bmp280-spi.c

  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
 15static 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
 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(context);
 35
 36	return spi_write_then_read(spi, reg, reg_size, val, 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(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
 63static 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
 70static 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
 78static 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
 85	chip_info = spi_get_device_match_data(spi);
 86
 87	if (chip_info->spi_read_extra_byte)
 88		bmp_regmap_bus = &bmp380_regmap_bus;
 89	else
 90		bmp_regmap_bus = &bmp280_regmap_bus;
 91
 92	regmap = devm_regmap_init(&spi->dev,
 93				  bmp_regmap_bus,
 94				  &spi->dev,
 95				  chip_info->regmap_config);
 96	if (IS_ERR(regmap)) {
 97		dev_err(&spi->dev, "failed to allocate register map\n");
 98		return PTR_ERR(regmap);
 99	}
100
101	return bmp280_common_probe(&spi->dev,
102				   regmap,
103				   chip_info,
104				   id->name,
105				   spi->irq);
106}
107
108static const struct of_device_id bmp280_of_spi_match[] = {
109	{ .compatible = "bosch,bmp085", .data = &bmp085_chip_info },
110	{ .compatible = "bosch,bmp180", .data = &bmp180_chip_info },
111	{ .compatible = "bosch,bmp181", .data = &bmp180_chip_info },
112	{ .compatible = "bosch,bmp280", .data = &bmp280_chip_info },
113	{ .compatible = "bosch,bme280", .data = &bme280_chip_info },
114	{ .compatible = "bosch,bmp380", .data = &bmp380_chip_info },
115	{ .compatible = "bosch,bmp580", .data = &bmp580_chip_info },
116	{ }
117};
118MODULE_DEVICE_TABLE(of, bmp280_of_spi_match);
119
120static const struct spi_device_id bmp280_spi_id[] = {
121	{ "bmp085", (kernel_ulong_t)&bmp085_chip_info },
122	{ "bmp180", (kernel_ulong_t)&bmp180_chip_info },
123	{ "bmp181", (kernel_ulong_t)&bmp180_chip_info },
124	{ "bmp280", (kernel_ulong_t)&bmp280_chip_info },
125	{ "bme280", (kernel_ulong_t)&bme280_chip_info },
126	{ "bmp380", (kernel_ulong_t)&bmp380_chip_info },
127	{ "bmp580", (kernel_ulong_t)&bmp580_chip_info },
128	{ }
129};
130MODULE_DEVICE_TABLE(spi, bmp280_spi_id);
131
132static struct spi_driver bmp280_spi_driver = {
133	.driver = {
134		.name = "bmp280",
135		.of_match_table = bmp280_of_spi_match,
136		.pm = pm_ptr(&bmp280_dev_pm_ops),
137	},
138	.id_table = bmp280_spi_id,
139	.probe = bmp280_spi_probe,
140};
141module_spi_driver(bmp280_spi_driver);
142
143MODULE_DESCRIPTION("BMP280 SPI bus driver");
144MODULE_LICENSE("GPL");
145MODULE_IMPORT_NS("IIO_BMP280");