Re: [v3 12/13] iio: imu: add BNO055 I2C driver

Jonathan Cameron
2022-02-19T16:56:34Z

On Thu, 17 Feb 2022 17:27:09 +0100
Andrea Merello <andrea.merello@gmail.com> wrote:

> This path adds an I2C driver for communicating to a BNO055 IMU via I2C
> bus and it enables the BNO055 core driver to work in this scenario.
>
> Signed-off-by: Andrea Merello <andrea.merello@iit.it>

Minor comment inline to add an of_device_id table.
Isn't i2c so much nicer than serial? :)

Thanks,

Jonathan

> ---
> drivers/iio/imu/bno055/Kconfig | 11 +++++++
> drivers/iio/imu/bno055/Makefile | 1 +
> drivers/iio/imu/bno055/bno055_i2c.c | 50 +++++++++++++++++++++++++++++
> 3 files changed, 62 insertions(+)
> create mode 100644 drivers/iio/imu/bno055/bno055_i2c.c
>
> diff --git a/drivers/iio/imu/bno055/Kconfig b/drivers/iio/imu/bno055/Kconfig
> index 8a83639ad2a9..3693a408e270 100644
> --- a/drivers/iio/imu/bno055/Kconfig
> +++ b/drivers/iio/imu/bno055/Kconfig
> @@ -12,3 +12,14 @@ config BOSCH_BNO055_SERIAL
>
> This driver can also be built as a module. If so, the module will be
> called bno055_sl.
> +
> +config BOSCH_BNO055_I2C
> + tristate "Bosch BNO055 attached via I2C bus"
> + depends on I2C
> + select REGMAP_I2C
> + select BOSCH_BNO055_IIO
> + help
> + Enable this to support Bosch BNO055 IMUs attached via I2C bus.
> +
> + This driver can also be built as a module. If so, the module will be
> + called bno055_i2c.
> diff --git a/drivers/iio/imu/bno055/Makefile b/drivers/iio/imu/bno055/Makefile
> index 416f0ff96de5..2fe2b0857903 100644
> --- a/drivers/iio/imu/bno055/Makefile
> +++ b/drivers/iio/imu/bno055/Makefile
> @@ -2,3 +2,4 @@
>
> obj-$(CONFIG_BOSCH_BNO055_IIO) += bno055.o
> obj-$(CONFIG_BOSCH_BNO055_SERIAL) += bno055_sl.o
> +obj-$(CONFIG_BOSCH_BNO055_I2C) += bno055_i2c.o
> diff --git a/drivers/iio/imu/bno055/bno055_i2c.c b/drivers/iio/imu/bno055/bno055_i2c.c
> new file mode 100644
> index 000000000000..9900e2a4d905
> --- /dev/null
> +++ b/drivers/iio/imu/bno055/bno055_i2c.c
> @@ -0,0 +1,50 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Support for I2C-interfaced Bosch BNO055 IMU.
> + *
> + * Copyright (C) 2021 Istituto Italiano di Tecnologia
> + * Electronic Design Laboratory
> + * Written by Andrea Merello <andrea.merello@iit.it>
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/regmap.h>
> +#include <linux/module.h>
> +
> +#include "bno055.h"
> +
> +#define BNO055_I2C_XFER_BURST_BREAK_THRESHOLD 3 /* FIXME */
> +
> +static int bno055_i2c_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct regmap *regmap =
> + devm_regmap_init_i2c(client, &bno055_regmap_config);
> +
> + if (IS_ERR(regmap)) {
> + dev_err(&client->dev, "Unable to init register map");
> + return PTR_ERR(regmap);
> + }
> +
> + return bno055_probe(&client->dev, regmap,
> + BNO055_I2C_XFER_BURST_BREAK_THRESHOLD, true);
> +}
> +
> +static const struct i2c_device_id bno055_i2c_id[] = {
> + {"bno055", 0},
> + { }
> +};
> +MODULE_DEVICE_TABLE(i2c, bno055_i2c_id);

No of_device_id table? Whilst the fallback path that
usese the i2c_device_id will mostly work, it leaves us in theory
more susceptible to naming clashes and is generally not as nice.
Hence definitely prefer it if we have an of_device_id table as well
as the i2c_device_id one.

> +
> +static struct i2c_driver bno055_driver = {
> + .driver = {
> + .name = "bno055-i2c",
> + },
> + .probe = bno055_i2c_probe,
> + .id_table = bno055_i2c_id
> +};
> +module_i2c_driver(bno055_driver);
> +
> +MODULE_AUTHOR("Andrea Merello");
> +MODULE_DESCRIPTION("Bosch BNO055 I2C interface");
> +MODULE_LICENSE("GPL v2");