summaryrefslogtreecommitdiffstats
path: root/drivers/auxdisplay/ht16k33.c
blob: 21393ec3b9a4a58fe13037f59be6a3d1466f747e (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
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
// SPDX-License-Identifier: GPL-2.0
/*
 * HT16K33 driver
 *
 * Author: Robin van der Gracht <robin@protonic.nl>
 *
 * Copyright: (C) 2016 Protonic Holland.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/of.h>
#include <linux/fb.h>
#include <linux/slab.h>
#include <linux/backlight.h>
#include <linux/input.h>
#include <linux/input/matrix_keypad.h>
#include <linux/workqueue.h>
#include <linux/mm.h>

/* Registers */
#define REG_SYSTEM_SETUP		0x20
#define REG_SYSTEM_SETUP_OSC_ON		BIT(0)

#define REG_DISPLAY_SETUP		0x80
#define REG_DISPLAY_SETUP_ON		BIT(0)

#define REG_ROWINT_SET			0xA0
#define REG_ROWINT_SET_INT_EN		BIT(0)
#define REG_ROWINT_SET_INT_ACT_HIGH	BIT(1)

#define REG_BRIGHTNESS			0xE0

/* Defines */
#define DRIVER_NAME			"ht16k33"

#define MIN_BRIGHTNESS			0x1
#define MAX_BRIGHTNESS			0x10

#define HT16K33_MATRIX_LED_MAX_COLS	8
#define HT16K33_MATRIX_LED_MAX_ROWS	16
#define HT16K33_MATRIX_KEYPAD_MAX_COLS	3
#define HT16K33_MATRIX_KEYPAD_MAX_ROWS	12

#define BYTES_PER_ROW		(HT16K33_MATRIX_LED_MAX_ROWS / 8)
#define HT16K33_FB_SIZE		(HT16K33_MATRIX_LED_MAX_COLS * BYTES_PER_ROW)

struct ht16k33_keypad {
	struct i2c_client *client;
	struct input_dev *dev;
	uint32_t cols;
	uint32_t rows;
	uint32_t row_shift;
	uint32_t debounce_ms;
	uint16_t last_key_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];

	wait_queue_head_t wait;
	bool stopped;
};

struct ht16k33_fbdev {
	struct fb_info *info;
	uint32_t refresh_rate;
	uint8_t *buffer;
	uint8_t *cache;
	struct delayed_work work;
};

struct ht16k33_priv {
	struct i2c_client *client;
	struct ht16k33_keypad keypad;
	struct ht16k33_fbdev fbdev;
};

static struct fb_fix_screeninfo ht16k33_fb_fix = {
	.id		= DRIVER_NAME,
	.type		= FB_TYPE_PACKED_PIXELS,
	.visual		= FB_VISUAL_MONO10,
	.xpanstep	= 0,
	.ypanstep	= 0,
	.ywrapstep	= 0,
	.line_length	= HT16K33_MATRIX_LED_MAX_ROWS,
	.accel		= FB_ACCEL_NONE,
};

static struct fb_var_screeninfo ht16k33_fb_var = {
	.xres = HT16K33_MATRIX_LED_MAX_ROWS,
	.yres = HT16K33_MATRIX_LED_MAX_COLS,
	.xres_virtual = HT16K33_MATRIX_LED_MAX_ROWS,
	.yres_virtual = HT16K33_MATRIX_LED_MAX_COLS,
	.bits_per_pixel = 1,
	.red = { 0, 1, 0 },
	.green = { 0, 1, 0 },
	.blue = { 0, 1, 0 },
	.left_margin = 0,
	.right_margin = 0,
	.upper_margin = 0,
	.lower_margin = 0,
	.vmode = FB_VMODE_NONINTERLACED,
};

static int ht16k33_display_on(struct ht16k33_priv *priv)
{
	uint8_t data = REG_DISPLAY_SETUP | REG_DISPLAY_SETUP_ON;

	return i2c_smbus_write_byte(priv->client, data);
}

static int ht16k33_display_off(struct ht16k33_priv *priv)
{
	return i2c_smbus_write_byte(priv->client, REG_DISPLAY_SETUP);
}

static void ht16k33_fb_queue(struct ht16k33_priv *priv)
{
	struct ht16k33_fbdev *fbdev = &priv->fbdev;

	schedule_delayed_work(&fbdev->work,
			      msecs_to_jiffies(HZ / fbdev->refresh_rate));
}

