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/of_device.h>
16 #include <linux/pm.h>
17 #include <linux/regulator/consumer.h>
18 
19 #include <drm/drm_atomic_helper.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 drm_connector connector;
45 	struct i2c_client *client;
46 	struct drm_bridge bridge;
47 	struct drm_panel *panel;
48 	struct regulator *v12;
49 	struct backlight_device *bl;
50 
51 	struct gpio_desc *gpio_slp;
52 	struct gpio_desc *gpio_rst;
53 
54 	u32 max_lane_count;
55 	u32 lane_count;
56 
57 	bool enabled;
58 };
59 
60 static inline struct ps8622_bridge *
61 		bridge_to_ps8622(struct drm_bridge *bridge)
62 {
63 	return container_of(bridge, struct ps8622_bridge, bridge);
64 }
65 
66 static inline struct ps8622_bridge *
67 		connector_to_ps8622(struct drm_connector *connector)
68 {
69 	return container_of(connector, struct ps8622_bridge, connector);
70 }
71 
72 static int ps8622_set(struct i2c_client *client, u8 page, u8 reg, u8 val)
73 {
74 	int ret;
75 	struct i2c_adapter *adap = client->adapter;
76 	struct i2c_msg msg;
77 	u8 data[] = {reg, val};
78 
79 	msg.addr = client->addr + page;
80 	msg.flags = 0;
81 	msg.len = sizeof(data);
82 	msg.buf = data;
83 
84 	ret = i2c_transfer(adap, &msg, 1);
85 	if (ret != 1)
86 		pr_warn("PS8622 I2C write (0x%02x,0x%02x,0x%02x) failed: %d\n",
87 			client->addr + page, reg, val, ret);
88 	return !(ret == 1);
89 }
90 
91 static int ps8622_send_config(struct ps8622_bridge *ps8622)
92 {
93 	struct i2c_client *cl = ps8622->client;
94 	int err = 0;
95 
96 	/* HPD low */
97 	err = ps8622_set(cl, 0x02, 0xa1, 0x01);
98 	if (err)
99 		goto error;
100 
101 	/* SW setting: [1:0] SW output 1.2V voltage is lower to 96% */
102 	err = ps8622_set(cl, 0x04, 0x14, 0x01);
103 	if (err)
104 		goto error;
105 
106 	/* RCO SS setting: [5:4] = b01 0.5%, b10 1%, b11 1.5% */
107 	err = ps8622_set(cl, 0x04, 0xe3, 0x20);
108 	if (err)
109 		goto error;
110 
111 	/* [7] RCO SS enable */
112 	err = ps8622_set(cl, 0x04, 0xe2, 0x80);
113 	if (err)
114 		goto error;
115 
116 	/* RPHY Setting
117 	 * [3:2] CDR tune wait cycle before measure for fine tune
118 	 * b00: 1us b01: 0.5us b10:2us, b11: 4us
119 	 */
120 	err = ps8622_set(cl, 0x04, 0x8a, 0x0c);
121 	if (err)
122 		goto error;
123 
124 	/* [3] RFD always on */
125 	err = ps8622_set(cl, 0x04, 0x89, 0x08);
126 	if (err)
127 		goto error;
128 
129 	/* CTN lock in/out: 20000ppm/80000ppm. Lock out 2 times. */
130 	err = ps8622_set(cl, 0x04, 0x71, 0x2d);
131 	if (err)
132 		goto error;
133 
134 	/* 2.7G CDR settings: NOF=40LSB for HBR CDR  setting */
135 	err = ps8622_set(cl, 0x04, 0x7d, 0x07);
136 	if (err)
137 		goto error;
138 
139 	/* [1:0] Fmin=+4bands */
140 	err = ps8622_set(cl, 0x04, 0x7b, 0x00);
141 	if (err)
142 		goto error;
143 
144 	/* [7:5] DCO_FTRNG=+-40% */
145 	err = ps8622_set(cl, 0x04, 0x7a, 0xfd);
146 	if (err)
147 		goto error;
148 
149 	/* 1.62G CDR settings: [5:2]NOF=64LSB [1:0]DCO scale is 2/5 */
150 	err = ps8622_set(cl, 0x04, 0xc0, 0x12);
