linux-kernel - Re: [PATCH v2 5/5] iio: dac: ltc2664: Add driver for LTC2664 and LTC2672

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Date: Thu, 23 May 2024 18:02:10 +0100
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: Kim Seer Paller <kimseer.paller@...log.com>
CC: <linux-kernel@...r.kernel.org>, <linux-iio@...r.kernel.org>,
	<devicetree@...r.kernel.org>, Jonathan Cameron <jic23@...nel.org>, "David
 Lechner" <dlechner@...libre.com>, Lars-Peter Clausen <lars@...afoo.de>, "Liam
 Girdwood" <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>, "Dimitri
 Fedrau" <dima.fedrau@...il.com>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Rob Herring <robh@...nel.org>, Conor Dooley <conor+dt@...nel.org>, Michael
 Hennerich <michael.hennerich@...log.com>, Nuno Sá <noname.nuno@...il.com>
Subject: Re: [PATCH v2 5/5] iio: dac: ltc2664: Add driver for LTC2664 and
 LTC2672

On Thu, 23 May 2024 11:19:09 +0800
Kim Seer Paller <kimseer.paller@...log.com> wrote:

> LTC2664 4 channel, 16 bit Voltage Output SoftSpan DAC
> LTC2672 5 channel, 16 bit Current Output Softspan DAC
> 
> Co-developed-by: Michael Hennerich <michael.hennerich@...log.com>
> Signed-off-by: Michael Hennerich <michael.hennerich@...log.com>
> Signed-off-by: Kim Seer Paller <kimseer.paller@...log.com>
Hi Kim,

A few minor things inline,

Jonathan

> diff --git a/drivers/iio/dac/ltc2664.c b/drivers/iio/dac/ltc2664.c
> new file mode 100644
> index 000000000000..488b841e6c66
> --- /dev/null
> +++ b/drivers/iio/dac/ltc2664.c
> @@ -0,0 +1,802 @@


> +static int ltc2664_set_span(const struct ltc2664_state *st, int min, int max,
> +			    int chan)
> +{
> +	const struct ltc2664_chip_info *chip_info = st->chip_info;
> +	const int (*span_helper)[2] = chip_info->span_helper;
> +	int span, ret;
> +
> +	st->iio_channels[chan].type = chip_info->measurement_type;
> +
> +	for (span = 0; span < chip_info->num_span; span++) {
> +		if (min == span_helper[span][0] && max == span_helper[span][1])
> +			break;
> +	}

Sanity check for no match?

> +
> +	ret = regmap_write(st->regmap, LTC2664_CMD_SPAN_N(chan),
> +			   (chip_info->id == LTC2672) ? span + 1 : span);
> +	if (ret)
> +		return ret;
> +
> +	return span;
> +}
> +
> +static int ltc2664_channel_config(struct ltc2664_state *st)
> +{
> +	const struct ltc2664_chip_info *chip_info = st->chip_info;
> +	struct device *dev = &st->spi->dev;
> +	u32 reg, tmp[2], mspan;
> +	int ret, span;
> +
> +	mspan = LTC2664_MSPAN_SOFTSPAN;
> +	ret = device_property_read_u32(dev, "adi,manual-span-operation-config",
> +				       &mspan);
> +	if (!ret) {
> +		if (!chip_info->manual_span_support)
> +			return dev_err_probe(dev, -EINVAL,
> +			       "adi,manual-span-operation-config not supported\n");
> +
> +		if (mspan > ARRAY_SIZE(ltc2664_mspan_lut))
> +			return dev_err_probe(dev, -EINVAL,
> +			       "adi,manual-span-operation-config not in range\n");
> +	}
> +
> +	st->rfsadj = 20000;
> +	ret = device_property_read_u32(dev, "adi,rfsadj-ohms", &st->rfsadj);
> +	if (!ret) {
> +		if (!chip_info->rfsadj_support)
> +			return dev_err_probe(dev, -EINVAL,
> +					     "adi,rfsadj-ohms not supported\n");
> +
> +		if (st->rfsadj < 19000 || st->rfsadj > 41000)
> +			return dev_err_probe(dev, -EINVAL,
> +					     "adi,rfsadj-ohms not in range\n");
> +	}
> +
> +	device_for_each_child_node_scoped(dev, child) {
> +		struct ltc2664_chan *chan;
> +
> +		ret = fwnode_property_read_u32(child, "reg", &reg);
> +		if (ret)
> +			return dev_err_probe(dev, ret,
> +					     "Failed to get reg property\n");
> +
> +		if (reg >= chip_info->num_channels)
> +			return dev_err_probe(dev, -EINVAL,
> +					     "reg bigger than: %d\n",
> +					     chip_info->num_channels);
> +
> +		chan = &st->channels[reg];
> +
> +		if (fwnode_property_read_bool(child, "adi,toggle-mode")) {
> +			chan->toggle_chan = true;
> +			/* assume sw toggle ABI */
> +			st->iio_channels[reg].ext_info = ltc2664_toggle_sym_ext_info;

chan->ext_info = ...

> +			/*
> +			 * Clear IIO_CHAN_INFO_RAW bit as toggle channels expose
> +			 * out_voltage/current_raw{0|1} files.
> +			 */
> +			__clear_bit(IIO_CHAN_INFO_RAW,
> +				    &st->iio_channels[reg].info_mask_separate);
> +		}
> +
> +		chan->raw[0] = ltc2664_mspan_lut[mspan][1];
> +		chan->raw[1] = ltc2664_mspan_lut[mspan][1];
> +
> +		chan->span = ltc2664_mspan_lut[mspan][0];
> +
> +		ret = fwnode_property_read_u32_array(child, "adi,output-range-microvolt",
> +						     tmp, ARRAY_SIZE(tmp));
> +		if (!ret && mspan == LTC2664_MSPAN_SOFTSPAN) {
> +			chan->span = ltc2664_set_span(st, tmp[0] / 1000,
> +						      tmp[1] / 1000, reg);
> +			if (span < 0)
> +				return dev_err_probe(dev, span,
> +						     "Failed to set span\n");
> +
> +		}
> +
> +		ret = fwnode_property_read_u32(child,
> +					       "adi,output-range-microamp",
> +					       &tmp[0]);
> +		if (!ret) {
> +			chan->span = ltc2664_set_span(st, 0, tmp[0] / 1000, reg);
> +			if (span < 0)
> +				return dev_err_probe(dev, span,
> +						     "Failed to set span\n");
> +		}
> +	}
> +
> +	return 0;
> +}