iio: imu: bmi270: Add spi driver for bmi270 imu

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@gmail.com>
Link: https://patch.msgid.link/20241002033628.681812-1-lanzano.alex@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/imu/bmi270/Kconfig b/drivers/iio/imu/bmi270/Kconfig
index a8db441872868410bee999b30e06ad5ba13f77ad..0ffd29794fda2f9ccda7d4d725c751d9dd86c829 100644 (file)
--- 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 ab4acaaee6d2afa26372be8c06b95a9bb9c6f6af..d96c96fc3d8328ef810fc0c082be8e38d15ca998 100644 (file)
--- 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 608b29ea58a31217e0f8a60b61f9d8181aabc080..8ac20ad7ee94da71b6981442349c6b60bc6eae2c 100644 (file)
--- 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 8e45343d647298752da06aae9537b380803126ec..aeda7c4228df54d77d9b762713fc05e6a17f1a26 100644 (file)
--- 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)
 {

diff --git a/drivers/iio/imu/bmi270/bmi270_i2c.c b/drivers/iio/imu/bmi270/bmi270_i2c.c
index f70dee2d8a64405bf46c976f7205e4ec96c031b3..e9025d22d5cc884ff1aeae081fae6e0c36b5a4bf 100644 (file)
--- 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 (file)
index 0000000..b53784d
--- /dev/null
+++ b/drivers/iio/imu/bmi270/bmi270_spi.c
@@ -0,0 +1,85 @@
+// 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/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);