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
50struct 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
63struct 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
71struct ht16k33_priv {
72	struct i2c_client *client;
73	struct ht16k33_keypad keypad;
74	struct ht16k33_fbdev fbdev;
75};
76
77static 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
88static 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
104static 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
111static int ht16k33_display_off(struct ht16k33_priv *priv)
112{
113	return i2c_smbus_write_byte(priv->client, REG_DISPLAY_SETUP);
114}
115
116static 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 */
126static 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);
165requeue:
166	ht16k33_fb_queue(priv);
167}
168
169static 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
194static 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
210static 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
217static 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 */
226static int ht16k33_blank(int blank, struct fb_info *info)
227{
228	return 0;
229}
230
231static 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
239static 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 */
254static 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
291static 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
305static 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
316static 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
326static 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
398static 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	if (client->irq <= 0) {
415		dev_err(&client->dev, "No IRQ specified\n");
416		return -EINVAL;
417	}
418
419	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
420	if (!priv)
421		return -ENOMEM;
422
423	priv->client = client;
424	i2c_set_clientdata(client, priv);
425	fbdev = &priv->fbdev;
426
427	err = ht16k33_initialize(priv);
428	if (err)
429		return err;
430
431	/* Backlight */
432	memset(&bl_props, 0, sizeof(struct backlight_properties));
433	bl_props.type = BACKLIGHT_RAW;
434	bl_props.max_brightness = MAX_BRIGHTNESS;
435
436	bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl",
437					    &client->dev, priv,
438					    &ht16k33_bl_ops, &bl_props);
439	if (IS_ERR(bl)) {
440		dev_err(&client->dev, "failed to register backlight\n");
441		return PTR_ERR(bl);
442	}
443
444	err = of_property_read_u32(node, "default-brightness-level",
445				   &dft_brightness);
446	if (err) {
447		dft_brightness = MAX_BRIGHTNESS;
448	} else if (dft_brightness > MAX_BRIGHTNESS) {
449		dev_warn(&client->dev,
450			 "invalid default brightness level: %u, using %u\n",
451			 dft_brightness, MAX_BRIGHTNESS);
452		dft_brightness = MAX_BRIGHTNESS;
453	}
454
455	bl->props.brightness = dft_brightness;
456	ht16k33_bl_update_status(bl);
457
458	/* Framebuffer (2 bytes per column) */
459	BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE);
460	fbdev->buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
461	if (!fbdev->buffer)
462		return -ENOMEM;
463
464	fbdev->cache = devm_kmalloc(&client->dev, HT16K33_FB_SIZE, GFP_KERNEL);
465	if (!fbdev->cache) {
466		err = -ENOMEM;
467		goto err_fbdev_buffer;
468	}
469
470	fbdev->info = framebuffer_alloc(0, &client->dev);
471	if (!fbdev->info) {
472		err = -ENOMEM;
473		goto err_fbdev_buffer;
474	}
475
476	err = of_property_read_u32(node, "refresh-rate-hz",
477		&fbdev->refresh_rate);
478	if (err) {
479		dev_err(&client->dev, "refresh rate not specified\n");
480		goto err_fbdev_info;
481	}
482	fb_bl_default_curve(fbdev->info, 0, MIN_BRIGHTNESS, MAX_BRIGHTNESS);
483
484	INIT_DELAYED_WORK(&fbdev->work, ht16k33_fb_update);
485	fbdev->info->fbops = &ht16k33_fb_ops;
486	fbdev->info->screen_base = (char __iomem *) fbdev->buffer;
487	fbdev->info->screen_size = HT16K33_FB_SIZE;
488	fbdev->info->fix = ht16k33_fb_fix;
489	fbdev->info->var = ht16k33_fb_var;
490	fbdev->info->bl_dev = bl;
491	fbdev->info->pseudo_palette = NULL;
492	fbdev->info->flags = FBINFO_FLAG_DEFAULT;
493	fbdev->info->par = priv;
494
495	err = register_framebuffer(fbdev->info);
496	if (err)
497		goto err_fbdev_info;
498
499	err = ht16k33_keypad_probe(client, &priv->keypad);
500	if (err)
501		goto err_fbdev_unregister;
502
503	ht16k33_fb_queue(priv);
504	return 0;
505
506err_fbdev_unregister:
507	unregister_framebuffer(fbdev->info);
508err_fbdev_info:
509	framebuffer_release(fbdev->info);
510err_fbdev_buffer:
511	free_page((unsigned long) fbdev->buffer);
512
513	return err;
514}
515
516static int ht16k33_remove(struct i2c_client *client)
517{
518	struct ht16k33_priv *priv = i2c_get_clientdata(client);
519	struct ht16k33_fbdev *fbdev = &priv->fbdev;
520
521	cancel_delayed_work_sync(&fbdev->work);
522	unregister_framebuffer(fbdev->info);
523	framebuffer_release(fbdev->info);
524	free_page((unsigned long) fbdev->buffer);
525
526	return 0;
527}
528
529static const struct i2c_device_id ht16k33_i2c_match[] = {
530	{ "ht16k33", 0 },
531	{ }
532};
533MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match);
534
535static const struct of_device_id ht16k33_of_match[] = {
536	{ .compatible = "holtek,ht16k33", },
537	{ }
538};
539MODULE_DEVICE_TABLE(of, ht16k33_of_match);
540
541static struct i2c_driver ht16k33_driver = {
542	.probe		= ht16k33_probe,
543	.remove		= ht16k33_remove,
544	.driver		= {
545		.name		= DRIVER_NAME,
546		.of_match_table	= of_match_ptr(ht16k33_of_match),
547	},
548	.id_table = ht16k33_i2c_match,
549};
550module_i2c_driver(ht16k33_driver);
551
552MODULE_DESCRIPTION("Holtek HT16K33 driver");
553MODULE_LICENSE("GPL");
554MODULE_AUTHOR("Robin van der Gracht <robin@protonic.nl>");
555