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
15static int bmp280_regmap_spi_write(void *context, const void *data,
16 size_t count)
17{
18 struct spi_device *spi = to_spi_device(dev: 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, txbuf: buf, n_tx: 2, NULL, n_rx: 0);
29}
30
31static 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(dev: context);
35
36 return spi_write_then_read(spi, txbuf: reg, n_tx: reg_size, rxbuf: val, n_rx: val_size);
37}
38
39static 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(dev: 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, txbuf: reg, n_tx: 1, rxbuf: rx_buf, n_rx: val_size + 1);
59 if (status)
60 return status;
61
62 memcpy(val, rx_buf + 1, val_size);
63
64 return 0;
65}
66
67static 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
74static 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
82static int bmp280_spi_probe(struct spi_device *spi)
83{
84 const struct spi_device_id *id = spi_get_device_id(sdev: 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(sdev: spi);
98
99 switch (chip_info->chip_id[0]) {
100 case BMP380_CHIP_ID:
101 case BMP390_CHIP_ID:
102 bmp_regmap_bus = &bmp380_regmap_bus;
103 break;
104 default:
105 bmp_regmap_bus = &bmp280_regmap_bus;
106 break;
107 }
108
109 regmap = devm_regmap_init(&spi->dev,
110 bmp_regmap_bus,
111 &spi->dev,
112 chip_info->regmap_config);
113 if (IS_ERR(ptr: regmap)) {
114 dev_err(&spi->dev, "failed to allocate register map\n");
115 return PTR_ERR(ptr: regmap);
116 }
117
118 return bmp280_common_probe(dev: &spi->dev,
119 regmap,
120 chip_info,
121 name: id->name,
122 irq: spi->irq);
123}
124
125static const struct of_device_id bmp280_of_spi_match[] = {
126 { .compatible = "bosch,bmp085", .data = &bmp180_chip_info },
127 { .compatible = "bosch,bmp180", .data = &bmp180_chip_info },
128 { .compatible = "bosch,bmp181", .data = &bmp180_chip_info },
129 { .compatible = "bosch,bmp280", .data = &bmp280_chip_info },
130 { .compatible = "bosch,bme280", .data = &bmp280_chip_info },
131 { .compatible = "bosch,bmp380", .data = &bmp380_chip_info },
132 { .compatible = "bosch,bmp580", .data = &bmp580_chip_info },
133 { },
134};
135MODULE_DEVICE_TABLE(of, bmp280_of_spi_match);
136
137static const struct spi_device_id bmp280_spi_id[] = {
138 { "bmp085", (kernel_ulong_t)&bmp180_chip_info },
139 { "bmp180", (kernel_ulong_t)&bmp180_chip_info },
140 { "bmp181", (kernel_ulong_t)&bmp180_chip_info },
141 { "bmp280", (kernel_ulong_t)&bmp280_chip_info },
142 { "bme280", (kernel_ulong_t)&bmp280_chip_info },
143 { "bmp380", (kernel_ulong_t)&bmp380_chip_info },
144 { "bmp580", (kernel_ulong_t)&bmp580_chip_info },
145 { }
146};
147MODULE_DEVICE_TABLE(spi, bmp280_spi_id);
148
149static struct spi_driver bmp280_spi_driver = {
150 .driver = {
151 .name = "bmp280",
152 .of_match_table = bmp280_of_spi_match,
153 .pm = pm_ptr(&bmp280_dev_pm_ops),
154 },
155 .id_table = bmp280_spi_id,
156 .probe = bmp280_spi_probe,
157};
158module_spi_driver(bmp280_spi_driver);
159
160MODULE_DESCRIPTION("BMP280 SPI bus driver");
161MODULE_LICENSE("GPL");
162MODULE_IMPORT_NS(IIO_BMP280);
163

source code of linux/drivers/iio/pressure/bmp280-spi.c