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
bmp280_regmap_spi_write(void * context,const void * data,size_t count)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
bmp280_regmap_spi_read(void * context,const void * reg,size_t reg_size,void * val,size_t val_size)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
bmp380_regmap_spi_read(void * context,const void * reg,size_t reg_size,void * val,size_t val_size)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
bmp280_spi_probe(struct spi_device * spi)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