platformio-mode layer

packages.el

(setq pio-packages
      '(
        (platformio-mode :toggle (configuration-layer/package-usedp 'projectile))
        ))

(defun pio/init-platformio-mode ()
  (use-package platformio-mode
    :defer t
    :init
    (progn
      (defun conditionally-enable ()
        "Enable `platformio-mode' only when a `platformio.ini' file is present in project root."
        (condition-case nil
            (when (projectile-verify-file "platformio.ini")
              (platformio-mode 1))
          (error nil)))
      (add-hook 'c++-mode-hook (conditionally-enable))
      (add-hook 'c-mode-hook (conditionally-enable)))
    :config
    (progn
      (platformio-setup-compile-buffer)
      (spacemacs/set-leader-keys-for-major-mode 'c++-mode
        "pb" 'platformio-build
        "pu" 'platformio-upload
        "pp" 'platformio-programmer-upload
        "ps" 'platformio-spiffs-upload
        "pc" 'platformio-clean
        "pd" 'platformio-update
        )
    )))

platformio-mode already provides a platformio-conditionally-enable function which is identical to your conditionally-enable here. To use it in the :init of use-package, you have to make it autoloadable using the :commands key, like here .

I am trying to create a good and complete platformio layer there, if you want you help you're welcome!