1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Toppoly TD043MTEA1 Panel Driver
4  *
5  * Copyright (C) 2019 Texas Instruments Incorporated
6  *
7  * Based on the omapdrm-specific panel-tpo-td043mtea1 driver
8  *
9  * Author: Gražvydas Ignotas <notasas@gmail.com>
10  */
11 
12 #include <linux/delay.h>
13 #include <linux/module.h>
14 #include <linux/regulator/consumer.h>
15 #include <linux/spi/spi.h>
16 
17 #include <drm/drm_connector.h>
18 #include <drm/drm_modes.h>
19 #include <drm/drm_panel.h>
20 
21 #define TPO_R02_MODE(x)			((x) & 7)
22 #define TPO_R02_MODE_800x480		7
23 #define TPO_R02_NCLK_RISING		BIT(3)
24 #define TPO_R02_HSYNC_HIGH		BIT(4)
25 #define TPO_R02_VSYNC_HIGH		BIT(5)
26 
27 #define TPO_R03_NSTANDBY		BIT(0)
28 #define TPO_R03_EN_CP_CLK		BIT(1)
29 #define TPO_R03_EN_VGL_PUMP		BIT(2)
30 #define TPO_R03_EN_PWM			BIT(3)
31 #define TPO_R03_DRIVING_CAP_100		BIT(4)
32 #define TPO_R03_EN_PRE_CHARGE		BIT(6)
33 #define TPO_R03_SOFTWARE_CTL		BIT(7)
34 
35 #define TPO_R04_NFLIP_H			BIT(0)
36 #define TPO_R04_NFLIP_V			BIT(1)
37 #define TPO_R04_CP_CLK_FREQ_1H		BIT(2)
38 #define TPO_R04_VGL_FREQ_1H		BIT(4)
39 
40 #define TPO_R03_VAL_NORMAL \
41 	(TPO_R03_NSTANDBY | TPO_R03_EN_CP_CLK | TPO_R03_EN_VGL_PUMP | \
42 	 TPO_R03_EN_PWM | TPO_R03_DRIVING_CAP_100 | TPO_R03_EN_PRE_CHARGE | \
43 	 TPO_R03_SOFTWARE_CTL)
44 
45 #define TPO_R03_VAL_STANDBY \
46 	(TPO_R03_DRIVING_CAP_100 | TPO_R03_EN_PRE_CHARGE | \
47 	 TPO_R03_SOFTWARE_CTL)
48 
49 static const u16 td043mtea1_def_gamma[12] = {
50 	105, 315, 381, 431, 490, 537, 579, 686, 780, 837, 880, 1023
51 };
52 
53 struct td043mtea1_panel {
54 	struct drm_panel panel;
55 
56 	struct spi_device *spi;
57 	struct regulator *vcc_reg;
58 	struct gpio_desc *reset_gpio;
59 
60 	unsigned int mode;
61 	u16 gamma[12];
62 	bool vmirror;
63 	bool powered_on;
64 	bool spi_suspended;
65 	bool power_on_resume;
66 };
67 
68 #define to_td043mtea1_device(p) container_of(p, struct td043mtea1_panel, panel)
69 
70 /* -----------------------------------------------------------------------------
71  * Hardware Access
72  */
73 
74 static int td043mtea1_write(struct td043mtea1_panel *lcd, u8 addr, u8 value)
75 {
76 	struct spi_message msg;
77 	struct spi_transfer xfer;
78 	u16 data;
79 	int ret;
80 
81 	spi_message_init(&msg);
82 
83 	memset(&xfer, 0, sizeof(xfer));
84 
85 	data = ((u16)addr << 10) | (1 << 8) | value;
86 	xfer.tx_buf = &data;
87 	xfer.bits_per_word = 16;
88 	xfer.len = 2;
89 	spi_message_add_tail(&xfer, &msg);
90 
91 	ret = spi_sync(lcd->spi, &msg);
92 	if (ret < 0)
93 		dev_warn(&lcd->spi->dev, "failed to write to LCD reg (%d)\n",
94 			 ret);
95 
96 	return ret;
97 }
98 
99 static void td043mtea1_write_gamma(struct td043mtea1_panel *lcd)
100 {
101 	const u16 *gamma = lcd->gamma;
102 	unsigned int i;
103 	u8 val;
104 
105 	/* gamma bits [9:8] */
106 	for (val = i = 0; i < 4; i++)
107 		val |= (gamma[i] & 0x300) >> ((i + 1) * 2);
108 	td043mtea1_write(lcd, 0x11, val);
109 
110 	for (val = i = 0; i < 4; i++)
111 		val |= (gamma[i + 4] & 0x300) >> ((i + 1) * 2);
112 	td043mtea1_write(lcd, 0x12, val);
113 
114 	for (val = i = 0; i < 4; i++)
115 		val |= (gamma[i + 8] & 0x300) >> ((i + 1) * 2);
116 	td043mtea1_write(lcd, 0x13, val);
117 
118 	/* gamma bits [7:0] */
119 	for (i = 0; i < 12; i++)
