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