Re: [PATCH v6 2/2] iio: accel: Add support for the Bosch-Sensortec BMI088

Jonathan Cameron
2021-01-20T20:26:08Z

On Tue, 19 Jan 2021 13:46:22 +0100
Mike Looijmans <mike.looijmans@topic.nl> wrote:

> The BMI088 is a combined module with both accelerometer and gyroscope.
> This adds the accelerometer driver support for the SPI interface.
> The gyroscope part is already supported by the BMG160 driver.
>
> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
> ---
>
> Changes in v6:
> Hope you have good memory - v5 was almost a year ago now
*laughs* fresh review so probably disagree with what I said back then on
something :)

A few really small comments inline seeing as you are respinning anyway.

> Remove superfluous *val=0
> Make sample_frequency selection into read_avail list
>
> Changes in v5:
> Add includes and forward defines in header
> BIT(7) instead of 0x80
> Reset already sets defaults, do not set them again
> Remove now unused bmi088_accel_set_bw
> Remove unused AXIS_MAX
> Use MASK define for ODR setting
> Explain buffer use and alignment
> Split bmi088_accel_set_power_state into "on" and "off" parts
> Cosmetic changes to improve readability
>
> Changes in v4:
> Remove unused #include directives
> Remove unused #defines for event and irq
> Replace (ret < 0) with (ret) for all regmap calls
> Consistent checking of IO errors in probe and init
> Removed #ifdef CONFIG_PM guard
> Use bitops for set_frequency instead of loop with shift
> s/__s16/s16/g
> Remove excess blank lines
> Don't return -EAGAIN in pm_runtime
>
> Changes in v3:
> Processed comments from Jonathan Cameron and Lars-Peter Clausen
> implement runtime PM (tested by code tracing) and sleep
> fix scale and offset factors for accel and temperature and
> return raw values instead of pre-scaled ones
> Use iio_device_{claim,release}_direct_mode
> Remove unused code and structs
> Use a cache-aligned buffer for bulk read
> Configure and enable caching register values
>
> Changes in v2:
> Remove unused typedefs and variables
> Fix error return when iio_device_register fails
>
> drivers/iio/accel/Kconfig | 18 +
> drivers/iio/accel/Makefile | 2 +
> drivers/iio/accel/bmi088-accel-core.c | 630 ++++++++++++++++++++++++++
> drivers/iio/accel/bmi088-accel-spi.c | 85 ++++
> drivers/iio/accel/bmi088-accel.h | 18 +
> 5 files changed, 753 insertions(+)
> create mode 100644 drivers/iio/accel/bmi088-accel-core.c
> create mode 100644 drivers/iio/accel/bmi088-accel-spi.c
> create mode 100644 drivers/iio/accel/bmi088-accel.h
>
> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
> index 2e0c62c39155..cceda3cecbcf 100644
> --- a/drivers/iio/accel/Kconfig
> +++ b/drivers/iio/accel/Kconfig
> @@ -157,6 +157,24 @@ config BMC150_ACCEL_SPI
> tristate
> select REGMAP_SPI
>
> +config BMI088_ACCEL
> + tristate "Bosch BMI088 Accelerometer Driver"
> + depends on SPI
> + select IIO_BUFFER
> + select IIO_TRIGGERED_BUFFER
> + select REGMAP
> + select BMI088_ACCEL_SPI
> + help
> + Say yes here to build support for the Bosch BMI088 accelerometer.
> +
> + This is a combo module with both accelerometer and gyroscope. This
> + driver only implements the accelerometer part, which has its own
> + address and register map. BMG160 provides the gyroscope driver.
> +
> +config BMI088_ACCEL_SPI
> + tristate
> + select REGMAP_SPI
> +
> config DA280
> tristate "MiraMEMS DA280 3-axis 14-bit digital accelerometer driver"
> depends on I2C
> diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
> index 4f6c1ebe13b0..32cd1342a31a 100644
> --- a/drivers/iio/accel/Makefile
> +++ b/drivers/iio/accel/Makefile
> @@ -20,6 +20,8 @@ obj-$(CONFIG_BMA400_SPI) += bma400_spi.o
> obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel-core.o
> obj-$(CONFIG_BMC150_ACCEL_I2C) += bmc150-accel-i2c.o
> obj-$(CONFIG_BMC150_ACCEL_SPI) += bmc150-accel-spi.o
> +obj-$(CONFIG_BMI088_ACCEL) += bmi088-accel-core.o
> +obj-$(CONFIG_BMI088_ACCEL_SPI) += bmi088-accel-spi.o
> obj-$(CONFIG_DA280) += da280.o
> obj-$(CONFIG_DA311) += da311.o
> obj-$(CONFIG_DMARD06) += dmard06.o
> diff --git a/drivers/iio/accel/bmi088-accel-core.c b/drivers/iio/accel/bmi088-accel-core.c
> new file mode 100644
> index 000000000000..788e54ed0728
> --- /dev/null
> +++ b/drivers/iio/accel/bmi088-accel-core.c
> @@ -0,0 +1,630 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * 3-axis accelerometer driver supporting following Bosch-Sensortec chips:
> + * - BMI088
> + *
> + * Copyright (c) 2018-2020, Topic Embedded Products
> + */
> +
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/delay.h>
As below. Alphabetical ordering preferred.

