iio:magnetometer: Add STMicroelectronics magnetometers driver

This patch adds a generic magnetometer driver for STMicroelectronics
magnetometers, currently it supports:
LSM303DLHC, LSM303DLM, LIS3MDL.
Signed-off-by: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/magnetometer/Kconfig

@@ -14,4 +14,34 @@ config HID_SENSOR_MAGNETOMETER_3D
 	  Say yes here to build support for the HID SENSOR
 	  Magnetometer 3D.
 
+config IIO_ST_MAGN_3AXIS
+	tristate "STMicroelectronics magnetometers 3-Axis Driver"
+	depends on (I2C || SPI_MASTER) && SYSFS
+	select IIO_ST_SENSORS_CORE
+	select IIO_ST_MAGN_I2C_3AXIS if (I2C)
+	select IIO_ST_MAGN_SPI_3AXIS if (SPI_MASTER)
+	select IIO_TRIGGERED_BUFFER if (IIO_BUFFER)
+	select IIO_ST_MAGN_BUFFER if (IIO_TRIGGERED_BUFFER)
+	help
+	  Say yes here to build support for STMicroelectronics magnetometers:
+	  LSM303DLHC, LSM303DLM, LIS3MDL.
+
+	  This driver can also be built as a module. If so, will be created
+	  these modules:
+	  - st_magn (core functions for the driver [it is mandatory]);
+	  - st_magn_i2c (necessary for the I2C devices [optional*]);
+	  - st_magn_spi (necessary for the SPI devices [optional*]);
+
+	  (*) one of these is necessary to do something.
+
+config IIO_ST_MAGN_I2C_3AXIS
+	tristate
+	depends on IIO_ST_MAGN_3AXIS
+	depends on IIO_ST_SENSORS_I2C
+
+config IIO_ST_MAGN_SPI_3AXIS
+	tristate
+	depends on IIO_ST_MAGN_3AXIS
+	depends on IIO_ST_SENSORS_SPI
+
 endmenu

drivers/iio/magnetometer/Makefile

@@ -3,3 +3,10 @@
 #
 
 obj-$(CONFIG_HID_SENSOR_MAGNETOMETER_3D) += hid-sensor-magn-3d.o
+
+obj-$(CONFIG_IIO_ST_MAGN_3AXIS) += st_magn.o
+st_magn-y := st_magn_core.o
+st_magn-$(CONFIG_IIO_BUFFER) += st_magn_buffer.o
+
+obj-$(CONFIG_IIO_ST_MAGN_I2C_3AXIS) += st_magn_i2c.o
+obj-$(CONFIG_IIO_ST_MAGN_SPI_3AXIS) += st_magn_spi.o

drivers/iio/magnetometer/st_magn.h

+/*
+ * STMicroelectronics magnetometers driver
+ *
+ * Copyright 2012-2013 STMicroelectronics Inc.
+ *
+ * Denis Ciocca <denis.ciocca@st.com>
+ * v. 1.0.0
+ * Licensed under the GPL-2.
+ */
+
+#ifndef ST_MAGN_H
+#define ST_MAGN_H
+
+#include <linux/types.h>
+#include <linux/iio/common/st_sensors.h>
+
+#define LSM303DLHC_MAGN_DEV_NAME	"lsm303dlhc_magn"
+#define LSM303DLM_MAGN_DEV_NAME		"lsm303dlm_magn"
+#define LIS3MDL_MAGN_DEV_NAME		"lis3mdl"
+
+int st_magn_common_probe(struct iio_dev *indio_dev);
+void st_magn_common_remove(struct iio_dev *indio_dev);
+
+#ifdef CONFIG_IIO_BUFFER
+int st_magn_allocate_ring(struct iio_dev *indio_dev);
+void st_magn_deallocate_ring(struct iio_dev *indio_dev);
+#else /* CONFIG_IIO_BUFFER */
+static inline int st_magn_probe_trigger(struct iio_dev *indio_dev, int irq)
+{
+	return 0;
+}
+static inline void st_magn_remove_trigger(struct iio_dev *indio_dev, int irq)
+{
+	return;
+}
+static inline int st_magn_allocate_ring(struct iio_dev *indio_dev)
+{
+	return 0;
+}
+static inline void st_magn_deallocate_ring(struct iio_dev *indio_dev)
+{
+}
+#endif /* CONFIG_IIO_BUFFER */
+
+#endif /* ST_MAGN_H */

