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Date:   Tue, 16 Apr 2019 10:05:40 +0200
From:   Boris Brezillon <boris.brezillon@collabora.com>
To:     Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Cc:     Vitor Soares <vitor.soares@synopsys.com>,
        linux-iio@vger.kernel.org, linux-i3c@lists.infradead.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Hartmut Knaack <knaack.h@gmx.de>,
        Jonathan Cameron <jic23@kernel.org>, bbrezillon@kernel.org,
        rafael@kernel.org, gregkh@linuxfoundation.org, broonie@kernel.org,
        joao.pinto@synopsys.com
Subject: Re: [PATCH 3/3] iio: imu: st_lsm6dsx: Add i3c basic support
Message-ID: <20190416100540.7adf1fe5@collabora.com>
In-Reply-To: <CAA2SeNJ1cTxAp6+5Q4Z5L4VFBfA3U4e11_Obpk8muD1Vh3v52A@mail.gmail.com>
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        <20190416082539.2f12b38f@collabora.com>
        <CAA2SeNJ1cTxAp6+5Q4Z5L4VFBfA3U4e11_Obpk8muD1Vh3v52A@mail.gmail.com>
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On Tue, 16 Apr 2019 09:58:33 +0200
Lorenzo Bianconi <lorenzo.bianconi83@gmail.com> wrote:

> >
> > On Mon, 15 Apr 2019 21:19:41 +0200
> > Vitor Soares <vitor.soares@synopsys.com> wrote:
> >  
> > > For today the st_lsm6dsx driver support lsm6dso sensor only in
> > > spi and i2c mode.
> > >
> > > The lsm6dso is also i3c capable so lets give i3c support to it.
> > >
> > > Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
> > > ---
> > >  drivers/iio/imu/st_lsm6dsx/Kconfig          |  8 +++-
> > >  drivers/iio/imu/st_lsm6dsx/Makefile         |  1 +
> > >  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i3c.c | 67 +++++++++++++++++++++++++++++
> > >  3 files changed, 75 insertions(+), 1 deletion(-)
> > >  create mode 100644 drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i3c.c
> > >
> > > diff --git a/drivers/iio/imu/st_lsm6dsx/Kconfig b/drivers/iio/imu/st_lsm6dsx/Kconfig
> > > index 094fd00..1ab9bbf 100644
> > > --- a/drivers/iio/imu/st_lsm6dsx/Kconfig
> > > +++ b/drivers/iio/imu/st_lsm6dsx/Kconfig
> > > @@ -1,11 +1,12 @@
> > >
> > >  config IIO_ST_LSM6DSX
> > >       tristate "ST_LSM6DSx driver for STM 6-axis IMU MEMS sensors"
> > > -     depends on (I2C || SPI)
> > > +     depends on (I2C || SPI || I3C)
> > >       select IIO_BUFFER
> > >       select IIO_KFIFO_BUF
> > >       select IIO_ST_LSM6DSX_I2C if (I2C)
> > >       select IIO_ST_LSM6DSX_SPI if (SPI_MASTER)
> > > +     select IIO_ST_LSM6DSX_I3C if (I3C)
> > >       help
> > >         Say yes here to build support for STMicroelectronics LSM6DSx imu
> > >         sensor. Supported devices: lsm6ds3, lsm6ds3h, lsm6dsl, lsm6dsm,
> > > @@ -23,3 +24,8 @@ config IIO_ST_LSM6DSX_SPI
> > >       tristate
> > >       depends on IIO_ST_LSM6DSX
> > >       select REGMAP_SPI
> > > +
> > > +config IIO_ST_LSM6DSX_I3C
> > > +     tristate
> > > +     depends on IIO_ST_LSM6DSX
> > > +     select REGMAP_I3C
> > > diff --git a/drivers/iio/imu/st_lsm6dsx/Makefile b/drivers/iio/imu/st_lsm6dsx/Makefile
> > > index e5f733c..c676965 100644
> > > --- a/drivers/iio/imu/st_lsm6dsx/Makefile
> > > +++ b/drivers/iio/imu/st_lsm6dsx/Makefile
> > > @@ -4,3 +4,4 @@ st_lsm6dsx-y := st_lsm6dsx_core.o st_lsm6dsx_buffer.o \
> > >  obj-$(CONFIG_IIO_ST_LSM6DSX) += st_lsm6dsx.o
> > >  obj-$(CONFIG_IIO_ST_LSM6DSX_I2C) += st_lsm6dsx_i2c.o
> > >  obj-$(CONFIG_IIO_ST_LSM6DSX_SPI) += st_lsm6dsx_spi.o
> > > +obj-$(CONFIG_IIO_ST_LSM6DSX_I3C) += st_lsm6dsx_i3c.o
> > > diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i3c.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i3c.c
> > > new file mode 100644
> > > index 0000000..2df5e70
> > > --- /dev/null
> > > +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i3c.c
> > > @@ -0,0 +1,67 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Copyright (c) 2018 Synopsys, Inc. and/or its affiliates.
> > > + *
> > > + * Author: Vitor Soares <vitor.soares@synopsys.com>
> > > + */
> > > +
> > > +#include <linux/kernel.h>
> > > +#include <linux/module.h>
> > > +#include <linux/i3c/device.h>
> > > +#include <linux/i3c/master.h>
> > > +#include <linux/slab.h>
> > > +#include <linux/of.h>
> > > +#include <linux/regmap.h>
> > > +
> > > +#include "st_lsm6dsx.h"
> > > +
> > > +#define NAME_SIZE    32
> > > +
> > > +struct st_lsm6dsx_i3c_data {
> > > +     char name[NAME_SIZE];  
> >
> >         const char *name;
> >  
> > > +     enum st_lsm6dsx_hw_id id;
> > > +};
> > > +
> > > +static const struct st_lsm6dsx_i3c_data hw_data[] = {  
> >
> > No need to make it an array, and it should probably be named
> > st_lsm6dso_data not hw_data.  
> 
> I guess it will be used even for future devices so I would prefer to
> make it an array with a 'general' name

