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 input_dev *dev;
  60         spinlock_t lock;
  61         struct delayed_work work;
  62         uint32_t cols;
  63         uint32_t rows;
  64         uint32_t row_shift;
  65         uint32_t debounce_ms;
  66         uint16_t last_key_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];
  67 };
  68
  69 struct ht16k33_fbdev {
  70         struct fb_info *info;
  71         uint32_t refresh_rate;
  72         uint8_t *buffer;
  73         uint8_t *cache;
  74         struct delayed_work work;
  75 };
  76
  77 struct ht16k33_priv {
  78         struct i2c_client *client;
  79         struct ht16k33_keypad keypad;
  80         struct ht16k33_fbdev fbdev;
  81         struct workqueue_struct *workqueue;
  82 };
  83
  84 static struct fb_fix_screeninfo ht16k33_fb_fix = {
  85         .id             = DRIVER_NAME,
  86         .type           = FB_TYPE_PACKED_PIXELS,
  87         .visual         = FB_VISUAL_MONO10,
  88         .xpanstep       = 0,
  89         .ypanstep       = 0,
  90         .ywrapstep      = 0,
  91         .line_length    = HT16K33_MATRIX_LED_MAX_ROWS,
  92         .accel          = FB_ACCEL_NONE,
  93 };
  94
  95 static struct fb_var_screeninfo ht16k33_fb_var = {
  96         .xres = HT16K33_MATRIX_LED_MAX_ROWS,
  97         .yres = HT16K33_MATRIX_LED_MAX_COLS,
  98         .xres_virtual = HT16K33_MATRIX_LED_MAX_ROWS,
  99         .yres_virtual = HT16K33_MATRIX_LED_MAX_COLS,
 100         .bits_per_pixel = 1,
 101         .red = { 0, 1, 0 },
 102         .green = { 0, 1, 0 },
 103         .blue = { 0, 1, 0 },
 104         .left_margin = 0,
 105         .right_margin = 0,
 106         .upper_margin = 0,
 107         .lower_margin = 0,
 108         .vmode = FB_VMODE_NONINTERLACED,
 109 };
 110
 111 static int ht16k33_display_on(struct ht16k33_priv *priv)
 112 {
 113         uint8_t data = REG_DISPLAY_SETUP | REG_DISPLAY_SETUP_ON;
 114
 115         return i2c_smbus_write_byte(priv->client, data);
 116 }
 117
 118 static int ht16k33_display_off(struct ht16k33_priv *priv)
 119 {
 120         return i2c_smbus_write_byte(priv->client, REG_DISPLAY_SETUP);
 121 }
 122
 123 static void ht16k33_fb_queue(struct ht16k33_priv *priv)
 124 {
 125         struct ht16k33_fbdev *fbdev = &priv->fbdev;
 126
 127         queue_delayed_work(priv->workqueue, &fbdev->work,
 128                 msecs_to_jiffies(HZ / fbdev->refresh_rate));
 129 }
 130
 131 static void ht16k33_keypad_queue(struct ht16k33_priv *priv)
 132 {
 133         struct ht16k33_keypad *keypad = &priv->keypad;
 134
 135         queue_delayed_work(priv->workqueue, &keypad->work,
 136                 msecs_to_jiffies(keypad->debounce_ms));
 137 }
 138
 139 /*
 140  * This gets the fb data from cache and copies it to ht16k33 display RAM
 141  */
 142 static void ht16k33_fb_update(struct work_struct *work)
 143 {
 144         struct ht16k33_fbdev *fbdev =
 145                 container_of(work, struct ht16k33_fbdev, work.work);
 146         struct ht16k33_priv *priv =
 147                 container_of(fbdev, struct ht16k33_priv, fbdev);
 148
 149         uint8_t *p1, *p2;
 150         int len, pos = 0, first = -1;
 151
 152         p1 = fbdev->cache;
 153         p2 = fbdev->buffer;
 154
 155         /* Search for the first byte with changes */
 156         while (pos < HT16K33_FB_SIZE && first < 0) {
 157                 if (*(p1++) - *(p2++))
 158                         first = pos;
 159                 pos++;
 160         }
 161
 162         /* No changes found */
 163         if (first < 0)
 164                 goto requeue;
 165
 166         len = HT16K33_FB_SIZE - first;
 167         p1 = fbdev->cache + HT16K33_FB_SIZE - 1;
 168         p2 = fbdev->buffer + HT16K33_FB_SIZE - 1;
