drivers/auxdisplay/ht16k33.c

   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, HZ / fbdev->refresh_rate);
 129 }
 130
 131 /*
 132  * This gets the fb data from cache and copies it to ht16k33 display RAM
 133  */
 134 static void ht16k33_fb_update(struct work_struct *work)
 135 {
 136         struct ht16k33_fbdev *fbdev =
 137                 container_of(work, struct ht16k33_fbdev, work.work);
 138         struct ht16k33_priv *priv =
 139                 container_of(fbdev, struct ht16k33_priv, fbdev);
 140
 141         uint8_t *p1, *p2;
 142         int len, pos = 0, first = -1;
 143
 144         p1 = fbdev->cache;
 145         p2 = fbdev->buffer;
 146
 147         /* Search for the first byte with changes */
 148         while (pos < HT16K33_FB_SIZE && first < 0) {
 149                 if (*(p1++) - *(p2++))
 150                         first = pos;
 151                 pos++;
 152         }
 153
 154         /* No changes found */
 155         if (first < 0)
 156                 goto requeue;
 157
 158         len = HT16K33_FB_SIZE - first;
 159         p1 = fbdev->cache + HT16K33_FB_SIZE - 1;
 160         p2 = fbdev->buffer + HT16K33_FB_SIZE - 1;
 161
 162         /* Determine i2c transfer length */
 163         while (len > 1) {
 164                 if (*(p1--) - *(p2--))
 165                         break;
 166                 len--;
 167         }
 168
 169         p1 = fbdev->cache + first;
 170         p2 = fbdev->buffer + first;
 171         if (!i2c_smbus_write_i2c_block_data(priv->client, first, len, p2))
 172                 memcpy(p1, p2, len);
 173 requeue:
 174         ht16k33_fb_queue(priv);
 175 }
 176
 177 static int ht16k33_initialize(struct ht16k33_priv *priv)
 178 {
 179         uint8_t byte;
 180         int err;
 181         uint8_t data[HT16K33_MATRIX_LED_MAX_COLS * 2];
 182
 183         /* Clear RAM (8 * 16 bits) */
 184         memset(data, 0, sizeof(data));
 185         err = i2c_smbus_write_block_data(priv->client, 0, sizeof(data), data);
 186         if (err)
 187                 return err;
 188
 189         /* Turn on internal oscillator */
 190         byte = REG_SYSTEM_SETUP_OSC_ON | REG_SYSTEM_SETUP;
 191         err = i2c_smbus_write_byte(priv->client, byte);
 192         if (err)
 193                 return err;
 194
 195         /* Configure INT pin */
 196         byte = REG_ROWINT_SET | REG_ROWINT_SET_INT_ACT_HIGH;
 197         if (priv->client->irq > 0)
 198                 byte |= REG_ROWINT_SET_INT_EN;
 199         return i2c_smbus_write_byte(priv->client, byte);
 200 }
 201
 202 static int ht16k33_bl_update_status(struct backlight_device *bl)
 203 {
 204         int brightness = bl->props.brightness;
 205         struct ht16k33_priv *priv = bl_get_data(bl);
 206
 207         if (bl->props.power != FB_BLANK_UNBLANK ||
 208             bl->props.fb_blank != FB_BLANK_UNBLANK ||
 209             bl->props.state & BL_CORE_FBBLANK || brightness == 0) {
 210                 return ht16k33_display_off(priv);
 211         }
 212
 213         ht16k33_display_on(priv);
 214         return i2c_smbus_write_byte(priv->client,
 215                                     REG_BRIGHTNESS | (brightness - 1));
 216 }
 217
 218 static int ht16k33_bl_check_fb(struct backlight_device *bl, struct fb_info *fi)
 219 {
 220         struct ht16k33_priv *priv = bl_get_data(bl);
 221
 222         return (fi == NULL) || (fi->par == priv);
 223 }
 224
 225 static const struct backlight_ops ht16k33_bl_ops = {
 226         .update_status  = ht16k33_bl_update_status,
 227         .check_fb       = ht16k33_bl_check_fb,
 228 };
 229
 230 /*
 231  * Blank events will be passed to the actual device handling the backlight when
 232  * we return zero here.
