diff options
Diffstat (limited to 'drivers/iio/chemical/bme680_spi.c')
| -rw-r--r-- | drivers/iio/chemical/bme680_spi.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/drivers/iio/chemical/bme680_spi.c b/drivers/iio/chemical/bme680_spi.c new file mode 100644 index 000000000000..c9fb05e8d0b9 --- /dev/null +++ b/drivers/iio/chemical/bme680_spi.c @@ -0,0 +1,125 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * BME680 - SPI Driver + * + * Copyright (C) 2018 Himanshu Jha <himanshujha199640@gmail.com> + */ +#include <linux/acpi.h> +#include <linux/module.h> +#include <linux/regmap.h> +#include <linux/spi/spi.h> + +#include "bme680.h" + +static int bme680_regmap_spi_write(void *context, const void *data, + size_t count) +{ + struct spi_device *spi = context; + u8 buf[2]; + + memcpy(buf, data, 2); + /* + * The SPI register address (= full register address without bit 7) + * and the write command (bit7 = RW = '0') + */ + buf[0] &= ~0x80; + + return spi_write_then_read(spi, buf, 2, NULL, 0); +} + +static int bme680_regmap_spi_read(void *context, const void *reg, + size_t reg_size, void *val, size_t val_size) +{ + struct spi_device *spi = context; + + return spi_write_then_read(spi, reg, reg_size, val, val_size); +} + +static struct regmap_bus bme680_regmap_bus = { + .write = bme680_regmap_spi_write, + .read = bme680_regmap_spi_read, + .reg_format_endian_default = REGMAP_ENDIAN_BIG, + .val_format_endian_default = REGMAP_ENDIAN_BIG, +}; + +static int bme680_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; + + spi->bits_per_word = 8; + ret = spi_setup(spi); + if (ret < 0) { + dev_err(&spi->dev, "spi_setup failed!\n"); + return ret; + } + + regmap = devm_regmap_init(&spi->dev, &bme680_regmap_bus, + &spi->dev, &bme680_regmap_config); + if (IS_ERR(regmap)) { + dev_err(&spi->dev, "Failed to register spi regmap %d\n", + (int)PTR_ERR(regmap)); + return PTR_ERR(regmap); + } + + ret = regmap_write(regmap, BME680_REG_SOFT_RESET_SPI, + BME680_CMD_SOFTRESET); + if (ret < 0) { + dev_err(&spi->dev, "Failed to reset chip\n"); + return ret; + } + + /* after power-on reset, Page 0(0x80-0xFF) of spi_mem_page is active */ + ret = regmap_read(regmap, BME680_REG_CHIP_SPI_ID, &val); + if (ret < 0) { + dev_err(&spi->dev, "Error reading SPI chip ID\n"); + return ret; + } + + if (val != BME680_CHIP_ID_VAL) { + dev_err(&spi->dev, "Wrong chip ID, got %x expected %x\n", + val, BME680_CHIP_ID_VAL); + return -ENODEV; + } + /* + * select Page 1 of spi_mem_page to enable access to + * to registers from address 0x00 to 0x7F. + */ + ret = regmap_write_bits(regmap, BME680_REG_STATUS, + BME680_SPI_MEM_PAGE_BIT, + BME680_SPI_MEM_PAGE_1_VAL); + if (ret < 0) { + dev_err(&spi->dev, "failed to set page 1 of spi_mem_page\n"); + return ret; + } + + return bme680_core_probe(&spi->dev, regmap, id->name); +} + +static const struct spi_device_id bme680_spi_id[] = { + {"bme680", 0}, + {}, +}; +MODULE_DEVICE_TABLE(spi, bme680_spi_id); + +static const struct acpi_device_id bme680_acpi_match[] = { + {"BME0680", 0}, + {}, +}; +MODULE_DEVICE_TABLE(acpi, bme680_acpi_match); + +static struct spi_driver bme680_spi_driver = { + .driver = { + .name = "bme680_spi", + .acpi_match_table = ACPI_PTR(bme680_acpi_match), + }, + .probe = bme680_spi_probe, + .id_table = bme680_spi_id, +}; +module_spi_driver(bme680_spi_driver); + +MODULE_AUTHOR("Himanshu Jha <himanshujha199640@gmail.com>"); +MODULE_DESCRIPTION("Bosch BME680 SPI driver"); +MODULE_LICENSE("GPL v2"); |