> +#include <linux/slab.h>
> +#include <linux/acpi.h>
> +#include <linux/pm.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/regmap.h>
> +#include <asm/unaligned.h>
> +
> +#include "bmi088-accel.h"
...

> +static int bmi088_accel_chip_init(struct bmi088_accel_data *data)
> +{
> + struct device *dev = regmap_get_device(data->regmap);
> + int ret, i;
> + unsigned int val;
> +
> + /* Do a dummy read to enable SPI interface, won't harm I2C */
> + regmap_read(data->regmap, BMI088_ACCEL_REG_INT_STATUS, &val);
> +
> + /*
> + * Reset chip to get it in a known good state. A delay of 1ms after
> + * reset is required according to the data sheet
> + */
> + ret = regmap_write(data->regmap, BMI088_ACCEL_REG_RESET,
> + BMI088_ACCEL_RESET_VAL);
> + if (ret)
> + return ret;
> +
> + usleep_range(1000, 2000);
> +
> + /* Do a dummy read again after a reset to enable the SPI interface */
> + regmap_read(data->regmap, BMI088_ACCEL_REG_INT_STATUS, &val);
> +
> + /* Read chip ID */
> + ret = regmap_read(data->regmap, BMI088_ACCEL_REG_CHIP_ID, &val);
> + if (ret) {
> + dev_err(dev, "Error: Reading chip id\n");
> + return ret;
> + }
> +
> + /* Validate chip ID */
> + for (i = 0; i < ARRAY_SIZE(bmi088_accel_chip_info_tbl); i++) {
> + if (bmi088_accel_chip_info_tbl[i].chip_id == val) {
> + data->chip_info = &bmi088_accel_chip_info_tbl[i];
> + break;
> + }
> + }
> + if (i == ARRAY_SIZE(bmi088_accel_chip_info_tbl)) {
> + dev_err(dev, "Invalid chip %x\n", val);
> + return -ENODEV;
> + }
> +
> + /* Enable accelerometer after reset */
> + return bmi088_accel_enable(data, true);

We bring the device up here, but I'm not seeing it turned off again
in either error paths of probe or remove.
Am I missing it somewhere?

