Re: [PATCH v4 1/1] pps: generators: pps_gen_parport: Switch to use module_parport_driver()

[Greg Kroah-Hartman]

On Mon, Feb 07, 2022 at 04:19:44PM +0200, Andy Shevchenko wrote:
> Switch to use module_parport_driver() to reduce boilerplate code.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Acked-by: Rodolfo Giometti <giometti@xxxxxxxxxxxx>
> ---
> 
> v4: made sure the proper version is taken into consideration
> v3: added Ack (Rodolfo), Cc'ed to Greg for picking it up
> 
>  drivers/pps/generators/pps_gen_parport.c | 42 ++++--------------------
>  1 file changed, 7 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/pps/generators/pps_gen_parport.c b/drivers/pps/generators/pps_gen_parport.c
> index 6a1af7664f3b..b3e084b75c23 100644
> --- a/drivers/pps/generators/pps_gen_parport.c
> +++ b/drivers/pps/generators/pps_gen_parport.c
> @@ -20,8 +20,6 @@
>  #include <linux/hrtimer.h>
>  #include <linux/parport.h>
>  
> -#define DRVDESC "parallel port PPS signal generator"
> -
>  #define SIGNAL		0
>  #define NO_SIGNAL	PARPORT_CONTROL_STROBE
>  
> @@ -180,6 +178,11 @@ static void parport_attach(struct parport *port)
>  {
>  	struct pardev_cb pps_cb;
>  
> +	if (send_delay > SEND_DELAY_MAX) {
> +		pr_err("delay value should be not greater then %d\n", SEND_DELAY_MAX);
> +		return;
> +	}
> +
>  	if (attached) {
>  		/* we already have a port */
>  		return;
> @@ -231,39 +234,8 @@ static struct parport_driver pps_gen_parport_driver = {
>  	.detach = parport_detach,
>  	.devmodel = true,
>  };
> -
> -/* module staff */
> -
> -static int __init pps_gen_parport_init(void)
> -{
> -	int ret;
> -
> -	pr_info(DRVDESC "\n");
> -
> -	if (send_delay > SEND_DELAY_MAX) {
> -		pr_err("delay value should be not greater"
> -				" then %d\n", SEND_DELAY_MAX);
> -		return -EINVAL;
> -	}
> -
> -	ret = parport_register_driver(&pps_gen_parport_driver);
> -	if (ret) {
> -		pr_err("unable to register with parport\n");
> -		return ret;
> -	}
> -
> -	return  0;
> -}
> -
> -static void __exit pps_gen_parport_exit(void)
> -{
> -	parport_unregister_driver(&pps_gen_parport_driver);
> -	pr_info("hrtimer avg error is %ldns\n", hrtimer_error);
> -}
> -
> -module_init(pps_gen_parport_init);
> -module_exit(pps_gen_parport_exit);
> +module_parport_driver(pps_gen_parport_driver);
>  
>  MODULE_AUTHOR("Alexander Gordeev <lasaine@xxxxxxxxxxxxx>");
> -MODULE_DESCRIPTION(DRVDESC);
> +MODULE_DESCRIPTION("parallel port PPS signal generator");
>  MODULE_LICENSE("GPL");
> -- 
> 2.34.1
> 

You changed the functionality here :(

Currently if send_delay is too big, loading the module will fail.

Now it succeeds but binding to a device fails, that's a functional
change.  Are you _SURE_ that is ok to do?

And why did you not mention any of this in the changelog text?  You
passed this off as a mere code cleanup, no functional change :(

thanks,

greg k-h