summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c
blob: 221db6512859faefe867be8d486ae35de3c2014d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright 2021 Google Inc.
 *
 * Panel driver for the Samsung ATNA33XC20 panel. This panel can't be handled
 * by the DRM_PANEL_SIMPLE driver because its power sequencing is non-standard.
 */

#include <linux/backlight.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>

#include <drm/drm_dp_aux_bus.h>
#include <drm/drm_dp_helper.h>
#include <drm/drm_edid.h>
#include <drm/drm_panel.h>

struct atana33xc20_panel {
	struct drm_panel base;
	bool prepared;
	bool enabled;
	bool el3_was_on;

	bool no_hpd;
	struct gpio_desc *hpd_gpio;

	struct regulator *supply;
	struct gpio_desc *el_on3_gpio;

	struct edid *edid;

	ktime_t powered_off_time;
	ktime_t powered_on_time;
	ktime_t el_on3_off_time;
};

static inline struct atana33xc20_panel *to_atana33xc20(struct drm_panel *panel)
{
	return container_of(panel, struct atana33xc20_panel, base);
}

static void atana33xc20_wait(ktime_t start_ktime, unsigned int min_ms)
{
	ktime_t now_ktime, min_ktime;

	min_ktime = ktime_add(start_ktime, ms_to_ktime(min_ms));
	now_ktime = ktime_get();

	if (ktime_before(now_ktime, min_ktime))
		msleep(ktime_to_ms(ktime_sub(min_ktime, now_ktime)) + 1);
}

static int atana33xc20_suspend(struct device *dev)
{
	struct atana33xc20_panel *p = dev_get_drvdata(dev);
	int ret;

	/*
	 * Note 3 (Example of power off sequence in detail) in spec
	 * specifies to wait 150 ms after deasserting EL3_ON before
	 * powering off.
	 */
	if (p->el3_was_on)
		atana33xc20_wait(p->el_on3_off_time, 150);

	ret = regulator_disable(p->supply);
	if (ret)
		return ret;
	p->powered_off_time = ktime_get();
	p->el3_was_on = false;

	return 0;
}

static int atana33xc20_resume(struct device *dev)
{
	struct atana33xc20_panel *p = dev_get_drvdata(dev);
	bool hpd_asserted = false;
	int ret;

	/* T12 (Power off time) is min 500 ms */
	atana33xc20_wait(p->powered_off_time, 500);

	ret = regulator_enable(p->supply);
	if (ret)
		return ret;
	p->powered_on_time = ktime_get();

	/*
	 * Handle HPD. Note: if HPD is hooked up to a dedicated pin on the
	 * eDP controller then "no_hpd" will be false _and_ "hpd_gpio" will be
	 * NULL. It's up to the controller driver to wait for HPD after
	 * preparing the panel in that case.
	 */
	if (p->no_hpd) {
		/* T3 VCC to HPD high is max 200 ms */
		msleep(200);
	} else if (p->hpd_gpio) {
		ret = readx_poll_timeout(gpiod_get_value_cansleep, p->hpd_gpio,
					 hpd_asserted, hpd_asserted,
					 1000, 200000);
		if (!hpd_asserted)
			dev_warn(dev, "Timeout waiting for HPD\n");
	}

	return 0;
}

static int atana33xc20_disable(struct drm_panel *panel)
{
	struct atana33xc20_panel *p = to_atana33xc20(panel);

	/* Disabling when already disabled is a no-op */
	if (!p->enabled)
		return 0;

	gpiod_set_value_cansleep(p->el_on3_gpio, 0);
	p->el_on3_off_time = ktime_get();
	p->enabled = false;

	/*
	 * Keep track of the fact that EL_ON3 was on but we haven't power
	 * cycled yet. This lets us know that "el_on3_off_time" is recent (we
	 * don't need to worry about ktime wraparounds) and also makes it
	 * obvious if we try to enable again without a power cycle (see the
	 * warning in atana33xc20_enable()).
	 */
	p->el3_was_on = true;

	/*
	 * Sleeping 20 ms here (after setting the GPIO) avoids a glitch when
	 * powering off.
	 */
	msleep(20);

	return 0;
}

static int atana33xc20_enable(struct drm_panel *panel)
{
	struct atana33xc20_panel *p = to_atana33xc20(panel);

	/* Enabling when already enabled is a no-op */
	if (p->enabled)
		return 0;

	/*
	 * Once EL_ON3 drops we absolutely need a power cycle before the next
	 * enable or the backlight will never come on again. The code ensures
	 * this because disable() is _always_ followed by unprepare() and
	 * unprepare() forces a suspend with pm_runtime_put_sync_suspend(),
	 * but let's track just to make sure since the requirement is so
	 * non-obvious.
	 */
	if (WARN_ON(p->el3_was_on))
		return -EIO;

	/*
	 * Note 2 (Example of power on sequence in detail) in spec specifies
	 * to wait 400 ms after powering on before asserting EL3_on.
	 */
	atana33xc20_wait(p->powered_on_time, 400);

	gpiod_set_value_cansleep(p->el_on3_gpio, 1);
	p->enabled = true;

	return 0;
}

static int atana33xc20_unprepare(struct drm_panel *panel)
{
	struct atana33xc20_panel *p = to_atana33xc20(panel);
	int ret;

	/* Unpreparing when already unprepared is a no-op */
	if (!p->prepared)
		return 0;

	/*
	 * Purposely do a put_sync, don't use autosuspend. The panel's tcon
	 * seems to sometimes crash when you stop giving it data and this is
	 * the best way to ensure it will come back.
	 *
	 * NOTE: we still want autosuspend for cases where we only turn on
	 * to get the EDID or otherwise send DP AUX commands to the panel.
	 */
	ret = pm_runtime_put_sync_suspend(panel->dev);
	if (ret < 0)
		return ret;
	p->prepared = false;

	return 0;
}

static int atana33xc20_prepare(struct drm_panel *panel)
{
	struct atana33xc20_panel *p = to_atana33xc20(panel);
	int ret;

