diff mbox series

[v1,6/7] iio: st_sensors: Add lsm9ds0 IMU support

Message ID 20210414195454.84183-6-andriy.shevchenko@linux.intel.com (mailing list archive)
State New
Headers show
Series [v1,1/7] iio: accel: st_accel: Move platform data from header to C file | expand

Commit Message

Andy Shevchenko April 14, 2021, 7:54 p.m. UTC
We can utilize separate drivers for accelerometer and magnetometer,
so here is the glue driver to enable LSM9DS0 IMU support.

The idea was suggested by Crestez Dan Leonard in [1]. The proposed change
was sent as RFC due to race condition concerns, which are indeed possible.

In order to amend the initial change, I went further by providing a specific
multi-instantiate probe driver that reuses existing accelerometer and
magnetometer.

[1]: https://lore.kernel.org/patchwork/patch/670353/

Suggested-by: Crestez Dan Leonard <leonard.crestez@intel.com>
Cc: mr.lahorde@laposte.net
Cc: Matija Podravec <matija_podravec@fastmail.fm>
Cc: Sergey Borishchenko <borischenko.sergey@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/iio/accel/st_accel_core.c            |  89 +++++++++-
 drivers/iio/imu/Kconfig                      |   1 +
 drivers/iio/imu/Makefile                     |   1 +
 drivers/iio/imu/st_lsm9ds0/Kconfig           |  28 ++++
 drivers/iio/imu/st_lsm9ds0/Makefile          |   5 +
 drivers/iio/imu/st_lsm9ds0/st_lsm9ds0.h      |  23 +++
 drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_core.c | 163 +++++++++++++++++++
 drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_i2c.c  |  84 ++++++++++
 drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_spi.c  |  83 ++++++++++
 drivers/iio/magnetometer/st_magn_core.c      |  98 +++++++++++
 include/linux/iio/common/st_sensors.h        |   2 +
 11 files changed, 576 insertions(+), 1 deletion(-)
 create mode 100644 drivers/iio/imu/st_lsm9ds0/Kconfig
 create mode 100644 drivers/iio/imu/st_lsm9ds0/Makefile
 create mode 100644 drivers/iio/imu/st_lsm9ds0/st_lsm9ds0.h
 create mode 100644 drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_core.c
 create mode 100644 drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_i2c.c
 create mode 100644 drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_spi.c

Comments

Jonathan Cameron April 18, 2021, 11:06 a.m. UTC | #1
On Wed, 14 Apr 2021 22:54:53 +0300
Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

> We can utilize separate drivers for accelerometer and magnetometer,
> so here is the glue driver to enable LSM9DS0 IMU support.
> 
> The idea was suggested by Crestez Dan Leonard in [1]. The proposed change
> was sent as RFC due to race condition concerns, which are indeed possible.

If you are going to mention races, good to give some flavour in here!


This driver makes me very nervous indeed.  I haven't 'found' any places
where the fact we'll write the same registers from each of the drivers
causes problems (e.g. int pin setup etc) but perhaps I'm missing something.

Shall we say that makes me rather keener to get eyes (and thought) on this
patch than normal :)


> 
> In order to amend the initial change, I went further by providing a specific
> multi-instantiate probe driver that reuses existing accelerometer and
> magnetometer.
> 
> [1]: https://lore.kernel.org/patchwork/patch/670353/
> 
> Suggested-by: Crestez Dan Leonard <leonard.crestez@intel.com>
> Cc: mr.lahorde@laposte.net
> Cc: Matija Podravec <matija_podravec@fastmail.fm>
> Cc: Sergey Borishchenko <borischenko.sergey@gmail.com>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

A few comments in here, though mostly about stuff related to the origin code
you are copying so perhaps not tidying them up is preferable because it would
complicate comparison of the two cases.
> ---
>  drivers/iio/accel/st_accel_core.c            |  89 +++++++++-
>  drivers/iio/imu/Kconfig                      |   1 +
>  drivers/iio/imu/Makefile                     |   1 +
>  drivers/iio/imu/st_lsm9ds0/Kconfig           |  28 ++++
>  drivers/iio/imu/st_lsm9ds0/Makefile          |   5 +
>  drivers/iio/imu/st_lsm9ds0/st_lsm9ds0.h      |  23 +++
>  drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_core.c | 163 +++++++++++++++++++
>  drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_i2c.c  |  84 ++++++++++
>  drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_spi.c  |  83 ++++++++++
>  drivers/iio/magnetometer/st_magn_core.c      |  98 +++++++++++
>  include/linux/iio/common/st_sensors.h        |   2 +
>  11 files changed, 576 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/iio/imu/st_lsm9ds0/Kconfig
>  create mode 100644 drivers/iio/imu/st_lsm9ds0/Makefile
>  create mode 100644 drivers/iio/imu/st_lsm9ds0/st_lsm9ds0.h
>  create mode 100644 drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_core.c
>  create mode 100644 drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_i2c.c
>  create mode 100644 drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_spi.c
> 
> diff --git a/drivers/iio/accel/st_accel_core.c b/drivers/iio/accel/st_accel_core.c
> index 5c258c1ca62d..dc32ebefe3fc 100644
> --- a/drivers/iio/accel/st_accel_core.c
> +++ b/drivers/iio/accel/st_accel_core.c
> @@ -980,7 +980,94 @@ static const struct st_sensor_settings st_accel_sensors_settings[] = {
>  		.multi_read_bit = true,
>  		.bootime = 2,
>  	},
> -
> +	{
> +		.wai = 0x49,
> +		.wai_addr = ST_SENSORS_DEFAULT_WAI_ADDRESS,
> +		.sensors_supported = {
> +			[0] = LSM9DS0_IMU_DEV_NAME,

What does the name attribute report for these?

Previously we've had the _accel etc postfix to differentiate the devices. I don't
suppose it matters to much though as easy enough to identify the accelerometer
etc from what channels are present.

Of course driver may get name from somewhere different anyway, I haven't checked,
just noticed this was different and wondered what the affect might be.