151 	if (err)
152 		goto error;
153 
154 	/* Gitune=-37% */
155 	err = ps8622_set(cl, 0x04, 0xc1, 0x92);
156 	if (err)
157 		goto error;
158 
159 	/* Fbstep=100% */
160 	err = ps8622_set(cl, 0x04, 0xc2, 0x1c);
161 	if (err)
162 		goto error;
163 
164 	/* [7] LOS signal disable */
165 	err = ps8622_set(cl, 0x04, 0x32, 0x80);
166 	if (err)
167 		goto error;
168 
169 	/* RPIO Setting: [7:4] LVDS driver bias current : 75% (250mV swing) */
170 	err = ps8622_set(cl, 0x04, 0x00, 0xb0);
171 	if (err)
172 		goto error;
173 
174 	/* [7:6] Right-bar GPIO output strength is 8mA */
175 	err = ps8622_set(cl, 0x04, 0x15, 0x40);
176 	if (err)
177 		goto error;
178 
179 	/* EQ Training State Machine Setting, RCO calibration start */
180 	err = ps8622_set(cl, 0x04, 0x54, 0x10);
181 	if (err)
182 		goto error;
183 
184 	/* Logic, needs more than 10 I2C command */
185 	/* [4:0] MAX_LANE_COUNT set to max supported lanes */
186 	err = ps8622_set(cl, 0x01, 0x02, 0x80 | ps8622->max_lane_count);
187 	if (err)
188 		goto error;
189 
190 	/* [4:0] LANE_COUNT_SET set to chosen lane count */
191 	err = ps8622_set(cl, 0x01, 0x21, 0x80 | ps8622->lane_count);
192 	if (err)
193 		goto error;
194 
195 	err = ps8622_set(cl, 0x00, 0x52, 0x20);
196 	if (err)
197 		goto error;
198 
199 	/* HPD CP toggle enable */
200 	err = ps8622_set(cl, 0x00, 0xf1, 0x03);
201 	if (err)
202 		goto error;
203 
204 	err = ps8622_set(cl, 0x00, 0x62, 0x41);
205 	if (err)
206 		goto error;
207 
208 	/* Counter number, add 1ms counter delay */
209 	err = ps8622_set(cl, 0x00, 0xf6, 0x01);
210 	if (err)
211 		goto error;
212 
213 	/* [6]PWM function control by DPCD0040f[7], default is PWM block */
214 	err = ps8622_set(cl, 0x00, 0x77, 0x06);
215 	if (err)
216 		goto error;
217 
218 	/* 04h Adjust VTotal toleranceto fix the 30Hz no display issue */
219 	err = ps8622_set(cl, 0x00, 0x4c, 0x04);
220 	if (err)
221 		goto error;
222 
223 	/* DPCD00400='h00, Parade OUI ='h001cf8 */
224 	err = ps8622_set(cl, 0x01, 0xc0, 0x00);
225 	if (err)
226 		goto error;
227 
228 	/* DPCD00401='h1c */
229 	err = ps8622_set(cl, 0x01, 0xc1, 0x1c);
230 	if (err)
231 		goto error;
232 
233 	/* DPCD00402='hf8 */
234 	err = ps8622_set(cl, 0x01, 0xc2, 0xf8);
235 	if (err)
236 		goto error;
237 
238 	/* DPCD403~408 = ASCII code, D2SLV5='h4432534c5635 */
239 	err = ps8622_set(cl, 0x01, 0xc3, 0x44);
240 	if (err)
241 		goto error;
242 
243 	/* DPCD404 */
244 	err = ps8622_set(cl, 0x01, 0xc4, 0x32);
245 	if (err)
246 		goto error;
247 
248 	/* DPCD405 */
249 	err = ps8622_set(cl, 0x01, 0xc5, 0x53);
250 	if (err)
251 		goto error;
252 
253 	/* DPCD406 */
254 	err = ps8622_set(cl, 0x01, 0xc6, 0x4c);
255 	if (err)
256 		goto error;
257 
258 	/* DPCD407 */
259 	err = ps8622_set(cl, 0x01, 0xc7, 0x56);
260 	if (err)
261 		goto error;
262 
263 	/* DPCD408 */
264 	err = ps8622_set(cl, 0x01, 0xc8, 0x35);
265 	if (err)
266 		goto error;
267 
268 	/* DPCD40A, Initial Code major revision '01' */
269 	err = ps8622_set(cl, 0x01, 0xca, 0x01);
270 	if (err)
