drivers/auxdisplay/ht16k33.c

   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
 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, HZ / fbdev->refresh_rate);
 121 }
 122
 123 /*
 124  * This gets the fb data from cache and copies it to ht16k33 display RAM
 125  */
 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
 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
 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
 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
 222 /*
 223  * Blank events will be passed to the actual device handling the backlight when
 224  * we return zero here.
 225  */
 226 static int ht16k33_blank(int blank, struct fb_info *info)
 227 {
 228         return 0;
 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         struct page *pages = virt_to_page(priv->fbdev.buffer);
 235
 236         return vm_map_pages_zero(vma, &pages, 1);
 237 }
 238
 239 static 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  */
 254 static 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
 291 static 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
 305 static 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
 316 static 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
 326 static 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
 398 static 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         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         /* Backlight */
 427         memset(&bl_props, 0, sizeof(struct backlight_properties));
 428         bl_props.type = BACKLIGHT_RAW;
 429         bl_props.max_brightness = MAX_BRIGHTNESS;
 430
 431         bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl",
 432                                             &client->dev, priv,
 433                                             &ht16k33_bl_ops, &bl_props);
 434         if (IS_ERR(bl)) {
 435                 dev_err(&client->dev, "failed to register backlight\n");
 436                 return PTR_ERR(bl);
 437         }
 438
 439         err = of_property_read_u32(node, "default-brightness-level",
 440                                    &dft_brightness);
 441         if (err) {
 442                 dft_brightness = MAX_BRIGHTNESS;
 443         } else if (dft_brightness > MAX_BRIGHTNESS) {
 444                 dev_warn(&client->dev,
 445                          "invalid default brightness level: %u, using %u\n",
 446                          dft_brightness, MAX_BRIGHTNESS);
 447                 dft_brightness = MAX_BRIGHTNESS;
 448         }
 449
 450         bl->props.brightness = dft_brightness;
 451         ht16k33_bl_update_status(bl);
 452
 453         /* Framebuffer (2 bytes per column) */
 454         BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE);
 455         fbdev->buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
 456         if (!fbdev->buffer)
 457                 return -ENOMEM;
 458
 459         fbdev->cache = devm_kmalloc(&client->dev, HT16K33_FB_SIZE, GFP_KERNEL);
 460         if (!fbdev->cache) {
 461                 err = -ENOMEM;
 462                 goto err_fbdev_buffer;
 463         }
 464
 465         fbdev->info = framebuffer_alloc(0, &client->dev);
 466         if (!fbdev->info) {
 467                 err = -ENOMEM;
 468                 goto err_fbdev_buffer;
 469         }
 470
 471         err = of_property_read_u32(node, "refresh-rate-hz",
 472                 &fbdev->refresh_rate);
 473         if (err) {
 474                 dev_err(&client->dev, "refresh rate not specified\n");
 475                 goto err_fbdev_info;
 476         }
 477         fb_bl_default_curve(fbdev->info, 0, MIN_BRIGHTNESS, MAX_BRIGHTNESS);
 478
 479         INIT_DELAYED_WORK(&fbdev->work, ht16k33_fb_update);
 480         fbdev->info->fbops = &ht16k33_fb_ops;
 481         fbdev->info->screen_base = (char __iomem *) fbdev->buffer;
 482         fbdev->info->screen_size = HT16K33_FB_SIZE;
 483         fbdev->info->fix = ht16k33_fb_fix;
 484         fbdev->info->var = ht16k33_fb_var;
 485         fbdev->info->bl_dev = bl;
 486         fbdev->info->pseudo_palette = NULL;
 487         fbdev->info->flags = FBINFO_FLAG_DEFAULT;
 488         fbdev->info->par = priv;
 489
 490         err = register_framebuffer(fbdev->info);
 491         if (err)
 492                 goto err_fbdev_info;
 493
 494         /* Keypad */
 495         if (client->irq > 0) {
 496                 err = ht16k33_keypad_probe(client, &priv->keypad);
 497                 if (err)
 498                         goto err_fbdev_unregister;
 499         }
 500
 501         ht16k33_fb_queue(priv);
 502         return 0;
 503
 504 err_fbdev_unregister:
 505         unregister_framebuffer(fbdev->info);
 506 err_fbdev_info:
 507         framebuffer_release(fbdev->info);
 508 err_fbdev_buffer:
 509         free_page((unsigned long) fbdev->buffer);
 510
 511         return err;
 512 }
 513
 514 static int ht16k33_remove(struct i2c_client *client)
 515 {
 516         struct ht16k33_priv *priv = i2c_get_clientdata(client);
 517         struct ht16k33_fbdev *fbdev = &priv->fbdev;
 518
 519         cancel_delayed_work_sync(&fbdev->work);
 520         unregister_framebuffer(fbdev->info);
 521         framebuffer_release(fbdev->info);
 522         free_page((unsigned long) fbdev->buffer);
 523
 524         return 0;
 525 }
 526
 527 static const struct i2c_device_id ht16k33_i2c_match[] = {
 528         { "ht16k33", 0 },
 529         { }
 530 };
 531 MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match);
 532
 533 static const struct of_device_id ht16k33_of_match[] = {
 534         { .compatible = "holtek,ht16k33", },
 535         { }
 536 };
 537 MODULE_DEVICE_TABLE(of, ht16k33_of_match);
 538
 539 static struct i2c_driver ht16k33_driver = {
 540         .probe          = ht16k33_probe,
 541         .remove         = ht16k33_remove,
 542         .driver         = {
 543                 .name           = DRIVER_NAME,
 544                 .of_match_table = of_match_ptr(ht16k33_of_match),
 545         },
 546         .id_table = ht16k33_i2c_match,
 547 };
 548 module_i2c_driver(ht16k33_driver);
 549
 550 MODULE_DESCRIPTION("Holtek HT16K33 driver");
 551 MODULE_LICENSE("GPL");
 552 MODULE_AUTHOR("Robin van der Gracht <robin@protonic.nl>");