drivers/leds/leds-pca955x.c:590:43: warning: '%d' directive output may be truncated writing between 1 and 11 bytes into a region of size 8

From: kernel test robot
Date: Sat Jan 06 2024 - 02:33:04 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 95c8a35f1c017327eab3b6a2ff5c04255737c856
commit: 7c4815929276b2e223eb6f2e49afe5071d4294a5 leds: pca955x: Let the core process the fwnode
date: 2 years, 5 months ago
config: x86_64-randconfig-006-20240105 (https://download.01.org/0day-ci/archive/20240106/202401061544.q6p3WSvR-lkp@xxxxxxxxx/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240106/202401061544.q6p3WSvR-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202401061544.q6p3WSvR-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

drivers/leds/leds-pca955x.c: In function 'pca955x_probe':
>> drivers/leds/leds-pca955x.c:590:43: warning: '%d' directive output may be truncated writing between 1 and 11 bytes into a region of size 8 [-Wformat-truncation=]
590 | "%d", i);
| ^~
drivers/leds/leds-pca955x.c:590:42: note: directive argument in the range [-2147483644, 2147483646]
590 | "%d", i);
| ^~~~
drivers/leds/leds-pca955x.c:589:33: note: 'snprintf' output between 2 and 12 bytes into a destination of size 8
589 | snprintf(default_label, sizeof(default_label),
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
590 | "%d", i);
| ~~~~~~~~


vim +590 drivers/leds/leds-pca955x.c

481
482 static int pca955x_probe(struct i2c_client *client,
483 const struct i2c_device_id *id)
484 {
485 struct pca955x *pca955x;
486 struct pca955x_led *pca955x_led;
487 struct pca955x_chipdef *chip;
488 struct led_classdev *led;
489 struct led_init_data init_data;
490 struct i2c_adapter *adapter;
491 int i, err;
492 struct pca955x_platform_data *pdata;
493 int ngpios = 0;
494 bool set_default_label = false;
495 bool keep_pwm = false;
496 char default_label[8];
497
498 chip = &pca955x_chipdefs[id->driver_data];
499 adapter = client->adapter;
500 pdata = dev_get_platdata(&client->dev);
501 if (!pdata) {
502 pdata = pca955x_get_pdata(client, chip);
503 if (IS_ERR(pdata))
504 return PTR_ERR(pdata);
505 }
506
507 /* Make sure the slave address / chip type combo given is possible */
508 if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
509 chip->slv_addr) {
510 dev_err(&client->dev, "invalid slave address %02x\n",
511 client->addr);
512 return -ENODEV;
513 }
514
515 dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
516 "slave address 0x%02x\n", client->name, chip->bits,
517 client->addr);
518
519 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
520 return -EIO;
521
522 if (pdata->num_leds != chip->bits) {
523 dev_err(&client->dev,
524 "board info claims %d LEDs on a %d-bit chip\n",
525 pdata->num_leds, chip->bits);
526 return -ENODEV;
527 }
528
529 pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
530 if (!pca955x)
531 return -ENOMEM;
532
533 pca955x->leds = devm_kcalloc(&client->dev, chip->bits,
534 sizeof(*pca955x_led), GFP_KERNEL);
535 if (!pca955x->leds)
536 return -ENOMEM;
537
538 i2c_set_clientdata(client, pca955x);
539
540 mutex_init(&pca955x->lock);
541 pca955x->client = client;
542 pca955x->chipdef = chip;
543
544 init_data.devname_mandatory = false;
545 init_data.devicename = "pca955x";
546
547 for (i = 0; i < chip->bits; i++) {
548 pca955x_led = &pca955x->leds[i];
549 pca955x_led->led_num = i;
550 pca955x_led->pca955x = pca955x;
551 pca955x_led->type = pdata->leds[i].type;
552
553 switch (pca955x_led->type) {
554 case PCA955X_TYPE_NONE:
555 break;
556 case PCA955X_TYPE_GPIO:
557 ngpios++;
558 break;
559 case PCA955X_TYPE_LED:
560 led = &pca955x_led->led_cdev;
561 led->brightness_set_blocking = pca955x_led_set;
562 led->brightness_get = pca955x_led_get;
563
564 if (pdata->leds[i].default_state ==
565 LEDS_GPIO_DEFSTATE_OFF) {
566 err = pca955x_led_set(led, LED_OFF);
567 if (err)
568 return err;
569 } else if (pdata->leds[i].default_state ==
570 LEDS_GPIO_DEFSTATE_ON) {
571 err = pca955x_led_set(led, LED_FULL);
572 if (err)
573 return err;
574 }
575
576 init_data.fwnode = pdata->leds[i].fwnode;
577
578 if (is_of_node(init_data.fwnode)) {
579 if (to_of_node(init_data.fwnode)->name[0] ==
580 '\0')
581 set_default_label = true;
582 else
583 set_default_label = false;
584 } else {
585 set_default_label = true;
586 }
587
588 if (set_default_label) {
589 snprintf(default_label, sizeof(default_label),
> 590 "%d", i);
591 init_data.default_label = default_label;
592 } else {
593 init_data.default_label = NULL;
594 }
595
596 err = devm_led_classdev_register_ext(&client->dev, led,
597 &init_data);
598 if (err)
599 return err;
600
601 /*
602 * For default-state == "keep", let the core update the
603 * brightness from the hardware, then check the
604 * brightness to see if it's using PWM1. If so, PWM1
605 * should not be written below.
606 */
607 if (pdata->leds[i].default_state ==
608 LEDS_GPIO_DEFSTATE_KEEP) {
609 if (led->brightness != LED_FULL &&
610 led->brightness != LED_OFF &&
611 led->brightness != LED_HALF)
612 keep_pwm = true;
613 }
614 }
615 }
616
617 /* PWM0 is used for half brightness or 50% duty cycle */
618 err = pca955x_write_pwm(client, 0, 255 - LED_HALF);
619 if (err)
620 return err;
621
622 if (!keep_pwm) {
623 /* PWM1 is used for variable brightness, default to OFF */
624 err = pca955x_write_pwm(client, 1, 0);
625 if (err)
626 return err;
627 }
628
629 /* Set to fast frequency so we do not see flashing */
630 err = pca955x_write_psc(client, 0, 0);
631 if (err)
632 return err;
633 err = pca955x_write_psc(client, 1, 0);
634 if (err)
635 return err;
636

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https://github.com/intel/lkp-tests/wiki