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/i2c.h>
 48#include <linux/media-bus-format.h>
 49#include <linux/module.h>
 50#include <linux/of.h>
 51#include <linux/of_device.h>
 52#include <linux/of_graph.h>
 53#include <linux/pm.h>
 54
 55#include <drm/drm_crtc.h>
 56#include <drm/drm_device.h>
 57#include <drm/drm_mipi_dsi.h>
 58#include <drm/drm_panel.h>
 59
 60#define RPI_DSI_DRIVER_NAME "rpi-ts-dsi"
 61
 62/* I2C registers of the Atmel microcontroller. */
 63enum REG_ADDR {
 64	REG_ID = 0x80,
 65	REG_PORTA, /* BIT(2) for horizontal flip, BIT(3) for vertical flip */
 66	REG_PORTB,
 67	REG_PORTC,
 68	REG_PORTD,
 69	REG_POWERON,
 70	REG_PWM,
 71	REG_DDRA,
 72	REG_DDRB,
 73	REG_DDRC,
 74	REG_DDRD,
 75	REG_TEST,
 76	REG_WR_ADDRL,
 77	REG_WR_ADDRH,
 78	REG_READH,
 79	REG_READL,
 80	REG_WRITEH,
 81	REG_WRITEL,
 82	REG_ID2,
 83};
 84
 85/* DSI D-PHY Layer Registers */
 86#define D0W_DPHYCONTTX		0x0004
 87#define CLW_DPHYCONTRX		0x0020
 88#define D0W_DPHYCONTRX		0x0024
 89#define D1W_DPHYCONTRX		0x0028
 90#define COM_DPHYCONTRX		0x0038
 91#define CLW_CNTRL		0x0040
 92#define D0W_CNTRL		0x0044
 93#define D1W_CNTRL		0x0048
 94#define DFTMODE_CNTRL		0x0054
 95
 96/* DSI PPI Layer Registers */
 97#define PPI_STARTPPI		0x0104
 98#define PPI_BUSYPPI		0x0108
 99#define PPI_LINEINITCNT		0x0110
100#define PPI_LPTXTIMECNT		0x0114
101#define PPI_CLS_ATMR		0x0140
102#define PPI_D0S_ATMR		0x0144
103#define PPI_D1S_ATMR		0x0148
104#define PPI_D0S_CLRSIPOCOUNT	0x0164
105#define PPI_D1S_CLRSIPOCOUNT	0x0168
106#define CLS_PRE			0x0180
107#define D0S_PRE			0x0184
108#define D1S_PRE			0x0188
109#define CLS_PREP		0x01A0
110#define D0S_PREP		0x01A4
111#define D1S_PREP		0x01A8
112#define CLS_ZERO		0x01C0
113#define D0S_ZERO		0x01C4
114#define D1S_ZERO		0x01C8
115#define PPI_CLRFLG		0x01E0
116#define PPI_CLRSIPO		0x01E4
117#define HSTIMEOUT		0x01F0
118#define HSTIMEOUTENABLE		0x01F4
119
120/* DSI Protocol Layer Registers */
121#define DSI_STARTDSI		0x0204
122#define DSI_BUSYDSI		0x0208
123#define DSI_LANEENABLE		0x0210
124# define DSI_LANEENABLE_CLOCK		BIT(0)
125# define DSI_LANEENABLE_D0		BIT(1)
126# define DSI_LANEENABLE_D1		BIT(2)
127
128#define DSI_LANESTATUS0		0x0214
129#define DSI_LANESTATUS1		0x0218
130#define DSI_INTSTATUS		0x0220
131#define DSI_INTMASK		0x0224
132#define DSI_INTCLR		0x0228
133#define DSI_LPTXTO		0x0230
134#define DSI_MODE		0x0260
135#define DSI_PAYLOAD0		0x0268
136#define DSI_PAYLOAD1		0x026C
137#define DSI_SHORTPKTDAT		0x0270
138#define DSI_SHORTPKTREQ		0x0274
139#define DSI_BTASTA		0x0278
140#define DSI_BTACLR		0x027C
141
142/* DSI General Registers */
143#define DSIERRCNT		0x0300
144#define DSISIGMOD		0x0304
145
146/* DSI Application Layer Registers */
147#define APLCTRL			0x0400
148#define APLSTAT			0x0404
149#define APLERR			0x0408
150#define PWRMOD			0x040C
151#define RDPKTLN			0x0410
152#define PXLFMT			0x0414
153#define MEMWRCMD		0x0418
154
155/* LCDC/DPI Host Registers */
156#define LCDCTRL			0x0420
157#define HSR			0x0424
158#define HDISPR			0x0428
159#define VSR			0x042C
160#define VDISPR			0x0430
161#define VFUEN			0x0434
162
163/* DBI-B Host Registers */
164#define DBIBCTRL		0x0440
165
166/* SPI Master Registers */
167#define SPICMR			0x0450
168#define SPITCR			0x0454
169
170/* System Controller Registers */
171#define SYSSTAT			0x0460
172#define SYSCTRL			0x0464
173#define SYSPLL1			0x0468
174#define SYSPLL2			0x046C
175#define SYSPLL3			0x0470
176#define SYSPMCTRL		0x047C
177
178/* GPIO Registers */
179#define GPIOC			0x0480
180#define GPIOO			0x0484
181#define GPIOI			0x0488
182
183/* I2C Registers */
184#define I2CCLKCTRL		0x0490
185
186/* Chip/Rev Registers */
187#define IDREG			0x04A0
188
189/* Debug Registers */
190#define WCMDQUEUE		0x0500
191#define RCMDQUEUE		0x0504
192
193struct rpi_touchscreen {
194	struct drm_panel base;
195	struct mipi_dsi_device *dsi;
196	struct i2c_client *i2c;
197};
198
199static const struct drm_display_mode rpi_touchscreen_modes[] = {
200	{
201		/* Modeline comes from the Raspberry Pi firmware, with HFP=1
202		 * plugged in and clock re-computed from that.