271 		goto error;
272 
273 	/* DPCD40B, Initial Code minor revision '05' */
274 	err = ps8622_set(cl, 0x01, 0xcb, 0x05);
275 	if (err)
276 		goto error;
277 
278 
279 	if (ps8622->bl) {
280 		/* DPCD720, internal PWM */
281 		err = ps8622_set(cl, 0x01, 0xa5, 0xa0);
282 		if (err)
283 			goto error;
284 
285 		/* FFh for 100% brightness, 0h for 0% brightness */
286 		err = ps8622_set(cl, 0x01, 0xa7,
287 				ps8622->bl->props.brightness);
288 		if (err)
289 			goto error;
290 	} else {
291 		/* DPCD720, external PWM */
292 		err = ps8622_set(cl, 0x01, 0xa5, 0x80);
293 		if (err)
294 			goto error;
295 	}
296 
297 	/* Set LVDS output as 6bit-VESA mapping, single LVDS channel */
298 	err = ps8622_set(cl, 0x01, 0xcc, 0x13);
299 	if (err)
300 		goto error;
301 
302 	/* Enable SSC set by register */
303 	err = ps8622_set(cl, 0x02, 0xb1, 0x20);
304 	if (err)
305 		goto error;
306 
307 	/* Set SSC enabled and +/-1% central spreading */
308 	err = ps8622_set(cl, 0x04, 0x10, 0x16);
309 	if (err)
310 		goto error;
311 
312 	/* Logic end */
313 	/* MPU Clock source: LC => RCO */
314 	err = ps8622_set(cl, 0x04, 0x59, 0x60);
315 	if (err)
316 		goto error;
317 
318 	/* LC -> RCO */
319 	err = ps8622_set(cl, 0x04, 0x54, 0x14);
320 	if (err)
321 		goto error;
322 
323 	/* HPD high */
324 	err = ps8622_set(cl, 0x02, 0xa1, 0x91);
325 
326 error:
327 	return err ? -EIO : 0;
328 }
329 
330 static int ps8622_backlight_update(struct backlight_device *bl)
331 {
332 	struct ps8622_bridge *ps8622 = dev_get_drvdata(&bl->dev);
333 	int ret, brightness = bl->props.brightness;
334 
335 	if (bl->props.power != FB_BLANK_UNBLANK ||
336 	    bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
337 		brightness = 0;
338 
339 	if (!ps8622->enabled)
340 		return -EINVAL;
341 
342 	ret = ps8622_set(ps8622->client, 0x01, 0xa7, brightness);
343 
344 	return ret;
345 }
346 
347 static const struct backlight_ops ps8622_backlight_ops = {
348 	.update_status	= ps8622_backlight_update,
349 };
350 
351 static void ps8622_pre_enable(struct drm_bridge *bridge)
352 {
353 	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
354 	int ret;
355 
356 	if (ps8622->enabled)
357 		return;
358 
359 	gpiod_set_value(ps8622->gpio_rst, 0);
360 
361 	if (ps8622->v12) {
362 		ret = regulator_enable(ps8622->v12);
363 		if (ret)
364 			DRM_ERROR("fails to enable ps8622->v12");
365 	}
366 
367 	if (drm_panel_prepare(ps8622->panel)) {
368 		DRM_ERROR("failed to prepare panel\n");
369 		return;
370 	}
371 
372 	gpiod_set_value(ps8622->gpio_slp, 1);
373 
374 	/*
375 	 * T1 is the range of time that it takes for the power to rise after we
376 	 * enable the lcd/ps8622 fet. T2 is the range of time in which the
377 	 * data sheet specifies we should deassert the reset pin.
378 	 *
379 	 * If it takes T1.max for the power to rise, we need to wait atleast
380 	 * T2.min before deasserting the reset pin. If it takes T1.min for the
381 	 * power to rise, we need to wait at most T2.max before deasserting the
382 	 * reset pin.
