drivers/leds/leds-turris-omnia.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * CZ.NIC's Turris Omnia LEDs driver
   4  *
   5  * 2020, 2023 by Marek Behún <kabel@kernel.org>
   6  */
   7
   8 #include <linux/i2c.h>
   9 #include <linux/led-class-multicolor.h>
  10 #include <linux/module.h>
  11 #include <linux/mutex.h>
  12 #include <linux/of.h>
  13
  14 #define OMNIA_BOARD_LEDS        12
  15 #define OMNIA_LED_NUM_CHANNELS  3
  16
  17 /* MCU controller commands at I2C address 0x2a */
  18 #define OMNIA_MCU_I2C_ADDR              0x2a
  19
  20 #define CMD_GET_STATUS_WORD             0x01
  21 #define STS_FEATURES_SUPPORTED          BIT(2)
  22
  23 #define CMD_GET_FEATURES                0x10
  24 #define FEAT_LED_GAMMA_CORRECTION       BIT(5)
  25
  26 /* LED controller commands at I2C address 0x2b */
  27 #define CMD_LED_MODE                    0x03
  28 #define CMD_LED_MODE_LED(l)             ((l) & 0x0f)
  29 #define CMD_LED_MODE_USER               0x10
  30
  31 #define CMD_LED_STATE                   0x04
  32 #define CMD_LED_STATE_LED(l)            ((l) & 0x0f)
  33 #define CMD_LED_STATE_ON                0x10
  34
  35 #define CMD_LED_COLOR                   0x05
  36 #define CMD_LED_SET_BRIGHTNESS          0x07
  37 #define CMD_LED_GET_BRIGHTNESS          0x08
  38
  39 #define CMD_SET_GAMMA_CORRECTION        0x30
  40 #define CMD_GET_GAMMA_CORRECTION        0x31
  41
  42 struct omnia_led {
  43         struct led_classdev_mc mc_cdev;
  44         struct mc_subled subled_info[OMNIA_LED_NUM_CHANNELS];
  45         u8 cached_channels[OMNIA_LED_NUM_CHANNELS];
  46         bool on, hwtrig;
  47         int reg;
  48 };
  49
  50 #define to_omnia_led(l)         container_of(l, struct omnia_led, mc_cdev)
  51
  52 struct omnia_leds {
  53         struct i2c_client *client;
  54         struct mutex lock;
  55         bool has_gamma_correction;
  56         struct omnia_led leds[];
  57 };
  58
  59 static int omnia_cmd_write_u8(const struct i2c_client *client, u8 cmd, u8 val)
  60 {
  61         u8 buf[2] = { cmd, val };
  62         int ret;
  63
  64         ret = i2c_master_send(client, buf, sizeof(buf));
  65
  66         return ret < 0 ? ret : 0;
  67 }
  68
  69 static int omnia_cmd_read_raw(struct i2c_adapter *adapter, u8 addr, u8 cmd,
  70                               void *reply, size_t len)
  71 {
  72         struct i2c_msg msgs[2];
  73         int ret;
  74
  75         msgs[0].addr = addr;
  76         msgs[0].flags = 0;
  77         msgs[0].len = 1;
  78         msgs[0].buf = &cmd;
  79         msgs[1].addr = addr;
  80         msgs[1].flags = I2C_M_RD;
  81         msgs[1].len = len;
  82         msgs[1].buf = reply;
  83
  84         ret = i2c_transfer(adapter, msgs, ARRAY_SIZE(msgs));
  85         if (likely(ret == ARRAY_SIZE(msgs)))
  86                 return 0;
  87         else if (ret < 0)
  88                 return ret;
  89         else
  90                 return -EIO;
  91 }
  92
  93 static int omnia_cmd_read_u8(const struct i2c_client *client, u8 cmd)
  94 {
  95         u8 reply;
  96         int err;
  97
  98         err = omnia_cmd_read_raw(client->adapter, client->addr, cmd, &reply, 1);
  99         if (err)
 100                 return err;
 101
 102         return reply;
 103 }
 104
 105 static int omnia_led_send_color_cmd(const struct i2c_client *client,
 106                                     struct omnia_led *led)
 107 {
 108         char cmd[5];
 109         int ret;
 110
 111         cmd[0] = CMD_LED_COLOR;
 112         cmd[1] = led->reg;
 113         cmd[2] = led->subled_info[0].brightness;
 114         cmd[3] = led->subled_info[1].brightness;
