linux-kernel - Re: [PATCH v18 3/3] Input: new da7280 haptic driver

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Date:   Wed, 29 Jul 2020 22:06:53 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
Cc:     Roy Im <roy.im.opensource@...semi.com>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Brian Masney <masneyb@...tation.org>,
        Greg KH <gregkh@...uxfoundation.org>,
        Lee Jones <lee.jones@...aro.org>, Luca Weiss <luca@...tu.xyz>,
        Maximilian Luz <luzmaximilian@...il.com>,
        Pascal PAILLET-LME <p.paillet@...com>,
        Rob Herring <robh@...nel.org>,
        Samuel Ortiz <sameo@...ux.intel.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Support Opensource <support.opensource@...semi.com>,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pwm@...r.kernel.org
Subject: Re: [PATCH v18 3/3] Input: new da7280 haptic driver

Hi Uwe,

On Wed, Jul 29, 2020 at 09:21:45AM +0200, Uwe Kleine-König wrote:
> Hello,
> 
> On Tue, Jul 28, 2020 at 11:36:38PM -0700, Dmitry Torokhov wrote:
> > > v9: 
> > > 	- Removed the header file and put the definitions into the c file.
> > > 	- Updated the pwm code and error logs with %pE
> > 
> > I believe the %pE is to format an escaped buffer, you probably want to
> > %pe (lowercase) to print errors. I am also not quite sure if we want to
> > use it in cases when we have non-pointer error, or we should stick with
> > %d as most of the kernel does.
> 
> compared with %d %pe is easier to understand as it emits "-ETIMEOUT"
> instead of "-110". And yes, %pE is wrong.

While I can see that symbolic name instead of a numeric constant might
be appealing, I do not believe that we want fragments like this with
endless conversions between integer and pointer errors:

	if (haptics->const_op_mode == DA7280_PWM_MODE) {
		haptics->pwm_dev = devm_pwm_get(dev, NULL);
		if (IS_ERR(haptics->pwm_dev)) {
			error = PTR_ERR(haptics->pwm_dev);
			if (error != -EPROBE_DEFER)
				dev_err(dev, "unable to request PWM: %pE\n",
					ERR_PTR(error));
			return error;
		}

Maybe we should introduce something like '%de' for the integer error
case? In the meantime I would prefer using %d when we have integer
error. We should not see these error messages anyway ;)

Thanks.

-- 
Dmitry