1 /* 2 * HT16K33 driver 3 * 4 * Author: Robin van der Gracht <robin@protonic.nl> 5 * 6 * Copyright: (C) 2016 Protonic Holland. 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 * This program is distributed in the hope that it will be useful, but 13 * WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * General Public License for more details. 16 */ 17 18 #include <linux/kernel.h> 19 #include <linux/module.h> 20 #include <linux/interrupt.h> 21 #include <linux/i2c.h> 22 #include <linux/of.h> 23 #include <linux/fb.h> 24 #include <linux/slab.h> 25 #include <linux/backlight.h> 26 #include <linux/input.h> 27 #include <linux/input/matrix_keypad.h> 28 #include <linux/workqueue.h> 29 #include <linux/mm.h> 30 31 /* Registers */ 32 #define REG_SYSTEM_SETUP 0x20 33 #define REG_SYSTEM_SETUP_OSC_ON BIT(0) 34 35 #define REG_DISPLAY_SETUP 0x80 36 #define REG_DISPLAY_SETUP_ON BIT(0) 37 38 #define REG_ROWINT_SET 0xA0 39 #define REG_ROWINT_SET_INT_EN BIT(0) 40 #define REG_ROWINT_SET_INT_ACT_HIGH BIT(1) 41 42 #define REG_BRIGHTNESS 0xE0 43 44 /* Defines */ 45 #define DRIVER_NAME "ht16k33" 46 47 #define MIN_BRIGHTNESS 0x1 48 #define MAX_BRIGHTNESS 0x10 49 50 #define HT16K33_MATRIX_LED_MAX_COLS 8 51 #define HT16K33_MATRIX_LED_MAX_ROWS 16 52 #define HT16K33_MATRIX_KEYPAD_MAX_COLS 3 53 #define HT16K33_MATRIX_KEYPAD_MAX_ROWS 12 54 55 #define BYTES_PER_ROW (HT16K33_MATRIX_LED_MAX_ROWS / 8) 56 #define HT16K33_FB_SIZE (HT16K33_MATRIX_LED_MAX_COLS * BYTES_PER_ROW) 57 58 struct ht16k33_keypad { 59 struct i2c_client *client; 60 struct input_dev *dev; 61 uint32_t cols; 62 uint32_t rows; 63 uint32_t row_shift; 64 uint32_t debounce_ms; 65 uint16_t last_key_state[HT16K33_MATRIX_KEYPAD_MAX_COLS]; 66 67 wait_queue_head_t wait; 68 bool stopped; 69 }; 70 71 struct ht16k33_fbdev { 72 struct fb_info *info; 73 uint32_t refresh_rate; 74 uint8_t *buffer; 75 uint8_t *cache; 76 struct delayed_work work; 77 }; 78 79 struct ht16k33_priv { 80 struct i2c_client *client; 81 struct ht16k33_keypad keypad; 82 struct ht16k33_fbdev fbdev; 83 }; 84 85 static struct fb_fix_screeninfo ht16k33_fb_fix = { 86 .id = DRIVER_NAME, 87 .type = FB_TYPE_PACKED_PIXELS, 88 .visual = FB_VISUAL_MONO10, 89 .xpanstep = 0, 90 .ypanstep = 0, 91 .ywrapstep = 0, 92 .line_length = HT16K33_MATRIX_LED_MAX_ROWS, 93 .accel = FB_ACCEL_NONE, 94 }; 95 96 static struct fb_var_screeninfo ht16k33_fb_var = { 97 .xres = HT16K33_MATRIX_LED_MAX_ROWS, 98 .yres = HT16K33_MATRIX_LED_MAX_COLS, 99 .xres_virtual = HT16K33_MATRIX_LED_MAX_ROWS, 100 .yres_virtual = HT16K33_MATRIX_LED_MAX_COLS, 101 .bits_per_pixel = 1, 102 .red = { 0, 1, 0 }, 103 .green = { 0, 1, 0 }, 104 .blue = { 0, 1, 0 }, 105 .left_margin = 0, 106 .right_margin = 0, 107 .upper_margin = 0, 108 .lower_margin = 0, 109 .vmode = FB_VMODE_NONINTERLACED, 110 }; 111 112 static int ht16k33_display_on(struct ht16k33_priv *priv) 113 { 114 uint8_t data = REG_DISPLAY_SETUP | REG_DISPLAY_SETUP_ON; 115 116 return i2c_smbus_write_byte(priv->client, data); 117 } 118 119 static int ht16k33_display_off(struct