 115         cmd[4] = led->subled_info[2].brightness;
 116
 117         /* Send the color change command */
 118         ret = i2c_master_send(client, cmd, 5);
 119         if (ret < 0)
 120                 return ret;
 121
 122         /* Cache the RGB channel brightnesses */
 123         for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i)
 124                 led->cached_channels[i] = led->subled_info[i].brightness;
 125
 126         return 0;
 127 }
 128
 129 /* Determine if the computed RGB channels are different from the cached ones */
 130 static bool omnia_led_channels_changed(struct omnia_led *led)
 131 {
 132         for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i)
 133                 if (led->subled_info[i].brightness != led->cached_channels[i])
 134                         return true;
 135
 136         return false;
 137 }
 138
 139 static int omnia_led_brightness_set_blocking(struct led_classdev *cdev,
 140                                              enum led_brightness brightness)
 141 {
 142         struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
 143         struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
 144         struct omnia_led *led = to_omnia_led(mc_cdev);
 145         int err = 0;
 146
 147         mutex_lock(&leds->lock);
 148
 149         /*
 150          * Only recalculate RGB brightnesses from intensities if brightness is
 151          * non-zero (if it is zero and the LED is in HW blinking mode, we use
 152          * max_brightness as brightness). Otherwise we won't be using them and
 153          * we can save ourselves some software divisions (Omnia's CPU does not
 154          * implement the division instruction).
 155          */
 156         if (brightness || led->hwtrig) {
 157                 led_mc_calc_color_components(mc_cdev, brightness ?:
 158                                                       cdev->max_brightness);
 159
 160                 /*
 161                  * Send color command only if brightness is non-zero and the RGB
 162                  * channel brightnesses changed.
 163                  */
 164                 if (omnia_led_channels_changed(led))
 165                         err = omnia_led_send_color_cmd(leds->client, led);
 166         }
 167
 168         /*
 169          * Send on/off state change only if (bool)brightness changed and the LED
 170          * is not being blinked by HW.
 171          */
 172         if (!err && !led->hwtrig && !brightness != !led->on) {
 173                 u8 state = CMD_LED_STATE_LED(led->reg);
 174
 175                 if (brightness)
 176                         state |= CMD_LED_STATE_ON;
 177
 178                 err = omnia_cmd_write_u8(leds->client, CMD_LED_STATE, state);
 179                 if (!err)
 180                         led->on = !!brightness;
 181         }
 182
 183         mutex_unlock(&leds->lock);
 184
 185         return err;
 186 }
 187
 188 static struct led_hw_trigger_type omnia_hw_trigger_type;
 189
 190 static int omnia_hwtrig_activate(struct led_classdev *cdev)
 191 {
 192         struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
 193         struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
 194         struct omnia_led *led = to_omnia_led(mc_cdev);
 195         int err = 0;
 196
 197         mutex_lock(&leds->lock);
 198
 199         if (!led->on) {
 200                 /*
 201                  * If the LED is off (brightness was set to 0), the last
 202                  * configured color was not necessarily sent to the MCU.
 203                  * Recompute with max_brightness and send if needed.