> +}
> +
> +int bmi088_accel_core_probe(struct device *dev, struct regmap *regmap,
> + int irq, const char *name, bool block_supported)
> +{
> + struct bmi088_accel_data *data;
> + struct iio_dev *indio_dev;
> + int ret;
> +
> + indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + data = iio_priv(indio_dev);
> + dev_set_drvdata(dev, indio_dev);
> +
> + data->regmap = regmap;
> +
> + ret = bmi088_accel_chip_init(data);
> + if (ret)
> + return ret;
> +
> + mutex_init(&data->mutex);
> +
> + indio_dev->dev.parent = dev;
> + indio_dev->channels = data->chip_info->channels;
> + indio_dev->num_channels = data->chip_info->num_channels;
> + indio_dev->name = name ? name : data->chip_info->name;
> + indio_dev->available_scan_masks = bmi088_accel_scan_masks;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->info = &bmi088_accel_info;
> +
> + ret = pm_runtime_set_active(dev);
> + if (ret)
> + return ret;
> +
> + pm_runtime_enable(dev);
> + pm_runtime_set_autosuspend_delay(dev, BMI088_AUTO_SUSPEND_DELAY_MS);
> + pm_runtime_use_autosuspend(dev);
> +
> + ret = iio_device_register(indio_dev);
> + if (ret)
> + dev_err(dev, "Unable to register iio device\n");
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(bmi088_accel_core_probe);
> +
> +int bmi088_accel_core_remove(struct device *dev)
> +{
> + struct iio_dev *indio_dev = dev_get_drvdata(dev);
> + struct bmi088_accel_data *data = iio_priv(indio_dev);
> +
> + iio_device_unregister(indio_dev);
> +
> + pm_runtime_disable(dev);
> + pm_runtime_set_suspended(dev);
> + pm_runtime_put_noidle(dev);
> +
> + mutex_lock(&data->mutex);
> + bmi088_accel_set_mode(data, BMI088_ACCEL_MODE_SUSPEND);
> + mutex_unlock(&data->mutex);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(bmi088_accel_core_remove);
> +
> +/* When going into system sleep, put the chip in power down */
> +static int __maybe_unused bmi088_accel_suspend(struct device *dev)
> +{
> + struct iio_dev *indio_dev = dev_get_drvdata(dev);
> + struct bmi088_accel_data *data = iio_priv(indio_dev);
> +
> + mutex_lock(&data->mutex);
> + bmi088_accel_set_mode(data, BMI088_ACCEL_MODE_SUSPEND);
> + bmi088_accel_enable(data, false);
> + mutex_unlock(&data->mutex);
> +
> + return 0;
> +}
> +
> +static int __maybe_unused bmi088_accel_resume(struct device *dev)
> +{
> + struct iio_dev *indio_dev = dev_get_drvdata(dev);
> + struct bmi088_accel_data *data = iio_priv(indio_dev);
> +
> + mutex_lock(&data->mutex);
> + bmi088_accel_enable(data, true);
> + bmi088_accel_set_mode(data, BMI088_ACCEL_MODE_ACTIVE);
> + mutex_unlock(&data->mutex);
> +
> + return 0;
> +}
> +
> +/* For runtime PM put the chip in suspend mode */
> +static int __maybe_unused bmi088_accel_runtime_suspend(struct device *dev)
> +{
> + struct iio_dev *indio_dev = dev_get_drvdata(dev);
> + struct bmi088_accel_data *data = iio_priv(indio_dev);
> +
> + return bmi088_accel_set_mode(data, BMI088_ACCEL_MODE_SUSPEND);
> +}
> +
> +static int __maybe_unused bmi088_accel_runtime_resume(struct device *dev)
> +{
> + struct iio_dev *indio_dev = dev_get_drvdata(dev);
> + struct bmi088_accel_data *data = iio_priv(indio_dev);
> + int ret;
> +
> + ret = bmi088_accel_set_mode(data, BMI088_ACCEL_MODE_ACTIVE);
> + if (ret)
> + return ret;
> +
> + usleep_range(BMI088_ACCEL_MAX_STARTUP_TIME_US,
> + BMI088_ACCEL_MAX_STARTUP_TIME_US * 2);
> +
> + return 0;
> +}
> +
> +const struct dev_pm_ops bmi088_accel_pm_ops = {
> + SET_SYSTEM_SLEEP_PM_OPS(bmi088_accel_suspend, bmi088_accel_resume)
> + SET_RUNTIME_PM_OPS(bmi088_accel_runtime_suspend,
> + bmi088_accel_runtime_resume, NULL)
> +};
> +EXPORT_SYMBOL_GPL(bmi088_accel_pm_ops);
> +
> +MODULE_AUTHOR("Niek van Agt <niek.van.agt@topicproducts.com>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("BMI088 accelerometer driver (core)");
> diff --git a/drivers/iio/accel/bmi088-accel-spi.c b/drivers/iio/accel/bmi088-accel-spi.c
> new file mode 100644
> index 000000000000..7794090b8e6d
> --- /dev/null
> +++ b/drivers/iio/accel/bmi088-accel-spi.c
> @@ -0,0 +1,85 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * 3-axis accelerometer driver supporting following Bosch-Sensortec chips:
> + * - BMI088
> + *
> + * Copyright (c) 2018-2020, Topic Embedded Products
> + */
> +
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/spi/spi.h>
> +#include <linux/regmap.h>

If no other reason for ordering ever so slight preference for
alphabetical order.

> +
> +#include "bmi088-accel.h"
> +
> +int bmi088_regmap_spi_write(void *context, const void *data, size_t count)
> +{
> + struct spi_device *spi = context;
> +
> + /* Write register is same as generic SPI */
> + return spi_write(spi, data, count);
> +}
> +
> +int bmi088_regmap_spi_read(void *context, const void *reg,
> + size_t reg_size, void *val, size_t val_size)
> +{
> + struct spi_device *spi = context;
> + u8 addr[2];
> +
> + addr[0] = *(u8 *)reg;
> + addr[0] |= BIT(7); /* Set RW = '1' */
> + addr[1] = 0; /* Read requires a dummy byte transfer */
> +
> + return spi_write_then_read(spi, addr, sizeof(addr), val, val_size);
> +}
> +
> +static struct regmap_bus bmi088_regmap_bus = {
> + .write = bmi088_regmap_spi_write,
> + .read = bmi088_regmap_spi_read,
> + .reg_format_endian_default = REGMAP_ENDIAN_BIG,
> + .val_format_endian_default = REGMAP_ENDIAN_BIG,

Aren't these both 8 bits, making endian rather irrelevant?

> +};
...