[0/1] iio: accel: bma400: add support for bma400 spi

Message

Dan Robertson May 22, 2020, 1:46 a.m. UTC

The Bosch Sensortec BMA400 3-axes ultra-low power supports a 4 wire
SPI ditital interface. This patch adds support for the device when
configured for SPI instead of I2C.

I was originally hoping to avoid using a regmap_bus definition, but the
register reads from the device are padded by a byte while register
writes are not padded. As a result, a regmap_config like the following
does not work.

const struct regmap_config bma400_regmap_spi_config = {
    reg_bits = 8,
    pad_bits = 8,
    val_bits = 8,
    read_flag_mask = BIT(7),
    max_register = BMA400_CMD_REG,
};

I used a regmap_bus structure with read and write implementations to
work around this, but would appreciate feedback on this approach and
my implementation.

Cheers,

 - Dan

Dan Robertson (1):
  iio: accel: bma400: add support for bma400 spi

 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