linux-kernel - Re: [PATCH 2/2] drivers: rtc: max31335: initial commit

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Message-ID: <202310311354329a21a9d0@mail.local>
Date:   Tue, 31 Oct 2023 14:54:32 +0100
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     "Miclaus, Antoniu" <Antoniu.Miclaus@...log.com>
Cc:     Guenter Roeck <linux@...ck-us.net>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Jean Delvare <jdelvare@...e.com>,
        "linux-rtc@...r.kernel.org" <linux-rtc@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-hwmon@...r.kernel.org" <linux-hwmon@...r.kernel.org>
Subject: Re: [PATCH 2/2] drivers: rtc: max31335: initial commit

On 31/10/2023 11:23:49+0000, Miclaus, Antoniu wrote:
> > > +	if (status != MAX31335_STATUS1_DEFAULT)
> > > +		dev_err_probe(&client->dev, -EINVAL,
> > > +			      "Unable to read from device.\n");
> > > +
> > 
> > That is misleading. The device returned an unexpected status.
> > I don't know if this really reflects a problem, but it is not
> > "Unable to read from device".
> > 
> 
> Since the device lacks an ID register, I found this as a suitable 
> replacement for checking that the communication with the
> device actually works before the probe function finishes
> successfully.
> 
> I will be more specific in the dev_err_probe message in the 
> upcoming patch version.
> 

What if this is a transient bus error and the device is actually present
and working?
 don't like this kind of check, they are not usually useful.

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com