xref: /openbmc/linux/drivers/auxdisplay/ht16k33.c (revision 840fe258) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * HT16K33 driver
4  *
5  * Author: Robin van der Gracht <robin@protonic.nl>
6  *
7  * Copyright: (C) 2016 Protonic Holland.
8  */
9 
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/interrupt.h>
13 #include <linux/i2c.h>
14 #include <linux/of.h>
15 #include <linux/fb.h>
16 #include <linux/slab.h>
17 #include <linux/backlight.h>
18 #include <linux/input.h>
19 #include <linux/input/matrix_keypad.h>
20 #include <linux/workqueue.h>
21 #include <linux/mm.h>
22 
23 /* Registers */
24 #define REG_SYSTEM_SETUP		0x20
25 #define REG_SYSTEM_SETUP_OSC_ON		BIT(0)
26 
27 #define REG_DISPLAY_SETUP		0x80
28 #define REG_DISPLAY_SETUP_ON		BIT(0)
29 
30 #define REG_ROWINT_SET			0xA0
31 #define REG_ROWINT_SET_INT_EN		BIT(0)
32 #define REG_ROWINT_SET_INT_ACT_HIGH	BIT(1)
33 
34 #define REG_BRIGHTNESS			0xE0
35 
36 /* Defines */
37 #define DRIVER_NAME			"ht16k33"
38 
39 #define MIN_BRIGHTNESS			0x1
40 #define MAX_BRIGHTNESS			0x10
41 
42 #define HT16K33_MATRIX_LED_MAX_COLS	8
43 #define HT16K33_MATRIX_LED_MAX_ROWS	16
44 #define HT16K33_MATRIX_KEYPAD_MAX_COLS	3
45 #define HT16K33_MATRIX_KEYPAD_MAX_ROWS	12
46 
47 #define BYTES_PER_ROW		(HT16K33_MATRIX_LED_MAX_ROWS / 8)
48 #define HT16K33_FB_SIZE		(HT16K33_MATRIX_LED_MAX_COLS * BYTES_PER_ROW)
49 
50 struct ht16k33_keypad {
51 	struct i2c_client *client;
52 	struct input_dev *dev;
53 	uint32_t cols;
54 	uint32_t rows;
55 	uint32_t row_shift;
56 	uint32_t debounce_ms;
57 	uint16_t last_key_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];
58 
59 	wait_queue_head_t wait;
60 	bool stopped;
61 };
62 
63 struct ht16k33_fbdev {
64 	struct fb_info *info;
65 	uint32_t refresh_rate;
66 	uint8_t *buffer;
67 	uint8_t *cache;
68 	struct delayed_work work;
69 };
70 
71 struct ht16k33_priv {
72 	struct i2c_client *client;
73 	struct ht16k33_keypad keypad;
74 	struct ht16k33_fbdev fbdev;
75 };
76 
77 static const struct fb_fix_screeninfo ht16k33_fb_fix = {
78 	.id		= DRIVER_NAME,
79 	.type		= FB_TYPE_PACKED_PIXELS,
80 	.visual		= FB_VISUAL_MONO10,
81 	.xpanstep	= 0,
82 	.ypanstep	= 0,
83 	.ywrapstep	= 0,
84 	.line_length	= HT16K33_MATRIX_LED_MAX_ROWS,
85 	.accel		= FB_ACCEL_NONE,
86 };
87 
88 static const struct fb_var_screeninfo ht16k33_fb_var = {
89 	.xres = HT16K33_MATRIX_LED_MAX_ROWS,
90 	.yres = HT16K33_MATRIX_LED_MAX_COLS,
91 	.xres_virtual = HT16K33_MATRIX_LED_MAX_ROWS,
92 	.yres_virtual = HT16K33_MATRIX_LED_MAX_COLS,
93 	.bits_per_pixel = 1,
94 	.red = { 0, 1, 0 },
95 	.green = { 0, 1, 0 },
96 	.blue = { 0, 1, 0 },
97 	.left_margin = 0,
98 	.right_margin = 0,
99 	.upper_margin = 0,
100 	.lower_margin = 0,
101 	.vmode = FB_VMODE_NONINTERLACED,
102 };
103 
104 static int ht16k33_display_on(struct ht16k33_priv *priv)
105 {
106 	uint8_t data = REG_DISPLAY_SETUP | REG_DISPLAY_SETUP_ON;
107 
108 	return i2c_smbus_write_byte(priv->client, data);
109 }
110 
111 static int ht16k33_display_off(struct ht16k33_priv *priv)
112 {
113 	return i2c_smbus_write_byte(priv->client, REG_DISPLAY_SETUP);
114 }
115 
