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. */
 65enum 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
195struct rpi_touchscreen {
196	struct drm_panel base;
197	struct mipi_dsi_device *dsi;
198	struct i2c_client *i2c;
199};
200
201static 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
219static struct rpi_touchscreen *panel_to_ts(struct drm_panel *panel)
220{
221	return container_of(panel, struct rpi_touchscreen, base);
222}
223
224static int rpi_touchscreen_i2c_read(struct rpi_touchscreen *ts, u8 reg)
225{
226	return i2c_smbus_read_byte_data(ts->i2c, reg);
227}
228
229static 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
239static int rpi_touchscreen_write(struct rpi_touchscreen *ts, u16 reg, u32 val)
240{
241#if 0
242	/* The firmware uses LP DSI transactions like this to bring up
243	 * the hardware, which should be faster than using I2C to then
244	 * pass to the Toshiba.  However, I was unable to get it to
245	 * work.
246	 */
247	u8 msg[] = {
248		reg,
249		reg >> 8,
250		val,
251		val >> 8,
252		val >> 16,
253		val >> 24,
254	};
255
256	mipi_dsi_dcs_write_buffer(ts->dsi, msg, sizeof(msg));
257#else
258	rpi_touchscreen_i2c_write(ts, REG_WR_ADDRH, reg >> 8);
259	rpi_touchscreen_i2c_write(ts, REG_WR_ADDRL, reg);
260	rpi_touchscreen_i2c_write(ts, REG_WRITEH, val >> 8);
261	rpi_touchscreen_i2c_write(ts, REG_WRITEL, val);
262#endif
263
264	return 0;
265}
266
267static int rpi_touchscreen_disable(struct drm_panel *panel)
268{
269	struct rpi_touchscreen *ts = panel_to_ts(panel);
270
271	rpi_touchscreen_i2c_write(ts, REG_PWM, 0);
272
273	rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);
274	udelay(1);
275
276	return 0;
277}
278
279static int rpi_touchscreen_noop(struct drm_panel *panel)
280{
281	return 0;
282}
283
284static int rpi_touchscreen_enable(struct drm_panel *panel)
285{
286	struct rpi_touchscreen *ts = panel_to_ts(panel);
287	int i;
288
289	rpi_touchscreen_i2c_write(ts, REG_POWERON, 1);
290	/* Wait for nPWRDWN to go low to indicate poweron is done. */
291	for (i = 0; i < 100; i++) {
292		if (rpi_touchscreen_i2c_read(ts, REG_PORTB) & 1)
293			break;
294	}
295
296	rpi_touchscreen_write(ts, DSI_LANEENABLE,
297			      DSI_LANEENABLE_CLOCK |
298			      DSI_LANEENABLE_D0);
299	rpi_touchscreen_write(ts, PPI_D0S_CLRSIPOCOUNT, 0x05);
300	rpi_touchscreen_write(ts, PPI_D1S_CLRSIPOCOUNT, 0x05);
301	rpi_touchscreen_write(ts, PPI_D0S_ATMR, 0x00);
302	rpi_touchscreen_write(ts, PPI_D1S_ATMR, 0x00);
303	rpi_touchscreen_write(ts, PPI_LPTXTIMECNT, 0x03);
304
305	rpi_touchscreen_write(ts, SPICMR, 0x00);
306	rpi_touchscreen_write(ts, LCDCTRL, 0x00100150);
307	rpi_touchscreen_write(ts, SYSCTRL, 0x040f);
308	msleep(100);
309
310	rpi_touchscreen_write(ts, PPI_STARTPPI, 0x01);
311	rpi_touchscreen_write(ts, DSI_STARTDSI, 0x01);
312	msleep(100);
313
314	/* Turn on the backlight. */
315	rpi_touchscreen_i2c_write(ts, REG_PWM, 255);
316
317	/* Default to the same orientation as the closed source
318	 * firmware used for the panel.  Runtime rotation
319	 * configuration will be supported using VC4's plane
320	 * orientation bits.
