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Message-ID: <591e8c9a4018938df17cdfb55306813858904d9d.camel@gmail.com>
Subject: Re: [PATCH v2 1/2] dt-bindings: adc: provide max34408/9 device tree
 binding document
From:   Ivan Mikhaylov <fr0st61te@gmail.com>
To:     Conor Dooley <conor@kernel.org>
Cc:     Jonathan Cameron <jic23@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>, linux-iio@vger.kernel.org,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org
Date:   Sat, 30 Sep 2023 22:38:58 +0300
In-Reply-To: <20230930-lusty-antihero-f381434ab682@spud>
References: <20230929200844.23316-1-fr0st61te@gmail.com>
         <20230929200844.23316-2-fr0st61te@gmail.com>
         <20230930-lusty-antihero-f381434ab682@spud>
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On Sat, 2023-09-30 at 10:37 +0100, Conor Dooley wrote:
> Hey,
>=20
> On Fri, Sep 29, 2023 at 11:08:43PM +0300, Ivan Mikhaylov wrote:
> > The hardware binding for i2c current monitoring device with
> > overcurrent
> > control.
> >=20
> > Signed-off-by: Ivan Mikhaylov <fr0st61te@gmail.com>
> > ---
> > =C2=A0.../bindings/iio/adc/maxim,max34408.yaml=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0 | 101
> > ++++++++++++++++++
> > =C2=A01 file changed, 101 insertions(+)
> > =C2=A0create mode 100644
> > Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml
> >=20
> > diff --git
> > a/Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml
> > b/Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml
> > new file mode 100644
> > index 000000000000..cdf89fa4c80e
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml
> > @@ -0,0 +1,101 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/adc/maxim,max34408.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Two- and four-channel current monitors with overcurrent
> > control
> > +
> > +maintainers:
> > +=C2=A0 - Ivan Mikhaylov <fr0st61te@gmail.com>
> > +
> > +description: |
> > +=C2=A0 The MAX34408/MAX34409 are two- and four-channel current monitor=
s
> > that are
> > +=C2=A0 configured and monitored with a standard I2C/SMBus serial
> > interface. Each
> > +=C2=A0 unidirectional current sensor offers precision high-side
> > operation with a
> > +=C2=A0 low full-scale sense voltage. The devices automatically sequenc=
e
> > through
> > +=C2=A0 two or four channels and collect the current-sense samples and
> > average them
> > +=C2=A0 to reduce the effect of impulse noise. The raw ADC samples are
> > compared to
> > +=C2=A0 user-programmable digital thresholds to indicate overcurrent
> > conditions.
> > +=C2=A0 Overcurrent conditions trigger a hardware output to provide an
> > immediate
> > +=C2=A0 indication to shut down any necessary external circuitry.
> > +
> > +=C2=A0 Specifications about the devices can be found at:
> > +=C2=A0
> > https://www.analog.com/media/en/technical-documentation/data-sheets/MAX=
34408-MAX34409.pdf
> > +
> > +properties:
> > +=C2=A0 compatible:
> > +=C2=A0=C2=A0=C2=A0 enum:
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 - maxim,max34408
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 - maxim,max34409
> > +
> > +=C2=A0 reg:
> > +=C2=A0=C2=A0=C2=A0 maxItems: 1
> > +
> > +=C2=A0 interrupts:
> > +=C2=A0=C2=A0=C2=A0 maxItems: 1
> > +
> > +=C2=A0 maxim,input1-rsense-val-micro-ohms:
> > +=C2=A0=C2=A0=C2=A0 description:
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Adjust the Rsense value to monitor high=
er or lower current
> > levels for
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 input 1.
> > +=C2=A0=C2=A0=C2=A0 enum: [250, 500, 1000, 5000, 10000, 50000, 100000, =
200000,
> > 500000]
> > +=C2=A0=C2=A0=C2=A0 default: 1000
> > +
> > +=C2=A0 maxim,input2-rsense-val-micro-ohms:
> > +=C2=A0=C2=A0=C2=A0 description:
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Adjust the Rsense value to monitor high=
er or lower current
> > levels for
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 input 2.
> > +=C2=A0=C2=A0=C2=A0 enum: [250, 500, 1000, 5000, 10000, 50000, 100000, =
200000,
> > 500000]
> > +=C2=A0=C2=A0=C2=A0 default: 1000
> > +
> > +=C2=A0 maxim,input3-rsense-val-micro-ohms:
> > +=C2=A0=C2=A0=C2=A0 description:
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Adjust the Rsense value to monitor high=
er or lower current
> > levels for
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 input 3.
> > +=C2=A0=C2=A0=C2=A0 enum: [250, 500, 1000, 5000, 10000, 50000, 100000, =
200000,
> > 500000]
> > +=C2=A0=C2=A0=C2=A0 default: 1000
> > +
> > +=C2=A0 maxim,input4-rsense-val-micro-ohms:
> > +=C2=A0=C2=A0=C2=A0 description:
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Adjust the Rsense value to monitor high=
er or lower current
> > levels for
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 input 4.
> > +=C2=A0=C2=A0=C2=A0 enum: [250, 500, 1000, 5000, 10000, 50000, 100000, =
200000,
> > 500000]
> > +=C2=A0=C2=A0=C2=A0 default: 1000
>=20
> Having 4 almost identical properties makes it seem like this should
> have
> some channel nodes, each containing an rsense-micro-ohms type
> property.

Conor, I'll look through.

>=20
> > +
> > +=C2=A0 maxim,shtdn:
> > +=C2=A0=C2=A0=C2=A0 description:
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Shutdown Output. Open-drain output. Thi=
s output transitions
> > to high impedance
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 when any of the digital comparator thre=
sholds are exceeded
> > as long as the ENA
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 pin is high.
> > +=C2=A0=C2=A0=C2=A0 type: boolean
>=20
> I don't understand what this property is used for. The description
> here,
> and below for "ena", read like they are the descriptions in the
> datasheet for the pin, rather than how to use the property.
>=20
> The drivers don't appear to contain users either - what is the point
> of
> these properties?

ena and shtdn physical pins of hardware, in the previous version
Jonathan asked about adding them into yaml even if it's not used in
code. should I do it in some other way?

>=20
> > +
> > +=C2=A0 maxim,ena:
> > +=C2=A0=C2=A0=C2=A0 description:
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 SHTDN Enable Input. CMOS digital input.=
 Connect to GND to
> > clear the latch and
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 unconditionally deassert (force low) th=
e SHTDN output and
> > reset the shutdown
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 delay. Connect to VDD to enable normal =
latch operation of
> > the SHTDN output.
> > +=C2=A0=C2=A0=C2=A0 type: boolean
> > +
> > +=C2=A0 supply-vdd: true
>=20
> As pointed out by the bot, this is not correct. You need to use a
> -supply affix, not a supply-prefix.

Oops.

Thanks.