1 /*
2  * Parade PS8622 eDP/LVDS bridge driver
3  *
4  * Copyright (C) 2014 Google, Inc.
5  *
6  * This software is licensed under the terms of the GNU General Public
7  * License version 2, as published by the Free Software Foundation, and
8  * may be copied, distributed, and modified under those terms.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  */
15 
16 #include <linux/backlight.h>
17 #include <linux/delay.h>
18 #include <linux/err.h>
19 #include <linux/gpio.h>
20 #include <linux/gpio/consumer.h>
21 #include <linux/i2c.h>
22 #include <linux/module.h>
23 #include <linux/of.h>
24 #include <linux/of_device.h>
25 #include <linux/pm.h>
26 #include <linux/regulator/consumer.h>
27 #include <drm/drm_atomic_helper.h>
28 #include <drm/drm_crtc.h>
29 #include <drm/drm_crtc_helper.h>
30 #include <drm/drm_of.h>
31 #include <drm/drm_panel.h>
32 #include <drm/drmP.h>
33 
34 /* Brightness scale on the Parade chip */
35 #define PS8622_MAX_BRIGHTNESS 0xff
36 
37 /* Timings taken from the version 1.7 datasheet for the PS8622/PS8625 */
38 #define PS8622_POWER_RISE_T1_MIN_US 10
39 #define PS8622_POWER_RISE_T1_MAX_US 10000
40 #define PS8622_RST_HIGH_T2_MIN_US 3000
41 #define PS8622_RST_HIGH_T2_MAX_US 30000
42 #define PS8622_PWMO_END_T12_MS 200
43 #define PS8622_POWER_FALL_T16_MAX_US 10000
44 #define PS8622_POWER_OFF_T17_MS 500
45 
46 #if ((PS8622_RST_HIGH_T2_MIN_US + PS8622_POWER_RISE_T1_MAX_US) > \
47 	(PS8622_RST_HIGH_T2_MAX_US + PS8622_POWER_RISE_T1_MIN_US))
48 #error "T2.min + T1.max must be less than T2.max + T1.min"
49 #endif
50 
51 struct ps8622_bridge {
52 	struct drm_connector connector;
53 	struct i2c_client *client;
54 	struct drm_bridge bridge;
55 	struct drm_panel *panel;
56 	struct regulator *v12;
57 	struct backlight_device *bl;
58 
59 	struct gpio_desc *gpio_slp;
60 	struct gpio_desc *gpio_rst;
61 
62 	u32 max_lane_count;
63 	u32 lane_count;
64 
65 	bool enabled;
66 };
67 
68 static inline struct ps8622_bridge *
69 		bridge_to_ps8622(struct drm_bridge *bridge)
70 {
71 	return container_of(bridge, struct ps8622_bridge, bridge);
72 }
73 
74 static inline struct ps8622_bridge *
75 		connector_to_ps8622(struct drm_connector *connector)
76 {
77 	return container_of(connector, struct ps8622_bridge, connector);
78 }
79 
80 static int ps8622_set(struct i2c_client *client, u8 page, u8 reg, u8 val)
81 {
82 	int ret;
83 	struct i2c_adapter *adap = client->adapter;
84 	struct i2c_msg msg;
85 	u8 data[] = {reg, val};
86 
87 	msg.addr = client->addr + page;
88 	msg.flags = 0;
89 	msg.len = sizeof(data);
90 	msg.buf = data;
91 
92 	ret = i2c_transfer(adap, &msg, 1);
93 	if (ret != 1)
94 		pr_warn("PS8622 I2C write (0x%02x,0x%02x,0x%02x) failed: %d\n",
95 			client->addr + page, reg, val, ret);
96 	return !(ret == 1);
97 }
98 
99 static int ps8622_send_config(struct ps8622_bridge *ps8622)
100 {
101 	struct i2c_client *cl = ps8622->client;
102 	int err = 0;
103 
104 	/* HPD low */
