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>

1 files changed, 98 insertions, 0 deletions

diff --git a/drivers/iio/magnetometer/st_magn_buffer.c b/drivers/iio/magnetometer/st_magn_buffer.c
new file mode 100644
index 000000000000..708857bdb47d
--- /dev/null
+++ b/drivers/iio/magnetometer/st_magn_buffer.c
@@ -0,0 +1,98 @@
+/*
+ * 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");