Add basic support for the Bosch Sensortec BMA400 3-axes ultra-low power
accelerometer when configured to use SPI.
Signed-off-by: Dan Robertson <dan@xxxxxxxxxxxxxxx>
---
drivers/iio/accel/Kconfig | 8 ++-
drivers/iio/accel/Makefile | 1 +
drivers/iio/accel/bma400_spi.c | 126 +++++++++++++++++++++++++++++++++
3 files changed, 134 insertions(+), 1 deletion(-)
create mode 100644 drivers/iio/accel/bma400_spi.c
diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index 24ebe9e76915..cb4ef367e5fa 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -116,18 +116,24 @@ config BMA400
tristate "Bosch BMA400 3-Axis Accelerometer Driver"
select REGMAP
select BMA400_I2C if I2C
+ select BMA400_SPI if I2C
help
Say Y here if you want to build a driver for the Bosch BMA400
triaxial acceleration sensor.
To compile this driver as a module, choose M here: the
module will be called bma400_core and you will also get
- bma400_i2c if I2C is enabled.
+ bma400_i2c if I2C is enabled and bma400_spi if SPI is
+ enabled.
config BMA400_I2C
tristate
depends on BMA400
+config BMA400_SPI
+ tristate
+ depends on BMA400
+
config BMC150_ACCEL
tristate "Bosch BMC150 Accelerometer Driver"
select IIO_BUFFER
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index 3a051cf37f40..4f6c1ebe13b0 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_BMA180) += bma180.o
obj-$(CONFIG_BMA220) += bma220_spi.o
obj-$(CONFIG_BMA400) += bma400_core.o
obj-$(CONFIG_BMA400_I2C) += bma400_i2c.o
+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
diff --git a/drivers/iio/accel/bma400_spi.c b/drivers/iio/accel/bma400_spi.c
new file mode 100644
index 000000000000..d92b37e1a657
--- /dev/null
+++ b/drivers/iio/accel/bma400_spi.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SPI IIO driver for Bosch BMA400 triaxial acceleration sensor.
+ *
+ * Copyright 2020 Dan Robertson <dan@xxxxxxxxxxxxxxx>
+ *
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+
+#include <linux/spi/spi.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "bma400.h"
+
+#define BMA400_MAX_SPI_READ 2
+#define BMA400_SPI_READ_BUFFER_SIZE (BMA400_MAX_SPI_READ + 1)
+
+static int bma400_regmap_spi_read(void *context,
+ const void *reg, size_t reg_size,
+ void *val, size_t val_size)
+{
+ struct device *dev = context;
+ struct spi_device *spi = to_spi_device(dev);
+ ssize_t status;
+ /*
+ * TODO(dlrobertson): What is a reasonable length to cap
+ * this at.
+ */
+ u8 result[BMA400_SPI_READ_BUFFER_SIZE];
+
+ if (val_size > BMA400_MAX_SPI_READ)
+ return -EINVAL;
+
+ status = spi_write_then_read(spi, reg, 1, result, val_size + 1);
+ if (status)
+ return status;
+
+ /*
+ * From the BMA400 datasheet:
+ *
+ * > For a basic read operation two bytes have to be read and the first
+ * > has to be dropped and the second byte must be interpreted.
+ */
+ memcpy(val, result + 1, val_size);
+
+ return 0;
+}
+
+static int bma400_regmap_spi_write(void *context, const void *data,
+ size_t count)
+{
+ struct device *dev = context;
+ struct spi_device *spi = to_spi_device(dev);
+
+ return spi_write(spi, data, count);
+}
+
+static struct regmap_bus bma400_regmap_bus = {
+ .read = bma400_regmap_spi_read,
+ .write = bma400_regmap_spi_write,
+ .read_flag_mask = BIT(7),
+ .max_raw_read = BMA400_MAX_SPI_READ,
+};
+
+static int bma400_spi_probe(struct spi_device *spi)
+{
+ struct regmap *regmap;
+ unsigned int val;
+ int ret;
+
+ regmap = devm_regmap_init(&spi->dev, &bma400_regmap_bus,
+ &spi->dev, &bma400_regmap_config);
+ if (IS_ERR(regmap)) {
+ dev_err(&spi->dev, "failed to create regmap\n");
+ return PTR_ERR(regmap);
+ }
+
+ /*
+ * Per the bma400 datasheet, the first SPI read may
+ * return garbage on the first read. The chip ID
+ * register will be read and checked again in the
+ * following probe.
+ */
+ ret = regmap_read(regmap, BMA400_CHIP_ID_REG, &val);
+ if (ret)
+ dev_err(&spi->dev, "Failed to read chip id register\n");
+
+ return bma400_probe(&spi->dev, regmap, "bma400");
+}
+
+static int bma400_spi_remove(struct spi_device *spi)
+{
+ return bma400_remove(&spi->dev);
+}
+
+static const struct spi_device_id bma400_spi_ids[] = {
+ { "bma400", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(spi, bma400_spi_ids);
+
+static const struct of_device_id bma400_of_spi_match[] = {
+ { .compatible = "bosch,bma400" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, bma400_of_spi_match);
+
+static struct spi_driver bma400_spi_driver = {
+ .driver = {
+ .name = "bma400",
+ .of_match_table = bma400_of_spi_match,
+ },
+ .probe = bma400_spi_probe,
+ .remove = bma400_spi_remove,
+ .id_table = bma400_spi_ids,
+};
+
+module_spi_driver(bma400_spi_driver);
+
+MODULE_AUTHOR("Dan Robertson <dan@xxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Bosch BMA400 triaxial acceleration sensor (SPI)");
+MODULE_LICENSE("GPL");
