drivers/iio/chemical/bme680_spi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * BME680 - SPI Driver
   4  *
   5  * Copyright (C) 2018 Himanshu Jha <himanshujha199640@gmail.com>
   6  */
   7 #include <linux/acpi.h>
   8 #include <linux/module.h>
   9 #include <linux/regmap.h>
  10 #include <linux/spi/spi.h>
  11
  12 #include "bme680.h"
  13
  14 static int bme680_regmap_spi_write(void *context, const void *data,
  15                                    size_t count)
  16 {
  17         struct spi_device *spi = context;
  18         u8 buf[2];
  19
  20         memcpy(buf, data, 2);
  21         /*
  22          * The SPI register address (= full register address without bit 7)
  23          * and the write command (bit7 = RW = '0')
  24          */
  25         buf[0] &= ~0x80;
  26
  27         return spi_write_then_read(spi, buf, 2, NULL, 0);
  28 }
  29
  30 static int bme680_regmap_spi_read(void *context, const void *reg,
  31                                   size_t reg_size, void *val, size_t val_size)
  32 {
  33         struct spi_device *spi = context;
  34
  35         return spi_write_then_read(spi, reg, reg_size, val, val_size);
  36 }
  37
  38 static struct regmap_bus bme680_regmap_bus = {
  39         .write = bme680_regmap_spi_write,
  40         .read = bme680_regmap_spi_read,
  41         .reg_format_endian_default = REGMAP_ENDIAN_BIG,
  42         .val_format_endian_default = REGMAP_ENDIAN_BIG,
  43 };
  44
  45 static int bme680_spi_probe(struct spi_device *spi)
  46 {
  47         const struct spi_device_id *id = spi_get_device_id(spi);
  48         struct regmap *regmap;
  49         unsigned int val;
  50         int ret;
  51
  52         spi->bits_per_word = 8;
  53         ret = spi_setup(spi);
  54         if (ret < 0) {
  55                 dev_err(&spi->dev, "spi_setup failed!\n");
  56                 return ret;
  57         }
  58
  59         regmap = devm_regmap_init(&spi->dev, &bme680_regmap_bus,
  60                                   &spi->dev, &bme680_regmap_config);
  61         if (IS_ERR(regmap)) {
  62                 dev_err(&spi->dev, "Failed to register spi regmap %d\n",
  63                                 (int)PTR_ERR(regmap));
  64                 return PTR_ERR(regmap);
  65         }
  66
  67         ret = regmap_write(regmap, BME680_REG_SOFT_RESET_SPI,
  68                            BME680_CMD_SOFTRESET);
  69         if (ret < 0) {
  70                 dev_err(&spi->dev, "Failed to reset chip\n");
  71                 return ret;
  72         }
  73
  74         /* after power-on reset, Page 0(0x80-0xFF) of spi_mem_page is active */
  75         ret = regmap_read(regmap, BME680_REG_CHIP_SPI_ID, &val);
  76         if (ret < 0) {
  77                 dev_err(&spi->dev, "Error reading SPI chip ID\n");
  78                 return ret;
  79         }
  80
  81         if (val != BME680_CHIP_ID_VAL) {
  82                 dev_err(&spi->dev, "Wrong chip ID, got %x expected %x\n",
  83                                 val, BME680_CHIP_ID_VAL);
  84                 return -ENODEV;
  85         }
  86         /*
  87          * select Page 1 of spi_mem_page to enable access to
  88          * to registers from address 0x00 to 0x7F.
  89          */
  90         ret = regmap_write_bits(regmap, BME680_REG_STATUS,
  91                                 BME680_SPI_MEM_PAGE_BIT,
  92                                 BME680_SPI_MEM_PAGE_1_VAL);
  93         if (ret < 0) {
  94                 dev_err(&spi->dev, "failed to set page 1 of spi_mem_page\n");
  95                 return ret;
  96         }
  97
  98         return bme680_core_probe(&spi->dev, regmap, id->name);
  99 }
 100
 101 static const struct spi_device_id bme680_spi_id[] = {
 102         {"bme680", 0},
 103         {},
 104 };
 105 MODULE_DEVICE_TABLE(spi, bme680_spi_id);
 106
 107 static const struct acpi_device_id bme680_acpi_match[] = {
 108         {"BME0680", 0},
 109         {},
 110 };
 111 MODULE_DEVICE_TABLE(acpi, bme680_acpi_match);
 112
 113 static struct spi_driver bme680_spi_driver = {
 114         .driver = {
 115                 .name                   = "bme680_spi",
 116                 .acpi_match_table       = ACPI_PTR(bme680_acpi_match),
 117         },
 118         .probe = bme680_spi_probe,
 119         .id_table = bme680_spi_id,
 120 };
 121 module_spi_driver(bme680_spi_driver);
 122
 123 MODULE_AUTHOR("Himanshu Jha <himanshujha199640@gmail.com>");
 124 MODULE_DESCRIPTION("Bosch BME680 SPI driver");
 125 MODULE_LICENSE("GPL v2");