ht16k33_priv *priv) 120 { 121 return i2c_smbus_write_byte(priv->client, REG_DISPLAY_SETUP); 122 } 123 124 static void ht16k33_fb_queue(struct ht16k33_priv *priv) 125 { 126 struct ht16k33_fbdev *fbdev = &priv->fbdev; 127 128 schedule_delayed_work(&fbdev->work, 129 msecs_to_jiffies(HZ / fbdev->refresh_rate)); 130 } 131 132 /* 133 * This gets the fb data from cache and copies it to ht16k33 display RAM 134 */ 135 static void ht16k33_fb_update(struct work_struct *work) 136 { 137 struct ht16k33_fbdev *fbdev = 138 container_of(work, struct ht16k33_fbdev, work.work); 139 struct ht16k33_priv *priv = 140 container_of(fbdev, struct ht16k33_priv, fbdev); 141 142 uint8_t *p1, *p2; 143 int len, pos = 0, first = -1; 144 145 p1 = fbdev->cache; 146 p2 = fbdev->buffer; 147 148 /* Search for the first byte with changes */ 149 while (pos < HT16K33_FB_SIZE && first < 0) { 150 if (*(p1++) - *(p2++)) 151 first = pos; 152 pos++; 153 } 154 155 /* No changes found */ 156 if (first < 0) 157 goto requeue; 158 159 len = HT16K33_FB_SIZE - first; 160 p1 = fbdev->cache + HT16K33_FB_SIZE - 1; 161 p2 = fbdev->buffer + HT16K33_FB_SIZE - 1; 162 163 /* Determine i2c transfer length */ 164 while (len > 1) { 165 if (*(p1--) - *(p2--)) 166 break; 167 len--; 168 } 169 170 p1 = fbdev->cache + first; 171 p2 = fbdev->buffer + first; 172 if (!i2c_smbus_write_i2c_block_data(priv->client, first, len, p2)) 173 memcpy(p1, p2, len); 174 requeue: 175 ht16k33_fb_queue(priv); 176 } 177 178 static int ht16k33_initialize(struct ht16k33_priv *priv) 179 { 180 uint8_t byte; 181 int err; 182 uint8_t data[HT16K33_MATRIX_LED_MAX_COLS * 2]; 183 184 /* Clear RAM (8 * 16 bits) */ 185 memset(data, 0, sizeof(data)); 186 err = i2c_smbus_write_block_data(priv->client, 0, sizeof(data), data); 187 if (err) 188 return err; 189 190 /* Turn on internal oscillator */ 191 byte = REG_SYSTEM_SETUP_OSC_ON | REG_SYSTEM_SETUP; 192 err = i2c_smbus_write_byte(priv->client, byte); 193 if (err) 194 return err; 195 196 /* Configure INT pin */ 197 byte = REG_ROWINT_SET | REG_ROWINT_SET_INT_ACT_HIGH; 198 if (priv->client->irq > 0) 199 byte |= REG_ROWINT_SET_INT_EN; 200 return i2c_smbus_write_byte(priv->client, byte); 201 } 202 203 static int ht16k33_bl_update_status(struct backlight_device *bl) 204 { 205 int brightness = bl->props.brightness; 206 struct ht16k33_priv *priv = bl_get_data(bl); 207 208 if (bl->props.power != FB_BLANK_UNBLANK || 209 bl->props.fb_blank != FB_BLANK_UNBLANK || 210 bl->props.state & BL_CORE_FBBLANK || brightness == 0) { 211 return ht16k33_display_off(priv); 212 } 213 214 ht16k33_display_on(priv); 215 return i2c_smbus_write_byte(priv->client, 216 REG_BRIGHTNESS | (brightness - 1)); 217 } 218 219 static int ht16k33_bl_check_fb(struct backlight_device *bl, struct fb_info *fi) 220 { 221 struct ht16k33_priv *priv = bl_get_data(bl); 222 223 return (fi == NULL) || (fi->par == priv); 224 } 225 226 static const struct backlight_ops ht16k33_bl_ops = { 227 .update_status = ht16k33_bl_update_status, 228 .check_fb = ht16k33_bl_check_fb, 229 }; 230 231 static int ht16k33_mmap(struct fb_info *info, struct vm_area_struct *vma) 232 { 233 struct ht16k33_priv *priv = info->par; 234 235 return vm_insert_page(vma, vma->vm_start, 236 virt_to_page(priv->fbdev.buffer)); 237 } 238 239 static struct fb_ops ht16k33_fb_ops = { 240 .owner = THIS_MODULE, 241 .fb_read = fb_sys_read, 242 .fb_write = fb_sys_write, 243 .fb_fillrect = sys_fillrect, 244 .fb_copyarea = sys_copyarea, 245 .fb_imageblit = sys_imageblit, 246 .fb_mmap = ht16k33_mmap, 247 }; 248 249 /* 250 * This gets the keys from keypad and reports it to input subsystem. 251 * Returns true if a key is pressed. 252 */ 253 static bool ht16k33_keypad_scan(struct ht16k33_keypad *keypad) 254 { 255 const unsigned short *keycodes = keypad->dev->keycode; 256 u16 new_state[HT16K33_MATRIX_KEYPAD_MAX_COLS]; 257 u8 data[HT16K33_MATRIX_KEYPAD_MAX_COLS * 2]; 258 unsigned long bits_changed; 259 int row, col, code; 260 bool pressed = false; 261 262 if (i2c_smbus_read_i2c_block_data(keypad->client, 0x40, 6, data) != 6) { 263 dev_err(&keypad->client->dev, "Failed to read key data\n"); 264 return false; 265 } 266 267 for (col = 0; col < keypad->cols; col++) { 268 new_state[col] = (data[col * 2 + 1] << 8) | data[col * 2]; 269 if (new_state[col]) 270 pressed = true; 271 bits_changed = keypad->last_key_state[col] ^ new_state[col]; 272 273 for_each_set_bit(row, &bits_changed, BITS_PER_LONG) { 274 code = MATRIX_SCAN_CODE(row, col, keypad->row_shift); 275 input_event(keypad->dev, EV_MSC, MSC_SCAN, code); 276 input_report_key(keypad->dev, keycodes[code], 277 new_state[col] & BIT(row)); 278 } 279 } 280 input_sync(keypad->dev); 281 memcpy(keypad->last_key_state, new_state, sizeof(u16) * keypad->cols); 282 283 return pressed; 284 } 285 286 static irqreturn_t ht16k33_keypad_irq_thread(int irq, void *dev) 287 { 288 struct ht16k33_keypad *keypad = dev; 289 290 do { 291 wait_event_timeout(keypad->wait, keypad->stopped, 292 msecs_to_jiffies(keypad->debounce_ms)); 293 if (keypad->stopped) 294 break; 295 } while (ht16k33_keypad_scan(keypad)); 296 297 return IRQ_HANDLED; 298 } 299 300 static int ht16k33_keypad_start(struct input_dev *dev) 301 { 302 struct ht16k33_keypad *keypad = input_get_drvdata(dev); 303 304 keypad->stopped = false; 305 mb(); 306 enable_irq(keypad->client->irq); 307 308 return 0; 309 } 310 311 static void ht16k33_keypad_stop(struct input_dev *dev) 312 { 313 struct ht16k33_keypad *keypad = input_get_drvdata(dev); 314 315 keypad->stopped = true; 316 mb(); 317 wake_up(&keypad->wait); 318 disable_irq(keypad->client->irq); 319 } 320 321 static int ht16k33_keypad_probe(struct i2c_client *client, 322 struct ht16k33_keypad *keypad) 323 { 324 struct device_node *node = client->dev.of_node; 325 u32 rows = HT16K33_MATRIX_KEYPAD_MAX_ROWS; 326 u32 cols = HT16K33_MATRIX_KEYPAD_MAX_COLS; 327 int err; 328 329 keypad->client = client; 330 init_waitqueue_head(&keypad->wait); 331 332 keypad->dev = devm_input_allocate_device(&client->dev); 333 if (!keypad->dev) 334 return -ENOMEM; 335 336 