 204                  */
 205                 led_mc_calc_color_components(mc_cdev, cdev->max_brightness);
 206
 207                 if (omnia_led_channels_changed(led))
 208                         err = omnia_led_send_color_cmd(leds->client, led);
 209         }
 210
 211         if (!err) {
 212                 /* Put the LED into MCU controlled mode */
 213                 err = omnia_cmd_write_u8(leds->client, CMD_LED_MODE,
 214                                          CMD_LED_MODE_LED(led->reg));
 215                 if (!err)
 216                         led->hwtrig = true;
 217         }
 218
 219         mutex_unlock(&leds->lock);
 220
 221         return err;
 222 }
 223
 224 static void omnia_hwtrig_deactivate(struct led_classdev *cdev)
 225 {
 226         struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
 227         struct omnia_led *led = to_omnia_led(lcdev_to_mccdev(cdev));
 228         int err;
 229
 230         mutex_lock(&leds->lock);
 231
 232         led->hwtrig = false;
 233
 234         /* Put the LED into software mode */
 235         err = omnia_cmd_write_u8(leds->client, CMD_LED_MODE,
 236                                  CMD_LED_MODE_LED(led->reg) |
 237                                  CMD_LED_MODE_USER);
 238
 239         mutex_unlock(&leds->lock);
 240
 241         if (err)
 242                 dev_err(cdev->dev, "Cannot put LED to software mode: %i\n",
 243                         err);
 244 }
 245
 246 static struct led_trigger omnia_hw_trigger = {
 247         .name           = "omnia-mcu",
 248         .activate       = omnia_hwtrig_activate,
 249         .deactivate     = omnia_hwtrig_deactivate,
 250         .trigger_type   = &omnia_hw_trigger_type,
 251 };
 252
 253 static int omnia_led_register(struct i2c_client *client, struct omnia_led *led,
 254                               struct device_node *np)
 255 {
 256         struct led_init_data init_data = {};
 257         struct device *dev = &client->dev;
 258         struct led_classdev *cdev;
 259         int ret, color;
 260
 261         ret = of_property_read_u32(np, "reg", &led->reg);
 262         if (ret || led->reg >= OMNIA_BOARD_LEDS) {
 263                 dev_warn(dev,
 264                          "Node %pOF: must contain 'reg' property with values between 0 and %i\n",
 265                          np, OMNIA_BOARD_LEDS - 1);
 266                 return 0;
 267         }
 268
 269         ret = of_property_read_u32(np, "color", &color);
 270         if (ret || color != LED_COLOR_ID_RGB) {
 271                 dev_warn(dev,
 272                          "Node %pOF: must contain 'color' property with value LED_COLOR_ID_RGB\n",
 273                          np);
 274                 return 0;
 275         }
 276
 277         led->subled_info[0].color_index = LED_COLOR_ID_RED;
 278         led->subled_info[1].color_index = LED_COLOR_ID_GREEN;
 279         led->subled_info[2].color_index = LED_COLOR_ID_BLUE;
 280
 281         /* Initial color is white */
 282         for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i) {
 283                 led->subled_info[i].intensity = 255;
 284                 led->subled_info[i].brightness = 255;
 285                 led->subled_info[i].channel = i;
 286         }
 287
 288         led->mc_cdev.subled_info = led->subled_info;
 289         led->mc_cdev.num_colors = OMNIA_LED_NUM_CHANNELS;
 290
 291         init_data.fwnode = &np->fwnode;
 292
 293         cdev = &led->mc_cdev.led_cdev;
 294         cdev->max_brightness = 255;
 295         cdev->brightness_set_blocking = omnia_led_brightness_set_blocking;
 296         cdev->trigger_type = &omnia_hw_trigger_type;
 297         /*
 298          * Use the omnia-mcu trigger as the default trigger. It may be rewritten
 299          * by LED class from the linux,default-trigger property.
 300          */
 301         cdev->default_trigger = omnia_hw_trigger.name;
 302
 303         /* put the LED into software mode */
 304         ret = omnia_cmd_write_u8(client, CMD_LED_MODE,
 305                                  CMD_LED_MODE_LED(led->reg) |
 306                                  CMD_LED_MODE_USER);
 307         if (ret) {
 308                 dev_err(dev, "Cannot set LED %pOF to software mode: %i\n", np,
 309                         ret);
 310                 return ret;
 311         }
 312
 313         /* disable the LED */
 314         ret = omnia_cmd_write_u8(client, CMD_LED_STATE,
 315                                  CMD_LED_STATE_LED(led->reg));
 316         if (ret) {
 317                 dev_err(dev, "Cannot set LED %pOF brightness: %i\n", np, ret);
 318                 return ret;
 319         }
 320
 321         /* Set initial color and cache it */
 322         ret = omnia_led_send_color_cmd(client, led);
 323         if (ret < 0) {
 324                 dev_err(dev, "Cannot set LED %pOF initial color: %i\n", np,
 325                         ret);
 326                 return ret;
 327         }
 328
 329         ret = devm_led_classdev_multicolor_register_ext(dev, &led->mc_cdev,
 330                                                         &init_data);
 331         if (ret < 0) {
 332                 dev_err(dev, "Cannot register LED %pOF: %i\n", np, ret);
 333                 return ret;
 334         }
 335
 336         return 1;
 337 }
 338
 339 /*
 340  * On the front panel of the Turris Omnia router there is also a button which
 341  * can be used to control the intensity of all the LEDs at once, so that if they
 342  * are too bright, user can dim them.