321	 */
322	rpi_touchscreen_i2c_write(ts, REG_PORTA, BIT(2));
323
324	return 0;
325}
326
327static int rpi_touchscreen_get_modes(struct drm_panel *panel)
328{
329	struct drm_connector *connector = panel->connector;
330	struct drm_device *drm = panel->drm;
331	unsigned int i, num = 0;
332	static const u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
333
334	for (i = 0; i < ARRAY_SIZE(rpi_touchscreen_modes); i++) {
335		const struct drm_display_mode *m = &rpi_touchscreen_modes[i];
336		struct drm_display_mode *mode;
337
338		mode = drm_mode_duplicate(drm, m);
339		if (!mode) {
340			dev_err(drm->dev, "failed to add mode %ux%u@%u\n",
341				m->hdisplay, m->vdisplay, m->vrefresh);
342			continue;
343		}
344
345		mode->type |= DRM_MODE_TYPE_DRIVER;
346
347		if (i == 0)
348			mode->type |= DRM_MODE_TYPE_PREFERRED;
349
350		drm_mode_set_name(mode);
351
352		drm_mode_probed_add(connector, mode);
353		num++;
354	}
355
356	connector->display_info.bpc = 8;
357	connector->display_info.width_mm = 154;
358	connector->display_info.height_mm = 86;
359	drm_display_info_set_bus_formats(&connector->display_info,
360					 &bus_format, 1);
361
362	return num;
363}
364
365static const struct drm_panel_funcs rpi_touchscreen_funcs = {
366	.disable = rpi_touchscreen_disable,
367	.unprepare = rpi_touchscreen_noop,
368	.prepare = rpi_touchscreen_noop,
369	.enable = rpi_touchscreen_enable,
370	.get_modes = rpi_touchscreen_get_modes,
371};
372
373static int rpi_touchscreen_probe(struct i2c_client *i2c,
374				 const struct i2c_device_id *id)
375{
376	struct device *dev = &i2c->dev;
377	struct rpi_touchscreen *ts;
378	struct device_node *endpoint, *dsi_host_node;
379	struct mipi_dsi_host *host;
380	int ret, ver;
381	struct mipi_dsi_device_info info = {
382		.type = RPI_DSI_DRIVER_NAME,
383		.channel = 0,
384		.node = NULL,
385	};
386
387	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
388	if (!ts)
389		return -ENOMEM;
390
391	i2c_set_clientdata(i2c, ts);
392
393	ts->i2c = i2c;
394
395	ver = rpi_touchscreen_i2c_read(ts, REG_ID);
396	if (ver < 0) {
397		dev_err(dev, "Atmel I2C read failed: %d\n", ver);
398		return -ENODEV;
399	}
400
401	switch (ver) {
402	case 0xde: /* ver 1 */
403	case 0xc3: /* ver 2 */
404		break;
405	default:
406		dev_err(dev, "Unknown Atmel firmware revision: 0x%02x\n", ver);
407		return -ENODEV;
408	}
409
410	/* Turn off at boot, so we can cleanly sequence powering on. */
411	rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);
412
413	/* Look up the DSI host.  It needs to probe before we do. */
414	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
415	dsi_host_node = of_graph_get_remote_port_parent(endpoint);
416	host = of_find_mipi_dsi_host_by_node(dsi_host_node);
417	of_node_put(dsi_host_node);
418	if (!host) {
419		of_node_put(endpoint);
420		return -EPROBE_DEFER;
421	}
422
423	info.node = of_graph_get_remote_port(endpoint);
424	of_node_put(endpoint);
425
426	ts->dsi = mipi_dsi_device_register_full(host, &info);
427	if (IS_ERR(ts->dsi)) {
428		dev_err(dev, "DSI device registration failed: %ld\n",
429			PTR_ERR(ts->dsi));
430		return PTR_ERR(ts->dsi);
431	}
432
433	ts->base.dev = dev;
434	ts->base.funcs = &rpi_touchscreen_funcs;
435
436	/* This appears last, as it's what will unblock the DSI host
437	 * driver's component bind function.
438	 */
439	ret = drm_panel_add(&ts->base);
440	if (ret)
441		return ret;
442
443	return 0;
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");