 169
 170         /* Determine i2c transfer length */
 171         while (len > 1) {
 172                 if (*(p1--) - *(p2--))
 173                         break;
 174                 len--;
 175         }
 176
 177         p1 = fbdev->cache + first;
 178         p2 = fbdev->buffer + first;
 179         if (!i2c_smbus_write_i2c_block_data(priv->client, first, len, p2))
 180                 memcpy(p1, p2, len);
 181 requeue:
 182         ht16k33_fb_queue(priv);
 183 }
 184
 185 static int ht16k33_keypad_start(struct input_dev *dev)
 186 {
 187         struct ht16k33_priv *priv = input_get_drvdata(dev);
 188         struct ht16k33_keypad *keypad = &priv->keypad;
 189
 190         /*
 191          * Schedule an immediate key scan to capture current key state;
 192          * columns will be activated and IRQs be enabled after the scan.
 193          */
 194         queue_delayed_work(priv->workqueue, &keypad->work, 0);
 195         return 0;
 196 }
 197
 198 static void ht16k33_keypad_stop(struct input_dev *dev)
 199 {
 200         struct ht16k33_priv *priv = input_get_drvdata(dev);
 201         struct ht16k33_keypad *keypad = &priv->keypad;
 202
 203         cancel_delayed_work(&keypad->work);
 204         /*
 205          * ht16k33_keypad_scan() will leave IRQs enabled;
 206          * we should disable them now.
 207          */
 208         disable_irq_nosync(priv->client->irq);
 209 }
 210
 211 static int ht16k33_initialize(struct ht16k33_priv *priv)
 212 {
 213         uint8_t byte;
 214         int err;
 215         uint8_t data[HT16K33_MATRIX_LED_MAX_COLS * 2];
 216
 217         /* Clear RAM (8 * 16 bits) */
 218         memset(data, 0, sizeof(data));
 219         err = i2c_smbus_write_block_data(priv->client, 0, sizeof(data), data);
 220         if (err)
 221                 return err;
 222
 223         /* Turn on internal oscillator */
 224         byte = REG_SYSTEM_SETUP_OSC_ON | REG_SYSTEM_SETUP;
 225         err = i2c_smbus_write_byte(priv->client, byte);
 226         if (err)
 227                 return err;
 228
 229         /* Configure INT pin */
 230         byte = REG_ROWINT_SET | REG_ROWINT_SET_INT_ACT_HIGH;
 231         if (priv->client->irq > 0)
 232                 byte |= REG_ROWINT_SET_INT_EN;
 233         return i2c_smbus_write_byte(priv->client, byte);
 234 }
 235
 236 /*
 237  * This gets the keys from keypad and reports it to input subsystem
 238  */
 239 static void ht16k33_keypad_scan(struct work_struct *work)
 240 {
 241         struct ht16k33_keypad *keypad =
 242                 container_of(work, struct ht16k33_keypad, work.work);
 243         struct ht16k33_priv *priv =
 244                 container_of(keypad, struct ht16k33_priv, keypad);
 245         const unsigned short *keycodes = keypad->dev->keycode;
 246         uint16_t bits_changed, new_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];
 247         uint8_t data[HT16K33_MATRIX_KEYPAD_MAX_COLS * 2];
 248         int row, col, code;
 249         bool reschedule = false;
 250
 251         if (i2c_smbus_read_i2c_block_data(priv->client, 0x40, 6, data) != 6) {
 252                 dev_err(&priv->client->dev, "Failed to read key data\n");
 253                 goto end;
 254         }
 255
 256         for (col = 0; col < keypad->cols; col++) {
 257                 new_state[col] = (data[col * 2 + 1] << 8) | data[col * 2];
 258                 if (new_state[col])
 259                         reschedule = true;
 260                 bits_changed = keypad->last_key_state[col] ^ new_state[col];
 261
 262                 while (bits_changed) {
 263                         row = ffs(bits_changed) - 1;
 264                         code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
