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
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, HZ / fbdev->refresh_rate);
121 }
122
123 /*
124 * This gets the fb data from cache and copies it to ht16k33 display RAM
125 */
ht16k33_fb_update(struct work_struct * work)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
ht16k33_initialize(struct ht16k33_priv * priv)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
ht16k33_bl_update_status(struct backlight_device * bl)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
ht16k33_bl_check_fb(struct backlight_device * bl,struct fb_info * fi)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
ht16k33_mmap(struct fb_info * info,struct vm_area_struct * vma)222 static int ht16k33_mmap(struct fb_info *info, struct vm_area_struct *vma)
223 {
224 struct ht16k33_priv *priv = info->par;
225 struct page *pages = virt_to_page(priv->fbdev.buffer);
226
227 return vm_map_pages_zero(vma, &pages, 1);
228 }
229
230 static const struct fb_ops ht16k33_fb_ops = {
231 .owner = THIS_MODULE,
232 .fb_read = fb_sys_read,
233 .fb_write = fb_sys_write,
234 .fb_fillrect = sys_fillrect,
235 .fb_copyarea = sys_copyarea,
236 .fb_imageblit = sys_imageblit,
237 .fb_mmap = ht16k33_mmap,
238 };
239
240 /*
241 * This gets the keys from keypad and reports it to input subsystem.
242 * Returns true if a key is pressed.
243 */
ht16k33_keypad_scan(struct ht16k33_keypad * keypad)244 static bool ht16k33_keypad_scan(struct ht16k33_keypad *keypad)
245 {
246 const unsigned short *keycodes = keypad->dev->keycode;
247 u16 new_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];
248 __le16 data[HT16K33_MATRIX_KEYPAD_MAX_COLS];
249 unsigned long bits_changed;
250 int row, col, code;
251 int rc;
252 bool pressed = false;
253
254 rc = i2c_smbus_read_i2c_block_data(keypad->client, 0x40,
255 sizeof(data), (u8 *)data);
256 if (rc != sizeof(data)) {
257 dev_err(&keypad->client->dev,
258 "Failed to read key data, rc=%d\n", rc);
259 return false;
260 }
261
262 for (col = 0; col < keypad->cols; col++) {
263 new_state[col] = le16_to_cpu(data[col]);
264 if (new_state[col])
265 pressed = true;
266 bits_changed = keypad->last_key_state[col] ^ new_state[col];
267
268 for_each_set_bit(row, &bits_changed, BITS_PER_LONG) {
269 code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
270 input_event(keypad->dev, EV_MSC, MSC_SCAN, code);
271 input_report_key(keypad->dev, keycodes[code],
272 new_state[col] & BIT(row));
273 }
274 }
275 input_sync(keypad->dev);
276 memcpy(keypad->last_key_state, new_state, sizeof(u16) * keypad->cols);
277
278 return pressed;
279 }
280
ht16k33_keypad_irq_thread(int irq,void * dev)281 static irqreturn_t ht16k33_keypad_irq_thread(int irq, void *dev)
282 {
283 struct ht16k33_keypad *keypad = dev;
284
285 do {
286 wait_event_timeout(keypad->wait, keypad->stopped,
287 msecs_to_jiffies(keypad->debounce_ms));
288 if (keypad->stopped)
289 break;
290 } while (ht16k33_keypad_scan(keypad));
291
292 return IRQ_HANDLED;
293 }
294
ht16k33_keypad_start(struct input_dev * dev)295 static int ht16k33_keypad_start(struct input_dev *dev)
296 {
297 struct ht16k33_keypad *keypad = input_get_drvdata(dev);
298
299 keypad->stopped = false;
300 mb();
301 enable_irq(keypad->client->irq);
302
303 return 0;
304 }
305
ht16k33_keypad_stop(struct input_dev * dev)306 static void ht16k33_keypad_stop(struct input_dev *dev)
307 {
