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/err.h>
   9 #include <linux/module.h>
  10 #include <linux/regmap.h>
  11 #include <linux/spi/spi.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[BME280_BURST_READ_BYTES + 1];
  44         ssize_t status;
  45
  46         if (val_size > BME280_BURST_READ_BYTES)
  47                 return -EINVAL;
  48
  49         /*
  50          * According to the BMP3xx datasheets, for a basic SPI read opertion,
  51          * the first byte needs to be dropped and the rest are the requested
  52          * data.
  53          */
  54         status = spi_write_then_read(spi, reg, 1, rx_buf, val_size + 1);
  55         if (status)
  56                 return status;
  57
  58         memcpy(val, rx_buf + 1, val_size);
  59
  60         return 0;
  61 }
  62
  63 static const struct regmap_bus bmp280_regmap_bus = {
  64         .write = bmp280_regmap_spi_write,
  65         .read = bmp280_regmap_spi_read,
  66         .reg_format_endian_default = REGMAP_ENDIAN_BIG,
  67         .val_format_endian_default = REGMAP_ENDIAN_BIG,
  68 };
  69
  70 static const struct regmap_bus bmp380_regmap_bus = {
  71         .write = bmp280_regmap_spi_write,
  72         .read = bmp380_regmap_spi_read,
  73         .read_flag_mask = BIT(7),
  74         .reg_format_endian_default = REGMAP_ENDIAN_BIG,
  75         .val_format_endian_default = REGMAP_ENDIAN_BIG,
  76 };
  77
  78 static int bmp280_spi_probe(struct spi_device *spi)
  79 {
  80         const struct spi_device_id *id = spi_get_device_id(spi);
  81         const struct bmp280_chip_info *chip_info;
  82         struct regmap_bus const *bmp_regmap_bus;
  83         struct regmap *regmap;
  84         int ret;
  85
  86         spi->bits_per_word = 8;
  87         ret = spi_setup(spi);
  88         if (ret < 0) {
  89                 dev_err(&spi->dev, "spi_setup failed!\n");
  90                 return ret;
  91         }
  92
  93         chip_info = spi_get_device_match_data(spi);
  94
  95         if (chip_info->spi_read_extra_byte)
  96                 bmp_regmap_bus = &bmp380_regmap_bus;
  97         else
  98                 bmp_regmap_bus = &bmp280_regmap_bus;
  99
 100         regmap = devm_regmap_init(&spi->dev,
 101                                   bmp_regmap_bus,
 102                                   &spi->dev,
 103                                   chip_info->regmap_config);
 104         if (IS_ERR(regmap)) {
 105                 dev_err(&spi->dev, "failed to allocate register map\n");
 106                 return PTR_ERR(regmap);
 107         }
 108
 109         return bmp280_common_probe(&spi->dev,
 110                                    regmap,
 111                                    chip_info,
 112                                    id->name,
 113                                    spi->irq);
 114 }
 115
 116 static const struct of_device_id bmp280_of_spi_match[] = {
 117         { .compatible = "bosch,bmp085", .data = &bmp085_chip_info },
 118         { .compatible = "bosch,bmp180", .data = &bmp180_chip_info },
 119         { .compatible = "bosch,bmp181", .data = &bmp180_chip_info },
 120         { .compatible = "bosch,bmp280", .data = &bmp280_chip_info },
 121         { .compatible = "bosch,bme280", .data = &bme280_chip_info },
 122         { .compatible = "bosch,bmp380", .data = &bmp380_chip_info },
 123         { .compatible = "bosch,bmp580", .data = &bmp580_chip_info },
 124         { },
 125 };
 126 MODULE_DEVICE_TABLE(of, bmp280_of_spi_match);
 127
 128 static const struct spi_device_id bmp280_spi_id[] = {
 129         { "bmp085", (kernel_ulong_t)&bmp085_chip_info },
 130         { "bmp180", (kernel_ulong_t)&bmp180_chip_info },
 131         { "bmp181", (kernel_ulong_t)&bmp180_chip_info },
 132         { "bmp280", (kernel_ulong_t)&bmp280_chip_info },
 133         { "bme280", (kernel_ulong_t)&bme280_chip_info },
 134         { "bmp380", (kernel_ulong_t)&bmp380_chip_info },
 135         { "bmp580", (kernel_ulong_t)&bmp580_chip_info },
 136         { }
 137 };
 138 MODULE_DEVICE_TABLE(spi, bmp280_spi_id);
 139
 140 static struct spi_driver bmp280_spi_driver = {
 141         .driver = {
 142                 .name = "bmp280",
 143                 .of_match_table = bmp280_of_spi_match,
 144                 .pm = pm_ptr(&bmp280_dev_pm_ops),
 145         },
 146         .id_table = bmp280_spi_id,
 147         .probe = bmp280_spi_probe,
 148 };
 149 module_spi_driver(bmp280_spi_driver);
 150
 151 MODULE_DESCRIPTION("BMP280 SPI bus driver");
 152 MODULE_LICENSE("GPL");
 153 MODULE_IMPORT_NS("IIO_BMP280");