116 static void ht16k33_fb_queue(struct ht16k33_priv *priv)
117 {
118 	struct ht16k33_fbdev *fbdev = &priv->fbdev;
119 
120 	schedule_delayed_work(&fbdev->work, HZ / fbdev->refresh_rate);
121 }
122 
123 /*
124  * This gets the fb data from cache and copies it to ht16k33 display RAM
125  */
126 static void ht16k33_fb_update(struct work_struct *work)
127 {
128 	struct ht16k33_fbdev *fbdev =
129 		container_of(work, struct ht16k33_fbdev, work.work);
130 	struct ht16k33_priv *priv =
131 		container_of(fbdev, struct ht16k33_priv, fbdev);
132 
133 	uint8_t *p1, *p2;
134 	int len, pos = 0, first = -1;
135 
136 	p1 = fbdev->cache;
137 	p2 = fbdev->buffer;
138 
139 	/* Search for the first byte with changes */
140 	while (pos < HT16K33_FB_SIZE && first < 0) {
141 		if (*(p1++) - *(p2++))
142 			first = pos;
143 		pos++;
144 	}
145 
146 	/* No changes found */
147 	if (first < 0)
148 		goto requeue;
149 
150 	len = HT16K33_FB_SIZE - first;
151 	p1 = fbdev->cache + HT16K33_FB_SIZE - 1;
152 	p2 = fbdev->buffer + HT16K33_FB_SIZE - 1;
153 
154 	/* Determine i2c transfer length */
155 	while (len > 1) {
156 		if (*(p1--) - *(p2--))
157 			break;
158 		len--;
159 	}
160 
161 	p1 = fbdev->cache + first;
162 	p2 = fbdev->buffer + first;
163 	if (!i2c_smbus_write_i2c_block_data(priv->client, first, len, p2))
164 		memcpy(p1, p2, len);
165 requeue:
166 	ht16k33_fb_queue(priv);
167 }
168 
169 static int ht16k33_initialize(struct ht16k33_priv *priv)
170 {
171 	uint8_t byte;
172 	int err;
173 	uint8_t data[HT16K33_MATRIX_LED_MAX_COLS * 2];
174 
175 	/* Clear RAM (8 * 16 bits) */
176 	memset(data, 0, sizeof(data));
177 	err = i2c_smbus_write_block_data(priv->client, 0, sizeof(data), data);
178 	if (err)
179 		return err;
180 
181 	/* Turn on internal oscillator */
182 	byte = REG_SYSTEM_SETUP_OSC_ON | REG_SYSTEM_SETUP;
183 	err = i2c_smbus_write_byte(priv->client, byte);
184 	if (err)
185 		return err;
186 
187 	/* Configure INT pin */
188 	byte = REG_ROWINT_SET | REG_ROWINT_SET_INT_ACT_HIGH;
189 	if (priv->client->irq > 0)
190 		byte |= REG_ROWINT_SET_INT_EN;
191 	return i2c_smbus_write_byte(priv->client, byte);
192 }
193 
194 static int ht16k33_bl_update_status(struct backlight_device *bl)
195 {
196 	int brightness = bl->props.brightness;
197 	struct ht16k33_priv *priv = bl_get_data(bl);
198 
199 	if (bl->props.power != FB_BLANK_UNBLANK ||
200 	    bl->props.fb_blank != FB_BLANK_UNBLANK ||
201 	    bl->props.state & BL_CORE_FBBLANK || brightness == 0) {
202 		return ht16k33_display_off(priv);
203 	}
204 
205 	ht16k33_display_on(priv);
206 	return i2c_smbus_write_byte(priv->client,
207 				    REG_BRIGHTNESS | (brightness - 1));
208 }
209 
210 static int ht16k33_bl_check_fb(struct backlight_device *bl, struct fb_info *fi)
211 {
212 	struct ht16k33_priv *priv = bl_get_data(bl);
213 
214 	return (fi == NULL) || (fi->par == priv);
215 }
216 
217 static const struct backlight_ops ht16k33_bl_ops = {
218 	.update_status	= ht16k33_bl_update_status,
219 	.check_fb	= ht16k33_bl_check_fb,
220 };
221 
222 /*
223  * Blank events will be passed to the actual device handling the backlight when
224  * we return zero here.
