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Message-ID: <f262dd8884e89bb36a72fe8fd5cb75cd9ae6fa08.camel@gmail.com>
Subject: Re: [PATCH v3 5/5] iio: dac: ltc2664: Add driver for LTC2664 and
 LTC2672
From: Nuno =?ISO-8859-1?Q?S=E1?= <noname.nuno@gmail.com>
To: Kim Seer Paller <kimseer.paller@analog.com>,
 linux-kernel@vger.kernel.org,  linux-iio@vger.kernel.org,
 devicetree@vger.kernel.org
Cc: Jonathan Cameron <jic23@kernel.org>, David Lechner
 <dlechner@baylibre.com>,  Lars-Peter Clausen <lars@metafoo.de>, Liam
 Girdwood <lgirdwood@gmail.com>, Mark Brown <broonie@kernel.org>, Dimitri
 Fedrau <dima.fedrau@gmail.com>, Krzysztof Kozlowski <krzk+dt@kernel.org>,
 Rob Herring <robh@kernel.org>, Conor Dooley <conor+dt@kernel.org>,  Michael
 Hennerich <michael.hennerich@analog.com>, kernel test robot <lkp@intel.com>
Date: Mon, 03 Jun 2024 15:12:36 +0200
In-Reply-To: <20240603012200.16589-6-kimseer.paller@analog.com>
References: <20240603012200.16589-1-kimseer.paller@analog.com>
	 <20240603012200.16589-6-kimseer.paller@analog.com>
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On Mon, 2024-06-03 at 09:22 +0800, Kim Seer Paller wrote:
> LTC2664 4 channel, 16 bit Voltage Output SoftSpan DAC
> LTC2672 5 channel, 16 bit Current Output Softspan DAC
>=20
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202405241141.kYcxrSem-lkp@i=
ntel.com/

The above could be dropped. This is still not merged code :)

> Co-developed-by: Michael Hennerich <michael.hennerich@analog.com>
> Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
> Signed-off-by: Kim Seer Paller <kimseer.paller@analog.com>
> ---

LGTM... just a couple of minor points/questions that you can maybe take on =
if a re-
spin is needed.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>

...

>=20
> +static int ltc2664_scale_get(const struct ltc2664_state *st, int c)
> +{
> +	const struct ltc2664_chan *chan =3D &st->channels[c];
> +	const int (*span_helper)[2] =3D st->chip_info->span_helper;
> +	int span, fs;
> +
> +	span =3D chan->span;
> +	if (span < 0)
> +		return span;
> +
> +	fs =3D span_helper[span][1] - span_helper[span][0];
> +
> +	return (fs / 2500) * st->vref;

no need for ()

...

>=20
> +static int ltc2664_channel_config(struct ltc2664_state *st)
> +{
> +	const struct ltc2664_chip_info *chip_info =3D st->chip_info;
> +	struct device *dev =3D &st->spi->dev;
> +	u32 reg, tmp[2], mspan;
> +	int ret, span =3D 0;
> +
> +	mspan =3D LTC2664_MSPAN_SOFTSPAN;
> +	ret =3D device_property_read_u32(dev, "adi,manual-span-operation-config=
",
> +				=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 &mspan);
> +	if (!ret) {
> +		if (!chip_info->manual_span_support)
> +			return dev_err_probe(dev, -EINVAL,
> +			=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 "adi,manual-span-operation-confi=
g not
> supported\n");
> +
> +		if (mspan > ARRAY_SIZE(ltc2664_mspan_lut))
> +			return dev_err_probe(dev, -EINVAL,
> +			=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 "adi,manual-span-operation-confi=
g not in range\n");
> +	}
> +
> +	st->rfsadj =3D 20000;
> +	ret =3D device_property_read_u32(dev, "adi,rfsadj-ohms", &st->rfsadj);
> +	if (!ret) {
> +		if (!chip_info->rfsadj_support)
> +			return dev_err_probe(dev, -EINVAL,
> +					=C2=A0=C2=A0=C2=A0=C2=A0 "adi,rfsadj-ohms not supported\n");
> +
> +		if (st->rfsadj < 19000 || st->rfsadj > 41000)
> +			return dev_err_probe(dev, -EINVAL,
> +					=C2=A0=C2=A0=C2=A0=C2=A0 "adi,rfsadj-ohms not in range\n");
> +	}
> +
> +	device_for_each_child_node_scoped(dev, child) {
> +		struct ltc2664_chan *chan;
> +
> +		ret =3D fwnode_property_read_u32(child, "reg", &reg);
> +		if (ret)
> +			return dev_err_probe(dev, ret,
> +					=C2=A0=C2=A0=C2=A0=C2=A0 "Failed to get reg property\n");
> +
> +		if (reg >=3D chip_info->num_channels)
> +			return dev_err_probe(dev, -EINVAL,
> +					=C2=A0=C2=A0=C2=A0=C2=A0 "reg bigger than: %d\n",
> +					=C2=A0=C2=A0=C2=A0=C2=A0 chip_info->num_channels);
> +
> +		chan =3D &st->channels[reg];
> +
> +		if (fwnode_property_read_bool(child, "adi,toggle-mode")) {
> +			chan->toggle_chan =3D true;
> +			/* assume sw toggle ABI */

Do we have any other option :)? For the ltc2668 driver (where this code cam=
e from),
we do have another way (driven by clocks) to toggle between outputs and hen=
ce the
comment.

BTW, there's a fair amount of duplicated code between this and ltc2668. At =
some point
we may see if it makes sense to add some common module. Anyways, fine for n=
ow.

- Nuno S=C3=A1