xref: /linux/drivers/auxdisplay/ht16k33.c (revision 4e0ae876f77bc01a7e77724dea57b4b82bd53244) 
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 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 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,
121 			      msecs_to_jiffies(HZ / fbdev->refresh_rate));
122 }
123 
124 /*
125  * This gets the fb data from cache and copies it to ht16k33 display RAM
126  */
127 static void ht16k33_fb_update(struct work_struct *work)
128 {
129 	struct ht16k33_fbdev *fbdev =
130 		container_of(work, struct ht16k33_fbdev, work.work);
131 	struct ht16k33_priv *priv =
132 		container_of(fbdev, struct ht16k33_priv, fbdev);
133 
134 	uint8_t *p1, *p2;
135 	int len, pos = 0, first = -1;
136 
137 	p1 = fbdev->cache;
138 	p2 = fbdev->buffer;
139 
140 	/* Search for the first byte with changes */
141 	while (pos < HT16K33_FB_SIZE && first < 0) {
142 		if (*(p1++) - *(p2++))
143 			first = pos;
144 		pos++;
145 	}
146 
147 	/* No changes found */
148 	if (first < 0)
149 		goto requeue;
150 
151 	len = HT16K33_FB_SIZE - first;
152 	p1 = fbdev->cache + HT16K33_FB_SIZE - 1;
153 	p2 = fbdev->buffer + HT16K33_FB_SIZE - 1;
154 
155 	/* Determine i2c transfer length */
156 	while (len > 1) {
157 		if (*(p1--) - *(p2--))
158 			break;
159 		len--;
160 	}
161 
162 	p1 = fbdev->cache + first;
163 	p2 = fbdev->buffer + first;
164 	if (!i2c_smbus_write_i2c_block_data(priv->client, first, len, p2))
165 		memcpy(p1, p2, len);
166 requeue:
167 	ht16k33_fb_queue(priv);
168 }
169 
170 static int ht16k33_initialize(struct ht16k33_priv *priv)
171 {
172 	uint8_t byte;
173 	int err;
174 	uint8_t data[HT16K33_MATRIX_LED_MAX_COLS * 2];
175 
176 	/* Clear RAM (8 * 16 bits) */
177 	memset(data, 0, sizeof(data));
178 	err = i2c_smbus_write_block_data(priv->client, 0, sizeof(data), data);
179 	if (err)
180 		return err;
181 
182 	/* Turn on internal oscillator */
183 	byte = REG_SYSTEM_SETUP_OSC_ON | REG_SYSTEM_SETUP;
184 	err = i2c_smbus_write_byte(priv->client, byte);
185 	if (err)
186 		return err;
187 
188 	/* Configure INT pin */
189 	byte = REG_ROWINT_SET | REG_ROWINT_SET_INT_ACT_HIGH;
190 	if (priv->client->irq > 0)
191 		byte |= REG_ROWINT_SET_INT_EN;
192 	return i2c_smbus_write_byte(priv->client, byte);
193 }
194 
195 static int ht16k33_bl_update_status(struct backlight_device *bl)
196 {
197 	int brightness = bl->props.brightness;
198 	struct ht16k33_priv *priv = bl_get_data(bl);
199 
200 	if (bl->props.power != FB_BLANK_UNBLANK ||
201 	    bl->props.fb_blank != FB_BLANK_UNBLANK ||
202 	    bl->props.state & BL_CORE_FBBLANK || brightness == 0) {
203 		return ht16k33_display_off(priv);
204 	}
205 
206 	ht16k33_display_on(priv);
207 	return i2c_smbus_write_byte(priv->client,
208 				    REG_BRIGHTNESS | (brightness - 1));
209 }
210 
211 static int ht16k33_bl_check_fb(struct backlight_device *bl, struct fb_info *fi)
212 {
213 	struct ht16k33_priv *priv = bl_get_data(bl);
214 
215 	return (fi == NULL) || (fi->par == priv);
216 }
217 
218 static const struct backlight_ops ht16k33_bl_ops = {
219 	.update_status	= ht16k33_bl_update_status,
220 	.check_fb	= ht16k33_bl_check_fb,
221 };
222 
223 static int ht16k33_mmap(struct fb_info *info, struct vm_area_struct *vma)
224 {
225 	struct ht16k33_priv *priv = info->par;
226 
227 	return vm_insert_page(vma, vma->vm_start,
228 			      virt_to_page(priv->fbdev.buffer));
229 }
230 
231 static struct fb_ops ht16k33_fb_ops = {
232 	.owner = THIS_MODULE,
233 	.fb_read = fb_sys_read,
234 	.fb_write = fb_sys_write,
235 	.fb_fillrect = sys_fillrect,
236 	.fb_copyarea = sys_copyarea,
237 	.fb_imageblit = sys_imageblit,
238 	.fb_mmap = ht16k33_mmap,
239 };
240 
241 /*
242  * This gets the keys from keypad and reports it to input subsystem.
