Implement SPI driver for the Bosch BMI270 6-axis IMU. Provide raw read
write access to acceleration and angle velocity measurements via the SPI
interface on the device.
Signed-off-by: Alex Lanzano <lanzano.alex@xxxxxxxxx>
---
Changes in v2:
- Remove unnecessary __le16 sample variable out of priv data
- Add static to regmap_config structures
- Sort includes in bmi270_spi.c alphabetically
- Rename "context" argument for spi regmap functions to "spi" and use it directly
- Replace spi_write with spi_write_then_read to ensure bounce buffer is
always used
---
drivers/iio/imu/bmi270/Kconfig | 12 ++++
drivers/iio/imu/bmi270/Makefile | 1 +
drivers/iio/imu/bmi270/bmi270.h | 1 +
drivers/iio/imu/bmi270/bmi270_core.c | 10 +---
drivers/iio/imu/bmi270/bmi270_i2c.c | 7 ++-
drivers/iio/imu/bmi270/bmi270_spi.c | 86 ++++++++++++++++++++++++++++
6 files changed, 109 insertions(+), 8 deletions(-)
create mode 100644 drivers/iio/imu/bmi270/bmi270_spi.c
diff --git a/drivers/iio/imu/bmi270/Kconfig b/drivers/iio/imu/bmi270/Kconfig
index a8db44187286..0ffd29794fda 100644
--- a/drivers/iio/imu/bmi270/Kconfig
+++ b/drivers/iio/imu/bmi270/Kconfig
@@ -18,3 +18,15 @@ config BMI270_I2C
This driver can also be built as a module. If so, the module will be
called bmi270_i2c.
+
+config BMI270_SPI
+ tristate "Bosch BMI270 SPI driver"
+ depends on SPI
+ select BMI270
+ select REGMAP_SPI
+ help
+ Enable support for the Bosch BMI270 6-Axis IMU connected to SPI
+ interface.
+
+ This driver can also be built as a module. If so, the module will be
+ called bmi270_spi.
diff --git a/drivers/iio/imu/bmi270/Makefile b/drivers/iio/imu/bmi270/Makefile
index ab4acaaee6d2..d96c96fc3d83 100644
--- a/drivers/iio/imu/bmi270/Makefile
+++ b/drivers/iio/imu/bmi270/Makefile
@@ -4,3 +4,4 @@
#
obj-$(CONFIG_BMI270) += bmi270_core.o
obj-$(CONFIG_BMI270_I2C) += bmi270_i2c.o
+obj-$(CONFIG_BMI270_SPI) += bmi270_spi.o
diff --git a/drivers/iio/imu/bmi270/bmi270.h b/drivers/iio/imu/bmi270/bmi270.h
index 608b29ea58a3..8ac20ad7ee94 100644
--- a/drivers/iio/imu/bmi270/bmi270.h
+++ b/drivers/iio/imu/bmi270/bmi270.h
@@ -4,6 +4,7 @@
#define BMI270_H_
#include <linux/regmap.h>
+#include <linux/iio/iio.h>
struct device;
struct bmi270_data {
diff --git a/drivers/iio/imu/bmi270/bmi270_core.c b/drivers/iio/imu/bmi270/bmi270_core.c
index 8e45343d6472..638ce2c30d0e 100644
--- a/drivers/iio/imu/bmi270/bmi270_core.c
+++ b/drivers/iio/imu/bmi270/bmi270_core.c
@@ -66,12 +66,6 @@ enum bmi270_scan {
BMI270_SCAN_GYRO_Z,
};
-const struct regmap_config bmi270_regmap_config = {
- .reg_bits = 8,
- .val_bits = 8,
-};
-EXPORT_SYMBOL_NS_GPL(bmi270_regmap_config, IIO_BMI270);
-
static int bmi270_get_data(struct bmi270_data *bmi270_device,
int chan_type, int axis, int *val)
{
@@ -90,7 +84,9 @@ static int bmi270_get_data(struct bmi270_data *bmi270_device,
return -EINVAL;
}
- ret = regmap_bulk_read(bmi270_device->regmap, reg, &sample, sizeof(sample));
+ ret = regmap_bulk_read(bmi270_device->regmap, reg,
+ &sample,
+ sizeof(sample));
