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 static int ht16k33_mmap(struct fb_info *info, struct vm_area_struct *vma)
 231 {
 232         struct ht16k33_priv *priv = info->par;
 233
 234         return vm_insert_page(vma, vma->vm_start,
 235                               virt_to_page(priv->fbdev.buffer));
 236 }
 237
 238 static struct fb_ops ht16k33_fb_ops = {
 239         .owner = THIS_MODULE,
 240         .fb_read = fb_sys_read,
 241         .fb_write = fb_sys_write,
 242         .fb_fillrect = sys_fillrect,
 243         .fb_copyarea = sys_copyarea,
 244         .fb_imageblit = sys_imageblit,
 245         .fb_mmap = ht16k33_mmap,
 246 };
 247
 248 /*
 249  * This gets the keys from keypad and reports it to input subsystem.
 250  * Returns true if a key is pressed.
 251  */
 252 static bool ht16k33_keypad_scan(struct ht16k33_keypad *keypad)
 253 {
 254         const unsigned short *keycodes = keypad->dev->keycode;
 255         u16 new_state[HT16K33_MATRIX_KEYPAD_MAX_COLS];
 256         __le16 data[HT16K33_MATRIX_KEYPAD_MAX_COLS];
 257         unsigned long bits_changed;
 258         int row, col, code;
 259         int rc;
 260         bool pressed = false;
 261
 262         rc = i2c_smbus_read_i2c_block_data(keypad->client, 0x40,
 263                                            sizeof(data), (u8 *)data);
 264         if (rc != sizeof(data)) {
 265                 dev_err(&keypad->client->dev,
 266                         "Failed to read key data, rc=%d\n", rc);
 267                 return false;
 268         }
 269
 270         for (col = 0; col < keypad->cols; col++) {
 271                 new_state[col] = le16_to_cpu(data[col]);
 272                 if (new_state[col])
 273                         pressed = true;
 274                 bits_changed = keypad->last_key_state[col] ^ new_state[col];
 275
 276                 for_each_set_bit(row, &bits_changed, BITS_PER_LONG) {
 277                         code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
 278                         input_event(keypad->dev, EV_MSC, MSC_SCAN, code);
 279                         input_report_key(keypad->dev, keycodes[code],
 280                                          new_state[col] & BIT(row));
 281                 }
 282         }
 283         input_sync(keypad->dev);
 284         memcpy(keypad->last_key_state, new_state, sizeof(u16) * keypad->cols);
 285
 286         return pressed;
 287 }
 288
 289 static irqreturn_t ht16k33_keypad_irq_thread(int irq, void *dev)
 290 {
 291         struct ht16k33_keypad *keypad = dev;
 292
 293         do {
 294                 wait_event_timeout(keypad->wait, keypad->stopped,
 295                                     msecs_to_jiffies(keypad->debounce_ms));
 296                 if (keypad->stopped)
 297                         break;
 298         } while (ht16k33_keypad_scan(keypad));
 299
 300         return IRQ_HANDLED;
 301 }
 302
 303 static int ht16k33_keypad_start(struct input_dev *dev)
 304 {
 305         struct ht16k33_keypad *keypad = input_get_drvdata(dev);
 306
 307         keypad->stopped = false;
 308         mb();
 309         enable_irq(keypad->client->irq);
 310
 311         return 0;
 312 }
 313
 314 static void ht16k33_keypad_stop(struct input_dev *dev)
 315 {
 316         struct ht16k33_keypad *keypad = input_get_drvdata(dev);
 317
 318         keypad->stopped = true;
 319         mb();
 320         wake_up(&keypad->wait);
 321         disable_irq(keypad->client->irq);
 322 }
 323
 324 static int ht16k33_keypad_probe(struct i2c_client *client,
 325                                 struct ht16k33_keypad *keypad)
 326 {
 327         struct device_node *node = client->dev.of_node;
 328         u32 rows = HT16K33_MATRIX_KEYPAD_MAX_ROWS;
 329         u32 cols = HT16K33_MATRIX_KEYPAD_MAX_COLS;
 330         int err;
 331
 332         keypad->client = client;
 333         init_waitqueue_head(&keypad->wait);
 334
 335         keypad->dev = devm_input_allocate_device(&client->dev);
 336         if (!keypad->dev)
 337                 return -ENOMEM;
 338
 339         input_set_drvdata(keypad->dev, keypad);
 340
 341         keypad->dev->name = DRIVER_NAME"-keypad";
 342         keypad->dev->id.bustype = BUS_I2C;
 343         keypad->dev->open = ht16k33_keypad_start;
 344         keypad->dev->close = ht16k33_keypad_stop;
 345
 346         if (!of_get_property(node, "linux,no-autorepeat", NULL))
 347                 __set_bit(EV_REP, keypad->dev->evbit);
 348
 349         err = of_property_read_u32(node, "debounce-delay-ms",
 350                                    &keypad->debounce_ms);
 351         if (err) {
 352                 dev_err(&client->dev, "key debounce delay not specified\n");
 353                 return err;
 354         }
 355
 356         err = matrix_keypad_parse_of_params(&client->dev, &rows, &cols);
 357         if (err)
 358                 return err;
 359         if (rows > HT16K33_MATRIX_KEYPAD_MAX_ROWS ||
 360             cols > HT16K33_MATRIX_KEYPAD_MAX_COLS) {
 361                 dev_err(&client->dev, "%u rows or %u cols out of range in DT\n",
 362                         rows, cols);
 363                 return -ERANGE;
 364         }
 365
 366         keypad->rows = rows;
 367         keypad->cols = cols;
 368         keypad->row_shift = get_count_order(cols);