243  * Returns true if a key is pressed.
244  */
245 static bool ht16k33_keypad_scan(struct ht16k33_keypad *keypad)
246 {
247 	const unsigned short *keycodes = keypad->dev->keycode;
248 	u16 new_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];
249 	__le16 data[HT16K33_MATRIX_KEYPAD_MAX_COLS];
250 	unsigned long bits_changed;
251 	int row, col, code;
252 	int rc;
253 	bool pressed = false;
254 
255 	rc = i2c_smbus_read_i2c_block_data(keypad->client, 0x40,
256 					   sizeof(data), (u8 *)data);
257 	if (rc != sizeof(data)) {
258 		dev_err(&keypad->client->dev,
259 			"Failed to read key data, rc=%d\n", rc);
260 		return false;
261 	}
262 
263 	for (col = 0; col < keypad->cols; col++) {
264 		new_state[col] = le16_to_cpu(data[col]);
265 		if (new_state[col])
266 			pressed = true;
267 		bits_changed = keypad->last_key_state[col] ^ new_state[col];
268 
269 		for_each_set_bit(row, &bits_changed, BITS_PER_LONG) {
270 			code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
271 			input_event(keypad->dev, EV_MSC, MSC_SCAN, code);
272 			input_report_key(keypad->dev, keycodes[code],
273 					 new_state[col] & BIT(row));
274 		}
275 	}
276 	input_sync(keypad->dev);
277 	memcpy(keypad->last_key_state, new_state, sizeof(u16) * keypad->cols);
278 
279 	return pressed;
280 }
281 
282 static irqreturn_t ht16k33_keypad_irq_thread(int irq, void *dev)
283 {
284 	struct ht16k33_keypad *keypad = dev;
285 
286 	do {
287 		wait_event_timeout(keypad->wait, keypad->stopped,
288 				    msecs_to_jiffies(keypad->debounce_ms));
289 		if (keypad->stopped)
290 			break;
291 	} while (ht16k33_keypad_scan(keypad));
292 
293 	return IRQ_HANDLED;
294 }
295 
296 static int ht16k33_keypad_start(struct input_dev *dev)
297 {
298 	struct ht16k33_keypad *keypad = input_get_drvdata(dev);
299 
300 	keypad->stopped = false;
301 	mb();
302 	enable_irq(keypad->client->irq);
303 
304 	return 0;
305 }
306 
307 static void ht16k33_keypad_stop(struct input_dev *dev)
308 {
309 	struct ht16k33_keypad *keypad = input_get_drvdata(dev);
310 
311 	keypad->stopped = true;
312 	mb();
313 	wake_up(&keypad->wait);
314 	disable_irq(keypad->client->irq);
315 }
316 
317 static int ht16k33_keypad_probe(struct i2c_client *client,
318 				struct ht16k33_keypad *keypad)
319 {
320 	struct device_node *node = client->dev.of_node;
321 	u32 rows = HT16K33_MATRIX_KEYPAD_MAX_ROWS;
322 	u32 cols = HT16K33_MATRIX_KEYPAD_MAX_COLS;
323 	int err;
324 
325 	keypad->client = client;
326 	init_waitqueue_head(&keypad->wait);
327 
328 	keypad->dev = devm_input_allocate_device(&client->dev);
329 	if (!keypad->dev)
330 		return -ENOMEM;
331 
332 	input_set_drvdata(keypad->dev, keypad);
333 
334 	keypad->dev->name = DRIVER_NAME"-keypad";
335 	keypad->dev->id.bustype = BUS_I2C;
336 	keypad->dev->open = ht16k33_keypad_start;
337 	keypad->dev->close = ht16k33_keypad_stop;
338 
339 	if (!of_get_property(node, "linux,no-autorepeat", NULL))
340 		__set_bit(EV_REP, keypad->dev->evbit);
341 
342 	err = of_property_read_u32(node, "debounce-delay-ms",
