Re: [PATCH v2 2/5] iio: pressure: bmp280: Add preinit callback

[Angel Iglesias <ang.iglesiasg@gmail.com>]

On Fri, 2022-12-30 at 18:18 +0000, Jonathan Cameron wrote:
> On Mon, 26 Dec 2022 15:29:21 +0100
> Angel Iglesias <ang.iglesiasg@gmail.com> wrote:
> 
> > Adds preinit callback to execute operations on probe before applying
> > initial configuration.
> > 
> > Signed-off-by: Angel Iglesias <ang.iglesiasg@gmail.com>
> > 
> > diff --git a/drivers/iio/pressure/bmp280-core.c
> > b/drivers/iio/pressure/bmp280-core.c
> > index 46959a91408f..c37cf2caec68 100644
> > --- a/drivers/iio/pressure/bmp280-core.c
> > +++ b/drivers/iio/pressure/bmp280-core.c
> > @@ -217,6 +217,7 @@ struct bmp280_chip_info {
> >         int (*read_press)(struct bmp280_data *, int *, int *);
> >         int (*read_humid)(struct bmp280_data *, int *, int *);
> >         int (*read_calib)(struct bmp280_data *);
> > +       int (*preinit)(struct bmp280_data *);
> >  };
> >  
> >  /*
> > @@ -935,6 +936,7 @@ static const struct bmp280_chip_info bmp280_chip_info =
> > {
> >         .read_temp = bmp280_read_temp,
> >         .read_press = bmp280_read_press,
> >         .read_calib = bmp280_read_calib,
> > +       .preinit = NULL,
> C standard guarantees those are set to NULL anyway + the default is obvious.
> Hence don't set them to NULL, just leave the automatic initialization of
> unspecified structure elements to handle it for you.

OK! Note to self: compiler knows best!

> >  };
> >  
> >  static int bme280_chip_config(struct bmp280_data *data)
> > @@ -979,6 +981,7 @@ static const struct bmp280_chip_info bme280_chip_info =
> > {
> >         .read_press = bmp280_read_press,
> >         .read_humid = bmp280_read_humid,
> >         .read_calib = bme280_read_calib,
> > +       .preinit = NULL,
> >  };
> >  
> >  /*
> > @@ -1220,6 +1223,12 @@ static const int bmp380_odr_table[][2] = {
> >         [BMP380_ODR_0_0015HZ]   = {0, 1526},
> >  };
> >  
> > +static int bmp380_preinit(struct bmp280_data *data)
> > +{
> > +       /* BMP3xx requires soft-reset as part of initialization */
> > +       return bmp380_cmd(data, BMP380_CMD_SOFT_RESET);
> > +}
> > +
> >  static int bmp380_chip_config(struct bmp280_data *data)
> >  {
> >         bool change = false, aux;
> > @@ -1349,6 +1358,7 @@ static const struct bmp280_chip_info bmp380_chip_info
> > = {
> >         .read_temp = bmp380_read_temp,
> >         .read_press = bmp380_read_press,
> >         .read_calib = bmp380_read_calib,
> > +       .preinit = bmp380_preinit,
> >  };
> >  
> >  static int bmp180_measure(struct bmp280_data *data, u8 ctrl_meas)
> > @@ -1604,6 +1614,7 @@ static const struct bmp280_chip_info bmp180_chip_info
> > = {
> >         .read_temp = bmp180_read_temp,
> >         .read_press = bmp180_read_press,
> >         .read_calib = bmp180_read_calib,
> > +       .preinit = NULL,
> >  };
> >  
> >  static irqreturn_t bmp085_eoc_irq(int irq, void *d)
> > @@ -1762,9 +1773,13 @@ int bmp280_common_probe(struct device *dev,
> >                 return -EINVAL;
> >         }
> >  
> > -       /* BMP3xx requires soft-reset as part of initialization */
> > -       if (chip_id == BMP380_CHIP_ID) {
> > -               ret = bmp380_cmd(data, BMP380_CMD_SOFT_RESET);
> > +       /*
> > +        * Some chips like the BMP3xx have preinit tasks to run
> > +        * before applying the initial configuration.
> > +        */
> I would drop this comment. It's kind of obvious that some devices need you
> to call something here - otherwise why have the clearly optional callback?
> The specific BMP3xx requirements are well commented in your new callback above
> so don't want to be here as well.
> 
> > +       if (data->chip_info->preinit) {
> > +               ret = data->chip_info->preinit(data);
> > +               dev_err(dev, "error running preinit tasks");
> 
> Error message printed on success...

Yup, sorry about that...

> 
> >                 if (ret < 0)
> >                         return ret;
> 
>                         return dev_err_probe(dev, ret, "error running preinit
> tasks");
> 
> >         }
> 
Thanks for your time!
Angel