308 struct ht16k33_keypad *keypad = input_get_drvdata(dev);
309
310 keypad->stopped = true;
311 mb();
312 wake_up(&keypad->wait);
313 disable_irq(keypad->client->irq);
314 }
315
ht16k33_keypad_probe(struct i2c_client * client,struct ht16k33_keypad * keypad)316 static int ht16k33_keypad_probe(struct i2c_client *client,
317 struct ht16k33_keypad *keypad)
318 {
319 struct device_node *node = client->dev.of_node;
320 u32 rows = HT16K33_MATRIX_KEYPAD_MAX_ROWS;
321 u32 cols = HT16K33_MATRIX_KEYPAD_MAX_COLS;
322 int err;
323
324 keypad->client = client;
325 init_waitqueue_head(&keypad->wait);
326
327 keypad->dev = devm_input_allocate_device(&client->dev);
328 if (!keypad->dev)
329 return -ENOMEM;
330
331 input_set_drvdata(keypad->dev, keypad);
332
333 keypad->dev->name = DRIVER_NAME"-keypad";
334 keypad->dev->id.bustype = BUS_I2C;
335 keypad->dev->open = ht16k33_keypad_start;
336 keypad->dev->close = ht16k33_keypad_stop;
337
338 if (!of_get_property(node, "linux,no-autorepeat", NULL))
339 __set_bit(EV_REP, keypad->dev->evbit);
340
341 err = of_property_read_u32(node, "debounce-delay-ms",
342 &keypad->debounce_ms);
343 if (err) {
344 dev_err(&client->dev, "key debounce delay not specified\n");
345 return err;
346 }
347
348 err = matrix_keypad_parse_of_params(&client->dev, &rows, &cols);
349 if (err)
350 return err;
351 if (rows > HT16K33_MATRIX_KEYPAD_MAX_ROWS ||
352 cols > HT16K33_MATRIX_KEYPAD_MAX_COLS) {
353 dev_err(&client->dev, "%u rows or %u cols out of range in DT\n",
354 rows, cols);
355 return -ERANGE;
356 }
357
358 keypad->rows = rows;
359 keypad->cols = cols;
360 keypad->row_shift = get_count_order(cols);
361
362 err = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL,
363 keypad->dev);
364 if (err) {
365 dev_err(&client->dev, "failed to build keymap\n");
366 return err;
367 }
368
369 err = devm_request_threaded_irq(&client->dev, client->irq,
370 NULL, ht16k33_keypad_irq_thread,
371 IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
372 DRIVER_NAME, keypad);
373 if (err) {
374 dev_err(&client->dev, "irq request failed %d, error %d\n",
375 client->irq, err);
376 return err;
377 }
378
379 ht16k33_keypad_stop(keypad->dev);
380
381 err = input_register_device(keypad->dev);
382 if (err)
383 return err;
384
385 return 0;
386 }
387
ht16k33_probe(struct i2c_client * client,const struct i2c_device_id * id)388 static int ht16k33_probe(struct i2c_client *client,
389 const struct i2c_device_id *id)
390 {
391 int err;
392 uint32_t dft_brightness;
393 struct backlight_device *bl;
394 struct backlight_properties bl_props;
395 struct ht16k33_priv *priv;
396 struct ht16k33_fbdev *fbdev;
397 struct device_node *node = client->dev.of_node;
398
399 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
400 dev_err(&client->dev, "i2c_check_functionality error\n");
401 return -EIO;
402 }
403
404 priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
405 if (!priv)
406 return -ENOMEM;
407
408 priv->client = client;
409 i2c_set_clientdata(client, priv);
410 fbdev = &priv->fbdev;
411
412 err = ht16k33_initialize(priv);
413 if (err)
414 return err;
415
416 /* Framebuffer (2 bytes per column) */
417 BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE);
418 fbdev->buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
419 if (!fbdev->buffer)
420 return -ENOMEM;
421
422 fbdev->cache = devm_kmalloc(&client->dev, HT16K33_FB_SIZE, GFP_KERNEL);
423 if (!fbdev->cache) {
424 err = -ENOMEM;
