linux-kernel - Re: [PATCH v4 4/5] iio: pressure: bmp280: Add support for BMP380 sensor family

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Message-ID: <38786c4f1217102840eccd50cd9df530caed2add.camel@gmail.com>
Date:   Mon, 01 Aug 2022 09:57:56 +0200
From:   Angel Iglesias <ang.iglesiasg@...il.com>
To:     Jonathan Cameron <jic23@...nel.org>
Cc:     linux-iio@...r.kernel.org, Lars-Peter Clausen <lars@...afoo.de>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Nikita Yushchenko <nikita.yoush@...entembedded.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Paul Cercueil <paul@...pouillou.net>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 4/5] iio: pressure: bmp280: Add support for BMP380
 sensor family

On dom, 2022-07-31 at 17:16 +0100, Jonathan Cameron wrote:
> On Sat, 23 Jul 2022 19:39:44 +0200
> Angel Iglesias <ang.iglesiasg@...il.com> wrote:
> 
> > Adds compatibility with the new generation of this sensor, the BMP380
> > 
> > Includes basic sensor initialization to do pressure and temp
> > measurements and allows tuning oversampling settings for each channel.
> > 
> > The compensation algorithms are adapted from the device datasheet and
> > the repository https://github.com/BoschSensortec/BMP3-Sensor-API
> > 
> > Signed-off-by: Angel Iglesias <ang.iglesiasg@...il.com>
> 
> Hi Angel,
> 
> A comment below. Follows on from comment on previous patch rather than being a
> suggestion to change anything in here (beyond what has already been raised by
> others!)
> 
> Jonathan
> 
> > +static int bmp380_read_calib(struct bmp280_data *data, unsigned int chip)
> > +{
> > +       struct bmp380_calib *calib = &data->calib.bmp380;
> > +       int ret;
> > +       u8 *buf;
> > +
> > +       buf = kmalloc(BMP380_CALIB_REG_COUNT, GFP_KERNEL);
> 
> Ah. The complexity in here explains somewhat why you did it with u8 in the
> previous
> patch.  Probably still better to have a __be16 buffer for that one though
> even though we can't do that here.

Yes, I thought that, although I had to make more cumbersome the conversions and
do the +2 increment on the enum with the index, it would be better to have a
somewhat more uniform structure in each calib reading function.

> > +       if (!buf)
> > +               return -ENOMEM;
> > +
> > +       /* Read temperature calibration values. */
> > +       ret = regmap_bulk_read(data->regmap, BMP380_REG_CALIB_TEMP_START,
> > buf,
> > +                              BMP380_CALIB_REG_COUNT);
> > +       if (ret < 0) {
> > +               dev_err(data->dev,
> > +                       "failed to read temperature calibration
> > parameters\n");
> > +               kfree(buf);
> > +               return ret;
> > +       }
> > +
> > +       /* Toss the temperature calibration data into the entropy pool */
> > +       add_device_randomness(buf, BMP380_CALIB_REG_COUNT);
> > +
> > +       /* Parse calibration data */
> > +       calib->T1 = get_unaligned_le16(&buf[BMP380_T1]);
> > +       calib->T2 = get_unaligned_le16(&buf[BMP380_T2]);
> > +       calib->T3 = buf[BMP380_T3];
> > +       calib->P1 = get_unaligned_le16(&buf[BMP380_P1]);
> > +       calib->P2 = get_unaligned_le16(&buf[BMP380_P2]);
> > +       calib->P3 = buf[BMP380_P3];
> > +       calib->P4 = buf[BMP380_P4];
> > +       calib->P5 = get_unaligned_le16(&buf[BMP380_P5]);
> > +       calib->P6 = get_unaligned_le16(&buf[BMP380_P6]);
> > +       calib->P7 = buf[BMP380_P7];
> > +       calib->P8 = buf[BMP380_P8];
> > +       calib->P9 = get_unaligned_le16(&buf[BMP380_P9]);
> > +       calib->P10 = buf[BMP380_P10];
> > +       calib->P11 = buf[BMP380_P11];
> > +
> > +       kfree(buf);
> > +       return 0;
> > +}
> > +

Thanks for your comments,

Kind regards,
Angel