drivers/iio/magnetometer/st_magn_buffer.c

+/*
+ * STMicroelectronics magnetometers driver
+ *
+ * Copyright 2012-2013 STMicroelectronics Inc.
+ *
+ * Denis Ciocca <denis.ciocca@st.com>
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/stat.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#include <linux/iio/common/st_sensors.h>
+#include "st_magn.h"
+
+static int st_magn_buffer_preenable(struct iio_dev *indio_dev)
+{
+	int err;
+
+	err = st_sensors_set_enable(indio_dev, true);
+	if (err < 0)
+		goto st_magn_set_enable_error;
+
+	err = iio_sw_buffer_preenable(indio_dev);
+
+st_magn_set_enable_error:
+	return err;
+}
+
+static int st_magn_buffer_postenable(struct iio_dev *indio_dev)
+{
+	int err;
+	struct st_sensor_data *mdata = iio_priv(indio_dev);
+
+	mdata->buffer_data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
+	if (mdata->buffer_data == NULL) {
+		err = -ENOMEM;
+		goto allocate_memory_error;
+	}
+
+	err = iio_triggered_buffer_postenable(indio_dev);
+	if (err < 0)
+		goto st_magn_buffer_postenable_error;
+
+	return err;
+
+st_magn_buffer_postenable_error:
+	kfree(mdata->buffer_data);
+allocate_memory_error:
+	return err;
+}
+
+static int st_magn_buffer_predisable(struct iio_dev *indio_dev)
+{
+	int err;
+	struct st_sensor_data *mdata = iio_priv(indio_dev);
+
+	err = iio_triggered_buffer_predisable(indio_dev);
+	if (err < 0)
+		goto st_magn_buffer_predisable_error;
+
+	err = st_sensors_set_enable(indio_dev, false);
+
+st_magn_buffer_predisable_error:
+	kfree(mdata->buffer_data);
+	return err;
+}
+
+static const struct iio_buffer_setup_ops st_magn_buffer_setup_ops = {
+	.preenable = &st_magn_buffer_preenable,
+	.postenable = &st_magn_buffer_postenable,
+	.predisable = &st_magn_buffer_predisable,
+};
+
+int st_magn_allocate_ring(struct iio_dev *indio_dev)
+{
+	return iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
+		&st_sensors_trigger_handler, &st_magn_buffer_setup_ops);
+}
+
+void st_magn_deallocate_ring(struct iio_dev *indio_dev)
+{
+	iio_triggered_buffer_cleanup(indio_dev);
+}
+
+MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics magnetometers buffer");
+MODULE_LICENSE("GPL v2");

drivers/iio/magnetometer/st_magn_i2c.c

+/*
+ * STMicroelectronics magnetometers driver
+ *
+ * Copyright 2012-2013 STMicroelectronics Inc.
+ *
+ * Denis Ciocca <denis.ciocca@st.com>
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger.h>
+
+#include <linux/iio/common/st_sensors.h>
+#include <linux/iio/common/st_sensors_i2c.h>
+#include "st_magn.h"
+
+static int st_magn_i2c_probe(struct i2c_client *client,
+						const struct i2c_device_id *id)
+{
+	struct iio_dev *indio_dev;
+	struct st_sensor_data *mdata;
+	int err;
+
+	indio_dev = iio_device_alloc(sizeof(*mdata));
+	if (indio_dev == NULL) {
+		err = -ENOMEM;
+		goto iio_device_alloc_error;
+	}
+
+	mdata = iio_priv(indio_dev);
+	mdata->dev = &client->dev;
+
+	st_sensors_i2c_configure(indio_dev, client, mdata);
+
+	err = st_magn_common_probe(indio_dev);
+	if (err < 0)
+		goto st_magn_common_probe_error;
+
+	return 0;
+
+st_magn_common_probe_error:
+	iio_device_free(indio_dev);
+iio_device_alloc_error:
+	return err;
+}
+
+static int st_magn_i2c_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	st_magn_common_remove(indio_dev);
+
+	return 0;
+}
+
+static const struct i2c_device_id st_magn_id_table[] = {
+	{ LSM303DLHC_MAGN_DEV_NAME },
+	{ LSM303DLM_MAGN_DEV_NAME },
+	{ LIS3MDL_MAGN_DEV_NAME },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, st_magn_id_table);
+
+static struct i2c_driver st_magn_driver = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.name = "st-magn-i2c",
+	},
+	.probe = st_magn_i2c_probe,
+	.remove = st_magn_i2c_remove,
+	.id_table = st_magn_id_table,
+};
+module_i2c_driver(st_magn_driver);
+
+MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics magnetometers i2c driver");
+MODULE_LICENSE("GPL v2");

drivers/iio/magnetometer/st_magn_spi.c

+/*
+ * STMicroelectronics magnetometers driver
+ *
+ * Copyright 2012-2013 STMicroelectronics Inc.
+ *
+ * Denis Ciocca <denis.ciocca@st.com>
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger.h>
+
+#include <linux/iio/common/st_sensors.h>
+#include <linux/iio/common/st_sensors_spi.h>
+#include "st_magn.h"
+
+static int st_magn_spi_probe(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev;
+	struct st_sensor_data *mdata;
+	int err;
+
+	indio_dev = iio_device_alloc(sizeof(*mdata));
+	if (indio_dev == NULL) {
+		err = -ENOMEM;
+		goto iio_device_alloc_error;
+	}
+
+	mdata = iio_priv(indio_dev);
+	mdata->dev = &spi->dev;
+
+	st_sensors_spi_configure(indio_dev, spi, mdata);
+
+	err = st_magn_common_probe(indio_dev);
+	if (err < 0)
+		goto st_magn_common_probe_error;
+
+	return 0;
+
+st_magn_common_probe_error:
+	iio_device_free(indio_dev);
+iio_device_alloc_error:
+	return err;
+}
+
+static int st_magn_spi_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	st_magn_common_remove(indio_dev);
+
+	return 0;
+}
+
+static const struct spi_device_id st_magn_id_table[] = {
+	{ LSM303DLHC_MAGN_DEV_NAME },
+	{ LSM303DLM_MAGN_DEV_NAME },
+	{ LIS3MDL_MAGN_DEV_NAME },
+	{},
+};
+MODULE_DEVICE_TABLE(spi, st_magn_id_table);
+
+static struct spi_driver st_magn_driver = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.name = "st-magn-spi",
+	},
+	.probe = st_magn_spi_probe,
+	.remove = st_magn_spi_remove,
+	.id_table = st_magn_id_table,
+};
+module_spi_driver(st_magn_driver);
+
+MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics magnetometers spi driver");
+MODULE_LICENSE("GPL v2");