samples: fade_led: use all available LEDs

#include <zephyr/device.h>

#include <zephyr/drivers/pwm.h>

static const struct pwm_dt_spec pwm_led0 = PWM_DT_SPEC_GET(DT_ALIAS(pwm_led0));

#define PWM_LED_ALIAS(i) DT_ALIAS(_CONCAT(pwm_led, i))

#define PWM_LED(i, _)                                                                              \

	IF_ENABLED(DT_NODE_EXISTS(PWM_LED_ALIAS(i)), (PWM_DT_SPEC_GET(PWM_LED_ALIAS(i)),))

#define MAX_LEDS 10

static const struct pwm_dt_spec pwm_leds[] = {LISTIFY(MAX_LEDS, PWM_LED, ())};

#define NUM_STEPS	50U

#define SLEEP_MSEC	25U

int main(void)

{

	uint32_t pulse_width = 0U;

	uint32_t step = pwm_led0.period / NUM_STEPS;

	uint32_t pulse_widths[ARRAY_SIZE(pwm_leds)];

	uint32_t steps[ARRAY_SIZE(pwm_leds)];

	uint8_t dir = 1U;

	int ret;

	printk("PWM-based LED fade\n");

	printk("PWM-based LED fade. Found %d LEDs\n", ARRAY_SIZE(pwm_leds));

	if (!pwm_is_ready_dt(&pwm_led0)) {

		printk("Error: PWM device %s is not ready\n",

		       pwm_led0.dev->name);

	for (size_t i = 0; i < ARRAY_SIZE(pwm_leds); i++) {

		pulse_widths[i] = 0;

		steps[i] = pwm_leds[i].period / NUM_STEPS;

		if (!pwm_is_ready_dt(&pwm_leds[i])) {

			printk("Error: PWM device %s is not ready\n", pwm_leds[i].dev->name);

			return 0;

		}

	}

	while (1) {

		ret = pwm_set_pulse_dt(&pwm_led0, pulse_width);

		for (size_t i = 0; i < ARRAY_SIZE(pwm_leds); i++) {

			ret = pwm_set_pulse_dt(&pwm_leds[i], pulse_widths[i]);

			if (ret) {

			printk("Error %d: failed to set pulse width\n", ret);

			return 0;

				printk("Error %d: failed to set pulse width for LED %d\n", ret, i);

			}

		printk("Using pulse width %d%%\n", 100 * pulse_width / pwm_led0.period);

			printk("LED %d: Using pulse width %d%%\n", i,

			       100 * pulse_widths[i] / pwm_leds[i].period);

			if (dir) {

			pulse_width += step;

			if (pulse_width >= pwm_led0.period) {

				pulse_width = pwm_led0.period - step;

				if (pulse_widths[i] + steps[i] >= pwm_leds[i].period) {

					pulse_widths[i] = pwm_leds[i].period;

					dir = 0U;

			}

				} else {

			if (pulse_width >= step) {

				pulse_width -= step;

					pulse_widths[i] += steps[i];

				}

			} else {

				pulse_width = step;

				if (pulse_widths[i] <= steps[i]) {

					pulse_widths[i] = 0;

					dir = 1U;

				} else {

					pulse_widths[i] -= steps[i];

				}

			}

		}