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/module.h>
8 #include <linux/spi/spi.h>
9 #include <linux/err.h>
10 #include <linux/regmap.h>
11 
12 #include "bmp280.h"
13 
14 static int bmp280_regmap_spi_write(void *context, const void *data,
15                                    size_t count)
16 {
17 	struct device *dev = context;
18 	struct spi_device *spi = to_spi_device(dev);
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 device *dev = context;
35 	struct spi_device *spi = to_spi_device(dev);
36 
37 	return spi_write_then_read(spi, reg, reg_size, val, val_size);
38 }
39 
40 static struct regmap_bus bmp280_regmap_bus = {
41 	.write = bmp280_regmap_spi_write,
42 	.read = bmp280_regmap_spi_read,
43 	.reg_format_endian_default = REGMAP_ENDIAN_BIG,
44 	.val_format_endian_default = REGMAP_ENDIAN_BIG,
45 };
46 
47 static int bmp280_spi_probe(struct spi_device *spi)
48 {
49 	const struct spi_device_id *id = spi_get_device_id(spi);
50 	struct regmap *regmap;
51 	const struct regmap_config *regmap_config;
52 	int ret;
53 
54 	spi->bits_per_word = 8;
55 	ret = spi_setup(spi);
56 	if (ret < 0) {
57 		dev_err(&spi->dev, "spi_setup failed!\n");
58 		return ret;
59 	}
60 
61 	switch (id->driver_data) {
62 	case BMP180_CHIP_ID:
63 		regmap_config = &bmp180_regmap_config;
64 		break;
65 	case BMP280_CHIP_ID:
66 	case BME280_CHIP_ID:
67 		regmap_config = &bmp280_regmap_config;
68 		break;
69 	default:
70 		return -EINVAL;
71 	}
72 
73 	regmap = devm_regmap_init(&spi->dev,
74 				  &bmp280_regmap_bus,
75 				  &spi->dev,
76 				  regmap_config);
77 	if (IS_ERR(regmap)) {
78 		dev_err(&spi->dev, "failed to allocate register map\n");
79 		return PTR_ERR(regmap);
80 	}
81 
82 	return bmp280_common_probe(&spi->dev,
83 				   regmap,
84 				   id->driver_data,
85 				   id->name,
86 				   spi->irq);
87 }
88 
89 static const struct of_device_id bmp280_of_spi_match[] = {
90 	{ .compatible = "bosch,bmp085", },
91 	{ .compatible = "bosch,bmp180", },
92 	{ .compatible = "bosch,bmp181", },
93 	{ .compatible = "bosch,bmp280", },
94 	{ .compatible = "bosch,bme280", },
95 	{ },
96 };
97 MODULE_DEVICE_TABLE(of, bmp280_of_spi_match);
98 
99 static const struct spi_device_id bmp280_spi_id[] = {
100 	{ "bmp180", BMP180_CHIP_ID },
101 	{ "bmp181", BMP180_CHIP_ID },
102 	{ "bmp280", BMP280_CHIP_ID },
103 	{ "bme280", BME280_CHIP_ID },
104 	{ }
105 };
106 MODULE_DEVICE_TABLE(spi, bmp280_spi_id);
107 
108 static struct spi_driver bmp280_spi_driver = {
109 	.driver = {
110 		.name = "bmp280",
111 		.of_match_table = bmp280_of_spi_match,
112 		.pm = &bmp280_dev_pm_ops,
113 	},
114 	.id_table = bmp280_spi_id,
115 	.probe = bmp280_spi_probe,
116 };
117 module_spi_driver(bmp280_spi_driver);
118 
119 MODULE_DESCRIPTION("BMP280 SPI bus driver");
120 MODULE_LICENSE("GPL");
121