>  
>  /* Default accel DRDY is available on INT1 pin */
> diff --git a/drivers/iio/imu/Kconfig b/drivers/iio/imu/Kconfig
> index f02883b08480..001ca2c3ff95 100644
> --- a/drivers/iio/imu/Kconfig
> +++ b/drivers/iio/imu/Kconfig
> @@ -94,6 +94,7 @@ config KMX61
>  source "drivers/iio/imu/inv_icm42600/Kconfig"
>  source "drivers/iio/imu/inv_mpu6050/Kconfig"
>  source "drivers/iio/imu/st_lsm6dsx/Kconfig"
> +source "drivers/iio/imu/st_lsm9ds0/Kconfig"
>  
>  endmenu
>  
> diff --git a/drivers/iio/imu/Makefile b/drivers/iio/imu/Makefile
> index 13e9ff442b11..c82748096c77 100644
> --- a/drivers/iio/imu/Makefile
> +++ b/drivers/iio/imu/Makefile
> @@ -26,3 +26,4 @@ obj-y += inv_mpu6050/
>  obj-$(CONFIG_KMX61) += kmx61.o
>  
>  obj-y += st_lsm6dsx/
> +obj-y += st_lsm9ds0/
> diff --git a/drivers/iio/imu/st_lsm9ds0/Kconfig b/drivers/iio/imu/st_lsm9ds0/Kconfig
> new file mode 100644
> index 000000000000..53b7017014f8
> --- /dev/null
> +++ b/drivers/iio/imu/st_lsm9ds0/Kconfig
> @@ -0,0 +1,28 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +
> +config IIO_ST_LSM9DS0
> +	tristate "STMicroelectronics LSM9DS0 IMU driver"
> +	depends on (I2C || SPI_MASTER) && SYSFS
> +	depends on !SENSORS_LIS3_I2C
> +	depends on !SENSORS_LIS3_SPI
> +	select IIO_ST_LSM9DS0_I2C if I2C
> +	select IIO_ST_LSM9DS0_SPI if SPI_MASTER
> +	select IIO_ST_ACCEL_3AXIS
> +	select IIO_ST_MAGN_3AXIS
> +
> +	help
> +	  Say yes here to build support for STMicroelectronics LSM9DS0 IMU
> +	  sensor. Supported devices: accelerometer/magnetometer of lsm9ds0.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called st_lsm9ds0.
> +
> +config IIO_ST_LSM9DS0_I2C
> +	tristate
> +	depends on IIO_ST_LSM9DS0
> +	select REGMAP_I2C
> +
> +config IIO_ST_LSM9DS0_SPI
> +	tristate
> +	depends on IIO_ST_LSM9DS0
> +	select REGMAP_SPI
> diff --git a/drivers/iio/imu/st_lsm9ds0/Makefile b/drivers/iio/imu/st_lsm9ds0/Makefile
> new file mode 100644
> index 000000000000..488af523f648
> --- /dev/null
> +++ b/drivers/iio/imu/st_lsm9ds0/Makefile
> @@ -0,0 +1,5 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +obj-$(CONFIG_IIO_ST_LSM9DS0) += st_lsm9ds0.o
> +st_lsm9ds0-y := st_lsm9ds0_core.o
> +obj-$(CONFIG_IIO_ST_LSM9DS0_I2C) += st_lsm9ds0_i2c.o
> +obj-$(CONFIG_IIO_ST_LSM9DS0_SPI) += st_lsm9ds0_spi.o
> diff --git a/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0.h b/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0.h
> new file mode 100644
> index 000000000000..146393afd9a7
> --- /dev/null
> +++ b/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0.h
> @@ -0,0 +1,23 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +// STMicroelectronics LSM9DS0 IMU driver
> +
> +#ifndef ST_LSM9DS0_H
> +#define ST_LSM9DS0_H
> +
> +struct iio_dev;
> +struct regulator;
> +
> +struct st_lsm9ds0 {
> +	struct device *dev;
> +	const char *name;
> +	int irq;
> +	struct iio_dev *accel;
> +	struct iio_dev *magn;
> +	struct regulator *vdd;
> +	struct regulator *vdd_io;
> +};
> +
> +int st_lsm9ds0_probe(struct st_lsm9ds0 *lsm9ds0, struct regmap *regmap);
> +int st_lsm9ds0_remove(struct st_lsm9ds0 *lsm9ds0);
> +
> +#endif /* ST_LSM9DS0_H */
> diff --git a/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_core.c b/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_core.c
> new file mode 100644
> index 000000000000..8204f7303fd7
> --- /dev/null
> +++ b/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_core.c
> @@ -0,0 +1,163 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * STMicroelectronics LSM9DS0 IMU driver
> + *
> + * Copyright (C) 2021, Intel Corporation
> + *
> + * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> + */
> +
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include <linux/iio/common/st_sensors.h>
> +#include <linux/iio/iio.h>
> +
> +#include "st_lsm9ds0.h"
> +
> +static int st_lsm9ds0_power_enable(struct device *dev, struct st_lsm9ds0 *lsm9ds0)
> +{
> +	int ret;
> +
> +	/* Regulators not mandatory, but if requested we should enable them. */

That's a bit of a missleading comment though cut and paste from the other driver
code.  Key is that they will be handled by stub regulators if we don't provide
the which is not really what that comment implies.
 
> +	lsm9ds0->vdd = devm_regulator_get(dev, "vdd");
> +	if (IS_ERR(lsm9ds0->vdd)) {
> +		dev_err(dev, "unable to get Vdd supply\n");
> +		return PTR_ERR(lsm9ds0->vdd);
> +	}
> +	ret = regulator_enable(lsm9ds0->vdd);
> +	if (ret) {
> +		dev_warn(dev, "Failed to enable specified Vdd supply\n");

Given we fail to probe if this is true, dev_warn seems a bit soft.