input_set_drvdata(keypad->dev, keypad); 337 338 keypad->dev->name = DRIVER_NAME"-keypad"; 339 keypad->dev->id.bustype = BUS_I2C; 340 keypad->dev->open = ht16k33_keypad_start; 341 keypad->dev->close = ht16k33_keypad_stop; 342 343 if (!of_get_property(node, "linux,no-autorepeat", NULL)) 344 __set_bit(EV_REP, keypad->dev->evbit); 345 346 err = of_property_read_u32(node, "debounce-delay-ms", 347 &keypad->debounce_ms); 348 if (err) { 349 dev_err(&client->dev, "key debounce delay not specified\n"); 350 return err; 351 } 352 353 err = matrix_keypad_parse_of_params(&client->dev, &rows, &cols); 354 if (err) 355 return err; 356 if (rows > HT16K33_MATRIX_KEYPAD_MAX_ROWS || 357 cols > HT16K33_MATRIX_KEYPAD_MAX_COLS) { 358 dev_err(&client->dev, "%u rows or %u cols out of range in DT\n", 359 rows, cols); 360 return -ERANGE; 361 } 362 363 keypad->rows = rows; 364 keypad->cols = cols; 365 keypad->row_shift = get_count_order(cols); 366 367 err = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL, 368 keypad->dev); 369 if (err) { 370 dev_err(&client->dev, "failed to build keymap\n"); 371 return err; 372 } 373 374 err = devm_request_threaded_irq(&client->dev, client->irq, 375 NULL, ht16k33_keypad_irq_thread, 376 IRQF_TRIGGER_HIGH | IRQF_ONESHOT, 377 DRIVER_NAME, keypad); 378 if (err) { 379 dev_err(&client->dev, "irq request failed %d, error %d\n", 380 client->irq, err); 381 return err; 382 } 383 384 ht16k33_keypad_stop(keypad->dev); 385 386 err = input_register_device(keypad->dev); 387 if (err) 388 return err; 389 390 return 0; 391 } 392 393 static int ht16k33_probe(struct i2c_client *client, 394 const struct i2c_device_id *id) 395 { 396 int err; 397 uint32_t dft_brightness; 398 struct backlight_device *bl; 399 struct backlight_properties bl_props; 400 struct ht16k33_priv *priv; 401 struct ht16k33_fbdev *fbdev; 402 struct device_node *node = client->dev.of_node; 403 404 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 405 dev_err(&client->dev, "i2c_check_functionality error\n"); 406 return -EIO; 407 } 408 409 if (client->irq <= 0) { 410 dev_err(&client->dev, "No IRQ specified\n"); 411 return -EINVAL; 412 } 413 414 priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL); 415 if (!priv) 416 return -ENOMEM; 417 418 priv->client = client; 419 i2c_set_clientdata(client, priv); 420 fbdev = &priv->fbdev; 421 422 err = ht16k33_initialize(priv); 423 if (err) 424 return err; 425 426 /* Framebuffer (2 bytes per column) */ 427 BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE); 428 fbdev->buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL); 429 if (!fbdev->buffer) 430 return -ENOMEM; 431 432 fbdev->cache = devm_kmalloc(&client->dev, HT16K33_FB_SIZE, GFP_KERNEL); 433 if (!fbdev->cache) { 434 err = -ENOMEM; 435 goto err_fbdev_buffer; 436 } 437 438 fbdev->info = framebuffer_alloc(0, &client->dev); 439 if (!fbdev->info) { 440 err = -ENOMEM; 441 goto err_fbdev_buffer; 442 } 443 444 err = of_property_read_u32(node, "refresh-rate-hz", 445 &fbdev->refresh_rate); 446 if (err) { 447 