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,
 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(new_state));
 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
 357         keypad->rows = rows;
 358         keypad->cols = cols;
 359         keypad->row_shift = get_count_order(cols);
 360
 361         err = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL,
 362                                          keypad->dev);
 363         if (err) {
 364                 dev_err(&client->dev, "failed to build keymap\n");
 365                 return err;
 366         }
 367
 368         err = devm_request_threaded_irq(&client->dev, client->irq,
 369                                         NULL, ht16k33_keypad_irq_thread,
 370                                         IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
 371                                         DRIVER_NAME, keypad);
 372         if (err) {
 373                 dev_err(&client->dev, "irq request failed %d, error %d\n",
 374                         client->irq, err);
 375                 return err;
 376         }
 377
 378         ht16k33_keypad_stop(keypad->dev);
 379
 380         err = input_register_device(keypad->dev);
 381         if (err)
 382                 return err;
 383
 384         return 0;
 385 }
 386
 387 static int ht16k33_probe(struct i2c_client *client,
 388                                   const struct i2c_device_id *id)
 389 {
 390         int err;
 391         uint32_t dft_brightness;
 392         struct backlight_device *bl;
 393         struct backlight_properties bl_props;
 394         struct ht16k33_priv *priv;
 395         struct ht16k33_fbdev *fbdev;
 396         struct device_node *node = client->dev.of_node;
 397
 398         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 399                 dev_err(&client->dev, "i2c_check_functionality error\n");
 400                 return -EIO;
 401         }
 402
 403         if (client->irq <= 0) {
 404                 dev_err(&client->dev, "No IRQ specified\n");
 405                 return -EINVAL;
 406         }
 407
 408         priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
 409         if (!priv)
 410                 return -ENOMEM;
 411
 412         priv->client = client;
 413         i2c_set_clientdata(client, priv);
 414         fbdev = &priv->fbdev;
 415
 416         err = ht16k33_initialize(priv);
 417         if (err)
 418                 return err;
 419
 420         /* Framebuffer (2 bytes per column) */
 421         BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE);
 422         fbdev->buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
 423         if (!fbdev->buffer)
 424                 return -ENOMEM;
 425
 426         fbdev->cache = devm_kmalloc(&client->dev, HT16K33_FB_SIZE, GFP_KERNEL);
 427         if (!fbdev->cache) {
 428                 err = -ENOMEM;
 429                 goto err_fbdev_buffer;
 430         }
 431
 432         fbdev->info = framebuffer_alloc(0, &client->dev);
 433         if (!fbdev->info) {
 434                 err = -ENOMEM;
 435                 goto err_fbdev_buffer;
 436         }
 437
 438         err = of_property_read_u32(node, "refresh-rate-hz",
 439                 &fbdev->refresh_rate);
 440         if (err) {
 441                 dev_err(&client->dev, "refresh rate not specified\n");
 442                 goto err_fbdev_info;
 443         }
 444         fb_bl_default_curve(fbdev->info, 0, MIN_BRIGHTNESS, MAX_BRIGHTNESS);
 445
 446         INIT_DELAYED_WORK(&fbdev->work, ht16k33_fb_update);
 447         fbdev->info->fbops = &ht16k33_fb_ops;
 448         fbdev->info->screen_base = (char __iomem *) fbdev->buffer;
 449         fbdev->info->screen_size = HT16K33_FB_SIZE;
 450         fbdev->info->fix = ht16k33_fb_fix;
 451         fbdev->info->var = ht16k33_fb_var;
 452         fbdev->info->pseudo_palette = NULL;
 453         fbdev->info->flags = FBINFO_FLAG_DEFAULT;
 454         fbdev->info->par = priv;
 455
 456         err = register_framebuffer(fbdev->info);
 457         if (err)
 458                 goto err_fbdev_info;
 459
 460         err = ht16k33_keypad_probe(client, &priv->keypad);
 461         if (err)
 462                 goto err_fbdev_unregister;
 463
 464         /* Backlight */
 465         memset(&bl_props, 0, sizeof(struct backlight_properties));
 466         bl_props.type = BACKLIGHT_RAW;
 467         bl_props.max_brightness = MAX_BRIGHTNESS;
 468
 469         bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl",
 470                                             &client->dev, priv,
 471                                             &ht16k33_bl_ops, &bl_props);
 472         if (IS_ERR(bl)) {
 473                 dev_err(&client->dev, "failed to register backlight\n");
 474                 err = PTR_ERR(bl);
 475                 goto err_fbdev_unregister;
 476         }
 477
 478         err = of_property_read_u32(node, "default-brightness-level",
 479                                    &dft_brightness);
 480         if (err) {
 481                 dft_brightness = MAX_BRIGHTNESS;
 482         } else if (dft_brightness > MAX_BRIGHTNESS) {
 483                 dev_warn(&client->dev,
 484                          "invalid default brightness level: %u, using %u\n",
 485                          dft_brightness, MAX_BRIGHTNESS);
 486                 dft_brightness = MAX_BRIGHTNESS;
 487         }
 488
 489         bl->props.brightness = dft_brightness;
 490         ht16k33_bl_update_status(bl);
 491
 492         ht16k33_fb_queue(priv);
 493         return 0;
 494
 495 err_fbdev_unregister:
 496         unregister_framebuffer(fbdev->info);
 497 err_fbdev_info:
 498         framebuffer_release(fbdev->info);
 499 err_fbdev_buffer:
 500         free_page((unsigned long) fbdev->buffer);
 501
 502         return err;
 503 }
 504
 505 static int ht16k33_remove(struct i2c_client *client)
 506 {
 507         struct ht16k33_priv *priv = i2c_get_clientdata(client);
 508         struct ht16k33_fbdev *fbdev = &priv->fbdev;
 509
 510         cancel_delayed_work(&fbdev->work);
 511         unregister_framebuffer(fbdev->info);
 512         framebuffer_release(fbdev->info);
 513         free_page((unsigned long) fbdev->buffer);
 514
 515         return 0;
 516 }
 517
 518 static const struct i2c_device_id ht16k33_i2c_match[] = {
 519         { "ht16k33", 0 },
 520         { }
 521 };
 522 MODULE_DEVICE_TABLE(i2c, ht16k33_i2c_match);
 523
 524 static const struct of_device_id ht16k33_of_match[] = {
 525         { .compatible = "holtek,ht16k33", },
 526         { }
 527 };
 528 MODULE_DEVICE_TABLE(of, ht16k33_of_match);
 529
 530 static struct i2c_driver ht16k33_driver = {
 531         .probe          = ht16k33_probe,
 532         .remove         = ht16k33_remove,
 533         .driver         = {
 534                 .name           = DRIVER_NAME,
 535                 .of_match_table = of_match_ptr(ht16k33_of_match),
 536         },
 537         .id_table = ht16k33_i2c_match,
 538 };
 539 module_i2c_driver(ht16k33_driver);
 540
 541 MODULE_DESCRIPTION("Holtek HT16K33 driver");
 542 MODULE_LICENSE("GPL");
 543 MODULE_AUTHOR("Robin van der Gracht <robin@protonic.nl>");