1 /*
2  * SPI interface for the BMP280 driver
3  *
4  * Inspired by the older BMP085 driver drivers/misc/bmp085-spi.c
5  */
6 #include <linux/module.h>
7 #include <linux/spi/spi.h>
8 #include <linux/err.h>
9 #include <linux/regmap.h>
10 
11 #include "bmp280.h"
12 
13 static int bmp280_regmap_spi_write(void *context, const void *data,
14                                    size_t count)
15 {
16 	struct device *dev = context;
17 	struct spi_device *spi = to_spi_device(dev);
18 	u8 buf[2];
19 
20 	memcpy(buf, data, 2);
21 	/*
22 	 * The SPI register address (= full register address without bit 7) and
23 	 * the write command (bit7 = RW = '0')
24 	 */
25 	buf[0] &= ~0x80;
26 
27 	return spi_write_then_read(spi, buf, 2, NULL, 0);
28 }
29 
30 static int bmp280_regmap_spi_read(void *context, const void *reg,
31                                   size_t reg_size, void *val, size_t val_size)
32 {
33 	struct device *dev = context;
34 	struct spi_device *spi = to_spi_device(dev);
35 
36 	return spi_write_then_read(spi, reg, reg_size, val, val_size);
37 }
38 
39 static struct regmap_bus bmp280_regmap_bus = {
40 	.write = bmp280_regmap_spi_write,
41 	.read = bmp280_regmap_spi_read,
42 	.reg_format_endian_default = REGMAP_ENDIAN_BIG,
43 	.val_format_endian_default = REGMAP_ENDIAN_BIG,
44 };
45 
46 static int bmp280_spi_probe(struct spi_device *spi)
47 {
48 	const struct spi_device_id *id = spi_get_device_id(spi);
49 	struct regmap *regmap;
50 	const struct regmap_config *regmap_config;
51 	int ret;
52 
53 	spi->bits_per_word = 8;
54 	ret = spi_setup(spi);
55 	if (ret < 0) {
56 		dev_err(&spi->dev, "spi_setup failed!\n");
57 		return ret;
58 	}
59 
60 	switch (id->driver_data) {
61 	case BMP180_CHIP_ID:
62 		regmap_config = &bmp180_regmap_config;
63 		break;
64 	case BMP280_CHIP_ID:
65 	case BME280_CHIP_ID:
66 		regmap_config = &bmp280_regmap_config;
67 		break;
68 	default:
69 		return -EINVAL;
70 	}
71 
72 	regmap = devm_regmap_init(&spi->dev,
73 				  &bmp280_regmap_bus,
74 				  &spi->dev,
75 				  regmap_config);
76 	if (IS_ERR(regmap)) {
77 		dev_err(&spi->dev, "failed to allocate register map\n");
78 		return PTR_ERR(regmap);
79 	}
80 
81 	return bmp280_common_probe(&spi->dev,
82 				   regmap,
83 				   id->driver_data,
84 				   id->name,
85 				   spi->irq);
86 }
87 
88 static int bmp280_spi_remove(struct spi_device *spi)
89 {
90 	return bmp280_common_remove(&spi->dev);
91 }
92 
93 static const struct of_device_id bmp280_of_spi_match[] = {
94 	{ .compatible = "bosch,bmp085", },
95 	{ .compatible = "bosch,bmp180", },
96 	{ .compatible = "bosch,bmp181", },
97 	{ .compatible = "bosch,bmp280", },
98 	{ .compatible = "bosch,bme280", },
99 	{ },
100 };
101 MODULE_DEVICE_TABLE(of, bmp280_of_spi_match);
102 
103 static const struct spi_device_id bmp280_spi_id[] = {
104 	{ "bmp180", BMP180_CHIP_ID },
105 	{ "bmp181", BMP180_CHIP_ID },
106 	{ "bmp280", BMP280_CHIP_ID },
107 	{ "bme280", BME280_CHIP_ID },
108 	{ }
109 };
110 MODULE_DEVICE_TABLE(spi, bmp280_spi_id);
111 
112 static struct spi_driver bmp280_spi_driver = {
113 	.driver = {
114 		.name = "bmp280",
115 		.of_match_table = bmp280_of_spi_match,
116 		.pm = &bmp280_dev_pm_ops,
117 	},
118 	.id_table = bmp280_spi_id,
119 	.probe = bmp280_spi_probe,
120 	.remove = bmp280_spi_remove,
121 };
122 module_spi_driver(bmp280_spi_driver);
123 
124 MODULE_DESCRIPTION("BMP280 SPI bus driver");
125 MODULE_LICENSE("GPL");
126