> +		return ret;
> +	}
> +
> +	lsm9ds0->vdd_io = devm_regulator_get(dev, "vddio");
> +	if (IS_ERR(lsm9ds0->vdd_io)) {
> +		dev_err(dev, "unable to get Vdd_IO supply\n");
> +		regulator_disable(lsm9ds0->vdd);
> +		return PTR_ERR(lsm9ds0->vdd_io);
> +	}
> +	ret = regulator_enable(lsm9ds0->vdd_io);
> +	if (ret) {
> +		dev_warn(dev, "Failed to enable specified Vdd_IO supply\n");
> +		regulator_disable(lsm9ds0->vdd);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
 +
> +static void st_lsm9ds0_power_disable(void *data)
> +{
> +	struct st_lsm9ds0 *lsm9ds0 = data;
> +
> +	regulator_disable(lsm9ds0->vdd_io);
> +	regulator_disable(lsm9ds0->vdd);
> +}
> +
> +static int devm_st_lsm9ds0_power_enable(struct st_lsm9ds0 *lsm9ds0)
> +{
> +	struct device *dev = lsm9ds0->dev;
> +	int ret;
> +
> +	ret = st_lsm9ds0_power_enable(dev, lsm9ds0);
> +	if (ret)
> +		return ret;
> +
> +	return devm_add_action_or_reset(dev, st_lsm9ds0_power_disable, lsm9ds0);
> +}
> +
> +static int st_lsm9ds0_probe_accel(struct st_lsm9ds0 *lsm9ds0, struct regmap *regmap)
> +{
> +	const struct st_sensor_settings *settings;
> +	struct device *dev = lsm9ds0->dev;
> +	struct st_sensor_data *data;
> +
> +	settings = st_accel_get_settings(lsm9ds0->name);
> +	if (!settings) {
> +		dev_err(dev, "device name %s not recognized.\n", lsm9ds0->name);
> +		return -ENODEV;
> +	}
> +
> +	lsm9ds0->accel = devm_iio_device_alloc(dev, sizeof(*data));
> +	if (!lsm9ds0->accel)
> +		return -ENOMEM;
> +
> +	lsm9ds0->accel->name = lsm9ds0->name;
> +
> +	data = iio_priv(lsm9ds0->accel);
> +	data->sensor_settings = (struct st_sensor_settings *)settings;
> +	data->dev = dev;
> +	data->irq = lsm9ds0->irq;
> +	data->regmap = regmap;
> +	data->vdd = lsm9ds0->vdd;
> +	data->vdd_io = lsm9ds0->vdd_io;
> +
> +	return st_accel_common_probe(lsm9ds0->accel);
> +}
> +
> +static int st_lsm9ds0_probe_magn(struct st_lsm9ds0 *lsm9ds0, struct regmap *regmap)
> +{
> +	const struct st_sensor_settings *settings;
> +	struct device *dev = lsm9ds0->dev;
> +	struct st_sensor_data *data;
> +
> +	settings = st_magn_get_settings(lsm9ds0->name);
> +	if (!settings) {
> +		dev_err(dev, "device name %s not recognized.\n", lsm9ds0->name);
> +		return -ENODEV;
> +	}
> +
> +	lsm9ds0->magn = devm_iio_device_alloc(dev, sizeof(*data));
> +	if (!lsm9ds0->magn)
> +		return -ENOMEM;
> +
> +	lsm9ds0->magn->name = lsm9ds0->name;
> +
> +	data = iio_priv(lsm9ds0->magn);
> +	data->sensor_settings = (struct st_sensor_settings *)settings;
> +	data->dev = dev;
> +	data->irq = lsm9ds0->irq;
> +	data->regmap = regmap;
> +	data->vdd = lsm9ds0->vdd;
> +	data->vdd_io = lsm9ds0->vdd_io;
> +
> +	return st_magn_common_probe(lsm9ds0->magn);
> +}
> +
> +int st_lsm9ds0_probe(struct st_lsm9ds0 *lsm9ds0, struct regmap *regmap)
> +{
> +	int ret;
> +
> +	ret = devm_st_lsm9ds0_power_enable(lsm9ds0);
> +	if (ret)
> +		return ret;
> +
> +	/* Setup accelerometer device */
> +	ret = st_lsm9ds0_probe_accel(lsm9ds0, regmap);
> +	if (ret)
> +		return ret;
> +
> +	/* Setup magnetometer device */
> +	ret = st_lsm9ds0_probe_magn(lsm9ds0, regmap);
> +	if (ret)
> +		st_accel_common_remove(lsm9ds0->accel);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(st_lsm9ds0_probe);
> +
> +int st_lsm9ds0_remove(struct st_lsm9ds0 *lsm9ds0)
> +{
> +	st_magn_common_remove(lsm9ds0->magn);
> +	st_accel_common_remove(lsm9ds0->accel);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(st_lsm9ds0_remove);
> +
> +MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
> +MODULE_DESCRIPTION("STMicroelectronics LSM9DS0 IMU core driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_i2c.c b/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_i2c.c
> new file mode 100644
> index 000000000000..50a36ab53bc3
> --- /dev/null
> +++ b/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_i2c.c
> @@ -0,0 +1,84 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * STMicroelectronics LSM9DS0 IMU driver
> + *
> + * Copyright (C) 2021, Intel Corporation
> + *
> + * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +
> +#include <linux/iio/common/st_sensors_i2c.h>
> +
> +#include "st_lsm9ds0.h"
> +
> +static const struct of_device_id st_lsm9ds0_of_match[] = {
> +	{
> +		.compatible = "st,lsm9ds0-imu",
> +		.data = LSM9DS0_IMU_DEV_NAME,
> +	},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, st_lsm9ds0_of_match);
> +
> +static const struct i2c_device_id st_lsm9ds0_id_table[] = {
> +	{ LSM9DS0_IMU_DEV_NAME },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, st_lsm9ds0_id_table);
> +
> +static const struct regmap_config st_lsm9ds0_regmap_config = {
> +	.reg_bits	= 8,
> +	.val_bits	= 8,
> +	.read_flag_mask	= 0x80,
> +};
> +
> +static int st_lsm9ds0_i2c_probe(struct i2c_client *client)
> +{
> +	const struct regmap_config *config = &st_lsm9ds0_regmap_config;
> +	struct device *dev = &client->dev;
> +	struct st_lsm9ds0 *lsm9ds0;
> +	struct regmap *regmap;
> +
> +	st_sensors_dev_name_probe(dev, client->name, sizeof(client->name));
> +
> +	lsm9ds0 = devm_kzalloc(dev, sizeof(*lsm9ds0), GFP_KERNEL);
> +	if (!lsm9ds0)
> +		return -ENOMEM;
> +
> +	lsm9ds0->dev = dev;
> +	lsm9ds0->name = client->name;
> +	lsm9ds0->irq = client->irq;
> +
> +	regmap = devm_regmap_init_i2c(client, config);
> +	if (IS_ERR(regmap))
> +		return PTR_ERR(regmap);
> +
> +	i2c_set_clientdata(client, lsm9ds0);
> +
> +	return st_lsm9ds0_probe(lsm9ds0, regmap);
> +}
> +
> +static int st_lsm9ds0_i2c_remove(struct i2c_client *client)
> +{
> +	return st_lsm9ds0_remove(i2c_get_clientdata(client));
> +}
> +
> +static struct i2c_driver st_lsm9ds0_driver = {
> +	.driver = {
> +		.name = "st-lsm9ds0-i2c",
> +		.of_match_table = st_lsm9ds0_of_match,
> +	},
> +	.probe_new = st_lsm9ds0_i2c_probe,
> +	.remove = st_lsm9ds0_i2c_remove,
> +	.id_table = st_lsm9ds0_id_table,
> +};
> +module_i2c_driver(st_lsm9ds0_driver);
> +
> +MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
> +MODULE_DESCRIPTION("STMicroelectronics LSM9DS0 IMU I2C driver");
> +MODULE_LICENSE("GPL v2");
Andy Shevchenko April 18, 2021, 1:49 p.m. UTC | #2
On Sun, Apr 18, 2021 at 2:07 PM Jonathan Cameron <jic23@kernel.org> wrote:

Thanks for review, my answers below.

