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 | |
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(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 | |
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(dev: context); |
35 | |
36 | return spi_write_then_read(spi, txbuf: reg, n_tx: reg_size, rxbuf: val, n_rx: 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(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 | |
67 | static 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 | |
74 | static 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 | |
82 | static 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 | |
125 | static 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 | }; |
135 | MODULE_DEVICE_TABLE(of, bmp280_of_spi_match); |
136 | |
137 | static 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 | }; |
147 | MODULE_DEVICE_TABLE(spi, bmp280_spi_id); |
148 | |
149 | static 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 | }; |
158 | module_spi_driver(bmp280_spi_driver); |
159 | |
160 | MODULE_DESCRIPTION("BMP280 SPI bus driver" ); |
161 | MODULE_LICENSE("GPL" ); |
162 | MODULE_IMPORT_NS(IIO_BMP280); |
163 | |