linux-kernel - Re: [PATCH v4 1/7] iio: accel: adxl345: Make data

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Message-ID: <20240328131500.068c82c3@jic23-huawei>
Date: Thu, 28 Mar 2024 13:15:00 +0000
From: Jonathan Cameron <jic23@...nel.org>
To: Lothar Rubusch <l.rubusch@...il.com>
Cc: lars@...afoo.de, Michael.Hennerich@...log.com, robh+dt@...nel.org,
 krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
 linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, eraretuya@...il.com
Subject: Re: [PATCH v4 1/7] iio: accel: adxl345: Make data_range obsolete

On Tue, 26 Mar 2024 21:59:34 +0100
Lothar Rubusch <l.rubusch@...il.com> wrote:

> On Mon, Mar 25, 2024 at 9:32 PM Jonathan Cameron <jic23@...nel.org> wrote:
> >
> > On Mon, 25 Mar 2024 15:33:50 +0000
> > Lothar Rubusch <l.rubusch@...il.com> wrote:
> >  
> > > Replace write() data_format by regmap_update_bits(), because
> > > bus specific pre-configuration may have happened before on
> > > the same register. Changes then need to be masked.
> > >
> > > Remove the data_range field from the struct adxl345_data,
> > > because it is not used anymore.
> > >
> > > Signed-off-by: Lothar Rubusch <l.rubusch@...il.com>
> > > ---
> > >  drivers/iio/accel/adxl345_core.c | 9 ++++-----
> > >  1 file changed, 4 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
> > > index 8bd30a23e..be6758015 100644
> > > --- a/drivers/iio/accel/adxl345_core.c
> > > +++ b/drivers/iio/accel/adxl345_core.c
> > > @@ -42,13 +42,13 @@
> > >  #define ADXL345_DATA_FORMAT_4G               1
> > >  #define ADXL345_DATA_FORMAT_8G               2
> > >  #define ADXL345_DATA_FORMAT_16G              3
> > > +#define ADXL345_DATA_FORMAT_MSK              ~((u8) BIT(6)) /* ignore spi-3wire */  
> >
> > I'm not keen on seeing masking of a bit we don't yet
> > handle done by value.  Can we instead build this up by what we 'want' to
> > write rather than don't. Will need a few more defines perhaps to cover
> > the masks of SELF_TEST, INT_INVERT, FULL_RES, Justify and Range.
> >  
> 
> Good point. Anyway, there is also an input driver implementation for
> the adxl345, mainly dealing with the interrupt feature as input
> device. Thus, for the iio implementation I would suggest to reduce the
> mask just to cover SELF_TEST and FULL_RES and leave INT_INVERT out. Is
> this ok?
yes, that sounds fine
> 
> > >
> > >  #define ADXL345_DEVID                        0xE5
> > >
> > >  struct adxl345_data {
> > >       const struct adxl345_chip_info *info;
> > >       struct regmap *regmap;
> > > -     u8 data_range;
> > >  };
> > >
> > >  #define ADXL345_CHANNEL(index, axis) {                                       \
> > > @@ -219,14 +219,13 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap)
> > >       data = iio_priv(indio_dev);
> > >       data->regmap = regmap;
> > >       /* Enable full-resolution mode */
> > > -     data->data_range = ADXL345_DATA_FORMAT_FULL_RES;
> > >       data->info = device_get_match_data(dev);
> > >       if (!data->info)
> > >               return -ENODEV;
> > >
> > > -     ret = regmap_write(data->regmap, ADXL345_REG_DATA_FORMAT,
> > > -                        data->data_range);
> > > -     if (ret < 0)
> > > +     ret = regmap_update_bits(regmap, ADXL345_REG_DATA_FORMAT,
> > > +                              ADXL345_DATA_FORMAT_MSK, ADXL345_DATA_FORMAT_FULL_RES);
> > > +     if (ret)
> > >               return dev_err_probe(dev, ret, "Failed to set data range\n");
> > >
> > >       indio_dev->name = data->info->name;  
> >