NuttX: How to add PWM support for STM32F7 boards? (stm32_pwm.h not found)

Question

I'd like to add PWM support to my nuttx board config. I am using an STM32F765VGT6 MCU.

I started implementing it like in the STM32F4Discovery config directory:

• add stm32_pwm_setup() in configs/<board_name>/src/<board_name>.h
• add configs/<board_name>/src/stm32_pwm.c:

#include <nuttx/config.h>

#include <errno.h>
#include <debug.h>

#include <nuttx/board.h>
#include <nuttx/drivers/pwm.h>

#include <arch/board/board.h>

#include "chip.h"
#include "up_arch.h"
#include "stm32_pwm.h"

#include "board_name.h"

#ifdef CONFIG_PWM

int stm32_pwm_setup(void) {
    static bool initialized = false;
    struct pwm_lowerhalf_s *pwm;
    int ret;

    /* Have we already initialized? */

    if (!initialized) {

#if defined(CONFIG_STM32F7_TIM1_PWM)
#if defined(CONFIG_STM32F7_TIM1_CH1OUT)
        pwm = stm32_pwminitialize(1);
        if (!pwm) {
            aerr("ERROR: Failed to get the STM32F7 PWM lower half\n");
            return -ENODEV;
        }

        ret = pwm_register(DEV_PWM3, pwm);
        if (ret < 0) {
            aerr("ERROR: pwm_register failed: %d\n", ret);
            return ret;
        }
#endif

/* ... */
/* other timers and channels */
/* ... */

        initialized = true;
    }

    return OK;
}

#endif /* CONFIG_PWM */

• append stm32_pwm.c in the Makefile (configs/<board_name>/src/Makefile)

However, I always get the compilation error that "stm32_pwm.h" was not found. Also, I cannot call stm32_pwm_initialize() in my configs/<board_name>/src/stm32_boot.c.

Did someone already implement NuttX PWM support on a STM32F7 or can give me a hint why I'm failing?

Answer 1

stm32_pwm.h cannot be included by applications, the include paths (intentionally) do not support. If you move the initialization code to configs/stm32f4discovery/src/stm32_bringup.c it should compile fine.

STM32F7? There is no stm32_pwm.h for STM32F7. No one has contributed the PWM driver. This time the compiler is right, the header file does not exist in arch/arm/src/stm32f7. The solution would be to port the PWM driver from a similar STM32 architecture. The choices are:

arch/arm/src/stm32 - Which includes L1, F0, F2, F3, and F4, and arch/arm/src/stm32l4 - Which is only STM32L4