116 lines
2.9 KiB
C
116 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* SPI IIO driver for Bosch BMA400 triaxial acceleration sensor.
|
|
*
|
|
* Copyright 2020 Dan Robertson <dan@dlrobertson.com>
|
|
*
|
|
*/
|
|
#include <linux/bits.h>
|
|
#include <linux/init.h>
|
|
#include <linux/mod_devicetable.h>
|
|
#include <linux/module.h>
|
|
#include <linux/regmap.h>
|
|
#include <linux/spi/spi.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);
|
|
u8 result[BMA400_SPI_READ_BUFFER_SIZE];
|
|
ssize_t status;
|
|
|
|
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)
|
|
{
|
|
const struct spi_device_id *id = spi_get_device_id(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. As the datasheet recommends, the
|
|
* chip ID register will be read here 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, spi->irq, id->name);
|
|
}
|
|
|
|
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,
|
|
.id_table = bma400_spi_ids,
|
|
};
|
|
|
|
module_spi_driver(bma400_spi_driver);
|
|
MODULE_AUTHOR("Dan Robertson <dan@dlrobertson.com>");
|
|
MODULE_DESCRIPTION("Bosch BMA400 triaxial acceleration sensor (SPI)");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_IMPORT_NS(IIO_BMA400);
|