203		 */
204		.clock = 25979400 / 1000,
205		.hdisplay = 800,
206		.hsync_start = 800 + 1,
207		.hsync_end = 800 + 1 + 2,
208		.htotal = 800 + 1 + 2 + 46,
209		.vdisplay = 480,
210		.vsync_start = 480 + 7,
211		.vsync_end = 480 + 7 + 2,
212		.vtotal = 480 + 7 + 2 + 21,
213	},
214};
215
216static struct rpi_touchscreen *panel_to_ts(struct drm_panel *panel)
217{
218	return container_of(panel, struct rpi_touchscreen, base);
219}
220
221static int rpi_touchscreen_i2c_read(struct rpi_touchscreen *ts, u8 reg)
222{
223	return i2c_smbus_read_byte_data(ts->i2c, reg);
224}
225
226static void rpi_touchscreen_i2c_write(struct rpi_touchscreen *ts,
227				      u8 reg, u8 val)
228{
229	int ret;
230
231	ret = i2c_smbus_write_byte_data(ts->i2c, reg, val);
232	if (ret)
233		dev_err(&ts->i2c->dev, "I2C write failed: %d\n", ret);
234}
235
236static int rpi_touchscreen_write(struct rpi_touchscreen *ts, u16 reg, u32 val)
237{
238	u8 msg[] = {
239		reg,
240		reg >> 8,
241		val,
242		val >> 8,
243		val >> 16,
244		val >> 24,
245	};
246
247	mipi_dsi_generic_write(ts->dsi, msg, sizeof(msg));
248
249	return 0;
250}
251
252static int rpi_touchscreen_disable(struct drm_panel *panel)
253{
254	struct rpi_touchscreen *ts = panel_to_ts(panel);
255
256	rpi_touchscreen_i2c_write(ts, REG_PWM, 0);
257
258	rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);
259	udelay(1);
260
261	return 0;
262}
263
264static int rpi_touchscreen_noop(struct drm_panel *panel)
265{
266	return 0;
267}
268
269static int rpi_touchscreen_prepare(struct drm_panel *panel)
270{
271	struct rpi_touchscreen *ts = panel_to_ts(panel);
272	int i;
273
274	rpi_touchscreen_i2c_write(ts, REG_POWERON, 1);
275	/* Wait for nPWRDWN to go low to indicate poweron is done. */
276	for (i = 0; i < 100; i++) {
277		if (rpi_touchscreen_i2c_read(ts, REG_PORTB) & 1)
278			break;
279	}
280
281	rpi_touchscreen_write(ts, DSI_LANEENABLE,
282			      DSI_LANEENABLE_CLOCK |
283			      DSI_LANEENABLE_D0);
284	rpi_touchscreen_write(ts, PPI_D0S_CLRSIPOCOUNT, 0x05);
285	rpi_touchscreen_write(ts, PPI_D1S_CLRSIPOCOUNT, 0x05);
286	rpi_touchscreen_write(ts, PPI_D0S_ATMR, 0x00);
287	rpi_touchscreen_write(ts, PPI_D1S_ATMR, 0x00);
288	rpi_touchscreen_write(ts, PPI_LPTXTIMECNT, 0x03);
289
290	rpi_touchscreen_write(ts, SPICMR, 0x00);
291	rpi_touchscreen_write(ts, LCDCTRL, 0x00100150);
292	rpi_touchscreen_write(ts, SYSCTRL, 0x040f);
293	msleep(100);
294
295	rpi_touchscreen_write(ts, PPI_STARTPPI, 0x01);
296	rpi_touchscreen_write(ts, DSI_STARTDSI, 0x01);
297	msleep(100);
298
299	return 0;
300}
301
302static int rpi_touchscreen_enable(struct drm_panel *panel)
303{
304	struct rpi_touchscreen *ts = panel_to_ts(panel);
305
306	/* Turn on the backlight. */
307	rpi_touchscreen_i2c_write(ts, REG_PWM, 255);
308
309	/* Default to the same orientation as the closed source
310	 * firmware used for the panel.  Runtime rotation
311	 * configuration will be supported using VC4's plane
312	 * orientation bits.
