summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/panel/panel-tpo-tpg110.c
blob: bee213ea1a42f22b601ebe6c7ac494646a1b8c3c (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
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
// SPDX-License-Identifier: GPL-2.0
/*
 * Panel driver for the TPO TPG110 400CH LTPS TFT LCD Single Chip
 * Digital Driver.
 *
 * This chip drives a TFT LCD, so it does not know what kind of
 * display is actually connected to it, so the width and height of that
 * display needs to be supplied from the machine configuration.
 *
 * Author:
 * Linus Walleij <linus.walleij@linaro.org>
 */
#include <drm/drm_modes.h>
#include <drm/drm_panel.h>
#include <drm/drm_print.h>

#include <linux/backlight.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>

#define TPG110_TEST			0x00
#define TPG110_CHIPID			0x01
#define TPG110_CTRL1			0x02
#define TPG110_RES_MASK			GENMASK(2, 0)
#define TPG110_RES_800X480		0x07
#define TPG110_RES_640X480		0x06
#define TPG110_RES_480X272		0x05
#define TPG110_RES_480X640		0x04
#define TPG110_RES_480X272_D		0x01 /* Dual scan: outputs 800x480 */
#define TPG110_RES_400X240_D		0x00 /* Dual scan: outputs 800x480 */
#define TPG110_CTRL2			0x03
#define TPG110_CTRL2_PM			BIT(0)
#define TPG110_CTRL2_RES_PM_CTRL	BIT(7)

/**
 * struct tpg110_panel_mode - lookup struct for the supported modes
 */
struct tpg110_panel_mode {
	/**
	 * @name: the name of this panel
	 */
	const char *name;
	/**
	 * @magic: the magic value from the detection register
	 */
	u32 magic;
	/**
	 * @mode: the DRM display mode for this panel
	 */
	struct drm_display_mode mode;
	/**
	 * @bus_flags: the DRM bus flags for this panel e.g. inverted clock
	 */
	u32 bus_flags;
};

/**
 * struct tpg110 - state container for the TPG110 panel
 */
struct tpg110 {
	/**
	 * @dev: the container device
	 */
	struct device *dev;
	/**
	 * @spi: the corresponding SPI device
	 */
	struct spi_device *spi;
	/**
	 * @panel: the DRM panel instance for this device
	 */
	struct drm_panel panel;
	/**
	 * @backlight: backlight for this panel
	 */
	struct backlight_device *backlight;
	/**
	 * @panel_type: the panel mode as detected
	 */
	const struct tpg110_panel_mode *panel_mode;
	/**
	 * @width: the width of this panel in mm
	 */
	u32 width;
	/**
	 * @height: the height of this panel in mm
	 */
	u32 height;
	/**
	 * @grestb: reset GPIO line
	 */
	struct gpio_desc *grestb;
};