 343  * The microcontroller cycles between 8 levels of this global brightness (from
 344  * 100% to 0%), but this setting can have any integer value between 0 and 100.
 345  * It is therefore convenient to be able to change this setting from software.
 346  * We expose this setting via a sysfs attribute file called "brightness". This
 347  * file lives in the device directory of the LED controller, not an individual
 348  * LED, so it should not confuse users.
 349  */
 350 static ssize_t brightness_show(struct device *dev, struct device_attribute *a,
 351                                char *buf)
 352 {
 353         struct i2c_client *client = to_i2c_client(dev);
 354         int ret;
 355
 356         ret = omnia_cmd_read_u8(client, CMD_LED_GET_BRIGHTNESS);
 357
 358         if (ret < 0)
 359                 return ret;
 360
 361         return sysfs_emit(buf, "%d\n", ret);
 362 }
 363
 364 static ssize_t brightness_store(struct device *dev, struct device_attribute *a,
 365                                 const char *buf, size_t count)
 366 {
 367         struct i2c_client *client = to_i2c_client(dev);
 368         unsigned long brightness;
 369         int err;
 370
 371         if (kstrtoul(buf, 10, &brightness))
 372                 return -EINVAL;
 373
 374         if (brightness > 100)
 375                 return -EINVAL;
 376
 377         err = omnia_cmd_write_u8(client, CMD_LED_SET_BRIGHTNESS, brightness);
 378
 379         return err ?: count;
 380 }
 381 static DEVICE_ATTR_RW(brightness);
 382
 383 static ssize_t gamma_correction_show(struct device *dev,
 384                                      struct device_attribute *a, char *buf)
 385 {
 386         struct i2c_client *client = to_i2c_client(dev);
 387         struct omnia_leds *leds = i2c_get_clientdata(client);
 388         int ret;
 389
 390         if (leds->has_gamma_correction) {
 391                 ret = omnia_cmd_read_u8(client, CMD_GET_GAMMA_CORRECTION);
 392                 if (ret < 0)
 393                         return ret;
 394         } else {
 395                 ret = 0;
 396         }
 397
 398         return sysfs_emit(buf, "%d\n", !!ret);
 399 }
 400
 401 static ssize_t gamma_correction_store(struct device *dev,
 402                                       struct device_attribute *a,
 403                                       const char *buf, size_t count)
 404 {
 405         struct i2c_client *client = to_i2c_client(dev);
 406         struct omnia_leds *leds = i2c_get_clientdata(client);
 407         bool val;
 408         int err;
 409
 410         if (!leds->has_gamma_correction)
 411                 return -EOPNOTSUPP;
 412
 413         if (kstrtobool(buf, &val) < 0)
 414                 return -EINVAL;
 415
 416         err = omnia_cmd_write_u8(client, CMD_SET_GAMMA_CORRECTION, val);
 417
 418         return err ?: count;
 419 }
 420 static DEVICE_ATTR_RW(gamma_correction);
 421
 422 static struct attribute *omnia_led_controller_attrs[] = {
 423         &dev_attr_brightness.attr,
 424         &dev_attr_gamma_correction.attr,
 425         NULL,
 426 };
 427 ATTRIBUTE_GROUPS(omnia_led_controller);
 428
 429 static int omnia_mcu_get_features(const struct i2c_client *client)
 430 {
 431         u16 reply;
 432         int err;
 433
 434         err = omnia_cmd_read_raw(client->adapter, OMNIA_MCU_I2C_ADDR,
 435                                  CMD_GET_STATUS_WORD, &reply, sizeof(reply));
 436         if (err)
 437                 return err;
 438
 439         /* Check whether MCU firmware supports the CMD_GET_FEAUTRES command */
 440         if (!(le16_to_cpu(reply) & STS_FEATURES_SUPPORTED))
 441                 return 0;
 442
 443         err = omnia_cmd_read_raw(client->adapter, OMNIA_MCU_I2C_ADDR,
 444                                  CMD_GET_FEATURES, &reply, sizeof(reply));