105 	err = ps8622_set(cl, 0x02, 0xa1, 0x01);
106 	if (err)
107 		goto error;
108 
109 	/* SW setting: [1:0] SW output 1.2V voltage is lower to 96% */
110 	err = ps8622_set(cl, 0x04, 0x14, 0x01);
111 	if (err)
112 		goto error;
113 
114 	/* RCO SS setting: [5:4] = b01 0.5%, b10 1%, b11 1.5% */
115 	err = ps8622_set(cl, 0x04, 0xe3, 0x20);
116 	if (err)
117 		goto error;
118 
119 	/* [7] RCO SS enable */
120 	err = ps8622_set(cl, 0x04, 0xe2, 0x80);
121 	if (err)
122 		goto error;
123 
124 	/* RPHY Setting
125 	 * [3:2] CDR tune wait cycle before measure for fine tune
126 	 * b00: 1us b01: 0.5us b10:2us, b11: 4us
127 	 */
128 	err = ps8622_set(cl, 0x04, 0x8a, 0x0c);
129 	if (err)
130 		goto error;
131 
132 	/* [3] RFD always on */
133 	err = ps8622_set(cl, 0x04, 0x89, 0x08);
134 	if (err)
135 		goto error;
136 
137 	/* CTN lock in/out: 20000ppm/80000ppm. Lock out 2 times. */
138 	err = ps8622_set(cl, 0x04, 0x71, 0x2d);
139 	if (err)
140 		goto error;
141 
142 	/* 2.7G CDR settings: NOF=40LSB for HBR CDR  setting */
143 	err = ps8622_set(cl, 0x04, 0x7d, 0x07);
144 	if (err)
145 		goto error;
146 
147 	/* [1:0] Fmin=+4bands */
148 	err = ps8622_set(cl, 0x04, 0x7b, 0x00);
149 	if (err)
150 		goto error;
151 
152 	/* [7:5] DCO_FTRNG=+-40% */
153 	err = ps8622_set(cl, 0x04, 0x7a, 0xfd);
154 	if (err)
155 		goto error;
156 
157 	/* 1.62G CDR settings: [5:2]NOF=64LSB [1:0]DCO scale is 2/5 */
158 	err = ps8622_set(cl, 0x04, 0xc0, 0x12);
159 	if (err)
160 		goto error;
161 
162 	/* Gitune=-37% */
163 	err = ps8622_set(cl, 0x04, 0xc1, 0x92);
164 	if (err)
165 		goto error;
166 
167 	/* Fbstep=100% */
168 	err = ps8622_set(cl, 0x04, 0xc2, 0x1c);
169 	if (err)
170 		goto error;
171 
172 	/* [7] LOS signal disable */
173 	err = ps8622_set(cl, 0x04, 0x32, 0x80);
174 	if (err)
175 		goto error;
176 
177 	/* RPIO Setting: [7:4] LVDS driver bias current : 75% (250mV swing) */
178 	err = ps8622_set(cl, 0x04, 0x00, 0xb0);
179 	if (err)
180 		goto error;
181 
182 	/* [7:6] Right-bar GPIO output strength is 8mA */
183 	err = ps8622_set(cl, 0x04, 0x15, 0x40);
184 	if (err)
185 		goto error;
186 
187 	/* EQ Training State Machine Setting, RCO calibration start */
188 	err = ps8622_set(cl, 0x04, 0x54, 0x10);
189 	if (err)
190 		goto error;
191 
192 	/* Logic, needs more than 10 I2C command */
193 	/* [4:0] MAX_LANE_COUNT set to max supported lanes */
194 	err = ps8622_set(cl, 0x01, 0x02, 0x80 | ps8622->max_lane_count);
195 	if (err)
196 		goto error;
197 
198 	/* [4:0] LANE_COUNT_SET set to chosen lane count */
199 	err = ps8622_set(cl, 0x01, 0x21, 0x80 | ps8622->lane_count);
200 	if (err)
201 		goto error;
202 
203 	err = ps8622_set(cl, 0x00, 0x52, 0x20);
204 	if (err)
205 		goto error;
206 
207 	/* HPD CP toggle enable */
208 	err = ps8622_set(cl, 0x00, 0xf1, 0x03);
209 	if (err)
210 		goto error;
211 
212 	err = ps8622_set(cl, 0x00, 0x62, 0x41);
213 	if (err)
214 		goto error;
215 
216 	/* Counter number, add 1ms counter delay */
