iio: pressure: bmp280: add SPI interface driver

This patch mimics the SPI functionality found in the misc driver in
drivers/misc/bh085-spi.c to make it possible to reuse the existing
BMP280/BMP180/BMP085 driver with all clients of the other driver.
The adoption is straight-forward since like the other driver, it is
a simple matter of using regmap.

This driver is also so obviously inspired/copied from the old misc
driver in drivers/misc/bmp085.c that I just took the liberty to
add in the authors of the other drivers + self in the core driver
file.

The MISC driver also supports a variant named "BMP181" so include
that here to be complete in comparison to the old driver.

The bus mapping code for SPI was written by Akinobu Mita.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Tested-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/pressure/Kconfig b/drivers/iio/pressure/Kconfig
index 3d0d311..d130cdc 100644 (file)
--- a/drivers/iio/pressure/Kconfig
+++ b/drivers/iio/pressure/Kconfig
@@ -7,17 +7,20 @@ menu "Pressure sensors"
 
 config BMP280
        tristate "Bosch Sensortec BMP180/BMP280 pressure sensor I2C driver"
-       depends on I2C
+       depends on (I2C || SPI_MASTER)
        depends on !(BMP085_I2C=y || BMP085_I2C=m)
+       depends on !(BMP085_SPI=y || BMP085_SPI=m)
        select REGMAP
        select BMP280_I2C if (I2C)
+       select BMP280_SPI if (SPI_MASTER)
        help
          Say yes here to build support for Bosch Sensortec BMP180 and BMP280
          pressure and temperature sensors. Also supports the BE280 with
          an additional humidity sensor channel.
 
-         To compile this driver as a module, choose M here: the modules
-         will be called bmp280-i2c and bmp280.
+         To compile this driver as a module, choose M here: the core module
+         will be called bmp280 and you will also get bmp280-i2c for I2C
+         and/or bmp280-spi for SPI support.
 
 config BMP280_I2C
        tristate
@@ -25,6 +28,12 @@ config BMP280_I2C
        depends on I2C
        select REGMAP_I2C
 
+config BMP280_SPI
+       tristate
+       depends on BMP280
+       depends on SPI_MASTER
+       select REGMAP
+
 config HID_SENSOR_PRESS
        depends on HID_SENSOR_HUB
        select IIO_BUFFER

diff --git a/drivers/iio/pressure/Makefile b/drivers/iio/pressure/Makefile
index 736f430..7f395be 100644 (file)
--- a/drivers/iio/pressure/Makefile
+++ b/drivers/iio/pressure/Makefile
@@ -6,6 +6,7 @@
 obj-$(CONFIG_BMP280) += bmp280.o
 bmp280-objs := bmp280-core.o bmp280-regmap.o
 obj-$(CONFIG_BMP280_I2C) += bmp280-i2c.o
+obj-$(CONFIG_BMP280_SPI) += bmp280-spi.o
 obj-$(CONFIG_HID_SENSOR_PRESS)   += hid-sensor-press.o
 obj-$(CONFIG_HP03) += hp03.o
 obj-$(CONFIG_MPL115) += mpl115.o

diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
index f1b5f8c..43bd0b0 100644 (file)
--- a/drivers/iio/pressure/bmp280-core.c
+++ b/drivers/iio/pressure/bmp280-core.c
@@ -1,5 +1,9 @@
 /*
+ * Copyright (c) 2010 Christoph Mair <christoph.mair@gmail.com>
+ * Copyright (c) 2012 Bosch Sensortec GmbH
+ * Copyright (c) 2012 Unixphere AB
  * Copyright (c) 2014 Intel Corporation
+ * Copyright (c) 2016 Linus Walleij <linus.walleij@linaro.org>
  *
  * Driver for Bosch Sensortec BMP180 and BMP280 digital pressure sensor.
  *

