1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Parade PS8622 eDP/LVDS bridge driver
4  *
5  * Copyright (C) 2014 Google, Inc.
6  */
7 
8 #include <linux/backlight.h>
9 #include <linux/delay.h>
10 #include <linux/err.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/i2c.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/pm.h>
16 #include <linux/regulator/consumer.h>
17 
18 #include <drm/drm_atomic_helper.h>
19 #include <drm/drm_bridge.h>
20 #include <drm/drm_crtc.h>
21 #include <drm/drm_of.h>
22 #include <drm/drm_panel.h>
23 #include <drm/drm_print.h>
24 #include <drm/drm_probe_helper.h>
25 
26 /* Brightness scale on the Parade chip */
27 #define PS8622_MAX_BRIGHTNESS 0xff
28 
29 /* Timings taken from the version 1.7 datasheet for the PS8622/PS8625 */
30 #define PS8622_POWER_RISE_T1_MIN_US 10
31 #define PS8622_POWER_RISE_T1_MAX_US 10000
32 #define PS8622_RST_HIGH_T2_MIN_US 3000
33 #define PS8622_RST_HIGH_T2_MAX_US 30000
34 #define PS8622_PWMO_END_T12_MS 200
35 #define PS8622_POWER_FALL_T16_MAX_US 10000
36 #define PS8622_POWER_OFF_T17_MS 500
37 
38 #if ((PS8622_RST_HIGH_T2_MIN_US + PS8622_POWER_RISE_T1_MAX_US) > \
39 	(PS8622_RST_HIGH_T2_MAX_US + PS8622_POWER_RISE_T1_MIN_US))
40 #error "T2.min + T1.max must be less than T2.max + T1.min"
41 #endif
42 
43 struct ps8622_bridge {
44 	struct i2c_client *client;
45 	struct drm_bridge bridge;
46 	struct drm_bridge *panel_bridge;
47 	struct regulator *v12;
48 	struct backlight_device *bl;
49 
50 	struct gpio_desc *gpio_slp;
51 	struct gpio_desc *gpio_rst;
52 
53 	u32 max_lane_count;
54 	u32 lane_count;
55 
56 	bool enabled;
57 };
58 
59 static inline struct ps8622_bridge *
60 		bridge_to_ps8622(struct drm_bridge *bridge)
61 {
62 	return container_of(bridge, struct ps8622_bridge, bridge);
63 }
64 
65 static int ps8622_set(struct i2c_client *client, u8 page, u8 reg, u8 val)
66 {
67 	int ret;
68 	struct i2c_adapter *adap = client->adapter;
69 	struct i2c_msg msg;
70 	u8 data[] = {reg, val};
71 
72 	msg.addr = client->addr + page;
73 	msg.flags = 0;
74 	msg.len = sizeof(data);
75 	msg.buf = data;
76 
77 	ret = i2c_transfer(adap, &msg, 1);
78 	if (ret != 1)
79 		pr_warn("PS8622 I2C write (0x%02x,0x%02x,0x%02x) failed: %d\n",
80 			client->addr + page, reg, val, ret);
81 	return !(ret == 1);
82 }
83 
84 static int ps8622_send_config(struct ps8622_bridge *ps8622)
85 {
86 	struct i2c_client *cl = ps8622->client;
87 	int err = 0;
88 
89 	/* HPD low */
90 	err = ps8622_set(cl, 0x02, 0xa1, 0x01);
91 	if (err)
92 		goto error;
93 
94 	/* SW setting: [1:0] SW output 1.2V voltage is lower to 96% */
95 	err = ps8622_set(cl, 0x04, 0x14, 0x01);
96 	if (err)
97 		goto error;
98 
99 	/* RCO SS setting: [5:4] = b01 0.5%, b10 1%, b11 1.5% */
100 	err = ps8622_set(cl, 0x04, 0xe3, 0x20);
101 	if (err)
102 		goto error;
103 
104 	/* [7] RCO SS enable */
105 	err = ps8622_set(cl, 0x04, 0xe2, 0x80);
106 	if (err)
107 		goto error;
108 
109 	/* RPHY Setting
110 	 * [3:2] CDR tune wait cycle before measure for fine tune
111 	 * b00: 1us b01: 0.5us b10:2us, b11: 4us
112 	 */
113 	err = ps8622_set(cl, 0x04, 0x8a, 0x0c);
114 	if (err)
115 		goto error;