217 	err = ps8622_set(cl, 0x00, 0xf6, 0x01);
218 	if (err)
219 		goto error;
220 
221 	/* [6]PWM function control by DPCD0040f[7], default is PWM block */
222 	err = ps8622_set(cl, 0x00, 0x77, 0x06);
223 	if (err)
224 		goto error;
225 
226 	/* 04h Adjust VTotal toleranceto fix the 30Hz no display issue */
227 	err = ps8622_set(cl, 0x00, 0x4c, 0x04);
228 	if (err)
229 		goto error;
230 
231 	/* DPCD00400='h00, Parade OUI ='h001cf8 */
232 	err = ps8622_set(cl, 0x01, 0xc0, 0x00);
233 	if (err)
234 		goto error;
235 
236 	/* DPCD00401='h1c */
237 	err = ps8622_set(cl, 0x01, 0xc1, 0x1c);
238 	if (err)
239 		goto error;
240 
241 	/* DPCD00402='hf8 */
242 	err = ps8622_set(cl, 0x01, 0xc2, 0xf8);
243 	if (err)
244 		goto error;
245 
246 	/* DPCD403~408 = ASCII code, D2SLV5='h4432534c5635 */
247 	err = ps8622_set(cl, 0x01, 0xc3, 0x44);
248 	if (err)
249 		goto error;
250 
251 	/* DPCD404 */
252 	err = ps8622_set(cl, 0x01, 0xc4, 0x32);
253 	if (err)
254 		goto error;
255 
256 	/* DPCD405 */
257 	err = ps8622_set(cl, 0x01, 0xc5, 0x53);
258 	if (err)
259 		goto error;
260 
261 	/* DPCD406 */
262 	err = ps8622_set(cl, 0x01, 0xc6, 0x4c);
263 	if (err)
264 		goto error;
265 
266 	/* DPCD407 */
267 	err = ps8622_set(cl, 0x01, 0xc7, 0x56);
268 	if (err)
269 		goto error;
270 
271 	/* DPCD408 */
272 	err = ps8622_set(cl, 0x01, 0xc8, 0x35);
273 	if (err)
274 		goto error;
275 
276 	/* DPCD40A, Initial Code major revision '01' */
277 	err = ps8622_set(cl, 0x01, 0xca, 0x01);
278 	if (err)
279 		goto error;
280 
281 	/* DPCD40B, Initial Code minor revision '05' */
282 	err = ps8622_set(cl, 0x01, 0xcb, 0x05);
283 	if (err)
284 		goto error;
285 
286 
287 	if (ps8622->bl) {
288 		/* DPCD720, internal PWM */
289 		err = ps8622_set(cl, 0x01, 0xa5, 0xa0);
290 		if (err)
291 			goto error;
292 
293 		/* FFh for 100% brightness, 0h for 0% brightness */
294 		err = ps8622_set(cl, 0x01, 0xa7,
295 				ps8622->bl->props.brightness);
296 		if (err)
297 			goto error;
298 	} else {
299 		/* DPCD720, external PWM */
300 		err = ps8622_set(cl, 0x01, 0xa5, 0x80);
301 		if (err)
302 			goto error;
303 	}
304 
305 	/* Set LVDS output as 6bit-VESA mapping, single LVDS channel */
306 	err = ps8622_set(cl, 0x01, 0xcc, 0x13);
307 	if (err)
308 		goto error;
309 
310 	/* Enable SSC set by register */
311 	err = ps8622_set(cl, 0x02, 0xb1, 0x20);
312 	if (err)
313 		goto error;
314 
315 	/* Set SSC enabled and +/-1% central spreading */
316 	err = ps8622_set(cl, 0x04, 0x10, 0x16);
317 	if (err)
318 		goto error;
319 
320 	/* Logic end */
321 	/* MPU Clock source: LC => RCO */
322 	err = ps8622_set(cl, 0x04, 0x59, 0x60);
323 	if (err)
324 		goto error;
325 
326 	/* LC -> RCO */
327 	err = ps8622_set(cl, 0x04, 0x54, 0x14);
328 	if (err)
329 		goto error;
330 
331 	/* HPD high */
332 	err = ps8622_set(cl, 0x02, 0xa1, 0x91);
333 
334 error:
335 	return err ? -EIO : 0;
336 }
337 
338 static int ps8622_backlight_update(struct backlight_device *bl)
339 {