 265                         input_event(keypad->dev, EV_MSC, MSC_SCAN, code);
 266                         input_report_key(keypad->dev, keycodes[code],
 267                                          new_state[col] & BIT(row));
 268                         bits_changed &= ~BIT(row);
 269                 }
 270         }
 271         input_sync(keypad->dev);
 272         memcpy(keypad->last_key_state, new_state, sizeof(new_state));
 273
 274 end:
 275         if (reschedule)
 276                 ht16k33_keypad_queue(priv);
 277         else
 278                 enable_irq(priv->client->irq);
 279 }
 280
 281 static irqreturn_t ht16k33_irq_thread(int irq, void *dev)
 282 {
 283         struct ht16k33_priv *priv = dev;
 284
 285         disable_irq_nosync(priv->client->irq);
 286         ht16k33_keypad_queue(priv);
 287
 288         return IRQ_HANDLED;
 289 }
 290
 291 static int ht16k33_bl_update_status(struct backlight_device *bl)
 292 {
 293         int brightness = bl->props.brightness;
 294         struct ht16k33_priv *priv = bl_get_data(bl);
 295
 296         if (bl->props.power != FB_BLANK_UNBLANK ||
 297             bl->props.fb_blank != FB_BLANK_UNBLANK ||
 298             bl->props.state & BL_CORE_FBBLANK || brightness == 0) {
 299                 return ht16k33_display_off(priv);
 300         }
 301
 302         ht16k33_display_on(priv);
 303         return i2c_smbus_write_byte(priv->client,
 304                                     REG_BRIGHTNESS | (brightness - 1));
 305 }
 306
 307 static int ht16k33_bl_check_fb(struct backlight_device *bl, struct fb_info *fi)
 308 {
 309         struct ht16k33_priv *priv = bl_get_data(bl);
 310
 311         return (fi == NULL) || (fi->par == priv);
 312 }
 313
 314 static const struct backlight_ops ht16k33_bl_ops = {
 315         .update_status  = ht16k33_bl_update_status,
 316         .check_fb       = ht16k33_bl_check_fb,
 317 };
 318
 319 static int ht16k33_mmap(struct fb_info *info, struct vm_area_struct *vma)
 320 {
 321         struct ht16k33_priv *priv = info->par;
 322
 323         return vm_insert_page(vma, vma->vm_start,
 324                               virt_to_page(priv->fbdev.buffer));
 325 }
 326
 327 static struct fb_ops ht16k33_fb_ops = {
 328         .owner = THIS_MODULE,
 329         .fb_read = fb_sys_read,
 330         .fb_write = fb_sys_write,
 331         .fb_fillrect = sys_fillrect,
 332         .fb_copyarea = sys_copyarea,
 333         .fb_imageblit = sys_imageblit,
 334         .fb_mmap = ht16k33_mmap,
 335 };
 336
 337 static int ht16k33_probe(struct i2c_client *client,
 338                                   const struct i2c_device_id *id)
 339 {
 340         int err;
 341         uint32_t rows, cols, dft_brightness;
 342         struct backlight_device *bl;
 343         struct backlight_properties bl_props;
 344         struct ht16k33_priv *priv;
 345         struct ht16k33_keypad *keypad;
 346         struct ht16k33_fbdev *fbdev;
 347         struct device_node *node = client->dev.of_node;
 348
 349         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 350                 dev_err(&client->dev, "i2c_check_functionality error\n");
 351                 return -EIO;
 352         }
 353
 354         if (client->irq <= 0) {
 355                 dev_err(&client->dev, "No IRQ specified\n");
 356                 return -EINVAL;
 357         }
 358
 359         priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
 360         if (!priv)
 361                 return -ENOMEM;
 362
 363         priv->client = client;
 364         i2c_set_clientdata(client, priv);
 365         fbdev = &priv->fbdev;
 366         keypad = &priv->keypad;
 367
 368         priv->workqueue = create_singlethread_workqueue(DRIVER_NAME "-wq");
 369         if (priv->workqueue == NULL)
