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