120 		td043mtea1_write(lcd, 0x14 + i, gamma[i] & 0xff);
121 }
122 
123 static int td043mtea1_write_mirror(struct td043mtea1_panel *lcd)
124 {
125 	u8 reg4 = TPO_R04_NFLIP_H | TPO_R04_NFLIP_V |
126 		TPO_R04_CP_CLK_FREQ_1H | TPO_R04_VGL_FREQ_1H;
127 	if (lcd->vmirror)
128 		reg4 &= ~TPO_R04_NFLIP_V;
129 
130 	return td043mtea1_write(lcd, 4, reg4);
131 }
132 
133 static int td043mtea1_power_on(struct td043mtea1_panel *lcd)
134 {
135 	int ret;
136 
137 	if (lcd->powered_on)
138 		return 0;
139 
140 	ret = regulator_enable(lcd->vcc_reg);
141 	if (ret < 0)
142 		return ret;
143 
144 	/* Wait for the panel to stabilize. */
145 	msleep(160);
146 
147 	gpiod_set_value(lcd->reset_gpio, 0);
148 
149 	td043mtea1_write(lcd, 2, TPO_R02_MODE(lcd->mode) | TPO_R02_NCLK_RISING);
150 	td043mtea1_write(lcd, 3, TPO_R03_VAL_NORMAL);
151 	td043mtea1_write(lcd, 0x20, 0xf0);
152 	td043mtea1_write(lcd, 0x21, 0xf0);
153 	td043mtea1_write_mirror(lcd);
154 	td043mtea1_write_gamma(lcd);
155 
156 	lcd->powered_on = true;
157 
158 	return 0;
159 }
160 
161 static void td043mtea1_power_off(struct td043mtea1_panel *lcd)
162 {
163 	if (!lcd->powered_on)
164 		return;
165 
166 	td043mtea1_write(lcd, 3, TPO_R03_VAL_STANDBY | TPO_R03_EN_PWM);
167 
168 	gpiod_set_value(lcd->reset_gpio, 1);
169 
170 	/* wait for at least 2 vsyncs before cutting off power */
171 	msleep(50);
172 
173 	td043mtea1_write(lcd, 3, TPO_R03_VAL_STANDBY);
174 
175 	regulator_disable(lcd->vcc_reg);
176 
177 	lcd->powered_on = false;
178 }
179 
180 /* -----------------------------------------------------------------------------
181  * sysfs
182  */
183 
184 static ssize_t vmirror_show(struct device *dev, struct device_attribute *attr,
185 			    char *buf)
186 {
187 	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
188 
189 	return sysfs_emit(buf, "%d\n", lcd->vmirror);
190 }
191 
192 static ssize_t vmirror_store(struct device *dev, struct device_attribute *attr,
193 			     const char *buf, size_t count)
194 {
195 	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
196 	int val;
197 	int ret;
198 
199 	ret = kstrtoint(buf, 0, &val);
200 	if (ret < 0)
201 		return ret;
202 
203 	lcd->vmirror = !!val;
204 
205 	ret = td043mtea1_write_mirror(lcd);
206 	if (ret < 0)
207 		return ret;
208 
209 	return count;
210 }
211 
212 static ssize_t mode_show(struct device *dev, struct device_attribute *attr,
213 			 char *buf)
214 {
215 	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
216 
217 	return sysfs_emit(buf, "%d\n", lcd->mode);
218 }
219 
220 static ssize_t mode_store(struct device *dev, struct device_attribute *attr,
221 			  const char *buf, size_t count)
222 {
223 	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
224 	long val;
225 	int ret;
226 
227 	ret = kstrtol(buf, 0, &val);
228 	if (ret != 0 || val & ~7)
229 		return -EINVAL;
230 
231 	lcd->mode = val;
232 
233 	val |= TPO_R02_NCLK_RISING;
234 	td043mtea1_write(lcd, 2, val);
235 
236 	return count;
237 }
238 
239 static ssize_t gamma_show(struct device *dev, struct device_attribute *attr,
240 			  char *buf)
241 {
242 	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
243 	ssize_t len = 0;
244 	unsigned int i;
245 	int ret;
246 
247 	for (i = 0; i < ARRAY_SIZE(lcd->gamma); i++) {