	/* Preparing when already prepared is a no-op */
	if (p->prepared)
		return 0;

	ret = pm_runtime_get_sync(panel->dev);
	if (ret < 0) {
		pm_runtime_put_autosuspend(panel->dev);
		return ret;
	}
	p->prepared = true;

	return 0;
}

static int atana33xc20_get_modes(struct drm_panel *panel,
				 struct drm_connector *connector)
{
	struct atana33xc20_panel *p = to_atana33xc20(panel);
	struct dp_aux_ep_device *aux_ep = to_dp_aux_ep_dev(panel->dev);
	int num = 0;

	pm_runtime_get_sync(panel->dev);

	if (!p->edid)
		p->edid = drm_get_edid(connector, &aux_ep->aux->ddc);
	num = drm_add_edid_modes(connector, p->edid);

	pm_runtime_mark_last_busy(panel->dev);
	pm_runtime_put_autosuspend(panel->dev);

	return num;
}

static const struct drm_panel_funcs atana33xc20_funcs = {
	.disable = atana33xc20_disable,
	.enable = atana33xc20_enable,
	.unprepare = atana33xc20_unprepare,
	.prepare = atana33xc20_prepare,
	.get_modes = atana33xc20_get_modes,
};

static void atana33xc20_runtime_disable(void *data)
{
	pm_runtime_disable(data);
}

static void atana33xc20_dont_use_autosuspend(void *data)
{
	pm_runtime_dont_use_autosuspend(data);
}

static int atana33xc20_probe(struct dp_aux_ep_device *aux_ep)
{
	struct atana33xc20_panel *panel;
	struct device *dev = &aux_ep->dev;
	int ret;

	panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
	if (!panel)
		return -ENOMEM;
	dev_set_drvdata(dev, panel);

	panel->supply = devm_regulator_get(dev, "power");
	if (IS_ERR(panel->supply))
		return dev_err_probe(dev, PTR_ERR(panel->supply),
				     "Failed to get power supply\n");

	panel->el_on3_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
	if (IS_ERR(panel->el_on3_gpio))
		return dev_err_probe(dev, PTR_ERR(panel->el_on3_gpio),
				     "Failed to get enable GPIO\n");

	panel->no_hpd = of_property_read_bool(dev->of_node, "no-hpd");
	if (!panel->no_hpd) {
		panel->hpd_gpio = devm_gpiod_get_optional(dev, "hpd", GPIOD_IN);
		if (IS_ERR(panel->hpd_gpio))
			return dev_err_probe(dev, PTR_ERR(panel->hpd_gpio),
					     "Failed to get HPD GPIO\n");
	}

	pm_runtime_enable(dev);
	ret = devm_add_action_or_reset(dev,  atana33xc20_runtime_disable, dev);
	if (ret)
		return ret;
	pm_runtime_set_autosuspend_delay(dev, 1000);
	pm_runtime_use_autosuspend(dev);
	ret = devm_add_action_or_reset(dev,  atana33xc20_dont_use_autosuspend, dev);
	if (ret)
		return ret;

	drm_panel_init(&panel->base, dev, &atana33xc20_funcs, DRM_MODE_CONNECTOR_eDP);

	pm_runtime_get_sync(dev);
	ret = drm_panel_dp_aux_backlight(&panel->base, aux_ep->aux);
	pm_runtime_mark_last_busy(dev);
	pm_runtime_put_autosuspend(dev);
	if (ret)
		return dev_err_probe(dev, ret,
				     "failed to register dp aux backlight\n");

	drm_panel_add(&panel->base);

	return 0;
}

static void atana33xc20_remove(struct dp_aux_ep_device *aux_ep)
{
	struct device *dev = &aux_ep->dev;
	struct atana33xc20_panel *panel = dev_get_drvdata(dev);

	drm_panel_remove(&panel->base);
	drm_panel_disable(&panel->base);
	drm_panel_unprepare(&panel->base);

	kfree(panel->edid);
}

static void atana33xc20_shutdown(struct dp_aux_ep_device *aux_ep)
{
	struct device *dev = &aux_ep->dev;
	struct atana33xc20_panel *panel = dev_get_drvdata(dev);

	drm_panel_disable(&panel->base);
	drm_panel_unprepare(&panel->base);
}

static const struct of_device_id atana33xc20_dt_match[] = {
	{ .compatible = "samsung,atna33xc20", },
	{ /* sentinal */ }
};
MODULE_DEVICE_TABLE(of, atana33xc20_dt_match);

static const struct dev_pm_ops atana33xc20_pm_ops = {
	SET_RUNTIME_PM_OPS(atana33xc20_suspend, atana33xc20_resume, NULL)
	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
				pm_runtime_force_resume)
};

static struct dp_aux_ep_driver atana33xc20_driver = {
	.driver = {
		.name		= "samsung_atana33xc20",
		.of_match_table = atana33xc20_dt_match,
		.pm		= &atana33xc20_pm_ops,
	},
	.probe = atana33xc20_probe,
	.remove = atana33xc20_remove,
	.shutdown = atana33xc20_shutdown,
};

static int __init atana33xc20_init(void)
{
	return dp_aux_dp_driver_register(&atana33xc20_driver);
}
module_init(atana33xc20_init);

static void __exit atana33xc20_exit(void)
{
	dp_aux_dp_driver_unregister(&atana33xc20_driver);
}
module_exit(atana33xc20_exit);

MODULE_DESCRIPTION("Samsung ATANA33XC20 Panel Driver");
MODULE_LICENSE("GPL v2");