425 goto err_fbdev_buffer;
426 }
427
428 fbdev->info = framebuffer_alloc(0, &client->dev);
429 if (!fbdev->info) {
430 err = -ENOMEM;
431 goto err_fbdev_buffer;
432 }
433
434 err = of_property_read_u32(node, "refresh-rate-hz",
435 &fbdev->refresh_rate);
436 if (err) {
437 dev_err(&client->dev, "refresh rate not specified\n");
438 goto err_fbdev_info;
439 }
440 fb_bl_default_curve(fbdev->info, 0, MIN_BRIGHTNESS, MAX_BRIGHTNESS);
441
442 INIT_DELAYED_WORK(&fbdev->work, ht16k33_fb_update);
443 fbdev->info->fbops = &ht16k33_fb_ops;
444 fbdev->info->screen_base = (char __iomem *) fbdev->buffer;
445 fbdev->info->screen_size = HT16K33_FB_SIZE;
446 fbdev->info->fix = ht16k33_fb_fix;
447 fbdev->info->var = ht16k33_fb_var;
448 fbdev->info->pseudo_palette = NULL;
449 fbdev->info->flags = FBINFO_FLAG_DEFAULT;
450 fbdev->info->par = priv;
451
452 err = register_framebuffer(fbdev->info);
453 if (err)
454 goto err_fbdev_info;
455
456 /* Keypad */
457 if (client->irq > 0) {
458 err = ht16k33_keypad_probe(client, &priv->keypad);
459 if (err)
460 goto err_fbdev_unregister;
461 }
462
463 /* Backlight */
464 memset(&bl_props, 0, sizeof(struct backlight_properties));
465 bl_props.type = BACKLIGHT_RAW;
466 bl_props.max_brightness = MAX_BRIGHTNESS;
467
468 bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl",
469 &client->dev, priv,
470 &ht16k33_bl_ops, &bl_props);
471 if (IS_ERR(bl)) {
472 dev_err(&client->dev, "failed to register backlight\n");
473 err = PTR_ERR(bl);
474 goto err_fbdev_unregister;
475 }
476
477 err = of_property_read_u32(node, "default-brightness-level",
478 &dft_brightness);
479 if (err) {
480 dft_brightness = MAX_BRIGHTNESS;
481 } else if (dft_brightness > MAX_BRIGHTNESS) {
482 dev_warn(&client->dev,
483 "invalid default brightness level: %u, using %u\n",
484 dft_brightness, MAX_BRIGHTNESS);
485 dft_brightness = MAX_BRIGHTNESS;
486 }
487
488 bl->props.brightness = dft_brightness;
489 ht16k33_bl_update_status(bl);
490
491 ht16k33_fb_queue(priv);
492 return 0;
493
494 err_fbdev_unregister:
495 unregister_framebuffer(fbdev->info);
496 err_fbdev_info:
497 framebuffer_release(fbdev->info);
498 err_fbdev_buffer:
499 free_page((unsigned long) fbdev->buffer);
500
501 return err;
502 }
503
ht16k33_remove(struct i2c_client * client)504 static int ht16k33_remove(struct i2c_client *client)
505 {
506 struct ht16k33_priv *priv = i2c_get_clientdata(client);
507 struct ht16k33_fbdev *fbdev = &priv->fbdev;
508
509 cancel_delayed_work_sync(&fbdev->work);
510 unregister_framebuffer(fbdev->info);
511 framebuffer_release(fbdev->info);
512 free_page((unsigned long) fbdev->buffer);
513
514 return 0;
515 }
516
517 static const struct i2c_device_id ht16k33_i2c_match[] = {
518 { "ht16k33", 0 },
519 { }
520 };
521 MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match);
522
523 static const struct of_device_id ht16k33_of_match[] = {
524 { .compatible = "holtek,ht16k33", },
525 { }
526 };
527 MODULE_DEVICE_TABLE(of, ht16k33_of_match);
528
529 static struct i2c_driver ht16k33_driver = {
530 .probe = ht16k33_probe,
531 .remove = ht16k33_remove,
532 .driver = {
533 .name = DRIVER_NAME,
534 .of_match_table = of_match_ptr(ht16k33_of_match),
535 },
536 .id_table = ht16k33_i2c_match,
537 };
538 module_i2c_driver(ht16k33_driver);
539
540 MODULE_DESCRIPTION("Holtek HT16K33 driver");
541 MODULE_LICENSE("GPL");
542 MODULE_AUTHOR("Robin van der Gracht <robin@protonic.nl>");
543
