iio: pressure: bmp280: split driver in logical parts

This splits the BMP280 driver in three logical parts: the core driver
bmp280-core that only operated on a struct device * and a struct regmap *,
the regmap driver bmp280-regmap that can be shared between I2C and other
transports and the I2C module driver bmp280-i2c.

Cleverly bake all functionality into a single object bmp280.o so that
we still get the same module binary built for the device in the end,
without any fuzz exporting symbols to the left and right.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/pressure/Makefile

@@ -4,6 +4,7 @@
 
 # When adding new entries keep the list in alphabetical order
 obj-$(CONFIG_BMP280) += bmp280.o
+bmp280-objs := bmp280-core.o bmp280-regmap.o bmp280-i2c.o
 obj-$(CONFIG_HID_SENSOR_PRESS)   += hid-sensor-press.o
 obj-$(CONFIG_HP03) += hp03.o
 obj-$(CONFIG_MPL115) += mpl115.o

drivers/iio/pressure/bmp280-i2c.c

+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/acpi.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+#include "bmp280.h"
+
+static int bmp280_i2c_probe(struct i2c_client *client,
+			    const struct i2c_device_id *id)
+{
+	struct regmap *regmap;
+	const struct regmap_config *regmap_config;
+
+	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_i2c(client, regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&client->dev, "failed to allocate register map\n");
+		return PTR_ERR(regmap);
+	}
+
+	return bmp280_common_probe(&client->dev,
+				   regmap,
+				   id->driver_data,
+				   id->name);
+}
+
+static int bmp280_i2c_remove(struct i2c_client *client)
+{
+	return bmp280_common_remove(&client->dev);
+}
+
+static const struct acpi_device_id bmp280_acpi_i2c_match[] = {
+	{"BMP0280", BMP280_CHIP_ID },
+	{"BMP0180", BMP180_CHIP_ID },
+	{"BMP0085", BMP180_CHIP_ID },
+	{"BME0280", BME280_CHIP_ID },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, bmp280_acpi_i2c_match);
+
+#ifdef CONFIG_OF
+static const struct of_device_id bmp280_of_i2c_match[] = {
+	{ .compatible = "bosch,bme280", .data = (void *)BME280_CHIP_ID },
+	{ .compatible = "bosch,bmp280", .data = (void *)BMP280_CHIP_ID },
+	{ .compatible = "bosch,bmp180", .data = (void *)BMP180_CHIP_ID },
+	{ .compatible = "bosch,bmp085", .data = (void *)BMP180_CHIP_ID },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, bmp280_of_i2c_match);
+#else
+#define bmp280_of_i2c_match NULL
+#endif
+
+static const struct i2c_device_id bmp280_i2c_id[] = {
+	{"bmp280", BMP280_CHIP_ID },
+	{"bmp180", BMP180_CHIP_ID },
+	{"bmp085", BMP180_CHIP_ID },
+	{"bme280", BME280_CHIP_ID },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, bmp280_i2c_id);
+
+static struct i2c_driver bmp280_i2c_driver = {
+	.driver = {
+		.name	= "bmp280",
+		.acpi_match_table = ACPI_PTR(bmp280_acpi_i2c_match),
+		.of_match_table = of_match_ptr(bmp280_of_i2c_match),
+	},
+	.probe		= bmp280_i2c_probe,
+	.remove		= bmp280_i2c_remove,
+	.id_table	= bmp280_i2c_id,
+};
+module_i2c_driver(bmp280_i2c_driver);
+
+MODULE_AUTHOR("Vlad Dogaru <vlad.dogaru@intel.com>");
+MODULE_DESCRIPTION("Driver for Bosch Sensortec BMP180/BMP280 pressure and temperature sensor");
+MODULE_LICENSE("GPL v2");