225  */
226 static int ht16k33_blank(int blank, struct fb_info *info)
227 {
228 	return 0;
229 }
230 
231 static int ht16k33_mmap(struct fb_info *info, struct vm_area_struct *vma)
232 {
233 	struct ht16k33_priv *priv = info->par;
234 	struct page *pages = virt_to_page(priv->fbdev.buffer);
235 
236 	return vm_map_pages_zero(vma, &pages, 1);
237 }
238 
239 static const struct fb_ops ht16k33_fb_ops = {
240 	.owner = THIS_MODULE,
241 	.fb_read = fb_sys_read,
242 	.fb_write = fb_sys_write,
243 	.fb_blank = ht16k33_blank,
244 	.fb_fillrect = sys_fillrect,
245 	.fb_copyarea = sys_copyarea,
246 	.fb_imageblit = sys_imageblit,
247 	.fb_mmap = ht16k33_mmap,
248 };
249 
250 /*
251  * This gets the keys from keypad and reports it to input subsystem.
252  * Returns true if a key is pressed.
253  */
254 static bool ht16k33_keypad_scan(struct ht16k33_keypad *keypad)
255 {
256 	const unsigned short *keycodes = keypad->dev->keycode;
257 	u16 new_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];
258 	__le16 data[HT16K33_MATRIX_KEYPAD_MAX_COLS];
259 	unsigned long bits_changed;
260 	int row, col, code;
261 	int rc;
262 	bool pressed = false;
263 
264 	rc = i2c_smbus_read_i2c_block_data(keypad->client, 0x40,
265 					   sizeof(data), (u8 *)data);
266 	if (rc != sizeof(data)) {
267 		dev_err(&keypad->client->dev,
268 			"Failed to read key data, rc=%d\n", rc);
269 		return false;
270 	}
271 
272 	for (col = 0; col < keypad->cols; col++) {
273 		new_state[col] = le16_to_cpu(data[col]);
274 		if (new_state[col])
275 			pressed = true;
276 		bits_changed = keypad->last_key_state[col] ^ new_state[col];
277 
278 		for_each_set_bit(row, &bits_changed, BITS_PER_LONG) {
279 			code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
280 			input_event(keypad->dev, EV_MSC, MSC_SCAN, code);
281 			input_report_key(keypad->dev, keycodes[code],
282 					 new_state[col] & BIT(row));
283 		}
284 	}
285 	input_sync(keypad->dev);
286 	memcpy(keypad->last_key_state, new_state, sizeof(u16) * keypad->cols);
287 
288 	return pressed;
289 }
290 
291 static irqreturn_t ht16k33_keypad_irq_thread(int irq, void *dev)
292 {
293 	struct ht16k33_keypad *keypad = dev;
294 
295 	do {
296 		wait_event_timeout(keypad->wait, keypad->stopped,
297 				    msecs_to_jiffies(keypad->debounce_ms));
298 		if (keypad->stopped)
299 			break;
300 	} while (ht16k33_keypad_scan(keypad));
301 
302 	return IRQ_HANDLED;
303 }
304 
305 static int ht16k33_keypad_start(struct input_dev *dev)
306 {
307 	struct ht16k33_keypad *keypad = input_get_drvdata(dev);
308 
309 	keypad->stopped = false;
310 	mb();
311 	enable_irq(keypad->client->irq);
312 
313 	return 0;
314 }
315 
316 static void ht16k33_keypad_stop(struct input_dev *dev)
317 {
318 	struct ht16k33_keypad *keypad = input_get_drvdata(dev);
319 
320 	keypad->stopped = true;
321 	mb();
322 	wake_up(&keypad->wait);
323 	disable_irq(keypad->client->irq);
324 }
325 
326 static int ht16k33_keypad_probe(struct i2c_client *client,
327 				struct ht16k33_keypad *keypad)
328 {
329 	struct device_node *node = client->dev.of_node;
330 	u32 rows = HT16K33_MATRIX_KEYPAD_MAX_ROWS;
331 	u32 cols = HT16K33_MATRIX_KEYPAD_MAX_COLS;
332 	int err;
333 
334 	keypad->client = client;