 233  */
 234 static int ht16k33_blank(int blank, struct fb_info *info)
 235 {
 236         return 0;
 237 }
 238
 239 static int ht16k33_mmap(struct fb_info *info, struct vm_area_struct *vma)
 240 {
 241         struct ht16k33_priv *priv = info->par;
 242
 243         return vm_insert_page(vma, vma->vm_start,
 244                               virt_to_page(priv->fbdev.buffer));
 245 }
 246
 247 static struct fb_ops ht16k33_fb_ops = {
 248         .owner = THIS_MODULE,
 249         .fb_read = fb_sys_read,
 250         .fb_write = fb_sys_write,
 251         .fb_blank = ht16k33_blank,
 252         .fb_fillrect = sys_fillrect,
 253         .fb_copyarea = sys_copyarea,
 254         .fb_imageblit = sys_imageblit,
 255         .fb_mmap = ht16k33_mmap,
 256 };
 257
 258 /*
 259  * This gets the keys from keypad and reports it to input subsystem.
 260  * Returns true if a key is pressed.
 261  */
 262 static bool ht16k33_keypad_scan(struct ht16k33_keypad *keypad)
 263 {
 264         const unsigned short *keycodes = keypad->dev->keycode;
 265         u16 new_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];
 266         __le16 data[HT16K33_MATRIX_KEYPAD_MAX_COLS];
 267         unsigned long bits_changed;
 268         int row, col, code;
 269         int rc;
 270         bool pressed = false;
 271
 272         rc = i2c_smbus_read_i2c_block_data(keypad->client, 0x40,
 273                                            sizeof(data), (u8 *)data);
 274         if (rc != sizeof(data)) {
 275                 dev_err(&keypad->client->dev,
 276                         "Failed to read key data, rc=%d\n", rc);
 277                 return false;
 278         }
 279
 280         for (col = 0; col < keypad->cols; col++) {
 281                 new_state[col] = le16_to_cpu(data[col]);
 282                 if (new_state[col])
 283                         pressed = true;
 284                 bits_changed = keypad->last_key_state[col] ^ new_state[col];
 285
 286                 for_each_set_bit(row, &bits_changed, BITS_PER_LONG) {
 287                         code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
 288                         input_event(keypad->dev, EV_MSC, MSC_SCAN, code);
 289                         input_report_key(keypad->dev, keycodes[code],
 290                                          new_state[col] & BIT(row));
 291                 }
 292         }
 293         input_sync(keypad->dev);
 294         memcpy(keypad->last_key_state, new_state, sizeof(u16) * keypad->cols);
 295
 296         return pressed;
 297 }
 298
 299 static irqreturn_t ht16k33_keypad_irq_thread(int irq, void *dev)
 300 {
 301         struct ht16k33_keypad *keypad = dev;
 302
 303         do {
 304                 wait_event_timeout(keypad->wait, keypad->stopped,
 305                                     msecs_to_jiffies(keypad->debounce_ms));
 306                 if (keypad->stopped)
 307                         break;
 308         } while (ht16k33_keypad_scan(keypad));
 309
 310         return IRQ_HANDLED;
 311 }
 312
 313 static int ht16k33_keypad_start(struct input_dev *dev)
 314 {
 315         struct ht16k33_keypad *keypad = input_get_drvdata(dev);
 316
 317         keypad->stopped = false;
 318         mb();
 319         enable_irq(keypad->client->irq);
 320
 321         return 0;
 322 }
 323
 324 static void ht16k33_keypad_stop(struct input_dev *dev)
 325 {
 326         struct ht16k33_keypad *keypad = input_get_drvdata(dev);
 327
 328         keypad->stopped = true;
 329         mb();
 330         wake_up(&keypad->wait);
 331         disable_irq(keypad->client->irq);
 332 }
 333
 334 static int ht16k33_keypad_probe(struct i2c_client *client,
 335                                 struct ht16k33_keypad *keypad)
 336 {
 337         struct device_node *node = client->dev.of_node;
 338         u32 rows = HT16K33_MATRIX_KEYPAD_MAX_ROWS;
 339         u32 cols = HT16K33_MATRIX_KEYPAD_MAX_COLS;
 340         int err;
 341
 342         keypad->client = client;
 343         init_waitqueue_head(&keypad->wait);
 344
 345         keypad->dev = devm_input_allocate_device(&client->dev);