if (ret)
return ret;
diff --git a/drivers/iio/imu/bmi270/bmi270_i2c.c b/drivers/iio/imu/bmi270/bmi270_i2c.c
index f70dee2d8a64..e9025d22d5cc 100644
--- a/drivers/iio/imu/bmi270/bmi270_i2c.c
+++ b/drivers/iio/imu/bmi270/bmi270_i2c.c
@@ -9,12 +9,17 @@
#include "bmi270.h"
+static const struct regmap_config bmi270_i2c_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+};
+
static int bmi270_i2c_probe(struct i2c_client *client)
{
struct regmap *regmap;
struct device *dev = &client->dev;
- regmap = devm_regmap_init_i2c(client, &bmi270_regmap_config);
+ regmap = devm_regmap_init_i2c(client, &bmi270_i2c_regmap_config);
if (IS_ERR(regmap))
return dev_err_probe(dev, PTR_ERR(regmap),
"Failed to init i2c regmap");
diff --git a/drivers/iio/imu/bmi270/bmi270_spi.c b/drivers/iio/imu/bmi270/bmi270_spi.c
new file mode 100644
index 000000000000..34d5ba6273bb
--- /dev/null
+++ b/drivers/iio/imu/bmi270/bmi270_spi.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+
+#include <linux/iio/iio.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#include "bmi270.h"
+
+/*
+ * The following two functions are taken from the BMI323 spi driver code.
+ * In section 6.4 of the BMI270 data it specifies that after a read
+ * operation the first data byte from the device is a dummy byte
+ */
+static int bmi270_regmap_spi_read(void *spi, const void *reg_buf,
+ size_t reg_size, void *val_buf,
+ size_t val_size)
+{
+ return spi_write_then_read(spi, reg_buf, reg_size, val_buf, val_size);
+}
+
+static int bmi270_regmap_spi_write(void *spi, const void *data,
+ size_t count)
+{
+ u8 *data_buff = (u8 *)data;
+
+ /*
+ * Remove the extra pad byte since its only needed for the read
+ * operation
+ */
+ data_buff[1] = data_buff[0];
+ return spi_write_then_read(spi, data_buff + 1, count - 1, NULL, 0);
+}
+
+static const struct regmap_bus bmi270_regmap_bus = {
+ .read = bmi270_regmap_spi_read,
+ .write = bmi270_regmap_spi_write,
+};
+
+static const struct regmap_config bmi270_spi_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .pad_bits = 8,
+ .read_flag_mask = BIT(7),
+};
+
+static int bmi270_spi_probe(struct spi_device *spi)
+{
+ struct regmap *regmap;
+ struct device *dev = &spi->dev;
+
+ regmap = devm_regmap_init(dev, &bmi270_regmap_bus, dev,
+ &bmi270_spi_regmap_config);
+ if (IS_ERR(regmap))
+ return dev_err_probe(dev, PTR_ERR(regmap),
+ "Failed to init i2c regmap");
+
+ return bmi270_core_probe(dev, regmap);
+}
+
+static const struct spi_device_id bmi270_spi_id[] = {
+ { "bmi270" },
+ { }
+};
+
+static const struct of_device_id bmi270_of_match[] = {
+ { .compatible = "bosch,bmi270" },
+ { }
+};
+
+static struct spi_driver bmi270_spi_driver = {
+ .driver = {
+ .name = "bmi270",
+ .of_match_table = bmi270_of_match,
+ },
+ .probe = bmi270_spi_probe,
+ .id_table = bmi270_spi_id,
+};
+module_spi_driver(bmi270_spi_driver);
+
+MODULE_AUTHOR("Alex Lanzano");
+MODULE_DESCRIPTION("BMI270 driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(IIO_BMI270);
--
2.46.2