335 	init_waitqueue_head(&keypad->wait);
336 
337 	keypad->dev = devm_input_allocate_device(&client->dev);
338 	if (!keypad->dev)
339 		return -ENOMEM;
340 
341 	input_set_drvdata(keypad->dev, keypad);
342 
343 	keypad->dev->name = DRIVER_NAME"-keypad";
344 	keypad->dev->id.bustype = BUS_I2C;
345 	keypad->dev->open = ht16k33_keypad_start;
346 	keypad->dev->close = ht16k33_keypad_stop;
347 
348 	if (!of_get_property(node, "linux,no-autorepeat", NULL))
349 		__set_bit(EV_REP, keypad->dev->evbit);
350 
351 	err = of_property_read_u32(node, "debounce-delay-ms",
352 				   &keypad->debounce_ms);
353 	if (err) {
354 		dev_err(&client->dev, "key debounce delay not specified\n");
355 		return err;
356 	}
357 
358 	err = matrix_keypad_parse_of_params(&client->dev, &rows, &cols);
359 	if (err)
360 		return err;
361 	if (rows > HT16K33_MATRIX_KEYPAD_MAX_ROWS ||
362 	    cols > HT16K33_MATRIX_KEYPAD_MAX_COLS) {
363 		dev_err(&client->dev, "%u rows or %u cols out of range in DT\n",
364 			rows, cols);
365 		return -ERANGE;
366 	}
367 
368 	keypad->rows = rows;
369 	keypad->cols = cols;
370 	keypad->row_shift = get_count_order(cols);
371 
372 	err = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL,
373 					 keypad->dev);
374 	if (err) {
375 		dev_err(&client->dev, "failed to build keymap\n");
376 		return err;
377 	}
378 
379 	err = devm_request_threaded_irq(&client->dev, client->irq,
380 					NULL, ht16k33_keypad_irq_thread,
381 					IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
382 					DRIVER_NAME, keypad);
383 	if (err) {
384 		dev_err(&client->dev, "irq request failed %d, error %d\n",
385 			client->irq, err);
386 		return err;
387 	}
388 
389 	ht16k33_keypad_stop(keypad->dev);
390 
391 	err = input_register_device(keypad->dev);
392 	if (err)
393 		return err;
394 
395 	return 0;
396 }
397 
398 static int ht16k33_probe(struct i2c_client *client,
399 				  const struct i2c_device_id *id)
400 {
401 	int err;
402 	uint32_t dft_brightness;
403 	struct backlight_device *bl;
404 	struct backlight_properties bl_props;
405 	struct ht16k33_priv *priv;
406 	struct ht16k33_fbdev *fbdev;
407 	struct device_node *node = client->dev.of_node;
408 
409 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
410 		dev_err(&client->dev, "i2c_check_functionality error\n");
411 		return -EIO;
412 	}
413 
414 	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
415 	if (!priv)
416 		return -ENOMEM;
417 
418 	priv->client = client;
419 	i2c_set_clientdata(client, priv);
420 	fbdev = &priv->fbdev;
421 
422 	err = ht16k33_initialize(priv);
423 	if (err)
424 		return err;
425 
426 	/* Backlight */
427 	memset(&bl_props, 0, sizeof(struct backlight_properties));
428 	bl_props.type = BACKLIGHT_RAW;
429 	bl_props.max_brightness = MAX_BRIGHTNESS;
430 
431 	bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl",
432 					    &client->dev, priv,
433 					    &ht16k33_bl_ops, &bl_props);
434 	if (IS_ERR(bl)) {
435 		dev_err(&client->dev, "failed to register backlight\n");
436 		return PTR_ERR(bl);
437 	}
438 
439 	err = of_property_read_u32(node, "default-brightness-level",
440 				   &dft_brightness);
441 	if (err) {
442 		dft_brightness = MAX_BRIGHTNESS;
443 	} else if (dft_brightness > MAX_BRIGHTNESS) {