116 
117 	/* [3] RFD always on */
118 	err = ps8622_set(cl, 0x04, 0x89, 0x08);
119 	if (err)
120 		goto error;
121 
122 	/* CTN lock in/out: 20000ppm/80000ppm. Lock out 2 times. */
123 	err = ps8622_set(cl, 0x04, 0x71, 0x2d);
124 	if (err)
125 		goto error;
126 
127 	/* 2.7G CDR settings: NOF=40LSB for HBR CDR  setting */
128 	err = ps8622_set(cl, 0x04, 0x7d, 0x07);
129 	if (err)
130 		goto error;
131 
132 	/* [1:0] Fmin=+4bands */
133 	err = ps8622_set(cl, 0x04, 0x7b, 0x00);
134 	if (err)
135 		goto error;
136 
137 	/* [7:5] DCO_FTRNG=+-40% */
138 	err = ps8622_set(cl, 0x04, 0x7a, 0xfd);
139 	if (err)
140 		goto error;
141 
142 	/* 1.62G CDR settings: [5:2]NOF=64LSB [1:0]DCO scale is 2/5 */
143 	err = ps8622_set(cl, 0x04, 0xc0, 0x12);
144 	if (err)
145 		goto error;
146 
147 	/* Gitune=-37% */
148 	err = ps8622_set(cl, 0x04, 0xc1, 0x92);
149 	if (err)
150 		goto error;
151 
152 	/* Fbstep=100% */
153 	err = ps8622_set(cl, 0x04, 0xc2, 0x1c);
154 	if (err)
155 		goto error;
156 
157 	/* [7] LOS signal disable */
158 	err = ps8622_set(cl, 0x04, 0x32, 0x80);
159 	if (err)
160 		goto error;
161 
162 	/* RPIO Setting: [7:4] LVDS driver bias current : 75% (250mV swing) */
163 	err = ps8622_set(cl, 0x04, 0x00, 0xb0);
164 	if (err)
165 		goto error;
166 
167 	/* [7:6] Right-bar GPIO output strength is 8mA */
168 	err = ps8622_set(cl, 0x04, 0x15, 0x40);
169 	if (err)
170 		goto error;
171 
172 	/* EQ Training State Machine Setting, RCO calibration start */
173 	err = ps8622_set(cl, 0x04, 0x54, 0x10);
174 	if (err)
175 		goto error;
176 
177 	/* Logic, needs more than 10 I2C command */
178 	/* [4:0] MAX_LANE_COUNT set to max supported lanes */
179 	err = ps8622_set(cl, 0x01, 0x02, 0x80 | ps8622->max_lane_count);
180 	if (err)
181 		goto error;
182 
183 	/* [4:0] LANE_COUNT_SET set to chosen lane count */
184 	err = ps8622_set(cl, 0x01, 0x21, 0x80 | ps8622->lane_count);
185 	if (err)
186 		goto error;
187 
188 	err = ps8622_set(cl, 0x00, 0x52, 0x20);
189 	if (err)
190 		goto error;
191 
192 	/* HPD CP toggle enable */
193 	err = ps8622_set(cl, 0x00, 0xf1, 0x03);
194 	if (err)
195 		goto error;
196 
197 	err = ps8622_set(cl, 0x00, 0x62, 0x41);
198 	if (err)
199 		goto error;
200 
201 	/* Counter number, add 1ms counter delay */
202 	err = ps8622_set(cl, 0x00, 0xf6, 0x01);
203 	if (err)
204 		goto error;
205 
206 	/* [6]PWM function control by DPCD0040f[7], default is PWM block */
207 	err = ps8622_set(cl, 0x00, 0x77, 0x06);
208 	if (err)
209 		goto error;
210 
211 	/* 04h Adjust VTotal toleranceto fix the 30Hz no display issue */
212 	err = ps8622_set(cl, 0x00, 0x4c, 0x04);
213 	if (err)
214 		goto error;
215 
216 	/* DPCD00400='h00, Parade OUI ='h001cf8 */
217 	err = ps8622_set(cl, 0x01, 0xc0, 0x00);
218 	if (err)
219 		goto error;
220 
221 	/* DPCD00401='h1c */
222 	err = ps8622_set(cl, 0x01, 0xc1, 0x1c);
223 	if (err)
224 		goto error;
225 
226 	/* DPCD00402='hf8 */
227 	err = ps8622_set(cl, 0x01, 0xc2, 0xf8);
228 	if (err)
229 		goto error;
230 
231 	/* DPCD403~408 = ASCII code, D2SLV5='h4432534c5635 */
232 	err = ps8622_set(cl, 0x01, 0xc3, 0x44);
233 	if (err)
234 		goto error;