 369
 370         err = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL,
 371                                          keypad->dev);
 372         if (err) {
 373                 dev_err(&client->dev, "failed to build keymap\n");
 374                 return err;
 375         }
 376
 377         err = devm_request_threaded_irq(&client->dev, client->irq,
 378                                         NULL, ht16k33_keypad_irq_thread,
 379                                         IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
 380                                         DRIVER_NAME, keypad);
 381         if (err) {
 382                 dev_err(&client->dev, "irq request failed %d, error %d\n",
 383                         client->irq, err);
 384                 return err;
 385         }
 386
 387         ht16k33_keypad_stop(keypad->dev);
 388
 389         err = input_register_device(keypad->dev);
 390         if (err)
 391                 return err;
 392
 393         return 0;
 394 }
 395
 396 static int ht16k33_probe(struct i2c_client *client,
 397                                   const struct i2c_device_id *id)
 398 {
 399         int err;
 400         uint32_t dft_brightness;
 401         struct backlight_device *bl;
 402         struct backlight_properties bl_props;
 403         struct ht16k33_priv *priv;
 404         struct ht16k33_fbdev *fbdev;
 405         struct device_node *node = client->dev.of_node;
 406
 407         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 408                 dev_err(&client->dev, "i2c_check_functionality error\n");
 409                 return -EIO;
 410         }
 411
 412         if (client->irq <= 0) {
 413                 dev_err(&client->dev, "No IRQ specified\n");
 414                 return -EINVAL;
 415         }
 416
 417         priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
 418         if (!priv)
 419                 return -ENOMEM;
 420
 421         priv->client = client;
 422         i2c_set_clientdata(client, priv);
 423         fbdev = &priv->fbdev;
 424
 425         err = ht16k33_initialize(priv);
 426         if (err)
 427                 return err;
 428
 429         /* Framebuffer (2 bytes per column) */
 430         BUILD_BUG_ON(PAGE_SIZE < HT16K33_FB_SIZE);
 431         fbdev->buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
 432         if (!fbdev->buffer)
 433                 return -ENOMEM;
 434
 435         fbdev->cache = devm_kmalloc(&client->dev, HT16K33_FB_SIZE, GFP_KERNEL);
 436         if (!fbdev->cache) {
 437                 err = -ENOMEM;
 438                 goto err_fbdev_buffer;
 439         }
 440
 441         fbdev->info = framebuffer_alloc(0, &client->dev);
 442         if (!fbdev->info) {
 443                 err = -ENOMEM;
 444                 goto err_fbdev_buffer;
 445         }
 446
 447         err = of_property_read_u32(node, "refresh-rate-hz",
 448                 &fbdev->refresh_rate);
 449         if (err) {
 450                 dev_err(&client->dev, "refresh rate not specified\n");
 451                 goto err_fbdev_info;
 452         }
 453         fb_bl_default_curve(fbdev->info, 0, MIN_BRIGHTNESS, MAX_BRIGHTNESS);
 454
 455         INIT_DELAYED_WORK(&fbdev->work, ht16k33_fb_update);
 456         fbdev->info->fbops = &ht16k33_fb_ops;
 457         fbdev->info->screen_base = (char __iomem *) fbdev->buffer;
 458         fbdev->info->screen_size = HT16K33_FB_SIZE;
 459         fbdev->info->fix = ht16k33_fb_fix;
 460         fbdev->info->var = ht16k33_fb_var;
 461         fbdev->info->pseudo_palette = NULL;
 462         fbdev->info->flags = FBINFO_FLAG_DEFAULT;
 463         fbdev->info->par = priv;
 464
 465         err = register_framebuffer(fbdev->info);
 466         if (err)
 467                 goto err_fbdev_info;
 468
 469         err = ht16k33_keypad_probe(client, &priv->keypad);
 470         if (err)
 471                 goto err_fbdev_unregister;
 472
 473         /* Backlight */
 474         memset(&bl_props, 0, sizeof(struct backlight_properties));
 475         bl_props.type = BACKLIGHT_RAW;
 476         bl_props.max_brightness = MAX_BRIGHTNESS;
 477
 478         bl = devm_backlight_device_register(&client->dev, DRIVER_NAME"-bl",
 479                                             &client->dev, priv,
 480                                             &ht16k33_bl_ops, &bl_props);
 481         if (IS_ERR(bl)) {
 482                 dev_err(&client->dev, "failed to register backlight\n");
 483                 err = PTR_ERR(bl);
 484                 goto err_fbdev_unregister;
 485         }
 486
 487         err = of_property_read_u32(node, "default-brightness-level",
 488                                    &dft_brightness);
 489         if (err) {
 490                 dft_brightness = MAX_BRIGHTNESS;
 491         } else if (dft_brightness > MAX_BRIGHTNESS) {
 492                 dev_warn(&client->dev,
 493                          "invalid default brightness level: %u, using %u\n",
 494                          dft_brightness, MAX_BRIGHTNESS);
 495                 dft_brightness = MAX_BRIGHTNESS;
 496         }
 497
 498         bl->props.brightness = dft_brightness;
 499         ht16k33_bl_update_status(bl);
 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>");