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 85 chip_info = spi_get_device_match_data(spi); 86 87 if (chip_info->spi_read_extra_byte) 88 bmp_regmap_bus = &bmp380_regmap_bus; 89 else 90 bmp_regmap_bus = &bmp280_regmap_bus; 91 92 regmap = devm_regmap_init(&spi->dev, 93 bmp_regmap_bus, 94 &spi->dev, 95 chip_info->regmap_config); 96 if (IS_ERR(regmap)) { 97 dev_err(&spi->dev, "failed to allocate register map\n"); 98 return PTR_ERR(regmap); 99 } 100 101 return bmp280_common_probe(&spi->dev, 102 regmap, 103 chip_info, 104 id->name, 105 spi->irq); 106 } 107 108 static const struct of_device_id bmp280_of_spi_match[] = { 109 { .compatible = "bosch,bmp085", .data = &bmp085_chip_info }, 110 { .compatible = "bosch,bmp180", .data = &bmp180_chip_info }, 111 { .compatible = "bosch,bmp181", .data = &bmp180_chip_info }, 112 { .compatible = "bosch,bmp280", .data = &bmp280_chip_info }, 113 { .compatible = "bosch,bme280", .data = &bme280_chip_info }, 114 { .compatible = "bosch,bmp380", .data = &bmp380_chip_info }, 115 { .compatible = "bosch,bmp580", .data = &bmp580_chip_info }, 116 { } 117 }; 118 MODULE_DEVICE_TABLE(of, bmp280_of_spi_match); 119 120 static const struct spi_device_id bmp280_spi_id[] = { 121 { "bmp085", (kernel_ulong_t)&bmp085_chip_info }, 122 { "bmp180", (kernel_ulong_t)&bmp180_chip_info }, 123 { "bmp181", (kernel_ulong_t)&bmp180_chip_info }, 124 { "bmp280", (kernel_ulong_t)&bmp280_chip_info }, 125 { "bme280", (kernel_ulong_t)&bme280_chip_info }, 126 { "bmp380", (kernel_ulong_t)&bmp380_chip_info }, 127 { "bmp580", (kernel_ulong_t)&bmp580_chip_info }, 128 { } 129 }; 130 MODULE_DEVICE_TABLE(spi, bmp280_spi_id); 131 132 static struct spi_driver bmp280_spi_driver = { 133 .driver = { 134 .name = "bmp280", 135 .of_match_table = bmp280_of_spi_match, 136 .pm = pm_ptr(&bmp280_dev_pm_ops), 137 }, 138 .id_table = bmp280_spi_id, 139 .probe = bmp280_spi_probe, 140 }; 141 module_spi_driver(bmp280_spi_driver); 142 143 MODULE_DESCRIPTION("BMP280 SPI bus driver"); 144 MODULE_LICENSE("GPL"); 145 MODULE_IMPORT_NS("IIO_BMP280"); 146