Re: [PATCH] USB: serial: xr: Add TIOCGRS485 and TIOCSRS485 ioctls

Jarkko Sonninen
2023-03-13T15:08:23Z

On 3/13/23 09:53, Greg Kroah-Hartman wrote:
> On Mon, Mar 13, 2023 at 09:49:26AM +0200, Jarkko Sonninen wrote:
>>>> +{
>>>> + void __user *argp = (void __user *)arg;
>>>> +
>>>> + switch (cmd) {
>>>> + case TIOCGRS485:
>>>> + return xr_get_rs485_config(tty, argp);
>>>> + case TIOCSRS485:
>>>> + return xr_set_rs485_config(tty, argp);
>>>> + }
>>>> + return -ENOIOCTLCMD;
>>> Wrong ioctl return value :(
>> What is the correct ioctl error return value ?
>> ENOIOCTLCMD was used in most places in usb serial as an error return.
> ENOTTY is the correct one for when an ioctl is not handled by the ioctl
> call.
>
> thanks,
>
> greg k-h

Using ENOTTY breaks all other tty ioctls.

- Jarkko