 346         if (!keypad->dev)
 347                 return -ENOMEM;
 348
 349         input_set_drvdata(keypad->dev, keypad);
 350
 351         keypad->dev->name = DRIVER_NAME"-keypad";
 352         keypad->dev->id.bustype = BUS_I2C;
 353         keypad->dev->open = ht16k33_keypad_start;
 354         keypad->dev->close = ht16k33_keypad_stop;
 355
 356         if (!of_get_property(node, "linux,no-autorepeat", NULL))
 357                 __set_bit(EV_REP, keypad->dev->evbit);
 358
 359         err = of_property_read_u32(node, "debounce-delay-ms",
 360                                    &keypad->debounce_ms);
 361         if (err) {
 362                 dev_err(&client->dev, "key debounce delay not specified\n");
 363                 return err;
 364         }
 365
 366         err = matrix_keypad_parse_of_params(&client->dev, &rows, &cols);
 367         if (err)
 368                 return err;
 369         if (rows > HT16K33_MATRIX_KEYPAD_MAX_ROWS ||
 370             cols > HT16K33_MATRIX_KEYPAD_MAX_COLS) {
 371                 dev_err(&client->dev, "%u rows or %u cols out of range in DT\n",
 372                         rows, cols);
 373                 return -ERANGE;
 374         }
 375
 376         keypad->rows = rows;
 377         keypad->cols = cols;
 378         keypad->row_shift = get_count_order(cols);
 379
 380         err = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL,
 381                                          keypad->dev);
 382         if (err) {
 383                 dev_err(&client->dev, "failed to build keymap\n");
 384                 return err;
 385         }
 386
 387         err = devm_request_threaded_irq(&client->dev, client->irq,
 388                                         NULL, ht16k33_keypad_irq_thread,
 389                                         IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
 390                                         DRIVER_NAME, keypad);
 391         if (err) {
 392                 dev_err(&client->dev, "irq request failed %d, error %d\n",
 393                         client->irq, err);
 394                 return err;
 395         }
 396
 397         ht16k33_keypad_stop(keypad->dev);
 398
 399         err = input_register_device(keypad->dev);
 400         if (err)
 401                 return err;
 402
 403         return 0;
 404 }
 405
 406 static int ht16k33_probe(struct i2c_client *client,
 407                                   const struct i2c_device_id *id)
 408 {
 409         int err;
 410         uint32_t dft_brightness;
 411         struct backlight_device *bl;
 412         struct backlight_properties bl_props;
 413         struct ht16k33_priv *priv;
 414         struct ht16k33_fbdev *fbdev;
 415         struct device_node *node = client->dev.of_node;
 416
 417         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 418                 dev_err(&client->dev, "i2c_check_functionality error\n");
 419                 return -EIO;
 420         }
 421
 422         if (client->irq <= 0) {
 423                 dev_err(&client->dev, "No IRQ specified\n");
 424                 return -EINVAL;
 425         }
 426
 427         priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
 428         if (!priv)
 429                 return -ENOMEM;
 430
 431         priv->client = client;
 432         i2c_set_clientdata(client, priv);
 433         fbdev = &priv->fbdev;
 434
 435         err = ht16k33_initialize(priv);
 436         if (err)
 437                 return err;
 438
 439         /* Backlight */
 440         memset(&bl_props, 0, sizeof(struct backlight_properties));
 441         bl_props.type = BACKLIGHT_RAW;
 442         bl_props.max_brightness = MAX_BRIGHTNESS;
 443
 444         bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl",
 445                                             &client->dev, priv,
 446                                             &ht16k33_bl_ops, &bl_props);
 447         if (IS_ERR(bl)) {
 448                 dev_err(&client->dev, "failed to register backlight\n");
 449                 return PTR_ERR(bl);
 450         }
 451
 452         err = of_property_read_u32(node, "default-brightness-level",
