm_display_mode *m = &rpi_touchscreen_modes[i];
324 		struct drm_display_mode *mode;
325 
326 		mode = drm_mode_duplicate(drm, m);
327 		if (!mode) {
328 			dev_err(drm->dev, "failed to add mode %ux%u@%u\n",
329 				m->hdisplay, m->vdisplay, m->vrefresh);
330 			continue;
331 		}
332 
333 		mode->type |= DRM_MODE_TYPE_DRIVER;
334 
335 		if (i == 0)
336 			mode->type |= DRM_MODE_TYPE_PREFERRED;
337 
338 		drm_mode_set_name(mode);
339 
340 		drm_mode_probed_add(connector, mode);
341 		num++;
342 	}
343 
344 	connector->display_info.bpc = 8;
345 	connector->display_info.width_mm = 154;
346 	connector->display_info.height_mm = 86;
347 	drm_display_info_set_bus_formats(&connector->display_info,
348 					 &bus_format, 1);
349 
350 	return num;
351 }
352 
353 static const struct drm_panel_funcs rpi_touchscreen_funcs = {
354 	.disable = rpi_touchscreen_disable,
355 	.unprepare = rpi_touchscreen_noop,
356 	.prepare = rpi_touchscreen_noop,
357 	.enable = rpi_touchscreen_enable,
358 	.get_modes = rpi_touchscreen_get_modes,
359 };
360 
361 static int rpi_touchscreen_probe(struct i2c_client *i2c,
362 				 const struct i2c_device_id *id)
363 {
364 	struct device *dev = &i2c->dev;
365 	struct rpi_touchscreen *ts;
366 	struct device_node *endpoint, *dsi_host_node;
367 	struct mipi_dsi_host *host;
368 	int ret, ver;
369 	struct mipi_dsi_device_info info = {
370 		.type = RPI_DSI_DRIVER_NAME,
371 		.channel = 0,
372 		.node = NULL,
373 	};
374 
375 	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
376 	if (!ts)
377 		return -ENOMEM;
378 
379 	i2c_set_clientdata(i2c, ts);
380 
381 	ts->i2c = i2c;
382 
383 	ver = rpi_touchscreen_i2c_read(ts, REG_ID);
384 	if (ver < 0) {
385 		dev_err(dev, "Atmel I2C read failed: %d\n", ver);
386 		return -ENODEV;
387 	}
388 
389 	switch (ver) {
390 	case 0xde: /* ver 1 */
391 	case 0xc3: /* ver 2 */
392 		break;
393 	default:
394 		dev_err(dev, "Unknown Atmel firmware revision: 0x%02x\n", ver);
395 		return -ENODEV;
396 	}
397 
398 	/* Turn off at boot, so we can cleanly sequence powering on. */
399 	rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);
400 
401 	/* Look up the DSI host.  It needs to probe before we do. */
402 	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
403 	dsi_host_node = of_graph_get_remote_port_parent(endpoint);
404 	host = of_find_mipi_dsi_host_by_node(dsi_host_node);
405 	of_node_put(dsi_host_node);
406 	if (!host) {
407 		of_node_put(endpoint);
408 		return -EPROBE_DEFER;
409 	}
410 
411 	info.node = of_graph_get_remote_port(endpoint);
412 	of_node_put(endpoint);
413 
414 	ts->dsi = mipi_dsi_device_register_full(host, &info);
415 	if (IS_ERR(ts->dsi)) {
416 		dev_err(dev, "DSI device registration failed: %ld\n",
417 			PTR_ERR(ts->dsi));
418 		return PTR_ERR(ts->dsi);
419 	}
420 
421 	ts->base.dev = dev;
422 	ts->base.funcs = &rpi_touchscreen_funcs;
423 
424 	/* This appears last, as it's what will unblock the DSI host
425 	 * driver's component bind function.
426 	 */
427 	ret = drm_panel_add(&ts->base);
428 	if (ret)
429 		return ret;
430 
431 	return 0;
432 }
433 
434 static int rpi_touchscreen_remove(struct i2c_client *i2c)
435 {
436 	struct rpi_touchscreen *ts = i2c_get_clientdata(i2c);
437 
438 	mipi_dsi_detach(ts->dsi);
439 
440 	drm_panel_remove(&ts->base);
441 
442 	mipi_dsi_device_unregister(ts->dsi);
443 	kfree(ts->dsi);
444 
445 	return 0;
446 }
447 
448 static int rpi_touchscreen_dsi_probe(struct mipi_dsi_device *dsi)
449 {
450 	int ret;
451 
452 	dsi->mode_flags = (MIPI_DSI_MODE_VIDEO |
453 			   MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
454 			   MIPI_DSI_MODE_LPM);
455 	dsi->format = MIPI_DSI_FMT_RGB888;
456 	dsi->lanes = 1;
457 
458 	ret = mipi_dsi_attach(dsi);
459 
460 	if (ret)
461 		dev_err(&dsi->dev, "failed to attach dsi to host: %d\n", ret);
462 
463 	return ret;
464 }
465 
466 static struct mipi_dsi_driver rpi_touchscreen_dsi_driver = {
467 	.driver.name = RPI_DSI_DRIVER_NAME,
468 	.probe = rpi_touchscreen_dsi_probe,
469 };
470 
471 static const struct of_device_id rpi_touchscreen_of_ids[] = {
472 	{ .compatible = "raspberrypi,7inch-touchscreen-panel" },
473 	{ } /* sentinel */
474 };
475 MODULE_DEVICE_TABLE(of, rpi_touchscreen_of_ids);
476 
477 static struct i2c_driver rpi_touchscreen_driver = {
478 	.driver = {
479 		.name = "rpi_touchscreen",
480 		.of_match_table = rpi_touchscreen_of_ids,
481 	},
482 	.probe = rpi_touchscreen_probe,
483 	.remove = rpi_touchscreen_remove,
484 };
485 
486 static int __init rpi_touchscreen_init(void)
487 {
488 	mipi_dsi_driver_register(&rpi_touchscreen_dsi_driver);
489 	return i2c_add_driver(&rpi_touchscreen_driver);
490 }
491 module_init(rpi_touchscreen_init);
492 
493 static void __exit rpi_touchscreen_exit(void)
494 {
495 	i2c_del_driver(&rpi_touchscreen_driver);
496 	mipi_dsi_driver_unregister(&rpi_touchscreen_dsi_driver);
497 }
498 module_exit(rpi_touchscreen_exit);
499 
500 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
501 MODULE_DESCRIPTION("Raspberry Pi 7-inch touchscreen driver");
502 MODULE_LICENSE("GPL v2");
503