340 	struct ps8622_bridge *ps8622 = dev_get_drvdata(&bl->dev);
341 	int ret, brightness = bl->props.brightness;
342 
343 	if (bl->props.power != FB_BLANK_UNBLANK ||
344 	    bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
345 		brightness = 0;
346 
347 	if (!ps8622->enabled)
348 		return -EINVAL;
349 
350 	ret = ps8622_set(ps8622->client, 0x01, 0xa7, brightness);
351 
352 	return ret;
353 }
354 
355 static const struct backlight_ops ps8622_backlight_ops = {
356 	.update_status	= ps8622_backlight_update,
357 };
358 
359 static void ps8622_pre_enable(struct drm_bridge *bridge)
360 {
361 	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
362 	int ret;
363 
364 	if (ps8622->enabled)
365 		return;
366 
367 	gpiod_set_value(ps8622->gpio_rst, 0);
368 
369 	if (ps8622->v12) {
370 		ret = regulator_enable(ps8622->v12);
371 		if (ret)
372 			DRM_ERROR("fails to enable ps8622->v12");
373 	}
374 
375 	if (drm_panel_prepare(ps8622->panel)) {
376 		DRM_ERROR("failed to prepare panel\n");
377 		return;
378 	}
379 
380 	gpiod_set_value(ps8622->gpio_slp, 1);
381 
382 	/*
383 	 * T1 is the range of time that it takes for the power to rise after we
384 	 * enable the lcd/ps8622 fet. T2 is the range of time in which the
385 	 * data sheet specifies we should deassert the reset pin.
386 	 *
387 	 * If it takes T1.max for the power to rise, we need to wait atleast
388 	 * T2.min before deasserting the reset pin. If it takes T1.min for the
389 	 * power to rise, we need to wait at most T2.max before deasserting the
390 	 * reset pin.
391 	 */
392 	usleep_range(PS8622_RST_HIGH_T2_MIN_US + PS8622_POWER_RISE_T1_MAX_US,
393 		     PS8622_RST_HIGH_T2_MAX_US + PS8622_POWER_RISE_T1_MIN_US);
394 
395 	gpiod_set_value(ps8622->gpio_rst, 1);
396 
397 	/* wait 20ms after RST high */
398 	usleep_range(20000, 30000);
399 
400 	ret = ps8622_send_config(ps8622);
401 	if (ret) {
402 		DRM_ERROR("Failed to send config to bridge (%d)\n", ret);
403 		return;
404 	}
405 
406 	ps8622->enabled = true;
407 }
408 
409 static void ps8622_enable(struct drm_bridge *bridge)
410 {
411 	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
412 
413 	if (drm_panel_enable(ps8622->panel)) {
414 		DRM_ERROR("failed to enable panel\n");
415 		return;
416 	}
417 }
418 
419 static void ps8622_disable(struct drm_bridge *bridge)
420 {
421 	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
422 
423 	if (drm_panel_disable(ps8622->panel)) {
424 		DRM_ERROR("failed to disable panel\n");
425 		return;
426 	}
427 	msleep(PS8622_PWMO_END_T12_MS);
428 }
429 
430 static void ps8622_post_disable(struct drm_bridge *bridge)
431 {
432 	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
433 
434 	if (!ps8622->enabled)
435 		return;
436 
437 	ps8622->enabled = false;
438 
439 	/*
440 	 * This doesn't matter if the regulators are turned off, but something
441 	 * else might keep them on. In that case, we want to assert the slp gpio
442 	 * to lower power.