dev_err(&client->dev, "refresh rate not specified\n"); 448 goto err_fbdev_info; 449 } 450 fb_bl_default_curve(fbdev->info, 0, MIN_BRIGHTNESS, MAX_BRIGHTNESS); 451 452 INIT_DELAYED_WORK(&fbdev->work, ht16k33_fb_update); 453 fbdev->info->fbops = &ht16k33_fb_ops; 454 fbdev->info->screen_base = (char __iomem *) fbdev->buffer; 455 fbdev->info->screen_size = HT16K33_FB_SIZE; 456 fbdev->info->fix = ht16k33_fb_fix; 457 fbdev->info->var = ht16k33_fb_var; 458 fbdev->info->pseudo_palette = NULL; 459 fbdev->info->flags = FBINFO_FLAG_DEFAULT; 460 fbdev->info->par = priv; 461 462 err = register_framebuffer(fbdev->info); 463 if (err) 464 goto err_fbdev_info; 465 466 err = ht16k33_keypad_probe(client, &priv->keypad); 467 if (err) 468 goto err_fbdev_unregister; 469 470 /* Backlight */ 471 memset(&bl_props, 0, sizeof(struct backlight_properties)); 472 bl_props.type = BACKLIGHT_RAW; 473 bl_props.max_brightness = MAX_BRIGHTNESS; 474 475 bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl", 476 &client->dev, priv, 477 &ht16k33_bl_ops, &bl_props); 478 if (IS_ERR(bl)) { 479 dev_err(&client->dev, "failed to register backlight\n"); 480 err = PTR_ERR(bl); 481 goto err_fbdev_unregister; 482 } 483 484 err = of_property_read_u32(node, "default-brightness-level", 485 &dft_brightness); 486 if (err) { 487 dft_brightness = MAX_BRIGHTNESS; 488 } else if (dft_brightness > MAX_BRIGHTNESS) { 489 dev_warn(&client->dev, 490 "invalid default brightness level: %u, using %u\n", 491 dft_brightness, MAX_BRIGHTNESS); 492 dft_brightness = MAX_BRIGHTNESS; 493 } 494 495 bl->props.brightness = dft_brightness; 496 ht16k33_bl_update_status(bl); 497 498 ht16k33_fb_queue(priv); 499 return 0; 500 501 err_fbdev_unregister: 502 unregister_framebuffer(fbdev->info); 503 err_fbdev_info: 504 framebuffer_release(fbdev->info); 505 err_fbdev_buffer: 506 free_page((unsigned long) fbdev->buffer); 507 508 return err; 509 } 510 511 static int ht16k33_remove(struct i2c_client *client) 512 { 513 struct ht16k33_priv *priv = i2c_get_clientdata(client); 514 struct ht16k33_fbdev *fbdev = &priv->fbdev; 515 516 cancel_delayed_work(&fbdev->work); 517 unregister_framebuffer(fbdev->info); 518 framebuffer_release(fbdev->info); 519 free_page((unsigned long) fbdev->buffer); 520 521 return 0; 522 } 523 524 static const struct i2c_device_id ht16k33_i2c_match[] = { 525 { "ht16k33", 0 }, 526 { } 527 }; 528 MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match); 529 530 static const struct of_device_id ht16k33_of_match[] = { 531 { .compatible = "holtek,ht16k33", }, 532 { } 533 }; 534 MODULE_DEVICE_TABLE(of, ht16k33_of_match); 535 536 static struct i2c_driver ht16k33_driver = { 537 .probe = ht16k33_probe, 538 .remove = ht16k33_remove, 539 .driver = { 540 .name = DRIVER_NAME, 541 .of_match_table = of_match_ptr(ht16k33_of_match), 542 }, 543 .id_table = ht16k33_i2c_match, 544 }; 545 module_i2c_driver(ht16k33_driver); 546 547 MODULE_DESCRIPTION("Holtek HT16K33 driver"); 548 MODULE_LICENSE("GPL"); 549 MODULE_AUTHOR("Robin van der Gracht <robin@protonic.nl>"); 550