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 = &bmp180_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)&bmp180_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); 154