/*
 * TPG110 modes, these are the simple modes, the dualscan modes that
 * take 400x240 or 480x272 in and display as 800x480 are not listed.
 */
static const struct tpg110_panel_mode tpg110_modes[] = {
	{
		.name = "800x480 RGB",
		.magic = TPG110_RES_800X480,
		.mode = {
			.clock = 33200,
			.hdisplay = 800,
			.hsync_start = 800 + 40,
			.hsync_end = 800 + 40 + 1,
			.htotal = 800 + 40 + 1 + 216,
			.vdisplay = 480,
			.vsync_start = 480 + 10,
			.vsync_end = 480 + 10 + 1,
			.vtotal = 480 + 10 + 1 + 35,
			.vrefresh = 60,
		},
		.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
	},
	{
		.name = "640x480 RGB",
		.magic = TPG110_RES_640X480,
		.mode = {
			.clock = 25200,
			.hdisplay = 640,
			.hsync_start = 640 + 24,
			.hsync_end = 640 + 24 + 1,
			.htotal = 640 + 24 + 1 + 136,
			.vdisplay = 480,
			.vsync_start = 480 + 18,
			.vsync_end = 480 + 18 + 1,
			.vtotal = 480 + 18 + 1 + 27,
			.vrefresh = 60,
		},
		.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
	},
	{
		.name = "480x272 RGB",
		.magic = TPG110_RES_480X272,
		.mode = {
			.clock = 9000,
			.hdisplay = 480,
			.hsync_start = 480 + 2,
			.hsync_end = 480 + 2 + 1,
			.htotal = 480 + 2 + 1 + 43,
			.vdisplay = 272,
			.vsync_start = 272 + 2,
			.vsync_end = 272 + 2 + 1,
			.vtotal = 272 + 2 + 1 + 12,
			.vrefresh = 60,
		},
		.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
	},
	{
		.name = "480x640 RGB",
		.magic = TPG110_RES_480X640,
		.mode = {
			.clock = 20500,
			.hdisplay = 480,
			.hsync_start = 480 + 2,
			.hsync_end = 480 + 2 + 1,
			.htotal = 480 + 2 + 1 + 43,
			.vdisplay = 640,
			.vsync_start = 640 + 4,
			.vsync_end = 640 + 4 + 1,
			.vtotal = 640 + 4 + 1 + 8,
			.vrefresh = 60,
		},
		.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
	},
	{
		.name = "400x240 RGB",
		.magic = TPG110_RES_400X240_D,
		.mode = {
			.clock = 8300,
			.hdisplay = 400,
			.hsync_start = 400 + 20,
			.hsync_end = 400 + 20 + 1,
			.htotal = 400 + 20 + 1 + 108,
			.vdisplay = 240,
			.vsync_start = 240 + 2,
			.vsync_end = 240 + 2 + 1,
			.vtotal = 240 + 2 + 1 + 20,
			.vrefresh = 60,
		},
		.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
	},
};

static inline struct tpg110 *
to_tpg110(struct drm_panel *panel)
{
	return container_of(panel, struct tpg110, panel);
}

static u8 tpg110_readwrite_reg(struct tpg110 *tpg, bool write,
			       u8 address, u8 outval)
{
	struct spi_message m;
	struct spi_transfer t[2];
	u8 buf[2];
	int ret;

	spi_message_init(&m);
	memset(t, 0, sizeof(t));

	if (write) {
		/*
		 * Clear address bit 0, 1 when writing, just to be sure
		 * The actual bit indicating a write here is bit 1, bit
		 * 0 is just surplus to pad it up to 8 bits.
		 */
		buf[0] = address << 2;
		buf[0] &= ~0x03;
		buf[1] = outval;

		t[0].bits_per_word = 8;
		t[0].tx_buf = &buf[0];
		t[0].len = 1;

		t[1].tx_buf = &buf[1];
		t[1].len = 1;
		t[1].bits_per_word = 8;
	} else {
		/* Set address bit 0 to 1 to read */
		buf[0] = address << 1;
		buf[0] |= 0x01;

		/*
		 * The last bit/clock is Hi-Z turnaround cycle, so we need
		 * to send only 7 bits here. The 8th bit is the high impedance
		 * turn-around cycle.
		 */
		t[0].bits_per_word = 7;
		t[0].tx_buf = &buf[0];
		t[0].len = 1;

		t[1].rx_buf = &buf[1];
		t[1].len = 1;
		t[1].bits_per_word = 8;
	}

	spi_message_add_tail(&t[0], &m);
	spi_message_add_tail(&t[1], &m);
	ret = spi_sync(tpg->spi, &m);
	if (ret) {
		DRM_DEV_ERROR(tpg->dev, "SPI message error %d\n", ret);
		return ret;
	}
	if (write)
		return 0;
	/* Read */
	return buf[1];
}

static u8 tpg110_read_reg(struct tpg110 *tpg, u8 address)
{
	return tpg110_readwrite_reg(tpg, false, address, 0);
}

static void tpg110_write_reg(struct tpg110 *tpg, u8 address, u8 outval)
{
	tpg110_readwrite_reg(tpg, true, address, outval);
}

static int tpg110_startup(struct tpg110 *tpg)
{
	u8 val;
	int i;