248 		ret = snprintf(buf + len, PAGE_SIZE - len, "%u ",
249 			       lcd->gamma[i]);
250 		if (ret < 0)
251 			return ret;
252 		len += ret;
253 	}
254 	buf[len - 1] = '\n';
255 
256 	return len;
257 }
258 
259 static ssize_t gamma_store(struct device *dev, struct device_attribute *attr,
260 			   const char *buf, size_t count)
261 {
262 	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
263 	unsigned int g[12];
264 	unsigned int i;
265 	int ret;
266 
267 	ret = sscanf(buf, "%u %u %u %u %u %u %u %u %u %u %u %u",
268 		     &g[0], &g[1], &g[2], &g[3], &g[4], &g[5],
269 		     &g[6], &g[7], &g[8], &g[9], &g[10], &g[11]);
270 	if (ret != 12)
271 		return -EINVAL;
272 
273 	for (i = 0; i < 12; i++)
274 		lcd->gamma[i] = g[i];
275 
276 	td043mtea1_write_gamma(lcd);
277 
278 	return count;
279 }
280 
281 static DEVICE_ATTR_RW(vmirror);
282 static DEVICE_ATTR_RW(mode);
283 static DEVICE_ATTR_RW(gamma);
284 
285 static struct attribute *td043mtea1_attrs[] = {
286 	&dev_attr_vmirror.attr,
287 	&dev_attr_mode.attr,
288 	&dev_attr_gamma.attr,
289 	NULL,
290 };
291 
292 static const struct attribute_group td043mtea1_attr_group = {
293 	.attrs = td043mtea1_attrs,
294 };
295 
296 /* -----------------------------------------------------------------------------
297  * Panel Operations
298  */
299 
300 static int td043mtea1_unprepare(struct drm_panel *panel)
301 {
302 	struct td043mtea1_panel *lcd = to_td043mtea1_device(panel);
303 
304 	if (!lcd->spi_suspended)
305 		td043mtea1_power_off(lcd);
306 
307 	return 0;
308 }
309 
310 static int td043mtea1_prepare(struct drm_panel *panel)
311 {
312 	struct td043mtea1_panel *lcd = to_td043mtea1_device(panel);
313 	int ret;
314 
315 	/*
316 	 * If we are resuming from system suspend, SPI might not be enabled
317 	 * yet, so we'll program the LCD from SPI PM resume callback.
318 	 */
319 	if (lcd->spi_suspended)
320 		return 0;
321 
322 	ret = td043mtea1_power_on(lcd);
323 	if (ret) {
324 		dev_err(&lcd->spi->dev, "%s: power on failed (%d)\n",
325 			__func__, ret);
326 		return ret;
327 	}
328 
329 	return 0;
330 }
331 
332 static const struct drm_display_mode td043mtea1_mode = {
333 	.clock = 36000,
334 	.hdisplay = 800,
335 	.hsync_start = 800 + 68,
336 	.hsync_end = 800 + 68 + 1,
337 	.htotal = 800 + 68 + 1 + 214,
338 	.vdisplay = 480,
339 	.vsync_start = 480 + 39,
340 	.vsync_end = 480 + 39 + 1,
341 	.vtotal = 480 + 39 + 1 + 34,
342 	.type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
343 	.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
344 	.width_mm = 94,
345 	.height_mm = 56,
346 };
347 
348 static int td043mtea1_get_modes(struct drm_panel *panel,
349 				struct drm_connector *connector)
350 {
351 	struct drm_display_mode *mode;
352 
353 	mode = drm_mode_duplicate(connector->dev, &td043mtea1_mode);
354 	if (!mode)
355 		return -ENOMEM;
356 
357 	drm_mode_set_name(mode);
358 	drm_mode_probed_add(connector, mode);
359 
360 	connector->display_info.width_mm = td043mtea1_mode.width_mm;
361 	connector->display_info.height_mm = td043mtea1_mode.height_mm;
362 	/*
363 	 * FIXME: According to the datasheet sync signals are sampled on the
364 	 * rising edge of the clock, but the code running on the OMAP3 Pandora
365 	 * indicates sampling on the falling edge. This should be tested on a
366 	 * real device.