235 
236 	/* DPCD404 */
237 	err = ps8622_set(cl, 0x01, 0xc4, 0x32);
238 	if (err)
239 		goto error;
240 
241 	/* DPCD405 */
242 	err = ps8622_set(cl, 0x01, 0xc5, 0x53);
243 	if (err)
244 		goto error;
245 
246 	/* DPCD406 */
247 	err = ps8622_set(cl, 0x01, 0xc6, 0x4c);
248 	if (err)
249 		goto error;
250 
251 	/* DPCD407 */
252 	err = ps8622_set(cl, 0x01, 0xc7, 0x56);
253 	if (err)
254 		goto error;
255 
256 	/* DPCD408 */
257 	err = ps8622_set(cl, 0x01, 0xc8, 0x35);
258 	if (err)
259 		goto error;
260 
261 	/* DPCD40A, Initial Code major revision '01' */
262 	err = ps8622_set(cl, 0x01, 0xca, 0x01);
263 	if (err)
264 		goto error;
265 
266 	/* DPCD40B, Initial Code minor revision '05' */
267 	err = ps8622_set(cl, 0x01, 0xcb, 0x05);
268 	if (err)
269 		goto error;
270 
271 
272 	if (ps8622->bl) {
273 		/* DPCD720, internal PWM */
274 		err = ps8622_set(cl, 0x01, 0xa5, 0xa0);
275 		if (err)
276 			goto error;
277 
278 		/* FFh for 100% brightness, 0h for 0% brightness */
279 		err = ps8622_set(cl, 0x01, 0xa7,
280 				ps8622->bl->props.brightness);
281 		if (err)
282 			goto error;
283 	} else {
284 		/* DPCD720, external PWM */
285 		err = ps8622_set(cl, 0x01, 0xa5, 0x80);
286 		if (err)
287 			goto error;
288 	}
289 
290 	/* Set LVDS output as 6bit-VESA mapping, single LVDS channel */
291 	err = ps8622_set(cl, 0x01, 0xcc, 0x13);
292 	if (err)
293 		goto error;
294 
295 	/* Enable SSC set by register */
296 	err = ps8622_set(cl, 0x02, 0xb1, 0x20);
297 	if (err)
298 		goto error;
299 
300 	/* Set SSC enabled and +/-1% central spreading */
301 	err = ps8622_set(cl, 0x04, 0x10, 0x16);
302 	if (err)
303 		goto error;
304 
305 	/* Logic end */
306 	/* MPU Clock source: LC => RCO */
307 	err = ps8622_set(cl, 0x04, 0x59, 0x60);
308 	if (err)
309 		goto error;
310 
311 	/* LC -> RCO */
312 	err = ps8622_set(cl, 0x04, 0x54, 0x14);
313 	if (err)
314 		goto error;
315 
316 	/* HPD high */
317 	err = ps8622_set(cl, 0x02, 0xa1, 0x91);
318 
319 error:
320 	return err ? -EIO : 0;
321 }
322 
323 static int ps8622_backlight_update(struct backlight_device *bl)
324 {
325 	struct ps8622_bridge *ps8622 = dev_get_drvdata(&bl->dev);
326 	int ret, brightness = backlight_get_brightness(bl);
327 
328 	if (!ps8622->enabled)
329 		return -EINVAL;
330 
331 	ret = ps8622_set(ps8622->client, 0x01, 0xa7, brightness);
332 
333 	return ret;
334 }
335 
336 static const struct backlight_ops ps8622_backlight_ops = {
337 	.update_status	= ps8622_backlight_update,
338 };
339 
340 static void ps8622_pre_enable(struct drm_bridge *bridge)
341 {
342 	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
343 	int ret;
344 
345 	if (ps8622->enabled)
346 		return;
347 
348 	gpiod_set_value(ps8622->gpio_rst, 0);
349 
350 	if (ps8622->v12) {
351 		ret = regulator_enable(ps8622->v12);
352 		if (ret)
353 			DRM_ERROR("fails to enable ps8622->v12");
354 	}
355 
356 	gpiod_set_value(ps8622->gpio_slp, 1);
357 
358 	/*
359 	 * T1 is the range of time that it takes for the power to rise after we
360 	 * enable the lcd/ps8622 fet. T2 is the range of time in which the
361 	 * data sheet specifies we should deassert the reset pin.