> On Wed, 14 Apr 2021 22:54:53 +0300
> Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
>
> > We can utilize separate drivers for accelerometer and magnetometer,
> > so here is the glue driver to enable LSM9DS0 IMU support.
> >
> > The idea was suggested by Crestez Dan Leonard in [1]. The proposed change
> > was sent as RFC due to race condition concerns, which are indeed possible.
>
> If you are going to mention races, good to give some flavour in here!

I meant that the initial idea is racy due to different devices
communicating to the same i2c address.
So, any sequence of transfers are not serialized and you may end up with

drv1 -> i2c
drv2 -> i2c
drv1 <- i2c # garbage

> This driver makes me very nervous indeed.

Why?! This one is race free as far as I can see. Or maybe I interpret
this wrongly and you are talking about initial RFC?

>  I haven't 'found' any places
> where the fact we'll write the same registers from each of the drivers
> causes problems (e.g. int pin setup etc) but perhaps I'm missing something.
>
> Shall we say that makes me rather keener to get eyes (and thought) on this
> patch than normal :)

How should I amend the commit message to state:
1. First idea (RFC by the link) *is* racy AFAIU
2. This one *is not* racy.

> > In order to amend the initial change,

You see, *in order to amend*, so here is the *amended* version.

> I went further by providing a specific
> > multi-instantiate probe driver that reuses existing accelerometer and
> > magnetometer.
> >
> > [1]: https://lore.kernel.org/patchwork/patch/670353/
> >
> > Suggested-by: Crestez Dan Leonard <leonard.crestez@intel.com>
> > Cc: mr.lahorde@laposte.net
> > Cc: Matija Podravec <matija_podravec@fastmail.fm>
> > Cc: Sergey Borishchenko <borischenko.sergey@gmail.com>
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>
> A few comments in here, though mostly about stuff related to the origin code
> you are copying so perhaps not tidying them up is preferable because it would
> complicate comparison of the two cases.

...

> > +     {
> > +             .wai = 0x49,
> > +             .wai_addr = ST_SENSORS_DEFAULT_WAI_ADDRESS,
> > +             .sensors_supported = {
> > +                     [0] = LSM9DS0_IMU_DEV_NAME,
>
> What does the name attribute report for these?
>
> Previously we've had the _accel etc postfix to differentiate the devices. I don't
> suppose it matters to much though as easy enough to identify the accelerometer
> etc from what channels are present.
>
> Of course driver may get name from somewhere different anyway, I haven't checked,
> just noticed this was different and wondered what the affect might be.

Yes, it has a postfix, that's why I leave it like this.

...

> > +static int st_lsm9ds0_power_enable(struct device *dev, struct st_lsm9ds0 *lsm9ds0)
> > +{
> > +     int ret;
> > +
> > +     /* Regulators not mandatory, but if requested we should enable them. */
>
> That's a bit of a missleading comment though cut and paste from the other driver
> code.  Key is that they will be handled by stub regulators if we don't provide
> the which is not really what that comment implies.

I see. I will remove it.

> > +     lsm9ds0->vdd = devm_regulator_get(dev, "vdd");
> > +     if (IS_ERR(lsm9ds0->vdd)) {
> > +             dev_err(dev, "unable to get Vdd supply\n");
> > +             return PTR_ERR(lsm9ds0->vdd);
> > +     }
> > +     ret = regulator_enable(lsm9ds0->vdd);
> > +     if (ret) {
> > +             dev_warn(dev, "Failed to enable specified Vdd supply\n");
>
> Given we fail to probe if this is true, dev_warn seems a bit soft.

Right.  I'll move to dev_err().

> > +             return ret;
> > +     }
> > +
> > +     lsm9ds0->vdd_io = devm_regulator_get(dev, "vddio");
> > +     if (IS_ERR(lsm9ds0->vdd_io)) {
> > +             dev_err(dev, "unable to get Vdd_IO supply\n");
> > +             regulator_disable(lsm9ds0->vdd);
> > +             return PTR_ERR(lsm9ds0->vdd_io);
> > +     }
> > +     ret = regulator_enable(lsm9ds0->vdd_io);
> > +     if (ret) {
> > +             dev_warn(dev, "Failed to enable specified Vdd_IO supply\n");

Ditto.

> > +             regulator_disable(lsm9ds0->vdd);
> > +             return ret;
> > +     }
> > +
> > +     return 0;
> > +}
Andy Shevchenko April 18, 2021, 1:59 p.m. UTC | #3
On Sun, Apr 18, 2021 at 4:49 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Sun, Apr 18, 2021 at 2:07 PM Jonathan Cameron <jic23@kernel.org> wrote:
>
> Thanks for review, my answers below.
>
> > On Wed, 14 Apr 2021 22:54:53 +0300
> > Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> >
> > > We can utilize separate drivers for accelerometer and magnetometer,
> > > so here is the glue driver to enable LSM9DS0 IMU support.
> > >
> > > The idea was suggested by Crestez Dan Leonard in [1]. The proposed change
> > > was sent as RFC due to race condition concerns, which are indeed possible.
> >
> > If you are going to mention races, good to give some flavour in here!
>
> I meant that the initial idea is racy due to different devices
> communicating to the same i2c address.
> So, any sequence of transfers are not serialized and you may end up with
>
> drv1 -> i2c
> drv2 -> i2c
> drv1 <- i2c # garbage
>
> > This driver makes me very nervous indeed.
>
> Why?! This one is race free as far as I can see. Or maybe I interpret
> this wrongly and you are talking about initial RFC?
>
> >  I haven't 'found' any places
> > where the fact we'll write the same registers from each of the drivers
> > causes problems (e.g. int pin setup etc) but perhaps I'm missing something.
> >
> > Shall we say that makes me rather keener to get eyes (and thought) on this
> > patch than normal :)
>
> How should I amend the commit message to state:
> 1. First idea (RFC by the link) *is* racy AFAIU
> 2. This one *is not* racy.