313	 */
314	rpi_touchscreen_i2c_write(ts, REG_PORTA, BIT(2));
315
316	return 0;
317}
318
319static int rpi_touchscreen_get_modes(struct drm_panel *panel,
320				     struct drm_connector *connector)
321{
322	unsigned int i, num = 0;
323	static const u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
324
325	for (i = 0; i < ARRAY_SIZE(rpi_touchscreen_modes); i++) {
326		const struct drm_display_mode *m = &rpi_touchscreen_modes[i];
327		struct drm_display_mode *mode;
328
329		mode = drm_mode_duplicate(connector->dev, m);
330		if (!mode) {
331			dev_err(panel->dev, "failed to add mode %ux%u@%u\n",
332				m->hdisplay, m->vdisplay,
333				drm_mode_vrefresh(m));
334			continue;
335		}
336
337		mode->type |= DRM_MODE_TYPE_DRIVER;
338
339		if (i == 0)
340			mode->type |= DRM_MODE_TYPE_PREFERRED;
341
342		drm_mode_set_name(mode);
343
344		drm_mode_probed_add(connector, mode);
345		num++;
346	}
347
348	connector->display_info.bpc = 8;
349	connector->display_info.width_mm = 154;
350	connector->display_info.height_mm = 86;
351	drm_display_info_set_bus_formats(&connector->display_info,
352					 &bus_format, 1);
353
354	return num;
355}
356
357static const struct drm_panel_funcs rpi_touchscreen_funcs = {
358	.disable = rpi_touchscreen_disable,
359	.unprepare = rpi_touchscreen_noop,
360	.prepare = rpi_touchscreen_prepare,
361	.enable = rpi_touchscreen_enable,
362	.get_modes = rpi_touchscreen_get_modes,
363};
364
365static int rpi_touchscreen_probe(struct i2c_client *i2c,
366				 const struct i2c_device_id *id)
367{
368	struct device *dev = &i2c->dev;
369	struct rpi_touchscreen *ts;
370	struct device_node *endpoint, *dsi_host_node;
371	struct mipi_dsi_host *host;
372	int ver;
373	struct mipi_dsi_device_info info = {
374		.type = RPI_DSI_DRIVER_NAME,
375		.channel = 0,
376		.node = NULL,
377	};
378
379	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
380	if (!ts)
381		return -ENOMEM;
382
383	i2c_set_clientdata(i2c, ts);
384
385	ts->i2c = i2c;
386
387	ver = rpi_touchscreen_i2c_read(ts, REG_ID);
388	if (ver < 0) {
389		dev_err(dev, "Atmel I2C read failed: %d\n", ver);
390		return -ENODEV;
391	}
392
393	switch (ver) {
394	case 0xde: /* ver 1 */
395	case 0xc3: /* ver 2 */
396		break;
397	default:
398		dev_err(dev, "Unknown Atmel firmware revision: 0x%02x\n", ver);
399		return -ENODEV;
400	}
401
402	/* Turn off at boot, so we can cleanly sequence powering on. */
403	rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);
404
405	/* Look up the DSI host.  It needs to probe before we do. */
406	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
407	if (!endpoint)
408		return -ENODEV;
409
410	dsi_host_node = of_graph_get_remote_port_parent(endpoint);
411	if (!dsi_host_node)
412		goto error;
413
414	host = of_find_mipi_dsi_host_by_node(dsi_host_node);
415	of_node_put(dsi_host_node);
416	if (!host) {
417		of_node_put(endpoint);
418		return -EPROBE_DEFER;
419	}
420
421	info.node = of_graph_get_remote_port(endpoint);
422	if (!info.node)
423		goto error;
424
425	of_node_put(endpoint);
426
427	ts->dsi = mipi_dsi_device_register_full(host, &info);
428	if (IS_ERR(ts->dsi)) {
429		dev_err(dev, "DSI device registration failed: %ld\n",
430			PTR_ERR(ts->dsi));
431		return PTR_ERR(ts->dsi);
432	}
433
434	drm_panel_init(&ts->base, dev, &rpi_touchscreen_funcs,
435		       DRM_MODE_CONNECTOR_DSI);
436
437	/* This appears last, as it's what will unblock the DSI host
438	 * driver's component bind function.
439	 */
440	drm_panel_add(&ts->base);
441
442	return 0;
443
444error:
445	of_node_put(endpoint);
446	return -ENODEV;
447}
448
449static void rpi_touchscreen_remove(struct i2c_client *i2c)
450{
451	struct rpi_touchscreen *ts = i2c_get_clientdata(i2c);
452
453	mipi_dsi_detach(ts->dsi);
454
455	drm_panel_remove(&ts->base);
456
457	mipi_dsi_device_unregister(ts->dsi);
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");