linux-kernel - Re: Fwd: [PATCH v14 0/3] PPS: pps-gpio PPS ECHO implementation

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Date:   Thu, 31 Jan 2019 12:40:08 +1100
From:   tom burkart <tom@...sec.com>
To:     Rodolfo Giometti <giometti@...eenne.com>
Cc:     Linux kernel mailing list <linux-kernel@...r.kernel.org>
Subject: Re: Fwd: [PATCH v14 0/3] PPS: pps-gpio PPS ECHO implementation

Quoting Rodolfo Giometti <giometti@...eenne.com>:

> I answered to your message, see here:
Whoops.  I missed it because I am not on the list, sorry.

> https://lkml.org/lkml/2019/1/4/399
------
Subject	Re: [PATCH v14 3/3] pps: pps-gpio pps-echo implementation

> +static void pps_gpio_echo(struct pps_device *pps, int event, void *data)
> +{
> +	/* add_timer() needs to write into info->echo_timer */
> +	struct pps_gpio_device_data *info;
> +
> +	info = data;

Maybe you can write as below and saving two lines and having better  
readability:

struct pps_gpio_device_data *info = data;

-----
Done.  Easy fix.
------

> +	/* fire the timer */
> +	if (info->pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) {
> +		info->echo_timer.expires = jiffies + info->echo_timeout;
> +		add_timer(&info->echo_timer);
> +	}
> +}

I think is better firing the timer if and only if we set the echo GPIO  
otherwise
it's useless...
------
Later in the patch:
@@ -152,6 +219,11 @@ static int pps_gpio_probe(struct platform_device *pdev)
         data->info.owner = THIS_MODULE;
         snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
                  pdev->name, pdev->id);
+       if (data->echo_pin) {
+               data->info.echo = pps_gpio_echo;
+               data->echo_timeout = msecs_to_jiffies(data->echo_active_ms);
+               timer_setup(&data->echo_timer,  
pps_gpio_echo_timer_callback, 0);
+       }

         /* register PPS source */
         pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT;

The pps-gpio-echo function only becomes callable when the echo GPIO is  
set hence I felt that the additional check here was superfluous.  Does  
my reasoning make sense?

> and here:
> https://lkml.org/lkml/2019/1/4/398
--------
Subject	Re: [PATCH v14 2/3] dt-bindings: pps: pps-gpio PPS ECHO implementation

I think this patch it's OK but I'm asking to myself if it should be  
merged with
next one... logically it describes what patch 3/3 does so why do we keep them
separated?
-------
I have separated it because scripts/checkpatch.pl insists it needs to  
be separated.

Tom