Re: [PATCH v2 3/3] iio: adc: ad7380: new driver for AD7380 ADCs

["Nuno Sá" <noname.nuno@gmail.com>]

On Wed, 2023-12-13 at 14:47 +0100, David Lechner wrote:
> On Wed, Dec 13, 2023 at 1:18 PM Nuno Sá <noname.nuno@gmail.com> wrote:
> > 
> > On Wed, 2023-12-13 at 05:21 -0600, David Lechner wrote:
> > > This adds a new driver for the AD7380 family ADCs.
> > > 
> > > The driver currently implements basic support for the AD7380, AD7381,
> > > AD7383, and AD7384 2-channel differential ADCs. Support for additional
> > > single-ended and 4-channel chips that use the same register map as well
> > > as additional features of the chip will be added in future patches.
> > > 
> > > Co-developed-by: Stefan Popa <stefan.popa@analog.com>
> > > Signed-off-by: Stefan Popa <stefan.popa@analog.com>
> > > Signed-off-by: David Lechner <dlechner@baylibre.com>
> > > ---
> > > 
> > > v2 changes:
> > > - Fixed CONFIG_AD7380 in Makefile
> > > - rx_buf = st->scan_data.raw instead of rx_buf = &st->scan_data
> > > - Moved iio_push_to_buffers_with_timestamp() outside of if statement
> > > - Removed extra blank lines
> > > - Renamed regulator disable function
> > > - Dropped checking of adi,sdo-mode property (regardless of the actual
> > >         wiring, we can always use 1-wire mode)
> > > - Added available_scan_masks (we always sample two channels at the same time
> > >   so we need to let userspace know this)
> > > - Added check for missing driver match data
> > > 
> > >  MAINTAINERS              |   1 +
> > >  drivers/iio/adc/Kconfig  |  16 ++
> > >  drivers/iio/adc/Makefile |   1 +
> > >  drivers/iio/adc/ad7380.c | 464 +++++++++++++++++++++++++++++++++++++++++++++++
> > >  4 files changed, 482 insertions(+)
> > > 
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index e2a998be5879..5a54620a31b8 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -438,6 +438,7 @@ S:  Supported
> > >  W:
> > > https://wiki.analog.com/resources/tools-software/linux-drivers/iio-adc/ad738x
> > >  W:     https://ez.analog.com/linux-software-drivers
> > >  F:     Documentation/devicetree/bindings/iio/adc/adi,ad7380.yaml
> > > +F:     drivers/iio/adc/ad7380.c
> > > 
> > >  AD7877 TOUCHSCREEN DRIVER
> > >  M:     Michael Hennerich <michael.hennerich@analog.com>
> > > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > > index 35f9867da12c..cbfd626712e3 100644
> > > --- a/drivers/iio/adc/Kconfig
> > > +++ b/drivers/iio/adc/Kconfig
> > > @@ -122,6 +122,22 @@ config AD7298
> > >           To compile this driver as a module, choose M here: the
> > >           module will be called ad7298.
> > > 
> > > +config AD7380
> > > +       tristate "Analog Devices AD7380 ADC driver"
> > > +       depends on SPI_MASTER
> > > +       select IIO_BUFFER
> > > +       select IIO_TRIGGER
> > > +       select IIO_TRIGGERED_BUFFER
> > > +       help
> > > +         AD7380 is a family of simultaneous sampling ADCs that share the same
> > > +         SPI register map and have similar pinouts.
> > > +
> > > +         Say yes here to build support for Analog Devices AD7380 ADC and
> > > +         similar chips.
> > > +
> > > +         To compile this driver as a module, choose M here: the module will be
> > > +         called ad7380.
> > > +
> > >  config AD7476
> > >         tristate "Analog Devices AD7476 1-channel ADCs driver and other similar
> > > devices from AD and TI"
> > >         depends on SPI
> > > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> > > index bee11d442af4..9c921c497655 100644
> > > --- a/drivers/iio/adc/Makefile
> > > +++ b/drivers/iio/adc/Makefile
> > > @@ -16,6 +16,7 @@ obj-$(CONFIG_AD7291) += ad7291.o
> > >  obj-$(CONFIG_AD7292) += ad7292.o
> > >  obj-$(CONFIG_AD7298) += ad7298.o
> > >  obj-$(CONFIG_AD7923) += ad7923.o
> > > +obj-$(CONFIG_AD7380) += ad7380.o
> > >  obj-$(CONFIG_AD7476) += ad7476.o
> > >  obj-$(CONFIG_AD7606_IFACE_PARALLEL) += ad7606_par.o
> > >  obj-$(CONFIG_AD7606_IFACE_SPI) += ad7606_spi.o
> > > diff --git a/drivers/iio/adc/ad7380.c b/drivers/iio/adc/ad7380.c
> > > new file mode 100644
> > > index 000000000000..b8025b636b67
> > > --- /dev/null
> > > +++ b/drivers/iio/adc/ad7380.c
