Issues with PWM device configuration and alias resolution in Zephyr

[jayesh0711]

Hello Zephyr Community,
I'm encountering errors when trying to build my Zephyr application for controlling an LED using PWM i am using mec1521 ASSY 6883 development board . Below are the details of my configuration:
Code Overview:
In the main.c file, I’m trying to control an LED using PWM, and here is the relevant code:
#include <zephyr/kernel.h>
#include <zephyr/sys/printk.h>
#include <zephyr/device.h>
#include <zephyr/drivers/pwm.h>

/* Define PWM specifications for the LED */
static const struct pwm_dt_spec pwm_led0 = PWM_DT_SPEC_GET(DT_ALIAS(pwm_led0));

#define MIN_PERIOD PWM_MSEC(1)
#define MAX_PERIOD PWM_SEC(1U)

void main(void) {
printk("PWM LED Control Example\n");

if (!pwm_is_ready_dt(&pwm_led0)) {
    printk("Error: PWM device is not ready\n");
    return;
}

uint32_t period = MAX_PERIOD;
uint8_t dir = 0; /* Direction of change: 0 = decrease, 1 = increase */

while (1) {
    /* Set PWM for the LED */
    pwm_set_dt(&pwm_led0, period, period / 2);
    printk("PWM Period: %u\n", period);

    /* Adjust period */
    if (dir) {
        period *= 2;
        if (period > MAX_PERIOD) {
            period = MAX_PERIOD / 2;
            dir = 0;
        }
    } else {
        period /= 2;
        if (period < MIN_PERIOD) {
            period = MIN_PERIOD * 2;
            dir = 1;
        }
    }

    k_sleep(K_MSEC(500)); /* Adjust delay as needed */
}

}

Device Tree Configuration:
Here is the relevant section from my .dts overlay:
& pwm-0 {
status = "okay";
channel-gpios = <&gpio_040_076 0xb GPIO_ACTIVE_HIGH>;
};

pwmleds {
compatible = "pwm-leds";
pwm_led0: pwm_led_0 {
pwms = <&pwm-0 0 PWM_MSEC(20) PWM_POLARITY_NORMAL>; /* Channel 0, Period 20ms /
label = "PWM_LED0";
};
};
/ Define PWM channel for LED2 /
& pwm_led0 {
pwms = <&pwm-0 0 PWM_MSEC(20) PWM_POLARITY_NORMAL>; / Channel 0 */
label = "PWM_LED2";
};

Errors Encountered:
When trying to build the project, I am receiving the following errors:

1. error: 'DT_N_ALIAS_pwm_led0_P_pwms_IDX_0_VAL_period' undeclared here (not in a function)
2. error: 'DT_N_ALIAS_pwm_led0_P_pwms_IDX_0_VAL_channel' undeclared here (not in a function)
3. error: '__device_dts_ord_DT_N_ALIAS_pwm_led0_P_pwms_IDX_0_PH_ORD' undeclared here (not in a function)
   The error seems to be related to how the PWM alias and associated properties are being handled.
   What I’ve Tried:
   • Verified the device tree overlay configuration.
   • Ensured that the aliases are correctly defined.
   • Checked if the PWM driver is correctly registered.
   Question:
   Could anyone help me understand why these undeclared errors are happening? Is there an issue with how I have defined the alias for the PWM LED, or am I missing something in the device tree setup? Any guidance on fixing these errors would be appreciated.
   Thanks in advance!

[jayesh0711]

I recently updated the repository with the suggestions provided, and now when I try to build the application for the mec15xxevb_assy6853 board, I'm encountering the following error:

CMake Error at /home/jayesh/zephyrproject/zephyr/cmake/modules/dts.cmake:311 (message):
gen_defines.py failed with result code: 1 - stderr contents:

devicetree error:
/home/jayesh/zephyrproject/zephyr/samples/basic/blinky_pwm/boards/mec15xxevb_assy6853_mec1501_hsz.overlay:46
(column 1): parse error: expected '/' or label reference (&foo)

Call Stack (most recent call first):
/home/jayesh/zephyrproject/zephyr/cmake/modules/zephyr_default.cmake:132 (include)
/home/jayesh/zephyrproject/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:66 (include)
/home/jayesh/zephyrproject/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:92 (include_boilerplate)
CMakeLists.txt:4 (find_package)

The error points to a parse issue in the mec15xxevb_assy6853_mec1501_hsz.overlay file at line 46. The expected format seems to be a / or label reference, but I'm not sure what went wrong in the overlay configuration.

Has anyone faced a similar issue? Could you suggest possible solutions or guide me in troubleshooting this parse error?

Here is the updated repository link: https://github.com/leenaarora18/pwm_updated_version_1.git

Thank you for your help!