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SubjectRE: [PATCH v6 1/2] iio: frequency: adrf6780: add support for ADRF6780
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Hello Andy,

Thanks for the review:

> -----Original Message-----
> From: Andy Shevchenko <andy.shevchenko@gmail.com>
> Sent: Friday, July 16, 2021 5:53 PM
> To: Miclaus, Antoniu <Antoniu.Miclaus@analog.com>
> Cc: linux-iio@vger.kernel.org; linux-kernel@vger.kernel.org;
> jic23@kernel.org; devicetree@vger.kernel.org
> Subject: Re: [PATCH v6 1/2] iio: frequency: adrf6780: add support for
> ADRF6780
>
> [External]
>
> On Fri, Jul 16, 2021 at 2:43 PM Antoniu Miclaus
> <antoniu.miclaus@analog.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
>
> Is it one line? If not, please put on one line and drop below the
> blank line so it will go as a tag.
Yes, it is one line.
>
> >
> > Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
>
> First question is why not to use the regmap API (I have heard it has
> gained support of 17 bit)?

Initially that was the plan, but after this patch:
https://github.com/torvalds/linux/commit/4191f19792bf91267835eb090d970e9cd6277a65
the custom write formats for regmap allow the read only via cached registers.

Therefore, I preferred using spi transfers for write/read to/from the device.
> ...
>
> > + depends on COMMON_CLK
>
> Is it mandatory for any function inside the device?

Yes. It will serve as LO input to the device.
>
> ...
>
> > +static int adrf6780_spi_read(struct adrf6780_dev *dev, unsigned int reg,
> > + unsigned int *val)
> > +{
> > + int ret;
> > + struct spi_transfer t = {0};
>
> > + dev->data[0] = 0x80 | (reg << 1);
>
> This 0x80 I guess is pretty much standard and regmap SPI supports it.
>
> > + dev->data[1] = 0x0;
> > + dev->data[2] = 0x0;
> > +
> > + t.rx_buf = &dev->data[0];
> > + t.tx_buf = &dev->data[0];
> > + t.len = 3;
> > +
> > + ret = spi_sync_transfer(dev->spi, &t, 1);
> > + if (ret)
> > + return ret;
> > +
> > + *val = (get_unaligned_be24(&dev->data[0]) >> 1) & GENMASK(15, 0);
> > +
> > + return ret;
> > +}
>
> ...
>
> > + usleep_range(200, 250);
>
> Needs a comment.
Will add in next patch version.
>
> --
> With Best Regards,
> Andy Shevchenko

Regards,
Antoniu
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