I find it more error-prone to reference an array with an opaque index
number than reference an instance with a name that clearly reflects
what HW it describes (see the I3C_DEVICE() entry at the end of the
driver), but okay.

> 
> Regards,
> Lorenzo
> 
> >  
> > > +     { ST_LSM6DSO_DEV_NAME, ST_LSM6DSO_ID },
> > > +};
> > > +
> > > +static const struct regmap_config st_lsm6dsx_i3c_regmap_config = {
> > > +     .reg_bits = 8,
> > > +     .val_bits = 8,
> > > +};
> > > +
> > > +static int st_lsm6dsx_i3c_probe(struct i3c_device *i3cdev)
> > > +{
> > > +     const struct i3c_device_id *id = i3c_get_device_id(i3cdev);  
> >
> >                                          i3c_device_match_id(i3cdev,
> >                                                              st_lsm6dsx_i3c_ids);
> >  
> > > +     const struct st_lsm6dsx_i3c_data *hw_data = id->data;
> > > +     struct regmap *regmap;
> > > +
> > > +     regmap = devm_regmap_init_i3c(i3cdev, &st_lsm6dsx_i3c_regmap_config);
> > > +     if (IS_ERR(regmap)) {
> > > +             dev_err(&i3cdev->dev, "Failed to register i3c regmap %d\n",
> > > +                     (int)PTR_ERR(regmap));
> > > +             return PTR_ERR(regmap);
> > > +     }
> > > +
> > > +     return st_lsm6dsx_probe(&i3cdev->dev, 0, hw_data->id,
> > > +                             hw_data->name, regmap);
> > > +}
> > > +
> > > +
> > > +static const struct i3c_device_id st_lsm6dsx_i3c_ids[] = {
> > > +     I3C_DEVICE(0x0104, 0x006C, &hw_data[0]),
> > > +     { /* sentinel */ },
> > > +};
> > > +MODULE_DEVICE_TABLE(i3c, st_lsm6dsx_i3c_ids);
> > > +
> > > +static struct i3c_driver st_lsm6dsx_driver = {
> > > +     .driver.name = "st_lsm6dsx_i3c",
> > > +     .probe = st_lsm6dsx_i3c_probe,
> > > +     .id_table = st_lsm6dsx_i3c_ids,  
> >
> > You should probably set the pm_ops here (st_lsm6dsx_pm_ops).
> >  
> > > +};
> > > +module_i3c_driver(st_lsm6dsx_driver);
> > > +
> > > +MODULE_AUTHOR("Vitor Soares <vitor.soares@synopsys.com>");
> > > +MODULE_DESCRIPTION("STMicroelectronics st_lsm6dsx i3c driver");
> > > +MODULE_LICENSE("GPL v2");
> > > +  
> >
> > You can remove this blank line.
> >  
> 
>