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 struct page *pages = virt_to_page(priv->fbdev.buffer); 227 228 return vm_map_pages_zero(vma, &pages, 1); 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