443 	 */
444 	gpiod_set_value(ps8622->gpio_slp, 0);
445 
446 	if (drm_panel_unprepare(ps8622->panel)) {
447 		DRM_ERROR("failed to unprepare panel\n");
448 		return;
449 	}
450 
451 	if (ps8622->v12)
452 		regulator_disable(ps8622->v12);
453 
454 	/*
455 	 * Sleep for at least the amount of time that it takes the power rail to
456 	 * fall to prevent asserting the rst gpio from doing anything.
457 	 */
458 	usleep_range(PS8622_POWER_FALL_T16_MAX_US,
459 		     2 * PS8622_POWER_FALL_T16_MAX_US);
460 	gpiod_set_value(ps8622->gpio_rst, 0);
461 
462 	msleep(PS8622_POWER_OFF_T17_MS);
463 }
464 
465 static int ps8622_get_modes(struct drm_connector *connector)
466 {
467 	struct ps8622_bridge *ps8622;
468 
469 	ps8622 = connector_to_ps8622(connector);
470 
471 	return drm_panel_get_modes(ps8622->panel);
472 }
473 
474 static const struct drm_connector_helper_funcs ps8622_connector_helper_funcs = {
475 	.get_modes = ps8622_get_modes,
476 };
477 
478 static const struct drm_connector_funcs ps8622_connector_funcs = {
479 	.fill_modes = drm_helper_probe_single_connector_modes,
480 	.destroy = drm_connector_cleanup,
481 	.reset = drm_atomic_helper_connector_reset,
482 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
483 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
484 };
485 
486 static int ps8622_attach(struct drm_bridge *bridge)
487 {
488 	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
489 	int ret;
490 
491 	if (!bridge->encoder) {
492 		DRM_ERROR("Parent encoder object not found");
493 		return -ENODEV;
494 	}
495 
496 	ps8622->connector.polled = DRM_CONNECTOR_POLL_HPD;
497 	ret = drm_connector_init(bridge->dev, &ps8622->connector,
498 			&ps8622_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
499 	if (ret) {
500 		DRM_ERROR("Failed to initialize connector with drm\n");
501 		return ret;
502 	}
503 	drm_connector_helper_add(&ps8622->connector,
504 					&ps8622_connector_helper_funcs);
505 	drm_connector_register(&ps8622->connector);
506 	drm_mode_connector_attach_encoder(&ps8622->connector,
507 							bridge->encoder);
508 
509 	if (ps8622->panel)
510 		drm_panel_attach(ps8622->panel, &ps8622->connector);
511 
512 	drm_helper_hpd_irq_event(ps8622->connector.dev);
513 
514 	return ret;
515 }
516 
517 static const struct drm_bridge_funcs ps8622_bridge_funcs = {
518 	.pre_enable = ps8622_pre_enable,
519 	.enable = ps8622_enable,
520 	.disable = ps8622_disable,
521 	.post_disable = ps8622_post_disable,
522 	.attach = ps8622_attach,
523 };
524 
525 static const struct of_device_id ps8622_devices[] = {
526 	{.compatible = "parade,ps8622",},
527 	{.compatible = "parade,ps8625",},
528 	{}
529 };
530 MODULE_DEVICE_TABLE(of, ps8622_devices);
531 
532 static int ps8622_probe(struct i2c_client *client,
533 					const struct i2c_device_id *id)
534 {
535 	struct device *dev = &client->dev;
536 	struct ps8622_bridge *ps8622;
537 	int ret;
538 
539 	ps8622 = devm_kzalloc(dev, sizeof(*ps8622), GFP_KERNEL);
540 	if (!ps8622)
