Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) client-ip=2620:137:e000::3:7;
Message-ID: <9dbb81f8-7c75-411d-a77c-b670302f0dfe@gmail.com>
Date:   Mon, 4 Dec 2023 18:49:21 +0200
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
From:   Ceclan Dumitru <mitrutzceclan@gmail.com>
Subject: Re: [PATCH v6 2/2] iio: adc: ad7173: add AD7173 driver
To:     Jonathan Cameron <jic23@kernel.org>
Cc:     linus.walleij@linaro.org, brgl@bgdev.pl, andy@kernel.org,
        linux-gpio@vger.kernel.org, Lars-Peter Clausen <lars@metafoo.de>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Michael Walle <michael@walle.cc>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Arnd Bergmann <arnd@arndb.de>,
        ChiaEn Wu <chiaen_wu@richtek.com>,
        Niklas Schnelle <schnelle@linux.ibm.com>,
        =?UTF-8?Q?Leonard_G=C3=B6hrs?= <l.goehrs@pengutronix.de>,
        Mike Looijmans <mike.looijmans@topic.nl>,
        Haibo Chen <haibo.chen@nxp.com>,
        Hugo Villeneuve <hvilleneuve@dimonoff.com>,
        Ceclan Dumitru <dumitru.ceclan@analog.com>,
        linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20231123152331.5751-1-user@HYB-hhAwRlzzMZb>
 <20231123152331.5751-2-user@HYB-hhAwRlzzMZb>
 <20231125172125.1b0f1ae7@jic23-huawei>
Content-Language: en-US
In-Reply-To: <20231125172125.1b0f1ae7@jic23-huawei>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk


On 11/25/23 19:21, Jonathan Cameron wrote:
> On Thu, 23 Nov 2023 17:23:22 +0200
> mitrutzceclan <mitrutzceclan@gmail.com> wrote:
> 
>> From: Dumitru Ceclan <mitrutzceclan@gmail.com>

...
>> +	st->regulators[0].supply = ad7173_ref_sel_str[AD7173_SETUP_REF_SEL_EXT_REF];
>> +	st->regulators[1].supply = ad7173_ref_sel_str[AD7173_SETUP_REF_SEL_EXT_REF2];
>> +	st->regulators[2].supply = ad7173_ref_sel_str[AD7173_SETUP_REF_SEL_AVDD1_AVSS];
>> +
>> +	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(st->regulators),
>> +				      st->regulators);
> 
> If only some of them are supplied, the driver works fine as long as no channel is using them?
> If so should probably get the optionally then check for availability of the ones you
> want.  I'm sure someone will just wire up ref.  Incidentally, ref2 isn't there for all chips
> I think, so we should not get it on the ones where it can't exist.
> 


This sets a dummy regulator in place if no proper supply is found. Then
the call regulator_get_voltage() on the dummy will fail. About getting
ref2, sure, I'll set the string only with the right ID.

...
>> +		ret = ad7173_get_ref_voltage_milli(st, (u8)ref_sel);
>> +		if (ret < 0)
>> +			return dev_err_probe(dev, ret,
>> +					     "Cannot use reference %u", ref_sel);

Here the probe would not continue if a channel selects a supply that is
not available in the DT.