444 		dev_warn(&client->dev,
445 			 "invalid default brightness level: %u, using %u\n",
446 			 dft_brightness, MAX_BRIGHTNESS);
447 		dft_brightness = MAX_BRIGHTNESS;
448 	}
449 
450 	bl->props.brightness = dft_brightness;
451 	ht16k33_bl_update_status(bl);
452 
453 	/* Framebuffer (2 bytes per column) */
454 	BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE);
455 	fbdev->buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
456 	if (!fbdev->buffer)
457 		return -ENOMEM;
458 
459 	fbdev->cache = devm_kmalloc(&client->dev, HT16K33_FB_SIZE, GFP_KERNEL);
460 	if (!fbdev->cache) {
461 		err = -ENOMEM;
462 		goto err_fbdev_buffer;
463 	}
464 
465 	fbdev->info = framebuffer_alloc(0, &client->dev);
466 	if (!fbdev->info) {
467 		err = -ENOMEM;
468 		goto err_fbdev_buffer;
469 	}
470 
471 	err = of_property_read_u32(node, "refresh-rate-hz",
472 		&fbdev->refresh_rate);
473 	if (err) {
474 		dev_err(&client->dev, "refresh rate not specified\n");
475 		goto err_fbdev_info;
476 	}
477 	fb_bl_default_curve(fbdev->info, 0, MIN_BRIGHTNESS, MAX_BRIGHTNESS);
478 
479 	INIT_DELAYED_WORK(&fbdev->work, ht16k33_fb_update);
480 	fbdev->info->fbops = &ht16k33_fb_ops;
481 	fbdev->info->screen_base = (char __iomem *) fbdev->buffer;
482 	fbdev->info->screen_size = HT16K33_FB_SIZE;
483 	fbdev->info->fix = ht16k33_fb_fix;
484 	fbdev->info->var = ht16k33_fb_var;
485 	fbdev->info->bl_dev = bl;
486 	fbdev->info->pseudo_palette = NULL;
487 	fbdev->info->flags = FBINFO_FLAG_DEFAULT;
488 	fbdev->info->par = priv;
489 
490 	err = register_framebuffer(fbdev->info);
491 	if (err)
492 		goto err_fbdev_info;
493 
494 	/* Keypad */
495 	if (client->irq > 0) {
496 		err = ht16k33_keypad_probe(client, &priv->keypad);
497 		if (err)
498 			goto err_fbdev_unregister;
499 	}
500 
501 	ht16k33_fb_queue(priv);
502 	return 0;
503 
504 err_fbdev_unregister:
505 	unregister_framebuffer(fbdev->info);
506 err_fbdev_info:
507 	framebuffer_release(fbdev->info);
508 err_fbdev_buffer:
509 	free_page((unsigned long) fbdev->buffer);
510 
511 	return err;
512 }
513 
514 static int ht16k33_remove(struct i2c_client *client)
515 {
516 	struct ht16k33_priv *priv = i2c_get_clientdata(client);
517 	struct ht16k33_fbdev *fbdev = &priv->fbdev;
518 
519 	cancel_delayed_work_sync(&fbdev->work);
520 	unregister_framebuffer(fbdev->info);
521 	framebuffer_release(fbdev->info);
522 	free_page((unsigned long) fbdev->buffer);
523 
524 	return 0;
525 }
526 
527 static const struct i2c_device_id ht16k33_i2c_match[] = {
528 	{ "ht16k33", 0 },
529 	{ }
530 };
531 MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match);
532 
533 static const struct of_device_id ht16k33_of_match[] = {
534 	{ .compatible = "holtek,ht16k33", },
535 	{ }
536 };
537 MODULE_DEVICE_TABLE(of, ht16k33_of_match);
538 
539 static struct i2c_driver ht16k33_driver = {
540 	.probe		= ht16k33_probe,
541 	.remove		= ht16k33_remove,
542 	.driver		= {
543 		.name		= DRIVER_NAME,
544 		.of_match_table	= of_match_ptr(ht16k33_of_match),
545 	},
546 	.id_table = ht16k33_i2c_match,
547 };
548 module_i2c_driver(ht16k33_driver);
549 
550 MODULE_DESCRIPTION("Holtek HT16K33 driver");
551 MODULE_LICENSE("GPL");
552 MODULE_AUTHOR("Robin van der Gracht <robin@protonic.nl>");
553