383 	 */
384 	usleep_range(PS8622_RST_HIGH_T2_MIN_US + PS8622_POWER_RISE_T1_MAX_US,
385 		     PS8622_RST_HIGH_T2_MAX_US + PS8622_POWER_RISE_T1_MIN_US);
386 
387 	gpiod_set_value(ps8622->gpio_rst, 1);
388 
389 	/* wait 20ms after RST high */
390 	usleep_range(20000, 30000);
391 
392 	ret = ps8622_send_config(ps8622);
393 	if (ret) {
394 		DRM_ERROR("Failed to send config to bridge (%d)\n", ret);
395 		return;
396 	}
397 
398 	ps8622->enabled = true;
399 }
400 
401 static void ps8622_enable(struct drm_bridge *bridge)
402 {
403 	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
404 
405 	if (drm_panel_enable(ps8622->panel)) {
406 		DRM_ERROR("failed to enable panel\n");
407 		return;
408 	}
409 }
410 
411 static void ps8622_disable(struct drm_bridge *bridge)
412 {
413 	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
414 
415 	if (drm_panel_disable(ps8622->panel)) {
416 		DRM_ERROR("failed to disable panel\n");
417 		return;
418 	}
419 	msleep(PS8622_PWMO_END_T12_MS);
420 }
421 
422 static void ps8622_post_disable(struct drm_bridge *bridge)
423 {
424 	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
425 
426 	if (!ps8622->enabled)
427 		return;
428 
429 	ps8622->enabled = false;
430 
431 	/*
432 	 * This doesn't matter if the regulators are turned off, but something
433 	 * else might keep them on. In that case, we want to assert the slp gpio
434 	 * to lower power.
435 	 */
436 	gpiod_set_value(ps8622->gpio_slp, 0);
437 
438 	if (drm_panel_unprepare(ps8622->panel)) {
439 		DRM_ERROR("failed to unprepare panel\n");
440 		return;
441 	}
442 
443 	if (ps8622->v12)
444 		regulator_disable(ps8622->v12);
445 
446 	/*
447 	 * Sleep for at least the amount of time that it takes the power rail to
448 	 * fall to prevent asserting the rst gpio from doing anything.
449 	 */
450 	usleep_range(PS8622_POWER_FALL_T16_MAX_US,
451 		     2 * PS8622_POWER_FALL_T16_MAX_US);
452 	gpiod_set_value(ps8622->gpio_rst, 0);
453 
454 	msleep(PS8622_POWER_OFF_T17_MS);
455 }
456 
457 static int ps8622_get_modes(struct drm_connector *connector)
458 {
459 	struct ps8622_bridge *ps8622;
460 
461 	ps8622 = connector_to_ps8622(connector);
462 
463 	return drm_panel_get_modes(ps8622->panel);
464 }
465 
466 static const struct drm_connector_helper_funcs ps8622_connector_helper_funcs = {
467 	.get_modes = ps8622_get_modes,
468 };
469 
470 static const struct drm_connector_funcs ps8622_connector_funcs = {
471 	.fill_modes = drm_helper_probe_single_connector_modes,
472 	.destroy = drm_connector_cleanup,
473 	.reset = drm_atomic_helper_connector_reset,
474 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
475 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
476 };
477 
478 static int ps8622_attach(struct drm_bridge *bridge)
479 {
480 	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
481 	int ret;
482 
483 	if (!bridge->encoder) {
484 		DRM_ERROR("Parent encoder object not found");
485 		return -ENODEV;
486 	}
487 
488 	ps8622->connector.polled = DRM_CONNECTOR_POLL_HPD;
489 	ret = drm_connector_init(bridge->dev, &ps8622->connector,
490 			&ps8622_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
491 	if (ret) {
492 		DRM_ERROR("Failed to initialize connector with drm\n");
493 		return ret;
494 	}
495 	drm_connector_helper_add(&ps8622->connector,
496 					&ps8622_connector_helper_funcs);
497 	drm_connector_register(&ps8622->connector);
498 	drm_connector_attach_encoder(&ps8622->connector,
499 							bridge->encoder);
500 
501 	if (ps8622->panel)
502 		drm_panel_attach(ps8622->panel, &ps8622->connector);
503 
504 	drm_helper_hpd_irq_event(ps8622->connector.dev);
505 
506 	return ret;
507 }
508 