I re-read this and now understand better what you meant.
So, it may be that the initial proposal may work without any
amendment, but since I haven't investigated much, I should rather use
the phrase "potentially racy". In my variant it's using one regmap for
both drivers (not two), which makes the register state consistent. Am
I wrong?
Do we have some places where we may write to the same register concurrently?
Jonathan Cameron April 18, 2021, 4:45 p.m. UTC | #4
On Sun, 18 Apr 2021 16:59:02 +0300
Andy Shevchenko <andy.shevchenko@gmail.com> wrote:

> On Sun, Apr 18, 2021 at 4:49 PM Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
> >
> > On Sun, Apr 18, 2021 at 2:07 PM Jonathan Cameron <jic23@kernel.org> wrote:
> >
> > Thanks for review, my answers below.
> >  
> > > On Wed, 14 Apr 2021 22:54:53 +0300
> > > Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> > >  
> > > > We can utilize separate drivers for accelerometer and magnetometer,
> > > > so here is the glue driver to enable LSM9DS0 IMU support.
> > > >
> > > > The idea was suggested by Crestez Dan Leonard in [1]. The proposed change
> > > > was sent as RFC due to race condition concerns, which are indeed possible.  
> > >
> > > If you are going to mention races, good to give some flavour in here!  
> >
> > I meant that the initial idea is racy due to different devices
> > communicating to the same i2c address.
> > So, any sequence of transfers are not serialized and you may end up with
> >
> > drv1 -> i2c
> > drv2 -> i2c
> > drv1 <- i2c # garbage
> >  
> > > This driver makes me very nervous indeed.  
> >
> > Why?! This one is race free as far as I can see. Or maybe I interpret
> > this wrongly and you are talking about initial RFC?
> >  
> > >  I haven't 'found' any places
> > > where the fact we'll write the same registers from each of the drivers
> > > causes problems (e.g. int pin setup etc) but perhaps I'm missing something.
> > >
> > > Shall we say that makes me rather keener to get eyes (and thought) on this
> > > patch than normal :)  
> >
> > How should I amend the commit message to state:
> > 1. First idea (RFC by the link) *is* racy AFAIU
> > 2. This one *is not* racy.  

Great.  I read it as meaning they were both potentially racey!
This is less worrying.

> 
> I re-read this and now understand better what you meant.
> So, it may be that the initial proposal may work without any
> amendment, but since I haven't investigated much, I should rather use
> the phrase "potentially racy". In my variant it's using one regmap for
> both drivers (not two), which makes the register state consistent. Am
> I wrong?

I think this approach is fine.  I'd be more worried about the two 'sub' drivers
not necessarily being happy that someone else touches state they care about.
There are places where I think we write the same value to the same register
twice during setup with this model, but that shouldn't matter.   I'm not 100%
sure that there aren't other cases though I think there aren't.

So what you have is probably fine, but more eyes would make me happier ;)

Lots of people care about this particular driver so hopefully we'll get
them.

> Do we have some places where we may write to the same register concurrently?
> 
Only ones I can find are the setup ones where it writes the same value twice
I think.  So *crosses fingers* :)

Given timing (missed merge window) we have masses of time to let this sit
on list a while and see if anyone can spot issues neither of us have found.

Jonathan
diff mbox series

Patch

diff --git a/drivers/iio/accel/st_accel_core.c b/drivers/iio/accel/st_accel_core.c
index 5c258c1ca62d..dc32ebefe3fc 100644
--- a/drivers/iio/accel/st_accel_core.c
+++ b/drivers/iio/accel/st_accel_core.c
@@ -980,7 +980,94 @@  static const struct st_sensor_settings st_accel_sensors_settings[] = {
 		.multi_read_bit = true,
 		.bootime = 2,
 	},
-
+	{
+		.wai = 0x49,
+		.wai_addr = ST_SENSORS_DEFAULT_WAI_ADDRESS,
+		.sensors_supported = {
+			[0] = LSM9DS0_IMU_DEV_NAME,
+		},
+		.ch = (struct iio_chan_spec *)st_accel_16bit_channels,
+		.odr = {
+			.addr = 0x20,
+			.mask = GENMASK(7, 4),
+			.odr_avl = {
+				{ 3, 0x01, },
+				{ 6, 0x02, },
+				{ 12, 0x03, },
+				{ 25, 0x04, },
+				{ 50, 0x05, },
+				{ 100, 0x06, },
+				{ 200, 0x07, },
+				{ 400, 0x08, },
+				{ 800, 0x09, },
+				{ 1600, 0x0a, },
+			},
+		},
+		.pw = {
+			.addr = 0x20,
+			.mask = GENMASK(7, 4),
+			.value_off = ST_SENSORS_DEFAULT_POWER_OFF_VALUE,
+		},
+		.enable_axis = {
+			.addr = ST_SENSORS_DEFAULT_AXIS_ADDR,
+			.mask = ST_SENSORS_DEFAULT_AXIS_MASK,
+		},
+		.fs = {
+			.addr = 0x21,
+			.mask = GENMASK(5, 3),
+			.fs_avl = {
+				[0] = {
+					.num = ST_ACCEL_FS_AVL_2G,
+					.value = 0x00,
+					.gain = IIO_G_TO_M_S_2(61),
+				},
+				[1] = {
+					.num = ST_ACCEL_FS_AVL_4G,
+					.value = 0x01,
+					.gain = IIO_G_TO_M_S_2(122),
+				},
+				[2] = {
+					.num = ST_ACCEL_FS_AVL_6G,
+					.value = 0x02,
+					.gain = IIO_G_TO_M_S_2(183),
+				},
+				[3] = {
+					.num = ST_ACCEL_FS_AVL_8G,
+					.value = 0x03,
+					.gain = IIO_G_TO_M_S_2(244),
+				},
+				[4] = {
+					.num = ST_ACCEL_FS_AVL_16G,
+					.value = 0x04,
+					.gain = IIO_G_TO_M_S_2(732),
+				},
+			},
+		},
+		.bdu = {
+			.addr = 0x20,
+			.mask = BIT(3),
+		},
+		.drdy_irq = {
+			.int1 = {
+				.addr = 0x22,
+				.mask = BIT(2),
+			},
+			.int2 = {
+				.addr = 0x23,
+				.mask = BIT(3),
+			},
+			.stat_drdy = {
+				.addr = ST_SENSORS_DEFAULT_STAT_ADDR,
+				.mask = GENMASK(2, 0),
+			},
+		},
+		.sim = {
+			.addr = 0x21,
+			.value = BIT(0),
+		},
+		.multi_read_bit = true,
+		.bootime = 2,
+	},
 };
 
