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Date:   Sat, 25 Nov 2023 19:15:29 +0000
From:   Jonathan Cameron <jic23@kernel.org>
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     Petre Rodan <petre.rodan@subdimension.ro>,
        linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org,
        Lars-Peter Clausen <lars@metafoo.de>,
        Angel Iglesias <ang.iglesiasg@gmail.com>,
        Matti Vaittinen <mazziesaccount@gmail.com>,
        Andreas Klinger <ak@it-klinger.de>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
Subject: Re: [PATCH 2/2] iio: pressure: driver for Honeywell HSC/SSC series
 pressure sensors
Message-ID: <20231125191529.2ed1ddfb@jic23-huawei>
In-Reply-To: <ZV3b5sUrGEj5ZOF0@smile.fi.intel.com>
References: <20231117164232.8474-1-petre.rodan@subdimension.ro>
        <20231117164232.8474-2-petre.rodan@subdimension.ro>
        <ZVtSm5f-Qyp8LFFp@smile.fi.intel.com>
        <ZV2a213oidterHYZ@sunspire>
        <ZV3b5sUrGEj5ZOF0@smile.fi.intel.com>
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> 
> > > > +	ret = devm_regulator_get_enable_optional(dev, "vdd");
> > > > +	if (ret == -EPROBE_DEFER)
> > > > +		return -EPROBE_DEFER;  
> > > 
> > > Oh, boy, this should check for ENODEV or so, yeah, regulator APIs a bit
> > > interesting.  
> > 
> > since I'm unable to test this I'd rather remove the block altogether.
> > if I go the ENODEV route my module will never load since I can't see any
> > vdd-supply support on my devboard.  
> 
> No, what I meant is to have something like
> 
> 	if (ret) {
> 		if (ret != -ENODEV)
> 			return ret;
> 		...regulator is not present...
> 	}
> 
> This is how it's being used in dozens of places in the kernel. Just utilize
> `git grep ...` which should be a top-10 tool for the Linux kernel developer.

As per my very late reply to previous email. Nope. This regulator is never
not present. It's just a question of whether the firmware tells us what
it is, or it is supplied with a stub regulator.