 370                 return -ENOMEM;
 371
 372         err = ht16k33_initialize(priv);
 373         if (err)
 374                 goto err_destroy_wq;
 375
 376         /* Framebuffer (2 bytes per column) */
 377         BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE);
 378         fbdev->buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
 379         if (!fbdev->buffer) {
 380                 err = -ENOMEM;
 381                 goto err_free_fbdev;
 382         }
 383
 384         fbdev->cache = devm_kmalloc(&client->dev, HT16K33_FB_SIZE, GFP_KERNEL);
 385         if (!fbdev->cache) {
 386                 err = -ENOMEM;
 387                 goto err_fbdev_buffer;
 388         }
 389
 390         fbdev->info = framebuffer_alloc(0, &client->dev);
 391         if (!fbdev->info) {
 392                 err = -ENOMEM;
 393                 goto err_fbdev_buffer;
 394         }
 395
 396         err = of_property_read_u32(node, "refresh-rate-hz",
 397                 &fbdev->refresh_rate);
 398         if (err) {
 399                 dev_err(&client->dev, "refresh rate not specified\n");
 400                 goto err_fbdev_info;
 401         }
 402         fb_bl_default_curve(fbdev->info, 0, MIN_BRIGHTNESS, MAX_BRIGHTNESS);
 403
 404         INIT_DELAYED_WORK(&fbdev->work, ht16k33_fb_update);
 405         fbdev->info->fbops = &ht16k33_fb_ops;
 406         fbdev->info->screen_base = (char __iomem *) fbdev->buffer;
 407         fbdev->info->screen_size = HT16K33_FB_SIZE;
 408         fbdev->info->fix = ht16k33_fb_fix;
 409         fbdev->info->var = ht16k33_fb_var;
 410         fbdev->info->pseudo_palette = NULL;
 411         fbdev->info->flags = FBINFO_FLAG_DEFAULT;
 412         fbdev->info->par = priv;
 413
 414         err = register_framebuffer(fbdev->info);
 415         if (err)
 416                 goto err_fbdev_info;
 417
 418         /* Keypad */
 419         keypad->dev = devm_input_allocate_device(&client->dev);
 420         if (!keypad->dev) {
 421                 err = -ENOMEM;
 422                 goto err_fbdev_unregister;
 423         }
 424
 425         keypad->dev->name = DRIVER_NAME"-keypad";
 426         keypad->dev->id.bustype = BUS_I2C;
 427         keypad->dev->open = ht16k33_keypad_start;
 428         keypad->dev->close = ht16k33_keypad_stop;
 429
 430         if (!of_get_property(node, "linux,no-autorepeat", NULL))
 431                 __set_bit(EV_REP, keypad->dev->evbit);
 432
 433         err = of_property_read_u32(node, "debounce-delay-ms",
 434                                    &keypad->debounce_ms);
 435         if (err) {
 436                 dev_err(&client->dev, "key debounce delay not specified\n");
 437                 goto err_fbdev_unregister;
 438         }
 439
 440         err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 441                                         ht16k33_irq_thread,
 442                                         IRQF_TRIGGER_RISING | IRQF_ONESHOT,
 443                                         DRIVER_NAME, priv);
 444         if (err) {
 445                 dev_err(&client->dev, "irq request failed %d, error %d\n",
 446                         client->irq, err);
 447                 goto err_fbdev_unregister;
 448         }
 449
 450         disable_irq_nosync(client->irq);
 451         rows = HT16K33_MATRIX_KEYPAD_MAX_ROWS;
 452         cols = HT16K33_MATRIX_KEYPAD_MAX_COLS;
 453         err = matrix_keypad_parse_of_params(&client->dev, &rows, &cols);
 454         if (err)
 455                 goto err_fbdev_unregister;
 456
 457         err = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL,
 458                                          keypad->dev);
 459         if (err) {
 460                 dev_err(&client->dev, "failed to build keymap\n");