 /* Default accel DRDY is available on INT1 pin */
diff --git a/drivers/iio/imu/Kconfig b/drivers/iio/imu/Kconfig
index f02883b08480..001ca2c3ff95 100644
--- a/drivers/iio/imu/Kconfig
+++ b/drivers/iio/imu/Kconfig
@@ -94,6 +94,7 @@  config KMX61
 source "drivers/iio/imu/inv_icm42600/Kconfig"
 source "drivers/iio/imu/inv_mpu6050/Kconfig"
 source "drivers/iio/imu/st_lsm6dsx/Kconfig"
+source "drivers/iio/imu/st_lsm9ds0/Kconfig"
 
 endmenu
 
diff --git a/drivers/iio/imu/Makefile b/drivers/iio/imu/Makefile
index 13e9ff442b11..c82748096c77 100644
--- a/drivers/iio/imu/Makefile
+++ b/drivers/iio/imu/Makefile
@@ -26,3 +26,4 @@  obj-y += inv_mpu6050/
 obj-$(CONFIG_KMX61) += kmx61.o
 
 obj-y += st_lsm6dsx/
+obj-y += st_lsm9ds0/
diff --git a/drivers/iio/imu/st_lsm9ds0/Kconfig b/drivers/iio/imu/st_lsm9ds0/Kconfig
new file mode 100644
index 000000000000..53b7017014f8
--- /dev/null
+++ b/drivers/iio/imu/st_lsm9ds0/Kconfig
@@ -0,0 +1,28 @@ 
+# SPDX-License-Identifier: GPL-2.0-only
+
+config IIO_ST_LSM9DS0
+	tristate "STMicroelectronics LSM9DS0 IMU driver"
+	depends on (I2C || SPI_MASTER) && SYSFS
+	depends on !SENSORS_LIS3_I2C
+	depends on !SENSORS_LIS3_SPI
+	select IIO_ST_LSM9DS0_I2C if I2C
+	select IIO_ST_LSM9DS0_SPI if SPI_MASTER
+	select IIO_ST_ACCEL_3AXIS
+	select IIO_ST_MAGN_3AXIS
+
+	help
+	  Say yes here to build support for STMicroelectronics LSM9DS0 IMU
+	  sensor. Supported devices: accelerometer/magnetometer of lsm9ds0.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called st_lsm9ds0.
+
+config IIO_ST_LSM9DS0_I2C
+	tristate
+	depends on IIO_ST_LSM9DS0
+	select REGMAP_I2C
+
+config IIO_ST_LSM9DS0_SPI
+	tristate
+	depends on IIO_ST_LSM9DS0
+	select REGMAP_SPI
diff --git a/drivers/iio/imu/st_lsm9ds0/Makefile b/drivers/iio/imu/st_lsm9ds0/Makefile
new file mode 100644
index 000000000000..488af523f648
--- /dev/null
+++ b/drivers/iio/imu/st_lsm9ds0/Makefile
@@ -0,0 +1,5 @@ 
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_IIO_ST_LSM9DS0) += st_lsm9ds0.o
+st_lsm9ds0-y := st_lsm9ds0_core.o
+obj-$(CONFIG_IIO_ST_LSM9DS0_I2C) += st_lsm9ds0_i2c.o
+obj-$(CONFIG_IIO_ST_LSM9DS0_SPI) += st_lsm9ds0_spi.o
diff --git a/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0.h b/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0.h
new file mode 100644
index 000000000000..146393afd9a7
--- /dev/null
+++ b/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0.h
@@ -0,0 +1,23 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+// STMicroelectronics LSM9DS0 IMU driver
+
+#ifndef ST_LSM9DS0_H
+#define ST_LSM9DS0_H
+
+struct iio_dev;
+struct regulator;
+
+struct st_lsm9ds0 {
+	struct device *dev;
+	const char *name;
+	int irq;
+	struct iio_dev *accel;
+	struct iio_dev *magn;
+	struct regulator *vdd;
+	struct regulator *vdd_io;
+};
+
+int st_lsm9ds0_probe(struct st_lsm9ds0 *lsm9ds0, struct regmap *regmap);
+int st_lsm9ds0_remove(struct st_lsm9ds0 *lsm9ds0);
+
+#endif /* ST_LSM9DS0_H */
diff --git a/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_core.c b/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_core.c
new file mode 100644
index 000000000000..8204f7303fd7
--- /dev/null
+++ b/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_core.c
@@ -0,0 +1,163 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * STMicroelectronics LSM9DS0 IMU driver
+ *
+ * Copyright (C) 2021, Intel Corporation
+ *
+ * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+
+#include <linux/iio/common/st_sensors.h>
+#include <linux/iio/iio.h>
+
+#include "st_lsm9ds0.h"
+
+static int st_lsm9ds0_power_enable(struct device *dev, struct st_lsm9ds0 *lsm9ds0)
+{
+	int ret;
+
+	/* Regulators not mandatory, but if requested we should enable them. */
+	lsm9ds0->vdd = devm_regulator_get(dev, "vdd");
+	if (IS_ERR(lsm9ds0->vdd)) {
+		dev_err(dev, "unable to get Vdd supply\n");
+		return PTR_ERR(lsm9ds0->vdd);
+	}
+	ret = regulator_enable(lsm9ds0->vdd);
+	if (ret) {
+		dev_warn(dev, "Failed to enable specified Vdd supply\n");
+		return ret;
+	}
+
+	lsm9ds0->vdd_io = devm_regulator_get(dev, "vddio");
+	if (IS_ERR(lsm9ds0->vdd_io)) {
+		dev_err(dev, "unable to get Vdd_IO supply\n");
+		regulator_disable(lsm9ds0->vdd);
+		return PTR_ERR(lsm9ds0->vdd_io);
+	}
+	ret = regulator_enable(lsm9ds0->vdd_io);
+	if (ret) {
+		dev_warn(dev, "Failed to enable specified Vdd_IO supply\n");
+		regulator_disable(lsm9ds0->vdd);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void st_lsm9ds0_power_disable(void *data)
+{
+	struct st_lsm9ds0 *lsm9ds0 = data;
+
+	regulator_disable(lsm9ds0->vdd_io);
+	regulator_disable(lsm9ds0->vdd);
+}
+
+static int devm_st_lsm9ds0_power_enable(struct st_lsm9ds0 *lsm9ds0)
+{
+	struct device *dev = lsm9ds0->dev;
+	int ret;
+
+	ret = st_lsm9ds0_power_enable(dev, lsm9ds0);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, st_lsm9ds0_power_disable, lsm9ds0);
+}
+
+static int st_lsm9ds0_probe_accel(struct st_lsm9ds0 *lsm9ds0, struct regmap *regmap)
+{
+	const struct st_sensor_settings *settings;
+	struct device *dev = lsm9ds0->dev;
+	struct st_sensor_data *data;
+
+	settings = st_accel_get_settings(lsm9ds0->name);
+	if (!settings) {
+		dev_err(dev, "device name %s not recognized.\n", lsm9ds0->name);
+		return -ENODEV;
+	}
+
+	lsm9ds0->accel = devm_iio_device_alloc(dev, sizeof(*data));
+	if (!lsm9ds0->accel)
+		return -ENOMEM;
+
+	lsm9ds0->accel->name = lsm9ds0->name;
+
+	data = iio_priv(lsm9ds0->accel);
+	data->sensor_settings = (struct st_sensor_settings *)settings;
+	data->dev = dev;
+	data->irq = lsm9ds0->irq;
+	data->regmap = regmap;
+	data->vdd = lsm9ds0->vdd;
+	data->vdd_io = lsm9ds0->vdd_io;
+
+	return st_accel_common_probe(lsm9ds0->accel);
+}
+
+static int st_lsm9ds0_probe_magn(struct st_lsm9ds0 *lsm9ds0, struct regmap *regmap)
+{
+	const struct st_sensor_settings *settings;
+	struct device *dev = lsm9ds0->dev;
+	struct st_sensor_data *data;
+
+	settings = st_magn_get_settings(lsm9ds0->name);
+	if (!settings) {
+		dev_err(dev, "device name %s not recognized.\n", lsm9ds0->name);
+		return -ENODEV;
+	}
+
+	lsm9ds0->magn = devm_iio_device_alloc(dev, sizeof(*data));
+	if (!lsm9ds0->magn)
+		return -ENOMEM;
+
+	lsm9ds0->magn->name = lsm9ds0->name;
+
