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
ht16k33_display_on(struct ht16k33_priv * priv)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
ht16k33_display_off(struct ht16k33_priv * priv)111 static int ht16k33_display_off(struct ht16k33_priv *priv)
112 {
113 return i2c_smbus_write_byte(priv->client, REG_DISPLAY_SETUP);
114 }
115
ht16k33_fb_queue(struct ht16k33_priv * priv)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 */
ht16k33_fb_update(struct work_struct * work)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
ht16k33_initialize(struct ht16k33_priv * priv)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
ht16k33_bl_update_status(struct backlight_device * bl)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
ht16k33_bl_check_fb(struct backlight_device * bl,struct fb_info * fi)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
ht16k33_mmap(struct fb_info * info,struct vm_area_struct * vma)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 */
ht16k33_keypad_scan(struct ht16k33_keypad * keypad)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
ht16k33_keypad_irq_thread(int irq,void * dev)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
ht16k33_keypad_start(struct input_dev * dev)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
ht16k33_keypad_stop(struct input_dev * dev)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
ht16k33_keypad_probe(struct i2c_client * client,struct ht16k33_keypad * keypad)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
ht16k33_probe(struct i2c_client * client,const struct i2c_device_id * id)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
ht16k33_remove(struct i2c_client * client)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(&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