drivers/iio/pressure/bmp280-regmap.c

+#include <linux/device.h>
+#include <linux/regmap.h>
+
+#include "bmp280.h"
+
+static bool bmp180_is_writeable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case BMP280_REG_CTRL_MEAS:
+	case BMP280_REG_RESET:
+		return true;
+	default:
+		return false;
+	};
+}
+
+static bool bmp180_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case BMP180_REG_OUT_XLSB:
+	case BMP180_REG_OUT_LSB:
+	case BMP180_REG_OUT_MSB:
+	case BMP280_REG_CTRL_MEAS:
+		return true;
+	default:
+		return false;
+	}
+}
+
+const struct regmap_config bmp180_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = BMP180_REG_OUT_XLSB,
+	.cache_type = REGCACHE_RBTREE,
+
+	.writeable_reg = bmp180_is_writeable_reg,
+	.volatile_reg = bmp180_is_volatile_reg,
+};
+
+static bool bmp280_is_writeable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case BMP280_REG_CONFIG:
+	case BMP280_REG_CTRL_HUMIDITY:
+	case BMP280_REG_CTRL_MEAS:
+	case BMP280_REG_RESET:
+		return true;
+	default:
+		return false;
+	};
+}
+
+static bool bmp280_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case BMP280_REG_HUMIDITY_LSB:
+	case BMP280_REG_HUMIDITY_MSB:
+	case BMP280_REG_TEMP_XLSB:
+	case BMP280_REG_TEMP_LSB:
+	case BMP280_REG_TEMP_MSB:
+	case BMP280_REG_PRESS_XLSB:
+	case BMP280_REG_PRESS_LSB:
+	case BMP280_REG_PRESS_MSB:
+	case BMP280_REG_STATUS:
+		return true;
+	default:
+		return false;
+	}
+}
+
+const struct regmap_config bmp280_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = BMP280_REG_HUMIDITY_LSB,
+	.cache_type = REGCACHE_RBTREE,
+
+	.writeable_reg = bmp280_is_writeable_reg,
+	.volatile_reg = bmp280_is_volatile_reg,
+};

