linux-kernel - RE: [PATCH v6 1/2] iio: frequency: adrf6780: add support for ADRF6780

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Message-ID: <CY4PR03MB3399CAA3C32707CE3564A44B9BE29@CY4PR03MB3399.namprd03.prod.outlook.com>
Date:   Tue, 20 Jul 2021 13:34:08 +0000
From:   "Miclaus, Antoniu" <Antoniu.Miclaus@...log.com>
To:     Jonathan Cameron <jic23@...nel.org>
CC:     "linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: RE: [PATCH v6 1/2] iio: frequency: adrf6780: add support for ADRF6780

Hello Jonathan,


> -----Original Message-----
> From: Jonathan Cameron <jic23@...nel.org>
> Sent: Saturday, July 17, 2021 4:26 PM
> To: Miclaus, Antoniu <Antoniu.Miclaus@...log.com>
> Cc: linux-iio@...r.kernel.org; linux-kernel@...r.kernel.org;
> devicetree@...r.kernel.org
> Subject: Re: [PATCH v6 1/2] iio: frequency: adrf6780: add support for
> ADRF6780
> 
> [External]
> 
> On Fri, 16 Jul 2021 14:42:09 +0300
> Antoniu Miclaus <antoniu.miclaus@...log.com> wrote:
> 
> > The ADRF6780 is a silicon germanium (SiGe) design, wideband,
> > microwave upconverter optimized for point to point microwave
> > radio designs operating in the 5.9 GHz to 23.6 GHz frequency
> > range.
> >
> > Datasheet:
> > https://www.analog.com/media/en/technical-documentation/data-
> sheets/ADRF6780.pdf
> >
> > Signed-off-by: Antoniu Miclaus <antoniu.miclaus@...log.com>
> Hi Antoniu
> 
> As it looks like we'll have a v7, a few trivial comments from me.
> 
> ...
> 
> > +
> > +static int adrf6780_init(struct adrf6780_dev *dev)
> > +{
> > +	int ret;
> > +	unsigned int chip_id, enable_reg, enable_reg_msk;
> > +	struct spi_device *spi = dev->spi;
> > +
> > +	/* Perform a software reset */
> > +	ret = adrf6780_reset(dev);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = adrf6780_spi_read(dev, ADRF6780_REG_CONTROL, &chip_id);
> > +	if (ret)
> > +		return ret;
> > +
> > +	chip_id = FIELD_GET(ADRF6780_CHIP_ID_MSK, chip_id);
> > +	if (chip_id != ADRF6780_CHIP_ID) {
> > +		dev_err(&spi->dev, "ADRF6780 Invalid Chip ID.\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	enable_reg_msk = ADRF6780_VGA_BUFFER_EN_MSK |
> > +			ADRF6780_DETECTOR_EN_MSK |
> > +			ADRF6780_LO_BUFFER_EN_MSK |
> > +			ADRF6780_IF_MODE_EN_MSK |
> > +			ADRF6780_IQ_MODE_EN_MSK |
> > +			ADRF6780_LO_X2_EN_MSK |
> > +			ADRF6780_LO_PPF_EN_MSK |
> > +			ADRF6780_LO_EN_MSK |
> > +			ADRF6780_UC_BIAS_EN_MSK;
> > +
> > +	enable_reg = FIELD_PREP(ADRF6780_VGA_BUFFER_EN_MSK, dev-
> >vga_buff_en) |
> > +			FIELD_PREP(ADRF6780_DETECTOR_EN_MSK, 1) |
> > +			FIELD_PREP(ADRF6780_LO_BUFFER_EN_MSK, dev-
> >lo_buff_en) |
> > +			FIELD_PREP(ADRF6780_IF_MODE_EN_MSK, dev-
> >if_mode_en) |
> > +			FIELD_PREP(ADRF6780_IQ_MODE_EN_MSK, dev-
> >iq_mode_en) |
> > +			FIELD_PREP(ADRF6780_LO_X2_EN_MSK, dev-
> >lo_x2_en) |
> > +			FIELD_PREP(ADRF6780_LO_PPF_EN_MSK, dev-
> >lo_ppf_en) |
> > +			FIELD_PREP(ADRF6780_LO_EN_MSK, dev->lo_en) |
> > +			FIELD_PREP(ADRF6780_UC_BIAS_EN_MSK, dev-
> >uc_bias_en);
> 
> Here we are probably turning on a bunch of stuff which will result in power
> usage.
> Would it be sensible to turn it off again in remove path?  (devm managed
> should be fine).

Most of these attributes are enabled by default after device reset.
Taking into account this statement, is it still worth adding a 'custom' remove path?

> 
> 
> > +
> > +	ret = adrf6780_spi_update_bits(dev, ADRF6780_REG_ENABLE,
> enable_reg_msk, enable_reg);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = adrf6780_spi_update_bits(dev, ADRF6780_REG_LO_PATH,
> > +
> 	ADRF6780_LO_SIDEBAND_MSK,
> > +
> 	FIELD_PREP(ADRF6780_LO_SIDEBAND_MSK, dev->lo_sideband));
> > +	if (ret)
> > +		return ret;
> > +
> > +	return adrf6780_spi_update_bits(dev,
> ADRF6780_REG_ADC_CONTROL,
> > +
> 	ADRF6780_VDET_OUTPUT_SELECT_MSK,
> > +
> 	FIELD_PREP(ADRF6780_VDET_OUTPUT_SELECT_MSK, dev-
> >vdet_out_en));
> > +}
> > +
> 
> > +static void adrf6780_dt_parse(struct adrf6780_dev *dev)
> 
> Trivial nitpick, but given this is all device property based (great)
> the dt naming is now misleading.  Perhaps _properties_parse() ?
> 
> > +{
> > +	struct spi_device *spi = dev->spi;
> > +
> > +	dev->vga_buff_en = device_property_read_bool(&spi->dev,
> "adi,vga-buff-en");
> > +	dev->lo_buff_en = device_property_read_bool(&spi->dev, "adi,lo-
> buff-en");
> > +	dev->if_mode_en = device_property_read_bool(&spi->dev, "adi,if-
> mode-en");
> > +	dev->iq_mode_en = device_property_read_bool(&spi->dev, "adi,iq-
> mode-en");
> > +	dev->lo_x2_en = device_property_read_bool(&spi->dev, "adi,lo-x2-
> en");
> > +	dev->lo_ppf_en = device_property_read_bool(&spi->dev, "adi,lo-
> ppf-en");
> > +	dev->lo_en = device_property_read_bool(&spi->dev, "adi,lo-en");
> > +	dev->uc_bias_en = device_property_read_bool(&spi->dev, "adi,uc-
> bias-en");
> > +	dev->lo_sideband = device_property_read_bool(&spi->dev, "adi,lo-
> sideband");
> > +	dev->vdet_out_en = device_property_read_bool(&spi->dev,
> "adi,vdet-out-en");
> > +}

--
Antoniu Miclăuş