 461                 goto err_fbdev_unregister;
 462         }
 463
 464         input_set_drvdata(keypad->dev, priv);
 465         keypad->rows = rows;
 466         keypad->cols = cols;
 467         keypad->row_shift = get_count_order(cols);
 468         INIT_DELAYED_WORK(&keypad->work, ht16k33_keypad_scan);
 469
 470         err = input_register_device(keypad->dev);
 471         if (err)
 472                 goto err_fbdev_unregister;
 473
 474         /* Backlight */
 475         memset(&bl_props, 0, sizeof(struct backlight_properties));
 476         bl_props.type = BACKLIGHT_RAW;
 477         bl_props.max_brightness = MAX_BRIGHTNESS;
 478
 479         bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl",
 480                                             &client->dev, priv,
 481                                             &ht16k33_bl_ops, &bl_props);
 482         if (IS_ERR(bl)) {
 483                 dev_err(&client->dev, "failed to register backlight\n");
 484                 err = PTR_ERR(bl);
 485                 goto err_keypad_unregister;
 486         }
 487
 488         err = of_property_read_u32(node, "default-brightness-level",
 489                                    &dft_brightness);
 490         if (err) {
 491                 dft_brightness = MAX_BRIGHTNESS;
 492         } else if (dft_brightness > MAX_BRIGHTNESS) {
 493                 dev_warn(&client->dev,
 494                          "invalid default brightness level: %u, using %u\n",
 495                          dft_brightness, MAX_BRIGHTNESS);
 496                 dft_brightness = MAX_BRIGHTNESS;
 497         }
 498
 499         bl->props.brightness = dft_brightness;
 500         ht16k33_bl_update_status(bl);
 501
 502         ht16k33_fb_queue(priv);
 503         return 0;
 504
 505 err_keypad_unregister:
 506         input_unregister_device(keypad->dev);
 507 err_fbdev_unregister:
 508         unregister_framebuffer(fbdev->info);
 509 err_fbdev_info:
 510         framebuffer_release(fbdev->info);
 511 err_fbdev_buffer:
 512         free_page((unsigned long) fbdev->buffer);
 513 err_free_fbdev:
 514         kfree(fbdev);
 515 err_destroy_wq:
 516         destroy_workqueue(priv->workqueue);
 517
 518         return err;
 519 }
 520
 521 static int ht16k33_remove(struct i2c_client *client)
 522 {
 523         struct ht16k33_priv *priv = i2c_get_clientdata(client);
 524         struct ht16k33_keypad *keypad = &priv->keypad;
 525         struct ht16k33_fbdev *fbdev = &priv->fbdev;
 526
 527         ht16k33_keypad_stop(keypad->dev);
 528
 529         cancel_delayed_work(&fbdev->work);
 530         unregister_framebuffer(fbdev->info);
 531         framebuffer_release(fbdev->info);
 532         free_page((unsigned long) fbdev->buffer);
 533
 534         destroy_workqueue(priv->workqueue);
 535         return 0;
 536 }
 537
 538 static const struct i2c_device_id ht16k33_i2c_match[] = {
 539         { "ht16k33", 0 },
 540         { }
 541 };
 542 MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match);
 543
 544 static const struct of_device_id ht16k33_of_match[] = {
 545         { .compatible = "holtek,ht16k33", },
 546         { }
 547 };
 548 MODULE_DEVICE_TABLE(of, ht16k33_of_match);
 549
 550 static struct i2c_driver ht16k33_driver = {
 551         .probe          = ht16k33_probe,
 552         .remove         = ht16k33_remove,
 553         .driver         = {
 554                 .name           = DRIVER_NAME,
 555                 .of_match_table = of_match_ptr(ht16k33_of_match),
 556         },
 557         .id_table = ht16k33_i2c_match,
 558 };
 559 module_i2c_driver(ht16k33_driver);
 560
 561 MODULE_DESCRIPTION("Holtek HT16K33 driver");
 562 MODULE_LICENSE("GPL");
 563 MODULE_AUTHOR("Robin van der Gracht <robin@protonic.nl>");