+	data = iio_priv(lsm9ds0->magn);
+	data->sensor_settings = (struct st_sensor_settings *)settings;
+	data->dev = dev;
+	data->irq = lsm9ds0->irq;
+	data->regmap = regmap;
+	data->vdd = lsm9ds0->vdd;
+	data->vdd_io = lsm9ds0->vdd_io;
+
+	return st_magn_common_probe(lsm9ds0->magn);
+}
+
+int st_lsm9ds0_probe(struct st_lsm9ds0 *lsm9ds0, struct regmap *regmap)
+{
+	int ret;
+
+	ret = devm_st_lsm9ds0_power_enable(lsm9ds0);
+	if (ret)
+		return ret;
+
+	/* Setup accelerometer device */
+	ret = st_lsm9ds0_probe_accel(lsm9ds0, regmap);
+	if (ret)
+		return ret;
+
+	/* Setup magnetometer device */
+	ret = st_lsm9ds0_probe_magn(lsm9ds0, regmap);
+	if (ret)
+		st_accel_common_remove(lsm9ds0->accel);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(st_lsm9ds0_probe);
+
+int st_lsm9ds0_remove(struct st_lsm9ds0 *lsm9ds0)
+{
+	st_magn_common_remove(lsm9ds0->magn);
+	st_accel_common_remove(lsm9ds0->accel);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(st_lsm9ds0_remove);
+
+MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
+MODULE_DESCRIPTION("STMicroelectronics LSM9DS0 IMU core driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_i2c.c b/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_i2c.c
new file mode 100644
index 000000000000..50a36ab53bc3
--- /dev/null
+++ b/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_i2c.c
@@ -0,0 +1,84 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * STMicroelectronics LSM9DS0 IMU driver
+ *
+ * Copyright (C) 2021, Intel Corporation
+ *
+ * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ */
+
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include <linux/iio/common/st_sensors_i2c.h>
+
+#include "st_lsm9ds0.h"
+
+static const struct of_device_id st_lsm9ds0_of_match[] = {
+	{
+		.compatible = "st,lsm9ds0-imu",
+		.data = LSM9DS0_IMU_DEV_NAME,
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, st_lsm9ds0_of_match);
+
+static const struct i2c_device_id st_lsm9ds0_id_table[] = {
+	{ LSM9DS0_IMU_DEV_NAME },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, st_lsm9ds0_id_table);
+
+static const struct regmap_config st_lsm9ds0_regmap_config = {
+	.reg_bits	= 8,
+	.val_bits	= 8,
+	.read_flag_mask	= 0x80,
+};
+
+static int st_lsm9ds0_i2c_probe(struct i2c_client *client)
+{
+	const struct regmap_config *config = &st_lsm9ds0_regmap_config;
+	struct device *dev = &client->dev;
+	struct st_lsm9ds0 *lsm9ds0;
+	struct regmap *regmap;
+
+	st_sensors_dev_name_probe(dev, client->name, sizeof(client->name));
+
+	lsm9ds0 = devm_kzalloc(dev, sizeof(*lsm9ds0), GFP_KERNEL);
+	if (!lsm9ds0)
+		return -ENOMEM;
+
+	lsm9ds0->dev = dev;
+	lsm9ds0->name = client->name;
+	lsm9ds0->irq = client->irq;
+
+	regmap = devm_regmap_init_i2c(client, config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	i2c_set_clientdata(client, lsm9ds0);
+
+	return st_lsm9ds0_probe(lsm9ds0, regmap);
+}
+
+static int st_lsm9ds0_i2c_remove(struct i2c_client *client)
+{
+	return st_lsm9ds0_remove(i2c_get_clientdata(client));
+}
+
+static struct i2c_driver st_lsm9ds0_driver = {
+	.driver = {
+		.name = "st-lsm9ds0-i2c",
+		.of_match_table = st_lsm9ds0_of_match,
+	},
+	.probe_new = st_lsm9ds0_i2c_probe,
+	.remove = st_lsm9ds0_i2c_remove,
+	.id_table = st_lsm9ds0_id_table,
+};
+module_i2c_driver(st_lsm9ds0_driver);
+
+MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
+MODULE_DESCRIPTION("STMicroelectronics LSM9DS0 IMU I2C driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_spi.c b/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_spi.c
new file mode 100644
index 000000000000..272c88990dd0
--- /dev/null
+++ b/drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_spi.c
@@ -0,0 +1,83 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * STMicroelectronics LSM9DS0 IMU driver
+ *
+ * Copyright (C) 2021, Intel Corporation
+ *
+ * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+
+#include <linux/iio/common/st_sensors_spi.h>
+
+#include "st_lsm9ds0.h"
+
+static const struct of_device_id st_lsm9ds0_of_match[] = {
+	{
+		.compatible = "st,lsm9ds0-imu",
+		.data = LSM9DS0_IMU_DEV_NAME,
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, st_lsm9ds0_of_match);
+
+static const struct spi_device_id st_lsm9ds0_id_table[] = {
+	{ LSM9DS0_IMU_DEV_NAME },
+	{}
+};
+MODULE_DEVICE_TABLE(spi, st_lsm9ds0_id_table);
+
+static const struct regmap_config st_lsm9ds0_regmap_config = {
+	.reg_bits	= 8,
+	.val_bits	= 8,
+	.read_flag_mask	= 0xc0,
+};
+
+static int st_lsm9ds0_spi_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct st_lsm9ds0 *lsm9ds0;
+	struct regmap *regmap;
+
+	st_sensors_dev_name_probe(dev, spi->modalias, sizeof(spi->modalias));
+
+	lsm9ds0 = devm_kzalloc(dev, sizeof(*lsm9ds0), GFP_KERNEL);
+	if (!lsm9ds0)
+		return -ENOMEM;
+
+	lsm9ds0->dev = dev;
+	lsm9ds0->name = spi->modalias;
+	lsm9ds0->irq = spi->irq;
+
+	regmap = devm_regmap_init_spi(spi, &st_lsm9ds0_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	spi_set_drvdata(spi, lsm9ds0);
+
+	return st_lsm9ds0_probe(lsm9ds0, regmap);
+}
+
+static int st_lsm9ds0_spi_remove(struct spi_device *spi)
+{
+	return st_lsm9ds0_remove(spi_get_drvdata(spi));
+}
+
+static struct spi_driver st_lsm9ds0_driver = {
+	.driver = {
+		.name = "st-lsm9ds0-spi",
+		.of_match_table = st_lsm9ds0_of_match,
+	},
+	.probe = st_lsm9ds0_spi_probe,
+	.remove = st_lsm9ds0_spi_remove,
+	.id_table = st_lsm9ds0_id_table,
+};
+module_spi_driver(st_lsm9ds0_driver);
+
+MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
+MODULE_DESCRIPTION("STMicroelectronics LSM9DS0 IMU SPI driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/magnetometer/st_magn_core.c b/drivers/iio/magnetometer/st_magn_core.c
index 018b2523edfe..34fd892a776a 100644
--- a/drivers/iio/magnetometer/st_magn_core.c
+++ b/drivers/iio/magnetometer/st_magn_core.c
@@ -33,6 +33,7 @@ 
 /* FULLSCALE */
 #define ST_MAGN_FS_AVL_1300MG			1300
 #define ST_MAGN_FS_AVL_1900MG			1900
+#define ST_MAGN_FS_AVL_2000MG			2000
 #define ST_MAGN_FS_AVL_2500MG			2500
 #define ST_MAGN_FS_AVL_4000MG			4000
 #define ST_MAGN_FS_AVL_4700MG			4700
@@ -53,6 +54,11 @@ 
 #define ST_MAGN_3_OUT_Y_L_ADDR			0x6a
 #define ST_MAGN_3_OUT_Z_L_ADDR			0x6c
 