drivers/iio/pressure/bmp280.h

+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/regmap.h>
+
+/* BMP280 specific registers */
+#define BMP280_REG_HUMIDITY_LSB		0xFE
+#define BMP280_REG_HUMIDITY_MSB		0xFD
+#define BMP280_REG_TEMP_XLSB		0xFC
+#define BMP280_REG_TEMP_LSB		0xFB
+#define BMP280_REG_TEMP_MSB		0xFA
+#define BMP280_REG_PRESS_XLSB		0xF9
+#define BMP280_REG_PRESS_LSB		0xF8
+#define BMP280_REG_PRESS_MSB		0xF7
+
+#define BMP280_REG_CONFIG		0xF5
+#define BMP280_REG_CTRL_MEAS		0xF4
+#define BMP280_REG_STATUS		0xF3
+#define BMP280_REG_CTRL_HUMIDITY	0xF2
+
+/* Due to non linear mapping, and data sizes we can't do a bulk read */
+#define BMP280_REG_COMP_H1		0xA1
+#define BMP280_REG_COMP_H2		0xE1
+#define BMP280_REG_COMP_H3		0xE3
+#define BMP280_REG_COMP_H4		0xE4
+#define BMP280_REG_COMP_H5		0xE5
+#define BMP280_REG_COMP_H6		0xE7
+
+#define BMP280_REG_COMP_TEMP_START	0x88
+#define BMP280_COMP_TEMP_REG_COUNT	6
+
+#define BMP280_REG_COMP_PRESS_START	0x8E
+#define BMP280_COMP_PRESS_REG_COUNT	18
+
+#define BMP280_FILTER_MASK		(BIT(4) | BIT(3) | BIT(2))
+#define BMP280_FILTER_OFF		0
+#define BMP280_FILTER_2X		BIT(2)
+#define BMP280_FILTER_4X		BIT(3)
+#define BMP280_FILTER_8X		(BIT(3) | BIT(2))
+#define BMP280_FILTER_16X		BIT(4)
+
+#define BMP280_OSRS_HUMIDITY_MASK	(BIT(2) | BIT(1) | BIT(0))
+#define BMP280_OSRS_HUMIDITIY_X(osrs_h)	((osrs_h) << 0)
+#define BMP280_OSRS_HUMIDITY_SKIP	0
+#define BMP280_OSRS_HUMIDITY_1X		BMP280_OSRS_HUMIDITIY_X(1)
+#define BMP280_OSRS_HUMIDITY_2X		BMP280_OSRS_HUMIDITIY_X(2)
+#define BMP280_OSRS_HUMIDITY_4X		BMP280_OSRS_HUMIDITIY_X(3)
+#define BMP280_OSRS_HUMIDITY_8X		BMP280_OSRS_HUMIDITIY_X(4)
+#define BMP280_OSRS_HUMIDITY_16X	BMP280_OSRS_HUMIDITIY_X(5)
+
+#define BMP280_OSRS_TEMP_MASK		(BIT(7) | BIT(6) | BIT(5))
+#define BMP280_OSRS_TEMP_SKIP		0
+#define BMP280_OSRS_TEMP_X(osrs_t)	((osrs_t) << 5)
+#define BMP280_OSRS_TEMP_1X		BMP280_OSRS_TEMP_X(1)
+#define BMP280_OSRS_TEMP_2X		BMP280_OSRS_TEMP_X(2)
+#define BMP280_OSRS_TEMP_4X		BMP280_OSRS_TEMP_X(3)
+#define BMP280_OSRS_TEMP_8X		BMP280_OSRS_TEMP_X(4)
+#define BMP280_OSRS_TEMP_16X		BMP280_OSRS_TEMP_X(5)
+
+#define BMP280_OSRS_PRESS_MASK		(BIT(4) | BIT(3) | BIT(2))
+#define BMP280_OSRS_PRESS_SKIP		0
+#define BMP280_OSRS_PRESS_X(osrs_p)	((osrs_p) << 2)
+#define BMP280_OSRS_PRESS_1X		BMP280_OSRS_PRESS_X(1)
+#define BMP280_OSRS_PRESS_2X		BMP280_OSRS_PRESS_X(2)
+#define BMP280_OSRS_PRESS_4X		BMP280_OSRS_PRESS_X(3)
+#define BMP280_OSRS_PRESS_8X		BMP280_OSRS_PRESS_X(4)
+#define BMP280_OSRS_PRESS_16X		BMP280_OSRS_PRESS_X(5)
+
+#define BMP280_MODE_MASK		(BIT(1) | BIT(0))
+#define BMP280_MODE_SLEEP		0
+#define BMP280_MODE_FORCED		BIT(0)
+#define BMP280_MODE_NORMAL		(BIT(1) | BIT(0))
+
+/* BMP180 specific registers */
+#define BMP180_REG_OUT_XLSB		0xF8
+#define BMP180_REG_OUT_LSB		0xF7
+#define BMP180_REG_OUT_MSB		0xF6
+
+#define BMP180_REG_CALIB_START		0xAA
+#define BMP180_REG_CALIB_COUNT		22
+
+#define BMP180_MEAS_SCO			BIT(5)
+#define BMP180_MEAS_TEMP		(0x0E | BMP180_MEAS_SCO)
+#define BMP180_MEAS_PRESS_X(oss)	((oss) << 6 | 0x14 | BMP180_MEAS_SCO)
+#define BMP180_MEAS_PRESS_1X		BMP180_MEAS_PRESS_X(0)
+#define BMP180_MEAS_PRESS_2X		BMP180_MEAS_PRESS_X(1)
+#define BMP180_MEAS_PRESS_4X		BMP180_MEAS_PRESS_X(2)
+#define BMP180_MEAS_PRESS_8X		BMP180_MEAS_PRESS_X(3)
+
+/* BMP180 and BMP280 common registers */
+#define BMP280_REG_CTRL_MEAS		0xF4
+#define BMP280_REG_RESET		0xE0
+#define BMP280_REG_ID			0xD0
+
+#define BMP180_CHIP_ID			0x55
+#define BMP280_CHIP_ID			0x58
+#define BME280_CHIP_ID			0x60
+#define BMP280_SOFT_RESET_VAL		0xB6
+
+/* Regmap configurations */
+extern const struct regmap_config bmp180_regmap_config;
+extern const struct regmap_config bmp280_regmap_config;
+
+/* Probe called from different transports */
+int bmp280_common_probe(struct device *dev,
+			struct regmap *regmap,
+			unsigned int chip,
+			const char *name);
+int bmp280_common_remove(struct device *dev);