362 	 *
363 	 * If it takes T1.max for the power to rise, we need to wait atleast
364 	 * T2.min before deasserting the reset pin. If it takes T1.min for the
365 	 * power to rise, we need to wait at most T2.max before deasserting the
366 	 * reset pin.
367 	 */
368 	usleep_range(PS8622_RST_HIGH_T2_MIN_US + PS8622_POWER_RISE_T1_MAX_US,
369 		     PS8622_RST_HIGH_T2_MAX_US + PS8622_POWER_RISE_T1_MIN_US);
370 
371 	gpiod_set_value(ps8622->gpio_rst, 1);
372 
373 	/* wait 20ms after RST high */
374 	usleep_range(20000, 30000);
375 
376 	ret = ps8622_send_config(ps8622);
377 	if (ret) {
378 		DRM_ERROR("Failed to send config to bridge (%d)\n", ret);
379 		return;
380 	}
381 
382 	ps8622->enabled = true;
383 }
384 
385 static void ps8622_disable(struct drm_bridge *bridge)
386 {
387 	/* Delay after panel is disabled */
388 	msleep(PS8622_PWMO_END_T12_MS);
389 }
390 
391 static void ps8622_post_disable(struct drm_bridge *bridge)
392 {
393 	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
394 
395 	if (!ps8622->enabled)
396 		return;
397 
398 	ps8622->enabled = false;
399 
400 	/*
401 	 * This doesn't matter if the regulators are turned off, but something
402 	 * else might keep them on. In that case, we want to assert the slp gpio
403 	 * to lower power.
404 	 */
405 	gpiod_set_value(ps8622->gpio_slp, 0);
406 
407 	if (ps8622->v12)
408 		regulator_disable(ps8622->v12);
409 
410 	/*
411 	 * Sleep for at least the amount of time that it takes the power rail to
412 	 * fall to prevent asserting the rst gpio from doing anything.
413 	 */
414 	usleep_range(PS8622_POWER_FALL_T16_MAX_US,
415 		     2 * PS8622_POWER_FALL_T16_MAX_US);
416 	gpiod_set_value(ps8622->gpio_rst, 0);
417 
418 	msleep(PS8622_POWER_OFF_T17_MS);
419 }
420 
421 static int ps8622_attach(struct drm_bridge *bridge,
422 			 enum drm_bridge_attach_flags flags)
423 {
424 	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
425 
426 	return drm_bridge_attach(ps8622->bridge.encoder, ps8622->panel_bridge,
427 				 &ps8622->bridge, flags);
428 }
429 
430 static const struct drm_bridge_funcs ps8622_bridge_funcs = {
431 	.pre_enable = ps8622_pre_enable,
432 	.disable = ps8622_disable,
433 	.post_disable = ps8622_post_disable,
434 	.attach = ps8622_attach,
435 };
436 
437 static const struct of_device_id ps8622_devices[] = {
438 	{.compatible = "parade,ps8622",},
439 	{.compatible = "parade,ps8625",},
440 	{}
441 };
442 MODULE_DEVICE_TABLE(of, ps8622_devices);
443 
444 static int ps8622_probe(struct i2c_client *client)
445 {
446 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
447 	struct device *dev = &client->dev;
448 	struct ps8622_bridge *ps8622;
449 	struct drm_bridge *panel_bridge;
450 	int ret;
451 
452 	ps8622 = devm_kzalloc(dev, sizeof(*ps8622), GFP_KERNEL);
453 	if (!ps8622)
454 		return -ENOMEM;
455 
456 	panel_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
457 	if (IS_ERR(panel_bridge))