+/* Special L addresses for sensor 4 */
+#define ST_MAGN_4_OUT_X_L_ADDR			0x08
+#define ST_MAGN_4_OUT_Y_L_ADDR			0x0a
+#define ST_MAGN_4_OUT_Z_L_ADDR			0x0c
+
 static const struct iio_chan_spec st_magn_16bit_channels[] = {
 	ST_SENSORS_LSM_CHANNELS(IIO_MAGN,
 			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
@@ -101,6 +107,22 @@  static const struct iio_chan_spec st_magn_3_16bit_channels[] = {
 	IIO_CHAN_SOFT_TIMESTAMP(3)
 };
 
+static const struct iio_chan_spec st_magn_4_16bit_channels[] = {
+	ST_SENSORS_LSM_CHANNELS(IIO_MAGN,
+			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
+			ST_SENSORS_SCAN_X, 1, IIO_MOD_X, 's', IIO_LE, 16, 16,
+			ST_MAGN_4_OUT_X_L_ADDR),
+	ST_SENSORS_LSM_CHANNELS(IIO_MAGN,
+			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
+			ST_SENSORS_SCAN_Y, 1, IIO_MOD_Y, 's', IIO_LE, 16, 16,
+			ST_MAGN_4_OUT_Y_L_ADDR),
+	ST_SENSORS_LSM_CHANNELS(IIO_MAGN,
+			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
+			ST_SENSORS_SCAN_Z, 1, IIO_MOD_Z, 's', IIO_LE, 16, 16,
+			ST_MAGN_4_OUT_Z_L_ADDR),
+	IIO_CHAN_SOFT_TIMESTAMP(3)
+};
+
 static const struct st_sensor_settings st_magn_sensors_settings[] = {
 	{
 		.wai = 0, /* This sensor has no valid WhoAmI report 0 */
@@ -380,6 +402,82 @@  static const struct st_sensor_settings st_magn_sensors_settings[] = {
 		.multi_read_bit = false,
 		.bootime = 2,
 	},
+	{
+		.wai = 0x49,
+		.wai_addr = ST_SENSORS_DEFAULT_WAI_ADDRESS,
+		.sensors_supported = {
+			[0] = LSM9DS0_IMU_DEV_NAME,
+		},
+		.ch = (struct iio_chan_spec *)st_magn_4_16bit_channels,
+		.odr = {
+			.addr = 0x24,
+			.mask = GENMASK(4, 2),
+			.odr_avl = {
+				{ 3, 0x00, },
+				{ 6, 0x01, },
+				{ 12, 0x02, },
+				{ 25, 0x03, },
+				{ 50, 0x04, },
+				{ 100, 0x05, },
+			},
+		},
+		.pw = {
+			.addr = 0x26,
+			.mask = GENMASK(1, 0),
+			.value_on = 0x00,
+			.value_off = 0x03,
+		},
+		.fs = {
+			.addr = 0x25,
+			.mask = GENMASK(6, 5),
+			.fs_avl = {
+				[0] = {
+					.num = ST_MAGN_FS_AVL_2000MG,
+					.value = 0x00,
+					.gain = 73,
+				},
+				[1] = {
+					.num = ST_MAGN_FS_AVL_4000MG,
+					.value = 0x01,
+					.gain = 146,
+				},
+				[2] = {
+					.num = ST_MAGN_FS_AVL_8000MG,
+					.value = 0x02,
+					.gain = 292,
+				},
+				[3] = {
+					.num = ST_MAGN_FS_AVL_12000MG,
+					.value = 0x03,
+					.gain = 438,
+				},
+			},
+		},
+		.bdu = {
+			.addr = 0x20,
+			.mask = BIT(3),
+		},
+		.drdy_irq = {
+			.int1 = {
+				.addr = 0x22,
+				.mask = BIT(1),
+			},
+			.int2 = {
+				.addr = 0x23,
+				.mask = BIT(2),
+			},
+			.stat_drdy = {
+				.addr = 0x07,
+				.mask = GENMASK(2, 0),
+			},
+		},
+		.sim = {
+			.addr = 0x21,
+			.value = BIT(0),
+		},
+		.multi_read_bit = true,
+		.bootime = 2,
+	},
 };
 
 /* Default magn DRDY is available on INT2 pin */
diff --git a/include/linux/iio/common/st_sensors.h b/include/linux/iio/common/st_sensors.h
index aa017b90fb06..0b9aeb479f48 100644
--- a/include/linux/iio/common/st_sensors.h
+++ b/include/linux/iio/common/st_sensors.h
@@ -20,6 +20,8 @@ 
 
 #include <linux/platform_data/st_sensors_pdata.h>
 
+#define LSM9DS0_IMU_DEV_NAME		"lsm9ds0"
+
 /*
  * Buffer size max case: 2bytes per channel, 3 channels in total +
  *			 8bytes timestamp channel (s64)