367 	 */
368 	connector->display_info.bus_flags = DRM_BUS_FLAG_DE_HIGH
369 					  | DRM_BUS_FLAG_SYNC_SAMPLE_NEGEDGE
370 					  | DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE;
371 
372 	return 1;
373 }
374 
375 static const struct drm_panel_funcs td043mtea1_funcs = {
376 	.unprepare = td043mtea1_unprepare,
377 	.prepare = td043mtea1_prepare,
378 	.get_modes = td043mtea1_get_modes,
379 };
380 
381 /* -----------------------------------------------------------------------------
382  * Power Management, Probe and Remove
383  */
384 
385 static int __maybe_unused td043mtea1_suspend(struct device *dev)
386 {
387 	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
388 
389 	if (lcd->powered_on) {
390 		td043mtea1_power_off(lcd);
391 		lcd->powered_on = true;
392 	}
393 
394 	lcd->spi_suspended = true;
395 
396 	return 0;
397 }
398 
399 static int __maybe_unused td043mtea1_resume(struct device *dev)
400 {
401 	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
402 	int ret;
403 
404 	lcd->spi_suspended = false;
405 
406 	if (lcd->powered_on) {
407 		lcd->powered_on = false;
408 		ret = td043mtea1_power_on(lcd);
409 		if (ret)
410 			return ret;
411 	}
412 
413 	return 0;
414 }
415 
416 static SIMPLE_DEV_PM_OPS(td043mtea1_pm_ops, td043mtea1_suspend,
417 			 td043mtea1_resume);
418 
419 static int td043mtea1_probe(struct spi_device *spi)
420 {
421 	struct td043mtea1_panel *lcd;
422 	int ret;
423 
424 	lcd = devm_kzalloc(&spi->dev, sizeof(*lcd), GFP_KERNEL);
425 	if (lcd == NULL)
426 		return -ENOMEM;
427 
428 	spi_set_drvdata(spi, lcd);
429 	lcd->spi = spi;
430 	lcd->mode = TPO_R02_MODE_800x480;
431 	memcpy(lcd->gamma, td043mtea1_def_gamma, sizeof(lcd->gamma));
432 
433 	lcd->vcc_reg = devm_regulator_get(&spi->dev, "vcc");
434 	if (IS_ERR(lcd->vcc_reg))
435 		return dev_err_probe(&spi->dev, PTR_ERR(lcd->vcc_reg),
436 				     "failed to get VCC regulator\n");
437 
438 	lcd->reset_gpio = devm_gpiod_get(&spi->dev, "reset", GPIOD_OUT_HIGH);
439 	if (IS_ERR(lcd->reset_gpio))
440 		return dev_err_probe(&spi->dev, PTR_ERR(lcd->reset_gpio),
441 				     "failed to get reset GPIO\n");
442 
443 	spi->bits_per_word = 16;
444 	spi->mode = SPI_MODE_0;
445 
446 	ret = spi_setup(spi);
447 	if (ret < 0) {
448 		dev_err(&spi->dev, "failed to setup SPI: %d\n", ret);
449 		return ret;
450 	}
451 
452 	ret = sysfs_create_group(&spi->dev.kobj, &td043mtea1_attr_group);
453 	if (ret < 0) {
454 		dev_err(&spi->dev, "failed to create sysfs files\n");
455 		return ret;
456 	}
457 
458 	drm_panel_init(&lcd->panel, &lcd->spi->dev, &td043mtea1_funcs,
459 		       DRM_MODE_CONNECTOR_DPI);
460 
461 	drm_panel_add(&lcd->panel);
462 
463 	return 0;
464 }
465 
466 static void td043mtea1_remove(struct spi_device *spi)
467 {
468 	struct td043mtea1_panel *lcd = spi_get_drvdata(spi);
469 
470 	drm_panel_remove(&lcd->panel);
471 	drm_panel_disable(&lcd->panel);
472 	drm_panel_unprepare(&lcd->panel);
473 
474 	sysfs_remove_group(&spi->dev.kobj, &td043mtea1_attr_group);
475 }
476 
477 static const struct of_device_id td043mtea1_of_match[] = {
478 	{ .compatible = "tpo,td043mtea1", },
479 	{ /* sentinel */ },
480 };
481 
482 MODULE_DEVICE_TABLE(of, td043mtea1_of_match);
483 
484 static const struct spi_device_id td043mtea1_ids[] = {
485 	{ "td043mtea1", 0 },
486 	{ /* sentinel */ }
487 };
488 
489 MODULE_DEVICE_TABLE(spi, td043mtea1_ids);
490 
491 static struct spi_driver td043mtea1_driver = {
492 	.probe		= td043mtea1_probe,
493 	.remove		= td043mtea1_remove,
494 	.id_table	= td043mtea1_ids,
495 	.driver		= {
496 		.name	= "panel-tpo-td043mtea1",
497 		.pm	= &td043mtea1_pm_ops,
498 		.of_match_table = td043mtea1_of_match,
499 	},
500 };
501 
502 module_spi_driver(td043mtea1_driver);
503 
504 MODULE_AUTHOR("Gražvydas Ignotas <notasas@gmail.com>");
505 MODULE_DESCRIPTION("TPO TD043MTEA1 Panel Driver");
506 MODULE_LICENSE("GPL");
507