Subject: Re: [PATCH v8 1/3] serdev: Add method to assert break signal over tty UART port

From: Simon Horman <[email-masked]>
Date: Sat, 11 Mar 2023 13:33:40 +0100

On Fri, Mar 10, 2023 at 11:49:19PM +0530, Neeraj Sanjay Kale wrote:
> Adds serdev_device_break_ctl() and an implementation for ttyport.
> This function simply calls the break_ctl in tty layer, which can
> assert a break signal over UART-TX line, if the tty and the
> underlying platform and UART peripheral supports this operation.
> 
> Signed-off-by: Neeraj Sanjay Kale <[email-masked]>
> ---
> v3: Add details to the commit message. (Greg KH)

...

> diff --git a/include/linux/serdev.h b/include/linux/serdev.h
> index 66f624fc618c..c065ef1c82f1 100644
> --- a/include/linux/serdev.h
> +++ b/include/linux/serdev.h

...

> @@ -255,6 +257,10 @@ static inline int serdev_device_set_tiocm(struct serdev_device *serdev, int set,
>  {
>  	return -ENOTSUPP;
>  }
> +static inline int serdev_device_break_ctl(struct serdev_device *serdev, int break_state)
> +{
> +	return -EOPNOTSUPP;

Is the use of -EOPNOTSUPP intentional here?
I see -ENOTSUPP is used elsewhere in this file.

> +}
>  static inline int serdev_device_write(struct serdev_device *sdev, const unsigned char *buf,
>  				      size_t count, unsigned long timeout)
>  {
> -- 
> 2.34.1
>