RE: [PATCH v4 3/3] iio: imu: st_lsm6dsx: add i3c basic support for LSM6DSO and LSM6DSR

[Vitor Soares <Vitor.Soares@synopsys.com>]

From: Boris Brezillon <boris.brezillon@collabora.com>
Date: Fri, Jul 12, 2019 at 17:14:29

> On Fri, 12 Jul 2019 13:53:30 +0200
> Vitor Soares <Vitor.Soares@synopsys.com> wrote:
> 
> > For today the st_lsm6dsx driver support LSM6DSO and LSM6DSR sensor only in
> > spi and i2c mode.
> > 
> > The LSM6DSO and LSM6DSR are also i3c capable so lets give i3c support to
> > them.
> > 
> > Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
> > Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > ---
> > Changes in v4:
> >   Remove hw_id variable
> > 
> > Changes in v3:
> >   Remove unnecessary st_lsm6dsx_i3c_data table used to hold device name
> >   Use st_lsm6dsx_probe new form
> > 
> > Changes in v2:
> >   Add support for LSM6DSR
> >   Set pm_ops to st_lsm6dsx_pm_ops
> > 
> >  drivers/iio/imu/st_lsm6dsx/Kconfig          |  8 +++-
> >  drivers/iio/imu/st_lsm6dsx/Makefile         |  1 +
> >  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i3c.c | 58 +++++++++++++++++++++++++++++
> >  3 files changed, 66 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 9e59297..6b5a73c 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..2e89524
> > --- /dev/null
> > +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i3c.c
> > @@ -0,0 +1,58 @@
> > +// 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"
> > +
> > +static const struct i3c_device_id st_lsm6dsx_i3c_ids[] = {
> > +	I3C_DEVICE(0x0104, 0x006C, (void *)ST_LSM6DSO_ID),
> > +	I3C_DEVICE(0x0104, 0x006B, (void *)ST_LSM6DSR_ID),
> 
> I think you need an uintptr_t cast here:
> 
> 	I3C_DEVICE(0x0104, 0x006C, (void *)(uintptr_t)ST_LSM6DSO_ID),
> 	I3C_DEVICE(0x0104, 0x006B, (void *)(uintptr_t)ST_LSM6DSR_ID),
> 
> otherwise gcc might complain that the integer and pointer do not have
> the same size (on 64-bit architectures).

I don't understand this part. Can you provide or point some background? 

> 
> > +	{ /* sentinel */ },
> > +};
> > +MODULE_DEVICE_TABLE(i3c, st_lsm6dsx_i3c_ids);
> > +
> > +static const struct regmap_config st_lsm6dsx_i3c_regmap_config = {
> > +	.reg_bits = 8,
> > +	.val_bits = 8,
> > +};
> 
> This can be moved ...
> 
> > +
> > +static int st_lsm6dsx_i3c_probe(struct i3c_device *i3cdev)
> > +{
> 
> ... here without the static and const qualifiers:

I understand that can be move to here, but I don't understand the 
advantages. Can you explain?

> 
> 	struct regmap_config regmap_config = {
> 		.reg_bits = 8,
> 		.val_bits = 8,
> 	};
> 
> > +	const struct i3c_device_id *id = i3c_device_match_id(i3cdev,
> > +							    st_lsm6dsx_i3c_ids);
> > +	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, (int)id->data, regmap);
> 
> uintptr_t cast here.
> 
> > +}
> > +
> > +static struct i3c_driver st_lsm6dsx_driver = {
> > +	.driver = {
> > +		.name = "st_lsm6dsx_i3c",
> > +		.pm = &st_lsm6dsx_pm_ops,
> > +	},
> > +	.probe = st_lsm6dsx_i3c_probe,
> > +	.id_table = st_lsm6dsx_i3c_ids,
> > +};
> > +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");

Best regards,
Vitor Soares



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