343 				   &keypad->debounce_ms);
344 	if (err) {
345 		dev_err(&client->dev, "key debounce delay not specified\n");
346 		return err;
347 	}
348 
349 	err = matrix_keypad_parse_of_params(&client->dev, &rows, &cols);
350 	if (err)
351 		return err;
352 	if (rows > HT16K33_MATRIX_KEYPAD_MAX_ROWS ||
353 	    cols > HT16K33_MATRIX_KEYPAD_MAX_COLS) {
354 		dev_err(&client->dev, "%u rows or %u cols out of range in DT\n",
355 			rows, cols);
356 		return -ERANGE;
357 	}
358 
359 	keypad->rows = rows;
360 	keypad->cols = cols;
361 	keypad->row_shift = get_count_order(cols);
362 
363 	err = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL,
364 					 keypad->dev);
365 	if (err) {
366 		dev_err(&client->dev, "failed to build keymap\n");
367 		return err;
368 	}
369 
370 	err = devm_request_threaded_irq(&client->dev, client->irq,
371 					NULL, ht16k33_keypad_irq_thread,
372 					IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
373 					DRIVER_NAME, keypad);
374 	if (err) {
375 		dev_err(&client->dev, "irq request failed %d, error %d\n",
376 			client->irq, err);
377 		return err;
378 	}
379 
380 	ht16k33_keypad_stop(keypad->dev);
381 
382 	err = input_register_device(keypad->dev);
383 	if (err)
384 		return err;
385 
386 	return 0;
387 }
388 
389 static int ht16k33_probe(struct i2c_client *client,
390 				  const struct i2c_device_id *id)
391 {
392 	int err;
393 	uint32_t dft_brightness;
394 	struct backlight_device *bl;
395 	struct backlight_properties bl_props;
396 	struct ht16k33_priv *priv;
397 	struct ht16k33_fbdev *fbdev;
398 	struct device_node *node = client->dev.of_node;
399 
400 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
401 		dev_err(&client->dev, "i2c_check_functionality error\n");
402 		return -EIO;
403 	}
404 
405 	if (client->irq <= 0) {
406 		dev_err(&client->dev, "No IRQ specified\n");
407 		return -EINVAL;
408 	}
409 
410 	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
411 	if (!priv)
412 		return -ENOMEM;
413 
414 	priv->client = client;
415 	i2c_set_clientdata(client, priv);
416 	fbdev = &priv->fbdev;
417 
418 	err = ht16k33_initialize(priv);
419 	if (err)
420 		return err;
421 
422 	/* Framebuffer (2 bytes per column) */
423 	BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE);
424 	fbdev->buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
425 	if (!fbdev->buffer)
426 		return -ENOMEM;
427 
428 	fbdev->cache = devm_kmalloc(&client->dev, HT16K33_FB_SIZE, GFP_KERNEL);
429 	if (!fbdev->cache) {
430 		err = -ENOMEM;
431 		goto err_fbdev_buffer;
432 	}
433 
434 	fbdev->info = framebuffer_alloc(0, &client->dev);
435 	if (!fbdev->info) {
436 		err = -ENOMEM;
437 		goto err_fbdev_buffer;
438 	}
439 
440 	err = of_property_read_u32(node, "refresh-rate-hz",
441 		&fbdev->refresh_rate);
442 	if (err) {
443 		dev_err(&client->dev, "refresh rate not specified\n");
444 		goto err_fbdev_info;
445 	}
446 	fb_bl_default_curve(fbdev->info, 0, MIN_BRIGHTNESS, MAX_BRIGHTNESS);
447 