/*
 * This gets the fb data from cache and copies it to ht16k33 display RAM
 */
static void ht16k33_fb_update(struct work_struct *work)
{
	struct ht16k33_fbdev *fbdev =
		container_of(work, struct ht16k33_fbdev, work.work);
	struct ht16k33_priv *priv =
		container_of(fbdev, struct ht16k33_priv, fbdev);

	uint8_t *p1, *p2;
	int len, pos = 0, first = -1;

	p1 = fbdev->cache;
	p2 = fbdev->buffer;

	/* Search for the first byte with changes */
	while (pos < HT16K33_FB_SIZE && first < 0) {
		if (*(p1++) - *(p2++))
			first = pos;
		pos++;
	}

	/* No changes found */
	if (first < 0)
		goto requeue;

	len = HT16K33_FB_SIZE - first;
	p1 = fbdev->cache + HT16K33_FB_SIZE - 1;
	p2 = fbdev->buffer + HT16K33_FB_SIZE - 1;

	/* Determine i2c transfer length */
	while (len > 1) {
		if (*(p1--) - *(p2--))
			break;
		len--;
	}

	p1 = fbdev->cache + first;
	p2 = fbdev->buffer + first;
	if (!i2c_smbus_write_i2c_block_data(priv->client, first, len, p2))
		memcpy(p1, p2, len);
requeue:
	ht16k33_fb_queue(priv);
}

static int ht16k33_initialize(struct ht16k33_priv *priv)
{
	uint8_t byte;
	int err;
	uint8_t data[HT16K33_MATRIX_LED_MAX_COLS * 2];

	/* Clear RAM (8 * 16 bits) */
	memset(data, 0, sizeof(data));
	err = i2c_smbus_write_block_data(priv->client, 0, sizeof(data), data);
	if (err)
		return err;

	/* Turn on internal oscillator */
	byte = REG_SYSTEM_SETUP_OSC_ON | REG_SYSTEM_SETUP;
	err = i2c_smbus_write_byte(priv->client, byte);
	if (err)
		return err;

	/* Configure INT pin */
	byte = REG_ROWINT_SET | REG_ROWINT_SET_INT_ACT_HIGH;
	if (priv->client->irq > 0)
		byte |= REG_ROWINT_SET_INT_EN;
	return i2c_smbus_write_byte(priv->client, byte);
}

static int ht16k33_bl_update_status(struct backlight_device *bl)
{
	int brightness = bl->props.brightness;
	struct ht16k33_priv *priv = bl_get_data(bl);

	if (bl->props.power != FB_BLANK_UNBLANK ||
	    bl->props.fb_blank != FB_BLANK_UNBLANK ||
	    bl->props.state & BL_CORE_FBBLANK || brightness == 0) {
		return ht16k33_display_off(priv);
	}

	ht16k33_display_on(priv);
	return i2c_smbus_write_byte(priv->client,
				    REG_BRIGHTNESS | (brightness - 1));
}

static int ht16k33_bl_check_fb(struct backlight_device *bl, struct fb_info *fi)
{
	struct ht16k33_priv *priv = bl_get_data(bl);

	return (fi == NULL) || (fi->par == priv);
}

static const struct backlight_ops ht16k33_bl_ops = {
	.update_status	= ht16k33_bl_update_status,
	.check_fb	= ht16k33_bl_check_fb,
};

static int ht16k33_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
	struct ht16k33_priv *priv = info->par;

	return vm_insert_page(vma, vma->vm_start,
			      virt_to_page(priv->fbdev.buffer));
}

static struct fb_ops ht16k33_fb_ops = {
	.owner = THIS_MODULE,
	.fb_read = fb_sys_read,
	.fb_write = fb_sys_write,
	.fb_fillrect = sys_fillrect,
	.fb_copyarea = sys_copyarea,
	.fb_imageblit = sys_imageblit,
	.fb_mmap = ht16k33_mmap,
};

/*
 * This gets the keys from keypad and reports it to input subsystem.
 * Returns true if a key is pressed.
 */
static bool ht16k33_keypad_scan(struct ht16k33_keypad *keypad)
{
	const unsigned short *keycodes = keypad->dev->keycode;
	u16 new_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];
	__le16 data[HT16K33_MATRIX_KEYPAD_MAX_COLS];
	unsigned long bits_changed;
	int row, col, code;
	int rc;
	bool pressed = false;

	rc = i2c_smbus_read_i2c_block_data(keypad->client, 0x40,
					   sizeof(data), (u8 *)data);
	if (rc != sizeof(data)) {
		dev_err(&keypad->client->dev,
			"Failed to read key data, rc=%d\n", rc);
		return false;
	}