	/* De-assert the reset signal */
	gpiod_set_value_cansleep(tpg->grestb, 0);
	usleep_range(1000, 2000);
	DRM_DEV_DEBUG(tpg->dev, "de-asserted GRESTB\n");

	/* Test display communication */
	tpg110_write_reg(tpg, TPG110_TEST, 0x55);
	val = tpg110_read_reg(tpg, TPG110_TEST);
	if (val != 0x55) {
		DRM_DEV_ERROR(tpg->dev, "failed communication test\n");
		return -ENODEV;
	}

	val = tpg110_read_reg(tpg, TPG110_CHIPID);
	DRM_DEV_INFO(tpg->dev, "TPG110 chip ID: %d version: %d\n",
		 val >> 4, val & 0x0f);

	/* Show display resolution */
	val = tpg110_read_reg(tpg, TPG110_CTRL1);
	val &= TPG110_RES_MASK;
	switch (val) {
	case TPG110_RES_400X240_D:
		DRM_DEV_INFO(tpg->dev,
			 "IN 400x240 RGB -> OUT 800x480 RGB (dual scan)\n");
		break;
	case TPG110_RES_480X272_D:
		DRM_DEV_INFO(tpg->dev,
			 "IN 480x272 RGB -> OUT 800x480 RGB (dual scan)\n");
		break;
	case TPG110_RES_480X640:
		DRM_DEV_INFO(tpg->dev, "480x640 RGB\n");
		break;
	case TPG110_RES_480X272:
		DRM_DEV_INFO(tpg->dev, "480x272 RGB\n");
		break;
	case TPG110_RES_640X480:
		DRM_DEV_INFO(tpg->dev, "640x480 RGB\n");
		break;
	case TPG110_RES_800X480:
		DRM_DEV_INFO(tpg->dev, "800x480 RGB\n");
		break;
	default:
		DRM_DEV_ERROR(tpg->dev, "ILLEGAL RESOLUTION 0x%02x\n", val);
		break;
	}

	/* From the producer side, this is the same resolution */
	if (val == TPG110_RES_480X272_D)
		val = TPG110_RES_480X272;

	for (i = 0; i < ARRAY_SIZE(tpg110_modes); i++) {
		const struct tpg110_panel_mode *pm;

		pm = &tpg110_modes[i];
		if (pm->magic == val) {
			tpg->panel_mode = pm;
			break;
		}
	}
	if (i == ARRAY_SIZE(tpg110_modes)) {
		DRM_DEV_ERROR(tpg->dev, "unsupported mode (%02x) detected\n",
			val);
		return -ENODEV;
	}

	val = tpg110_read_reg(tpg, TPG110_CTRL2);
	DRM_DEV_INFO(tpg->dev, "resolution and standby is controlled by %s\n",
		 (val & TPG110_CTRL2_RES_PM_CTRL) ? "software" : "hardware");
	/* Take control over resolution and standby */
	val |= TPG110_CTRL2_RES_PM_CTRL;
	tpg110_write_reg(tpg, TPG110_CTRL2, val);

	return 0;
}

static int tpg110_disable(struct drm_panel *panel)
{
	struct tpg110 *tpg = to_tpg110(panel);
	u8 val;

	/* Put chip into standby */
	val = tpg110_read_reg(tpg, TPG110_CTRL2_PM);
	val &= ~TPG110_CTRL2_PM;
	tpg110_write_reg(tpg, TPG110_CTRL2_PM, val);

	backlight_disable(tpg->backlight);

	return 0;
}

static int tpg110_enable(struct drm_panel *panel)
{
	struct tpg110 *tpg = to_tpg110(panel);
	u8 val;

	backlight_enable(tpg->backlight);