448 	INIT_DELAYED_WORK(&fbdev->work, ht16k33_fb_update);
449 	fbdev->info->fbops = &ht16k33_fb_ops;
450 	fbdev->info->screen_base = (char __iomem *) fbdev->buffer;
451 	fbdev->info->screen_size = HT16K33_FB_SIZE;
452 	fbdev->info->fix = ht16k33_fb_fix;
453 	fbdev->info->var = ht16k33_fb_var;
454 	fbdev->info->pseudo_palette = NULL;
455 	fbdev->info->flags = FBINFO_FLAG_DEFAULT;
456 	fbdev->info->par = priv;
457 
458 	err = register_framebuffer(fbdev->info);
459 	if (err)
460 		goto err_fbdev_info;
461 
462 	err = ht16k33_keypad_probe(client, &priv->keypad);
463 	if (err)
464 		goto err_fbdev_unregister;
465 
466 	/* Backlight */
467 	memset(&bl_props, 0, sizeof(struct backlight_properties));
468 	bl_props.type = BACKLIGHT_RAW;
469 	bl_props.max_brightness = MAX_BRIGHTNESS;
470 
471 	bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl",
472 					    &client->dev, priv,
473 					    &ht16k33_bl_ops, &bl_props);
474 	if (IS_ERR(bl)) {
475 		dev_err(&client->dev, "failed to register backlight\n");
476 		err = PTR_ERR(bl);
477 		goto err_fbdev_unregister;
478 	}
479 
480 	err = of_property_read_u32(node, "default-brightness-level",
481 				   &dft_brightness);
482 	if (err) {
483 		dft_brightness = MAX_BRIGHTNESS;
484 	} else if (dft_brightness > MAX_BRIGHTNESS) {
485 		dev_warn(&client->dev,
486 			 "invalid default brightness level: %u, using %u\n",
487 			 dft_brightness, MAX_BRIGHTNESS);
488 		dft_brightness = MAX_BRIGHTNESS;
489 	}
490 
491 	bl->props.brightness = dft_brightness;
492 	ht16k33_bl_update_status(bl);
493 
494 	ht16k33_fb_queue(priv);
495 	return 0;
496 
497 err_fbdev_unregister:
498 	unregister_framebuffer(fbdev->info);
499 err_fbdev_info:
500 	framebuffer_release(fbdev->info);
501 err_fbdev_buffer:
502 	free_page((unsigned long) fbdev->buffer);
503 
504 	return err;
505 }
506 
507 static int ht16k33_remove(struct i2c_client *client)
508 {
509 	struct ht16k33_priv *priv = i2c_get_clientdata(client);
510 	struct ht16k33_fbdev *fbdev = &priv->fbdev;
511 
512 	cancel_delayed_work_sync(&fbdev->work);
513 	unregister_framebuffer(fbdev->info);
514 	framebuffer_release(fbdev->info);
515 	free_page((unsigned long) fbdev->buffer);
516 
517 	return 0;
518 }
519 
520 static const struct i2c_device_id ht16k33_i2c_match[] = {
521 	{ "ht16k33", 0 },
522 	{ }
523 };
524 MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match);
525 
526 static const struct of_device_id ht16k33_of_match[] = {
527 	{ .compatible = "holtek,ht16k33", },
528 	{ }
529 };
530 MODULE_DEVICE_TABLE(of, ht16k33_of_match);
531 
532 static struct i2c_driver ht16k33_driver = {
533 	.probe		= ht16k33_probe,
534 	.remove		= ht16k33_remove,
535 	.driver		= {
536 		.name		= DRIVER_NAME,
537 		.of_match_table	= of_match_ptr(ht16k33_of_match),
538 	},
539 	.id_table = ht16k33_i2c_match,
540 };
541 module_i2c_driver(ht16k33_driver);
542 
543 MODULE_DESCRIPTION("Holtek HT16K33 driver");
544 MODULE_LICENSE("GPL");
545 MODULE_AUTHOR("Robin van der Gracht <robin@protonic.nl>");
546