458 		return PTR_ERR(panel_bridge);
459 
460 	ps8622->panel_bridge = panel_bridge;
461 	ps8622->client = client;
462 
463 	ps8622->v12 = devm_regulator_get(dev, "vdd12");
464 	if (IS_ERR(ps8622->v12)) {
465 		dev_info(dev, "no 1.2v regulator found for PS8622\n");
466 		ps8622->v12 = NULL;
467 	}
468 
469 	ps8622->gpio_slp = devm_gpiod_get(dev, "sleep", GPIOD_OUT_HIGH);
470 	if (IS_ERR(ps8622->gpio_slp)) {
471 		ret = PTR_ERR(ps8622->gpio_slp);
472 		dev_err(dev, "cannot get gpio_slp %d\n", ret);
473 		return ret;
474 	}
475 
476 	/*
477 	 * Assert the reset pin high to avoid the bridge being
478 	 * initialized prematurely
479 	 */
480 	ps8622->gpio_rst = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
481 	if (IS_ERR(ps8622->gpio_rst)) {
482 		ret = PTR_ERR(ps8622->gpio_rst);
483 		dev_err(dev, "cannot get gpio_rst %d\n", ret);
484 		return ret;
485 	}
486 
487 	ps8622->max_lane_count = id->driver_data;
488 
489 	if (of_property_read_u32(dev->of_node, "lane-count",
490 						&ps8622->lane_count)) {
491 		ps8622->lane_count = ps8622->max_lane_count;
492 	} else if (ps8622->lane_count > ps8622->max_lane_count) {
493 		dev_info(dev, "lane-count property is too high,"
494 						"using max_lane_count\n");
495 		ps8622->lane_count = ps8622->max_lane_count;
496 	}
497 
498 	if (!of_property_read_bool(dev->of_node, "use-external-pwm")) {
499 		ps8622->bl = backlight_device_register("ps8622-backlight",
500 				dev, ps8622, &ps8622_backlight_ops,
501 				NULL);
502 		if (IS_ERR(ps8622->bl)) {
503 			DRM_ERROR("failed to register backlight\n");
504 			ret = PTR_ERR(ps8622->bl);
505 			ps8622->bl = NULL;
506 			return ret;
507 		}
508 		ps8622->bl->props.max_brightness = PS8622_MAX_BRIGHTNESS;
509 		ps8622->bl->props.brightness = PS8622_MAX_BRIGHTNESS;
510 	}
511 
512 	ps8622->bridge.funcs = &ps8622_bridge_funcs;
513 	ps8622->bridge.type = DRM_MODE_CONNECTOR_LVDS;
514 	ps8622->bridge.of_node = dev->of_node;
515 	drm_bridge_add(&ps8622->bridge);
516 
517 	i2c_set_clientdata(client, ps8622);
518 
519 	return 0;
520 }
521 
522 static void ps8622_remove(struct i2c_client *client)
523 {
524 	struct ps8622_bridge *ps8622 = i2c_get_clientdata(client);
525 
526 	backlight_device_unregister(ps8622->bl);
527 	drm_bridge_remove(&ps8622->bridge);
528 }
529 
530 static const struct i2c_device_id ps8622_i2c_table[] = {
531 	/* Device type, max_lane_count */
532 	{"ps8622", 1},
533 	{"ps8625", 2},
534 	{},
535 };
536 MODULE_DEVICE_TABLE(i2c, ps8622_i2c_table);
537 
538 static struct i2c_driver ps8622_driver = {
539 	.id_table	= ps8622_i2c_table,
540 	.probe		= ps8622_probe,
541 	.remove		= ps8622_remove,
542 	.driver		= {
543 		.name	= "ps8622",
544 		.of_match_table = ps8622_devices,
545 	},
546 };
547 module_i2c_driver(ps8622_driver);
548 
549 MODULE_AUTHOR("Vincent Palatin <vpalatin@chromium.org>");
550 MODULE_DESCRIPTION("Parade ps8622/ps8625 eDP-LVDS converter driver");
551 MODULE_LICENSE("GPL v2");
552