 453                                    &dft_brightness);
 454         if (err) {
 455                 dft_brightness = MAX_BRIGHTNESS;
 456         } else if (dft_brightness > MAX_BRIGHTNESS) {
 457                 dev_warn(&client->dev,
 458                          "invalid default brightness level: %u, using %u\n",
 459                          dft_brightness, MAX_BRIGHTNESS);
 460                 dft_brightness = MAX_BRIGHTNESS;
 461         }
 462
 463         bl->props.brightness = dft_brightness;
 464         ht16k33_bl_update_status(bl);
 465
 466         /* Framebuffer (2 bytes per column) */
 467         BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE);
 468         fbdev->buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
 469         if (!fbdev->buffer)
 470                 return -ENOMEM;
 471
 472         fbdev->cache = devm_kmalloc(&client->dev, HT16K33_FB_SIZE, GFP_KERNEL);
 473         if (!fbdev->cache) {
 474                 err = -ENOMEM;
 475                 goto err_fbdev_buffer;
 476         }
 477
 478         fbdev->info = framebuffer_alloc(0, &client->dev);
 479         if (!fbdev->info) {
 480                 err = -ENOMEM;
 481                 goto err_fbdev_buffer;
 482         }
 483
 484         err = of_property_read_u32(node, "refresh-rate-hz",
 485                 &fbdev->refresh_rate);
 486         if (err) {
 487                 dev_err(&client->dev, "refresh rate not specified\n");
 488                 goto err_fbdev_info;
 489         }
 490         fb_bl_default_curve(fbdev->info, 0, MIN_BRIGHTNESS, MAX_BRIGHTNESS);
 491
 492         INIT_DELAYED_WORK(&fbdev->work, ht16k33_fb_update);
 493         fbdev->info->fbops = &ht16k33_fb_ops;
 494         fbdev->info->screen_base = (char __iomem *) fbdev->buffer;
 495         fbdev->info->screen_size = HT16K33_FB_SIZE;
 496         fbdev->info->fix = ht16k33_fb_fix;
 497         fbdev->info->var = ht16k33_fb_var;
 498         fbdev->info->bl_dev = bl;
 499         fbdev->info->pseudo_palette = NULL;
 500         fbdev->info->flags = FBINFO_FLAG_DEFAULT;
 501         fbdev->info->par = priv;
 502
 503         err = register_framebuffer(fbdev->info);
 504         if (err)
 505                 goto err_fbdev_info;
 506
 507         err = ht16k33_keypad_probe(client, &priv->keypad);
 508         if (err)
 509                 goto err_fbdev_unregister;
 510
 511         ht16k33_fb_queue(priv);
 512         return 0;
 513
 514 err_fbdev_unregister:
 515         unregister_framebuffer(fbdev->info);
 516 err_fbdev_info:
 517         framebuffer_release(fbdev->info);
 518 err_fbdev_buffer:
 519         free_page((unsigned long) fbdev->buffer);
 520
 521         return err;
 522 }
 523
 524 static int ht16k33_remove(struct i2c_client *client)
 525 {
 526         struct ht16k33_priv *priv = i2c_get_clientdata(client);
 527         struct ht16k33_fbdev *fbdev = &priv->fbdev;
 528
 529         cancel_delayed_work_sync(&fbdev->work);
 530         unregister_framebuffer(fbdev->info);
 531         framebuffer_release(fbdev->info);
 532         free_page((unsigned long) fbdev->buffer);
 533
 534         return 0;
 535 }
 536
 537 static const struct i2c_device_id ht16k33_i2c_match[] = {
 538         { "ht16k33", 0 },
 539         { }
 540 };
 541 MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match);
 542
 543 static const struct of_device_id ht16k33_of_match[] = {
 544         { .compatible = "holtek,ht16k33", },
 545         { }
 546 };
 547 MODULE_DEVICE_TABLE(of, ht16k33_of_match);
 548
 549 static struct i2c_driver ht16k33_driver = {
 550         .probe          = ht16k33_probe,
 551         .remove         = ht16k33_remove,
 552         .driver         = {
 553                 .name           = DRIVER_NAME,
 554                 .of_match_table = of_match_ptr(ht16k33_of_match),
 555         },
 556         .id_table = ht16k33_i2c_match,
 557 };
 558 module_i2c_driver(ht16k33_driver);
 559
 560 MODULE_DESCRIPTION("Holtek HT16K33 driver");
 561 MODULE_LICENSE("GPL");
 562 MODULE_AUTHOR("Robin van der Gracht <robin@protonic.nl>");