 445         if (err)
 446                 return err;
 447
 448         return le16_to_cpu(reply);
 449 }
 450
 451 static int omnia_leds_probe(struct i2c_client *client)
 452 {
 453         struct device *dev = &client->dev;
 454         struct device_node *np = dev_of_node(dev);
 455         struct omnia_leds *leds;
 456         struct omnia_led *led;
 457         int ret, count;
 458
 459         count = of_get_available_child_count(np);
 460         if (!count) {
 461                 dev_err(dev, "LEDs are not defined in device tree!\n");
 462                 return -ENODEV;
 463         } else if (count > OMNIA_BOARD_LEDS) {
 464                 dev_err(dev, "Too many LEDs defined in device tree!\n");
 465                 return -EINVAL;
 466         }
 467
 468         leds = devm_kzalloc(dev, struct_size(leds, leds, count), GFP_KERNEL);
 469         if (!leds)
 470                 return -ENOMEM;
 471
 472         leds->client = client;
 473         i2c_set_clientdata(client, leds);
 474
 475         ret = omnia_mcu_get_features(client);
 476         if (ret < 0) {
 477                 dev_err(dev, "Cannot determine MCU supported features: %d\n",
 478                         ret);
 479                 return ret;
 480         }
 481
 482         leds->has_gamma_correction = ret & FEAT_LED_GAMMA_CORRECTION;
 483         if (!leds->has_gamma_correction) {
 484                 dev_info(dev,
 485                          "Your board's MCU firmware does not support the LED gamma correction feature.\n");
 486                 dev_info(dev,
 487                          "Consider upgrading MCU firmware with the omnia-mcutool utility.\n");
 488         }
 489
 490         mutex_init(&leds->lock);
 491
 492         ret = devm_led_trigger_register(dev, &omnia_hw_trigger);
 493         if (ret < 0) {
 494                 dev_err(dev, "Cannot register private LED trigger: %d\n", ret);
 495                 return ret;
 496         }
 497
 498         led = &leds->leds[0];
 499         for_each_available_child_of_node_scoped(np, child) {
 500                 ret = omnia_led_register(client, led, child);
 501                 if (ret < 0)
 502                         return ret;
 503
 504                 led += ret;
 505         }
 506
 507         return 0;
 508 }
 509
 510 static void omnia_leds_remove(struct i2c_client *client)
 511 {
 512         u8 buf[5];
 513
 514         /* put all LEDs into default (HW triggered) mode */
 515         omnia_cmd_write_u8(client, CMD_LED_MODE,
 516                            CMD_LED_MODE_LED(OMNIA_BOARD_LEDS));
 517
 518         /* set all LEDs color to [255, 255, 255] */
 519         buf[0] = CMD_LED_COLOR;
 520         buf[1] = OMNIA_BOARD_LEDS;
 521         buf[2] = 255;
 522         buf[3] = 255;
 523         buf[4] = 255;
 524
 525         i2c_master_send(client, buf, 5);
 526 }
 527
 528 static const struct of_device_id of_omnia_leds_match[] = {
 529         { .compatible = "cznic,turris-omnia-leds", },
 530         {},
 531 };
 532 MODULE_DEVICE_TABLE(of, of_omnia_leds_match);
 533
 534 static const struct i2c_device_id omnia_id[] = {
 535         { "omnia" },
 536         { }
 537 };
 538 MODULE_DEVICE_TABLE(i2c, omnia_id);
 539
 540 static struct i2c_driver omnia_leds_driver = {
 541         .probe          = omnia_leds_probe,
 542         .remove         = omnia_leds_remove,
 543         .id_table       = omnia_id,
 544         .driver         = {
 545                 .name   = "leds-turris-omnia",
 546                 .of_match_table = of_omnia_leds_match,
 547                 .dev_groups = omnia_led_controller_groups,
 548         },
 549 };
 550
 551 module_i2c_driver(omnia_leds_driver);
 552
 553 MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");
 554 MODULE_DESCRIPTION("CZ.NIC's Turris Omnia LEDs");
 555 MODULE_LICENSE("GPL v2");