drivers/iio/pressure/bmp280-spi.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * SPI interface for the BMP280 driver
   4  *
   5  * Inspired by the older BMP085 driver drivers/misc/bmp085-spi.c
   6  */
   7 #include <linux/bits.h>
   8 #include <linux/module.h>
   9 #include <linux/spi/spi.h>
  10 #include <linux/err.h>
  11 #include <linux/regmap.h>
  12
  13 #include "bmp280.h"
  14
  15 static int bmp280_regmap_spi_write(void *context, const void *data,
  16                                    size_t count)
  17 {
  18         struct spi_device *spi = to_spi_device(context);
  19         u8 buf[2];
  20
  21         memcpy(buf, data, 2);
  22         /*
  23          * The SPI register address (= full register address without bit 7) and
  24          * the write command (bit7 = RW = '0')
  25          */
  26         buf[0] &= ~0x80;
  27
  28         return spi_write_then_read(spi, buf, 2, NULL, 0);
  29 }
  30
  31 static int bmp280_regmap_spi_read(void *context, const void *reg,
  32                                   size_t reg_size, void *val, size_t val_size)
  33 {
  34         struct spi_device *spi = to_spi_device(context);
  35
  36         return spi_write_then_read(spi, reg, reg_size, val, val_size);
  37 }
  38
  39 static int bmp380_regmap_spi_read(void *context, const void *reg,
  40                                   size_t reg_size, void *val, size_t val_size)
  41 {
  42         struct spi_device *spi = to_spi_device(context);
  43         u8 rx_buf[4];
  44         ssize_t status;
  45
  46         /*
  47          * Maximum number of consecutive bytes read for a temperature or
  48          * pressure measurement is 3.
  49          */
  50         if (val_size > 3)
  51                 return -EINVAL;
  52
  53         /*
  54          * According to the BMP3xx datasheets, for a basic SPI read opertion,
  55          * the first byte needs to be dropped and the rest are the requested
  56          * data.
  57          */
  58         status = spi_write_then_read(spi, reg, 1, rx_buf, val_size + 1);
  59         if (status)
  60                 return status;
  61
  62         memcpy(val, rx_buf + 1, val_size);
  63
  64         return 0;
  65 }
  66
  67 static struct regmap_bus bmp280_regmap_bus = {
  68         .write = bmp280_regmap_spi_write,
  69         .read = bmp280_regmap_spi_read,
  70         .reg_format_endian_default = REGMAP_ENDIAN_BIG,
  71         .val_format_endian_default = REGMAP_ENDIAN_BIG,
  72 };
  73
  74 static struct regmap_bus bmp380_regmap_bus = {
  75         .write = bmp280_regmap_spi_write,
  76         .read = bmp380_regmap_spi_read,
  77         .read_flag_mask = BIT(7),
  78         .reg_format_endian_default = REGMAP_ENDIAN_BIG,
  79         .val_format_endian_default = REGMAP_ENDIAN_BIG,
  80 };
  81
  82 static int bmp280_spi_probe(struct spi_device *spi)
  83 {
  84         const struct spi_device_id *id = spi_get_device_id(spi);
  85         const struct bmp280_chip_info *chip_info;
  86         struct regmap_bus *bmp_regmap_bus;
  87         struct regmap *regmap;
  88         int ret;
  89
  90         spi->bits_per_word = 8;
  91         ret = spi_setup(spi);
  92         if (ret < 0) {
  93                 dev_err(&spi->dev, "spi_setup failed!\n");
  94                 return ret;
  95         }
  96
  97         chip_info = spi_get_device_match_data(spi);
  98
  99         if (chip_info->spi_read_extra_byte)
 100                 bmp_regmap_bus = &bmp380_regmap_bus;
 101         else
 102                 bmp_regmap_bus = &bmp280_regmap_bus;
 103
 104         regmap = devm_regmap_init(&spi->dev,
 105                                   bmp_regmap_bus,
 106                                   &spi->dev,
 107                                   chip_info->regmap_config);
 108         if (IS_ERR(regmap)) {
 109                 dev_err(&spi->dev, "failed to allocate register map\n");
 110                 return PTR_ERR(regmap);
 111         }
 112
 113         return bmp280_common_probe(&spi->dev,
 114                                    regmap,
 115                                    chip_info,
 116                                    id->name,
 117                                    spi->irq);
 118 }
 119
 120 static const struct of_device_id bmp280_of_spi_match[] = {
 121         { .compatible = "bosch,bmp085", .data = &bmp180_chip_info },
 122         { .compatible = "bosch,bmp180", .data = &bmp180_chip_info },
 123         { .compatible = "bosch,bmp181", .data = &bmp180_chip_info },
 124         { .compatible = "bosch,bmp280", .data = &bmp280_chip_info },
 125         { .compatible = "bosch,bme280", .data = &bme280_chip_info },
 126         { .compatible = "bosch,bmp380", .data = &bmp380_chip_info },
 127         { .compatible = "bosch,bmp580", .data = &bmp580_chip_info },
 128         { },
 129 };
 130 MODULE_DEVICE_TABLE(of, bmp280_of_spi_match);
 131
 132 static const struct spi_device_id bmp280_spi_id[] = {
 133         { "bmp085", (kernel_ulong_t)&bmp180_chip_info },
 134         { "bmp180", (kernel_ulong_t)&bmp180_chip_info },
 135         { "bmp181", (kernel_ulong_t)&bmp180_chip_info },
 136         { "bmp280", (kernel_ulong_t)&bmp280_chip_info },
 137         { "bme280", (kernel_ulong_t)&bme280_chip_info },
 138         { "bmp380", (kernel_ulong_t)&bmp380_chip_info },
 139         { "bmp580", (kernel_ulong_t)&bmp580_chip_info },
 140         { }
 141 };
 142 MODULE_DEVICE_TABLE(spi, bmp280_spi_id);
 143
 144 static struct spi_driver bmp280_spi_driver = {
 145         .driver = {
 146                 .name = "bmp280",
 147                 .of_match_table = bmp280_of_spi_match,
 148                 .pm = pm_ptr(&bmp280_dev_pm_ops),
 149         },
 150         .id_table = bmp280_spi_id,
 151         .probe = bmp280_spi_probe,
 152 };
 153 module_spi_driver(bmp280_spi_driver);
 154
 155 MODULE_DESCRIPTION("BMP280 SPI bus driver");
 156 MODULE_LICENSE("GPL");
 157 MODULE_IMPORT_NS(IIO_BMP280);