	/* Take chip out of standby */
	val = tpg110_read_reg(tpg, TPG110_CTRL2_PM);
	val |= TPG110_CTRL2_PM;
	tpg110_write_reg(tpg, TPG110_CTRL2_PM, val);

	return 0;
}

/**
 * tpg110_get_modes() - return the appropriate mode
 * @panel: the panel to get the mode for
 *
 * This currently does not present a forest of modes, instead it
 * presents the mode that is configured for the system under use,
 * and which is detected by reading the registers of the display.
 */
static int tpg110_get_modes(struct drm_panel *panel,
			    struct drm_connector *connector)
{
	struct tpg110 *tpg = to_tpg110(panel);
	struct drm_display_mode *mode;

	connector->display_info.width_mm = tpg->width;
	connector->display_info.height_mm = tpg->height;
	connector->display_info.bus_flags = tpg->panel_mode->bus_flags;

	mode = drm_mode_duplicate(connector->dev, &tpg->panel_mode->mode);
	drm_mode_set_name(mode);
	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;

	mode->width_mm = tpg->width;
	mode->height_mm = tpg->height;

	drm_mode_probed_add(connector, mode);

	return 1;
}

static const struct drm_panel_funcs tpg110_drm_funcs = {
	.disable = tpg110_disable,
	.enable = tpg110_enable,
	.get_modes = tpg110_get_modes,
};

static int tpg110_probe(struct spi_device *spi)
{
	struct device *dev = &spi->dev;
	struct device_node *np = dev->of_node;
	struct tpg110 *tpg;
	int ret;

	tpg = devm_kzalloc(dev, sizeof(*tpg), GFP_KERNEL);
	if (!tpg)
		return -ENOMEM;
	tpg->dev = dev;

	/* We get the physical display dimensions from the DT */
	ret = of_property_read_u32(np, "width-mm", &tpg->width);
	if (ret)
		DRM_DEV_ERROR(dev, "no panel width specified\n");
	ret = of_property_read_u32(np, "height-mm", &tpg->height);
	if (ret)
		DRM_DEV_ERROR(dev, "no panel height specified\n");

	/* Look for some optional backlight */
	tpg->backlight = devm_of_find_backlight(dev);
	if (IS_ERR(tpg->backlight))
		return PTR_ERR(tpg->backlight);

	/* This asserts the GRESTB signal, putting the display into reset */
	tpg->grestb = devm_gpiod_get(dev, "grestb", GPIOD_OUT_HIGH);
	if (IS_ERR(tpg->grestb)) {
		DRM_DEV_ERROR(dev, "no GRESTB GPIO\n");
		return -ENODEV;
	}

	spi->bits_per_word = 8;
	spi->mode |= SPI_3WIRE_HIZ;
	ret = spi_setup(spi);
	if (ret < 0) {
		DRM_DEV_ERROR(dev, "spi setup failed.\n");
		return ret;
	}
	tpg->spi = spi;

	ret = tpg110_startup(tpg);
	if (ret)
		return ret;

	drm_panel_init(&tpg->panel, dev, &tpg110_drm_funcs,
		       DRM_MODE_CONNECTOR_DPI);
	spi_set_drvdata(spi, tpg);

	return drm_panel_add(&tpg->panel);
}

static int tpg110_remove(struct spi_device *spi)
{
	struct tpg110 *tpg = spi_get_drvdata(spi);

	drm_panel_remove(&tpg->panel);
	return 0;
}

static const struct of_device_id tpg110_match[] = {
	{ .compatible = "tpo,tpg110", },
	{},
};
MODULE_DEVICE_TABLE(of, tpg110_match);

static struct spi_driver tpg110_driver = {
	.probe		= tpg110_probe,
	.remove		= tpg110_remove,
	.driver		= {
		.name	= "tpo-tpg110-panel",
		.of_match_table = tpg110_match,
	},
};
module_spi_driver(tpg110_driver);

MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
MODULE_DESCRIPTION("TPO TPG110 panel driver");
MODULE_LICENSE("GPL v2");