	for (col = 0; col < keypad->cols; col++) {
		new_state[col] = le16_to_cpu(data[col]);
		if (new_state[col])
			pressed = true;
		bits_changed = keypad->last_key_state[col] ^ new_state[col];

		for_each_set_bit(row, &bits_changed, BITS_PER_LONG) {
			code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
			input_event(keypad->dev, EV_MSC, MSC_SCAN, code);
			input_report_key(keypad->dev, keycodes[code],
					 new_state[col] & BIT(row));
		}
	}
	input_sync(keypad->dev);
	memcpy(keypad->last_key_state, new_state, sizeof(u16) * keypad->cols);

	return pressed;
}

static irqreturn_t ht16k33_keypad_irq_thread(int irq, void *dev)
{
	struct ht16k33_keypad *keypad = dev;

	do {
		wait_event_timeout(keypad->wait, keypad->stopped,
				    msecs_to_jiffies(keypad->debounce_ms));
		if (keypad->stopped)
			break;
	} while (ht16k33_keypad_scan(keypad));

	return IRQ_HANDLED;
}

static int ht16k33_keypad_start(struct input_dev *dev)
{
	struct ht16k33_keypad *keypad = input_get_drvdata(dev);

	keypad->stopped = false;
	mb();
	enable_irq(keypad->client->irq);

	return 0;
}

static void ht16k33_keypad_stop(struct input_dev *dev)
{
	struct ht16k33_keypad *keypad = input_get_drvdata(dev);

	keypad->stopped = true;
	mb();
	wake_up(&keypad->wait);
	disable_irq(keypad->client->irq);
}

static int ht16k33_keypad_probe(struct i2c_client *client,
				struct ht16k33_keypad *keypad)
{
	struct device_node *node = client->dev.of_node;
	u32 rows = HT16K33_MATRIX_KEYPAD_MAX_ROWS;
	u32 cols = HT16K33_MATRIX_KEYPAD_MAX_COLS;
	int err;

	keypad->client = client;
	init_waitqueue_head(&keypad->wait);

	keypad->dev = devm_input_allocate_device(&client->dev);
	if (!keypad->dev)
		return -ENOMEM;

	input_set_drvdata(keypad->dev, keypad);

	keypad->dev->name = DRIVER_NAME"-keypad";
	keypad->dev->id.bustype = BUS_I2C;
	keypad->dev->open = ht16k33_keypad_start;
	keypad->dev->close = ht16k33_keypad_stop;

	if (!of_get_property(node, "linux,no-autorepeat", NULL))
		__set_bit(EV_REP, keypad->dev->evbit);

	err = of_property_read_u32(node, "debounce-delay-ms",
				   &keypad->debounce_ms);
	if (err) {
		dev_err(&client->dev, "key debounce delay not specified\n");
		return err;
	}

	err = matrix_keypad_parse_of_params(&client->dev, &rows, &cols);
	if (err)
		return err;
	if (rows > HT16K33_MATRIX_KEYPAD_MAX_ROWS ||
	    cols > HT16K33_MATRIX_KEYPAD_MAX_COLS) {
		dev_err(&client->dev, "%u rows or %u cols out of range in DT\n",
			rows, cols);
		return -ERANGE;
	}

	keypad->rows = rows;
	keypad->cols = cols;
	keypad->row_shift = get_count_order(cols);

	err = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL,
					 keypad->dev);
	if (err) {
		dev_err(&client->dev, "failed to build keymap\n");
		return err;
	}

	err = devm_request_threaded_irq(&client->dev, client->irq,
					NULL, ht16k33_keypad_irq_thread,
					IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
					DRIVER_NAME, keypad);
	if (err) {
		dev_err(&client->dev, "irq request failed %d, error %d\n",
			client->irq, err);
		return err;
	}

	ht16k33_keypad_stop(keypad->dev);

	err = input_register_device(keypad->dev);
	if (err)
		return err;

	return 0;
}

static int ht16k33_probe(struct i2c_client *client,
				  const struct i2c_device_id *id)
{
	int err;
	uint32_t dft_brightness;
	struct backlight_device *bl;
	struct backlight_properties bl_props;
	struct ht16k33_priv *priv;
	struct ht16k33_fbdev *fbdev;
	struct device_node *node = client->dev.of_node;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
		dev_err(&client->dev, "i2c_check_functionality error\n");
		return -EIO;
	}

	if (client->irq <= 0) {
		dev_err(&client->dev, "No IRQ specified\n");
		return -EINVAL;
	}