> > > @@ -0,0 +1,464 @@
> > > +// SPDX-License-Identifier: GPL-2.0-only
> > > +/*
> > > + * Analog Devices AD738x Simultaneous Sampling SAR ADCs
> > > + *
> > > + * Copyright 2017 Analog Devices Inc.
> > > + * Copyright 2023 BayLibre, SAS
> > > + */
> > > +
> > > +#include <linux/bitfield.h>
> > > +#include <linux/bitops.h>
> > > +#include <linux/cleanup.h>
> > > +#include <linux/device.h>
> > > +#include <linux/err.h>
> > > +#include <linux/kernel.h>
> > > +#include <linux/module.h>
> > > +#include <linux/regmap.h>
> > > +#include <linux/regulator/consumer.h>
> > > +#include <linux/slab.h>
> > > +#include <linux/spi/spi.h>
> > > +#include <linux/sysfs.h>
> > > +
> > > +#include <linux/iio/buffer.h>
> > > +#include <linux/iio/iio.h>
> > > +#include <linux/iio/sysfs.h>
> > > +#include <linux/iio/trigger_consumer.h>
> > > +#include <linux/iio/triggered_buffer.h>
> > > +
> > 
> > ...
> > 
> > > 
> > > +static int ad7380_probe(struct spi_device *spi)
> > > +{
> > > +       struct iio_dev *indio_dev;
> > > +       struct ad7380_state *st;
> > > +       int ret;
> > > +
> > > +       indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> > > +       if (!indio_dev)
> > > +               return -ENOMEM;
> > > +
> > > +       st = iio_priv(indio_dev);
> > > +       st->spi = spi;
> > > +       st->chip_info = spi_get_device_match_data(spi);
> > > +       if (!st->chip_info)
> > > +               return dev_err_probe(&spi->dev, -EINVAL, "missing match
> > > data\n");
> > > +
> > > +       st->vref = devm_regulator_get_optional(&spi->dev, "refio");
> > > +       if (IS_ERR(st->vref)) {
> > > +               /*
> > > +                * If there is no REFIO supply, then it means that we are using
> > > +                * the internal 2.5V reference.
> > > +                */
> > > +               if (PTR_ERR(st->vref) == -ENODEV)
> > > +                       st->vref = NULL;
> > > +               else
> > > +                       return dev_err_probe(&spi->dev, PTR_ERR(st->vref),
> > > +                                            "Failed to get refio
> > > regulator\n");
> > > +       }
> > > +
> > > +       if (st->vref) {
> > > +               ret = regulator_enable(st->vref);
> > > +               if (ret)
> > > +                       return ret;
> > > +
> > > +               ret = devm_add_action_or_reset(&spi->dev,
> > > ad7380_regulator_disable,
> > > +                                              st->vref);
> > > +               if (ret)
> > > +                       return ret;
> > > +       }
> > > +
> > > +       st->regmap = devm_regmap_init(&spi->dev, NULL, st,
> > > &ad7380_regmap_config);
> > > +       if (IS_ERR(st->regmap))
> > > +               return dev_err_probe(&spi->dev, PTR_ERR(st->regmap),
> > > +                                    "failed to allocate register map\n");
> > 
> > Still not using a regmap_bus... You could at least argue in the last version why
> > you're not doing it rather than ignoring the comment :).
> > 
> > I'm asking for it because it already happened (in IIO) to me and I was asked for
> > implementing the bus. You also gain things like regmap core handling endianism
> > and
> > formatting the work buffer for you (eg: regmap_bulk_read() could be more
> > efficient),
> > 
> > > +       indio_dev->channels = st->chip_info->channels;
> > > +       indio_dev->num_channels = st->chip_info->num_channels;
> > > +       indio_dev->dev.parent = &spi->dev;
> > 
> > still not addressed...
> > 
> > With at least the above (for the regmap_bus I'll leave the ultimate decision to
> > Jonathan - not a deal breaker for me):
> > 
> > Reviewed-by: Nuno Sa <nuno.sa@analog.com>
> > 
> > 
> > - Nuno Sá
> > 
> 
> Sorry, I did not mean to ignore these. I just did a bad job of
> double-checking that I addressed all comments before sending v2. :-(
> 

no worries (done that and will do it again) :)

> If we need a v3, I will look into regmap_bus but at leas

Well, at least 'indio_dev->dev.parent = &spi->dev;' should be removed. But yeah, if
the regmap_bus is not to be required then Jonathan might just do it while applying.

- Nuno Sá