On 10 April 2016 at 14:47, Joachim Eastwood <manabian@xxxxxxxxx> wrote: > Hi Cristina, > > On 9 April 2016 at 10:24, Cristina Moraru <cristina.moraru09@xxxxxxxxx> wrote: >> Add implementation for Maxim MAX5487, MAX5488, MAX5489 >> digital potentiometers. >> >> Datasheet: >> http://datasheets.maximintegrated.com/en/ds/MAX5487-MAX5489.pdf >> >> Signed-off-by: Cristina Moraru <cristina.moraru09@xxxxxxxxx> >> CC: Daniel Baluta <daniel.baluta@xxxxxxxxx> >> --- > ... >> +static int max5487_read_raw(struct iio_dev *indio_dev, >> + struct iio_chan_spec const *chan, >> + int *val, int *val2, long mask) >> +{ >> + struct max5487_data *data = iio_priv(indio_dev); >> + >> + if (mask != IIO_CHAN_INFO_SCALE) >> + return -EINVAL; >> + >> + *val = 1000 * data->kohms; >> + *val2 = MAX5487_MAX_POS; > > Newline before return. > >> + return IIO_VAL_FRACTIONAL; >> +} >> + >> +static int max5487_write_raw(struct iio_dev *indio_dev, >> + struct iio_chan_spec const *chan, >> + int val, int val2, long mask) >> +{ >> + struct max5487_data *data = iio_priv(indio_dev); >> + >> + switch (mask) { >> + case IIO_CHAN_INFO_RAW: >> + if (val < 0 || val > MAX5487_MAX_POS) >> + return -EINVAL; >> + return regmap_write(data->regmap, chan->address, val); >> + default: >> + return -EINVAL; >> + } >> + return -EINVAL; > > To be consistent with your max5487_read_raw() function you could do a: > if (mask != IIO_CHAN_INFO_RAW) > return -EINVAL; > > >> +static const struct iio_info max5487_info = { >> + .read_raw = &max5487_read_raw, >> + .write_raw = &max5487_write_raw, > > Address operator should be unnecessary on functions. > > >> + data->regmap = devm_regmap_init_spi(spi, &max5487_regmap_config); >> + if (IS_ERR(data->regmap)) >> + return PTR_ERR(data->regmap); > > Nothing wrong with using regmap here, but since you are only using > simple regmap_write()'s you might as well have used spi_write() > directly. I am not telling you to switch, but I don't see the point of > using regmap here. Looking again: it seem that spi.h doesn't have a function that do write(cmd, data) which regmap does. So I guess that is one reason for using regmap. But it wouldn't be hard to create a write(cmd, data)-function for spi either. Just wrap spi_write() and have a local buf var. I am a bit surprised that spi.h doesn't have such a function as it should be quite a common pattern for spi chips. > > Which reminds me; for regmap you need to select REGMAP_SPI in your > Kconfig entry. > > > regards, > Joachim Eastwood -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
