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. */
 64enum 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
194struct rpi_touchscreen {
195	struct drm_panel base;
196	struct mipi_dsi_device *dsi;
197	struct i2c_client *i2c;
198};
199
200static 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
218static struct rpi_touchscreen *panel_to_ts(struct drm_panel *panel)
219{
220	return container_of(panel, struct rpi_touchscreen, base);
221}
222
223static int rpi_touchscreen_i2c_read(struct rpi_touchscreen *ts, u8 reg)
224{
225	return i2c_smbus_read_byte_data(ts->i2c, reg);
226}
227
228static 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
238static 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
254static 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
266static int rpi_touchscreen_noop(struct drm_panel *panel)
267{
268	return 0;
269}
270
271static 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
314static 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
352static 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
360static 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
441error:
442	of_node_put(endpoint);
443	return -ENODEV;
444}
445
446static 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
460static 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
478static struct mipi_dsi_driver rpi_touchscreen_dsi_driver = {
479	.driver.name = RPI_DSI_DRIVER_NAME,
480	.probe = rpi_touchscreen_dsi_probe,
481};
482
483static const struct of_device_id rpi_touchscreen_of_ids[] = {
484	{ .compatible = "raspberrypi,7inch-touchscreen-panel" },
485	{ } /* sentinel */
486};
487MODULE_DEVICE_TABLE(of, rpi_touchscreen_of_ids);
488
489static 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
498static 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}
503module_init(rpi_touchscreen_init);
504
505static void __exit rpi_touchscreen_exit(void)
506{
507	i2c_del_driver(&rpi_touchscreen_driver);
508	mipi_dsi_driver_unregister(&rpi_touchscreen_dsi_driver);
509}
510module_exit(rpi_touchscreen_exit);
511
512MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
513MODULE_DESCRIPTION("Raspberry Pi 7-inch touchscreen driver");
514MODULE_LICENSE("GPL v2");