509 static const struct drm_bridge_funcs ps8622_bridge_funcs = {
510 	.pre_enable = ps8622_pre_enable,
511 	.enable = ps8622_enable,
512 	.disable = ps8622_disable,
513 	.post_disable = ps8622_post_disable,
514 	.attach = ps8622_attach,
515 };
516 
517 static const struct of_device_id ps8622_devices[] = {
518 	{.compatible = "parade,ps8622",},
519 	{.compatible = "parade,ps8625",},
520 	{}
521 };
522 MODULE_DEVICE_TABLE(of, ps8622_devices);
523 
524 static int ps8622_probe(struct i2c_client *client,
525 					const struct i2c_device_id *id)
526 {
527 	struct device *dev = &client->dev;
528 	struct ps8622_bridge *ps8622;
529 	int ret;
530 
531 	ps8622 = devm_kzalloc(dev, sizeof(*ps8622), GFP_KERNEL);
532 	if (!ps8622)
533 		return -ENOMEM;
534 
535 	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &ps8622->panel, NULL);
536 	if (ret)
537 		return ret;
538 
539 	ps8622->client = client;
540 
541 	ps8622->v12 = devm_regulator_get(dev, "vdd12");
542 	if (IS_ERR(ps8622->v12)) {
543 		dev_info(dev, "no 1.2v regulator found for PS8622\n");
544 		ps8622->v12 = NULL;
545 	}
546 
547 	ps8622->gpio_slp = devm_gpiod_get(dev, "sleep", GPIOD_OUT_HIGH);
548 	if (IS_ERR(ps8622->gpio_slp)) {
549 		ret = PTR_ERR(ps8622->gpio_slp);
550 		dev_err(dev, "cannot get gpio_slp %d\n", ret);
551 		return ret;
552 	}
553 
554 	/*
555 	 * Assert the reset pin high to avoid the bridge being
556 	 * initialized prematurely
557 	 */
558 	ps8622->gpio_rst = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
559 	if (IS_ERR(ps8622->gpio_rst)) {
560 		ret = PTR_ERR(ps8622->gpio_rst);
561 		dev_err(dev, "cannot get gpio_rst %d\n", ret);
562 		return ret;
563 	}
564 
565 	ps8622->max_lane_count = id->driver_data;
566 
567 	if (of_property_read_u32(dev->of_node, "lane-count",
568 						&ps8622->lane_count)) {
569 		ps8622->lane_count = ps8622->max_lane_count;
570 	} else if (ps8622->lane_count > ps8622->max_lane_count) {
571 		dev_info(dev, "lane-count property is too high,"
572 						"using max_lane_count\n");
573 		ps8622->lane_count = ps8622->max_lane_count;
574 	}
575 
576 	if (!of_find_property(dev->of_node, "use-external-pwm", NULL)) {
577 		ps8622->bl = backlight_device_register("ps8622-backlight",
578 				dev, ps8622, &ps8622_backlight_ops,
579 				NULL);
580 		if (IS_ERR(ps8622->bl)) {
581 			DRM_ERROR("failed to register backlight\n");
582 			ret = PTR_ERR(ps8622->bl);
583 			ps8622->bl = NULL;
584 			return ret;
585 		}
586 		ps8622->bl->props.max_brightness = PS8622_MAX_BRIGHTNESS;
587 		ps8622->bl->props.brightness = PS8622_MAX_BRIGHTNESS;
588 	}
589 
590 	ps8622->bridge.funcs = &ps8622_bridge_funcs;
591 	ps8622->bridge.of_node = dev->of_node;
592 	drm_bridge_add(&ps8622->bridge);
593 
594 	i2c_set_clientdata(client, ps8622);
595 
596 	return 0;
597 }
598 
599 static int ps8622_remove(struct i2c_client *client)
600 {
601 	struct ps8622_bridge *ps8622 = i2c_get_clientdata(client);
602 
603 	backlight_device_unregister(ps8622->bl);
604 	drm_bridge_remove(&ps8622->bridge);
605 
606 	return 0;
607 }
608 
609 static const struct i2c_device_id ps8622_i2c_table[] = {
610 	/* Device type, max_lane_count */
611 	{"ps8622", 1},
612 	{"ps8625", 2},
613 	{},
614 };
615 MODULE_DEVICE_TABLE(i2c, ps8622_i2c_table);
616 
617 static struct i2c_driver ps8622_driver = {
618 	.id_table	= ps8622_i2c_table,
619 	.probe		= ps8622_probe,
620 	.remove		= ps8622_remove,
621 	.driver		= {
622 		.name	= "ps8622",
623 		.of_match_table = ps8622_devices,
624 	},
625 };
626 module_i2c_driver(ps8622_driver);
627 
628 MODULE_AUTHOR("Vincent Palatin <vpalatin@chromium.org>");
629 MODULE_DESCRIPTION("Parade ps8622/ps8625 eDP-LVDS converter driver");
630 MODULE_LICENSE("GPL v2");
631