diff --git a/drivers/iio/pressure/bmp280-spi.c b/drivers/iio/pressure/bmp280-spi.c
new file mode 100644 (file)
index 0000000..216e64b
--- /dev/null
+++ b/drivers/iio/pressure/bmp280-spi.c
@@ -0,0 +1,123 @@
+/*
+ * SPI interface for the BMP280 driver
+ *
+ * Inspired by the older BMP085 driver drivers/misc/bmp085-spi.c
+ */
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include <linux/err.h>
+#include <linux/regmap.h>
+
+#include "bmp280.h"
+
+static int bmp280_regmap_spi_write(void *context, const void *data,
+                                   size_t count)
+{
+       struct device *dev = context;
+       struct spi_device *spi = to_spi_device(dev);
+       u8 buf[2];
+
+       memcpy(buf, data, 2);
+       /*
+        * The SPI register address (= full register address without bit 7) and
+        * the write command (bit7 = RW = '0')
+        */
+       buf[0] &= ~0x80;
+
+       return spi_write_then_read(spi, buf, 2, NULL, 0);
+}
+
+static int bmp280_regmap_spi_read(void *context, const void *reg,
+                                  size_t reg_size, void *val, size_t val_size)
+{
+       struct device *dev = context;
+       struct spi_device *spi = to_spi_device(dev);
+
+       return spi_write_then_read(spi, reg, reg_size, val, val_size);
+}
+
+static struct regmap_bus bmp280_regmap_bus = {
+       .write = bmp280_regmap_spi_write,
+       .read = bmp280_regmap_spi_read,
+       .reg_format_endian_default = REGMAP_ENDIAN_BIG,
+       .val_format_endian_default = REGMAP_ENDIAN_BIG,
+};
+
+static int bmp280_spi_probe(struct spi_device *spi)
+{
+       const struct spi_device_id *id = spi_get_device_id(spi);
+       struct regmap *regmap;
+       const struct regmap_config *regmap_config;
+       int ret;
+
+       spi->bits_per_word = 8;
+       ret = spi_setup(spi);
+       if (ret < 0) {
+               dev_err(&spi->dev, "spi_setup failed!\n");
+               return ret;
+       }
+
+       switch (id->driver_data) {
+       case BMP180_CHIP_ID:
+               regmap_config = &bmp180_regmap_config;
+               break;
+       case BMP280_CHIP_ID:
+       case BME280_CHIP_ID:
+               regmap_config = &bmp280_regmap_config;
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       regmap = devm_regmap_init(&spi->dev,
+                                 &bmp280_regmap_bus,
+                                 &spi->dev,
+                                 regmap_config);
+       if (IS_ERR(regmap)) {
+               dev_err(&spi->dev, "failed to allocate register map\n");
+               return PTR_ERR(regmap);
+       }
+
+       return bmp280_common_probe(&spi->dev,
+                                  regmap,
+                                  id->driver_data,
+                                  id->name);
+}
+
+static int bmp280_spi_remove(struct spi_device *spi)
+{
+       return bmp280_common_remove(&spi->dev);
+}
+
+static const struct of_device_id bmp280_of_spi_match[] = {
+       { .compatible = "bosch,bmp085", },
+       { .compatible = "bosch,bmp180", },
+       { .compatible = "bosch,bmp181", },
+       { .compatible = "bosch,bmp280", },
+       { .compatible = "bosch,bme280", },
+       { },
+};
+MODULE_DEVICE_TABLE(of, bmp280_of_spi_match);
+
+static const struct spi_device_id bmp280_spi_id[] = {
+       { "bmp180", BMP180_CHIP_ID },
+       { "bmp181", BMP180_CHIP_ID },
+       { "bmp280", BMP280_CHIP_ID },
+       { "bme280", BME280_CHIP_ID },
+       { }
+};
+MODULE_DEVICE_TABLE(spi, bmp280_spi_id);
+
+static struct spi_driver bmp280_spi_driver = {
+       .driver = {
+               .name = "bmp280",
+               .of_match_table = bmp280_of_spi_match,
+       },
+       .id_table = bmp280_spi_id,
+       .probe = bmp280_spi_probe,
+       .remove = bmp280_spi_remove,
+};
+module_spi_driver(bmp280_spi_driver);
+
+MODULE_DESCRIPTION("BMP280 SPI bus driver");
+MODULE_LICENSE("GPL");