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

	priv->client = client;
	i2c_set_clientdata(client, priv);
	fbdev = &priv->fbdev;

	err = ht16k33_initialize(priv);
	if (err)
		return err;

	/* Framebuffer (2 bytes per column) */
	BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE);
	fbdev->buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
	if (!fbdev->buffer)
		return -ENOMEM;

	fbdev->cache = devm_kmalloc(&client->dev, HT16K33_FB_SIZE, GFP_KERNEL);
	if (!fbdev->cache) {
		err = -ENOMEM;
		goto err_fbdev_buffer;
	}

	fbdev->info = framebuffer_alloc(0, &client->dev);
	if (!fbdev->info) {
		err = -ENOMEM;
		goto err_fbdev_buffer;
	}

	err = of_property_read_u32(node, "refresh-rate-hz",
		&fbdev->refresh_rate);
	if (err) {
		dev_err(&client->dev, "refresh rate not specified\n");
		goto err_fbdev_info;
	}
	fb_bl_default_curve(fbdev->info, 0, MIN_BRIGHTNESS, MAX_BRIGHTNESS);

	INIT_DELAYED_WORK(&fbdev->work, ht16k33_fb_update);
	fbdev->info->fbops = &ht16k33_fb_ops;
	fbdev->info->screen_base = (char __iomem *) fbdev->buffer;
	fbdev->info->screen_size = HT16K33_FB_SIZE;
	fbdev->info->fix = ht16k33_fb_fix;
	fbdev->info->var = ht16k33_fb_var;
	fbdev->info->pseudo_palette = NULL;
	fbdev->info->flags = FBINFO_FLAG_DEFAULT;
	fbdev->info->par = priv;

	err = register_framebuffer(fbdev->info);
	if (err)
		goto err_fbdev_info;

	err = ht16k33_keypad_probe(client, &priv->keypad);
	if (err)
		goto err_fbdev_unregister;

	/* Backlight */
	memset(&bl_props, 0, sizeof(struct backlight_properties));
	bl_props.type = BACKLIGHT_RAW;
	bl_props.max_brightness = MAX_BRIGHTNESS;

	bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl",
					    &client->dev, priv,
					    &ht16k33_bl_ops, &bl_props);
	if (IS_ERR(bl)) {
		dev_err(&client->dev, "failed to register backlight\n");
		err = PTR_ERR(bl);
		goto err_fbdev_unregister;
	}

	err = of_property_read_u32(node, "default-brightness-level",
				   &dft_brightness);
	if (err) {
		dft_brightness = MAX_BRIGHTNESS;
	} else if (dft_brightness > MAX_BRIGHTNESS) {
		dev_warn(&client->dev,
			 "invalid default brightness level: %u, using %u\n",
			 dft_brightness, MAX_BRIGHTNESS);
		dft_brightness = MAX_BRIGHTNESS;
	}

	bl->props.brightness = dft_brightness;
	ht16k33_bl_update_status(bl);

	ht16k33_fb_queue(priv);
	return 0;

err_fbdev_unregister:
	unregister_framebuffer(fbdev->info);
err_fbdev_info:
	framebuffer_release(fbdev->info);
err_fbdev_buffer:
	free_page((unsigned long) fbdev->buffer);

	return err;
}

static int ht16k33_remove(struct i2c_client *client)
{
	struct ht16k33_priv *priv = i2c_get_clientdata(client);
	struct ht16k33_fbdev *fbdev = &priv->fbdev;

	cancel_delayed_work_sync(&fbdev->work);
	unregister_framebuffer(fbdev->info);
	framebuffer_release(fbdev->info);
	free_page((unsigned long) fbdev->buffer);

	return 0;
}

static const struct i2c_device_id ht16k33_i2c_match[] = {
	{ "ht16k33", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match);

static const struct of_device_id ht16k33_of_match[] = {
	{ .compatible = "holtek,ht16k33", },
	{ }
};
MODULE_DEVICE_TABLE(of, ht16k33_of_match);

static struct i2c_driver ht16k33_driver = {
	.probe		= ht16k33_probe,
	.remove		= ht16k33_remove,
	.driver		= {
		.name		= DRIVER_NAME,
		.of_match_table	= of_match_ptr(ht16k33_of_match),
	},
	.id_table = ht16k33_i2c_match,
};
module_i2c_driver(ht16k33_driver);

MODULE_DESCRIPTION("Holtek HT16K33 driver");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Robin van der Gracht <robin@protonic.nl>");
OpenPOWER on IntegriCloud