541 		return -ENOMEM;
542 
543 	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &ps8622->panel, NULL);
544 	if (ret)
545 		return ret;
546 
547 	ps8622->client = client;
548 
549 	ps8622->v12 = devm_regulator_get(dev, "vdd12");
550 	if (IS_ERR(ps8622->v12)) {
551 		dev_info(dev, "no 1.2v regulator found for PS8622\n");
552 		ps8622->v12 = NULL;
553 	}
554 
555 	ps8622->gpio_slp = devm_gpiod_get(dev, "sleep", GPIOD_OUT_HIGH);
556 	if (IS_ERR(ps8622->gpio_slp)) {
557 		ret = PTR_ERR(ps8622->gpio_slp);
558 		dev_err(dev, "cannot get gpio_slp %d\n", ret);
559 		return ret;
560 	}
561 
562 	/*
563 	 * Assert the reset pin high to avoid the bridge being
564 	 * initialized prematurely
565 	 */
566 	ps8622->gpio_rst = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
567 	if (IS_ERR(ps8622->gpio_rst)) {
568 		ret = PTR_ERR(ps8622->gpio_rst);
569 		dev_err(dev, "cannot get gpio_rst %d\n", ret);
570 		return ret;
571 	}
572 
573 	ps8622->max_lane_count = id->driver_data;
574 
575 	if (of_property_read_u32(dev->of_node, "lane-count",
576 						&ps8622->lane_count)) {
577 		ps8622->lane_count = ps8622->max_lane_count;
578 	} else if (ps8622->lane_count > ps8622->max_lane_count) {
579 		dev_info(dev, "lane-count property is too high,"
580 						"using max_lane_count\n");
581 		ps8622->lane_count = ps8622->max_lane_count;
582 	}
583 
584 	if (!of_find_property(dev->of_node, "use-external-pwm", NULL)) {
585 		ps8622->bl = backlight_device_register("ps8622-backlight",
586 				dev, ps8622, &ps8622_backlight_ops,
587 				NULL);
588 		if (IS_ERR(ps8622->bl)) {
589 			DRM_ERROR("failed to register backlight\n");
590 			ret = PTR_ERR(ps8622->bl);
591 			ps8622->bl = NULL;
592 			return ret;
593 		}
594 		ps8622->bl->props.max_brightness = PS8622_MAX_BRIGHTNESS;
595 		ps8622->bl->props.brightness = PS8622_MAX_BRIGHTNESS;
596 	}
597 
598 	ps8622->bridge.funcs = &ps8622_bridge_funcs;
599 	ps8622->bridge.of_node = dev->of_node;
600 	drm_bridge_add(&ps8622->bridge);
601 
602 	i2c_set_clientdata(client, ps8622);
603 
604 	return 0;
605 }
606 
607 static int ps8622_remove(struct i2c_client *client)
608 {
609 	struct ps8622_bridge *ps8622 = i2c_get_clientdata(client);
610 
611 	backlight_device_unregister(ps8622->bl);
612 	drm_bridge_remove(&ps8622->bridge);
613 
614 	return 0;
615 }
616 
617 static const struct i2c_device_id ps8622_i2c_table[] = {
618 	/* Device type, max_lane_count */
619 	{"ps8622", 1},
620 	{"ps8625", 2},
621 	{},
622 };
623 MODULE_DEVICE_TABLE(i2c, ps8622_i2c_table);
624 
625 static struct i2c_driver ps8622_driver = {
626 	.id_table	= ps8622_i2c_table,
627 	.probe		= ps8622_probe,
628 	.remove		= ps8622_remove,
629 	.driver		= {
630 		.name	= "ps8622",
631 		.of_match_table = ps8622_devices,
632 	},
633 };
634 module_i2c_driver(ps8622_driver);
635 
636 MODULE_AUTHOR("Vincent Palatin <vpalatin@chromium.org>");
637 MODULE_DESCRIPTION("Parade ps8622/ps8625 eDP-LVDS converter driver");
638 MODULE_LICENSE("GPL v2");
639