staging:iio:imu ADIS16400 and ADIS16405 driver

Signed-off-by: Manuel Stahl <manuel.stahl@iis.fraunhofer.de>
Signed-off-by: Barry Song <Barry.Song@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/iio/imu/adis16400_ring.c b/drivers/staging/iio/imu/adis16400_ring.c
new file mode 100644
index 0000000..5529b32
--- /dev/null
+++ b/drivers/staging/iio/imu/adis16400_ring.c
@@ -0,0 +1,245 @@
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/gpio.h>
+#include <linux/workqueue.h>
+#include <linux/mutex.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/spi/spi.h>
+#include <linux/sysfs.h>
+#include <linux/list.h>
+
+#include "../iio.h"
+#include "../sysfs.h"
+#include "../ring_sw.h"
+#include "../accel/accel.h"
+#include "../trigger.h"
+#include "adis16400.h"
+
+/**
+ * combine_8_to_16() utility function to munge to u8s into u16
+ **/
+static inline u16 combine_8_to_16(u8 lower, u8 upper)
+{
+	u16 _lower = lower;
+	u16 _upper = upper;
+	return _lower | (_upper << 8);
+}
+
+static IIO_SCAN_EL_C(supply, ADIS16400_SCAN_SUPPLY, IIO_SIGNED(14),
+		     ADIS16400_SUPPLY_OUT, NULL);
+
+static IIO_SCAN_EL_C(gyro_x, ADIS16400_SCAN_GYRO_X, IIO_SIGNED(14),
+		     ADIS16400_XGYRO_OUT, NULL);
+static IIO_SCAN_EL_C(gyro_y, ADIS16400_SCAN_GYRO_Y, IIO_SIGNED(14),
+		     ADIS16400_YGYRO_OUT, NULL);
+static IIO_SCAN_EL_C(gyro_z, ADIS16400_SCAN_GYRO_Z, IIO_SIGNED(14),
+		     ADIS16400_ZGYRO_OUT, NULL);
+
+static IIO_SCAN_EL_C(accel_x, ADIS16400_SCAN_ACC_X, IIO_SIGNED(14),
+		     ADIS16400_XACCL_OUT, NULL);
+static IIO_SCAN_EL_C(accel_y, ADIS16400_SCAN_ACC_Y, IIO_SIGNED(14),
+		     ADIS16400_YACCL_OUT, NULL);
+static IIO_SCAN_EL_C(accel_z, ADIS16400_SCAN_ACC_Z, IIO_SIGNED(14),
+		     ADIS16400_ZACCL_OUT, NULL);
+
+static IIO_SCAN_EL_C(magn_x, ADIS16400_SCAN_MAGN_X, IIO_SIGNED(14),
+		     ADIS16400_XMAGN_OUT, NULL);
+static IIO_SCAN_EL_C(magn_y, ADIS16400_SCAN_MAGN_Y, IIO_SIGNED(14),
+		     ADIS16400_YMAGN_OUT, NULL);
+static IIO_SCAN_EL_C(magn_z, ADIS16400_SCAN_MAGN_Z, IIO_SIGNED(14),
+		     ADIS16400_ZMAGN_OUT, NULL);
+
+static IIO_SCAN_EL_C(temp, ADIS16400_SCAN_TEMP, IIO_SIGNED(12),
+		     ADIS16400_TEMP_OUT, NULL);
+static IIO_SCAN_EL_C(adc_0, ADIS16400_SCAN_ADC_0, IIO_SIGNED(12),
+		     ADIS16400_AUX_ADC, NULL);
+
+static IIO_SCAN_EL_TIMESTAMP(12);
+
+static struct attribute *adis16400_scan_el_attrs[] = {
+	&iio_scan_el_supply.dev_attr.attr,
+	&iio_scan_el_gyro_x.dev_attr.attr,
+	&iio_scan_el_gyro_y.dev_attr.attr,
+	&iio_scan_el_gyro_z.dev_attr.attr,
+	&iio_scan_el_accel_x.dev_attr.attr,
+	&iio_scan_el_accel_y.dev_attr.attr,
+	&iio_scan_el_accel_z.dev_attr.attr,
+	&iio_scan_el_magn_x.dev_attr.attr,
+	&iio_scan_el_magn_y.dev_attr.attr,
+	&iio_scan_el_magn_z.dev_attr.attr,
+	&iio_scan_el_temp.dev_attr.attr,
+	&iio_scan_el_adc_0.dev_attr.attr,
+	&iio_scan_el_timestamp.dev_attr.attr,
+	NULL,
+};
+
+static struct attribute_group adis16400_scan_el_group = {
+	.attrs = adis16400_scan_el_attrs,
+	.name = "scan_elements",
+};
+
+/**
+ * adis16400_poll_func_th() top half interrupt handler called by trigger
+ * @private_data:	iio_dev
+ **/
+static void adis16400_poll_func_th(struct iio_dev *indio_dev)
+{
+	struct adis16400_state *st = iio_dev_get_devdata(indio_dev);
+	st->last_timestamp = indio_dev->trig->timestamp;
+	schedule_work(&st->work_trigger_to_ring);
+	/* Indicate that this interrupt is being handled */
+
+	/* Technically this is trigger related, but without this
+	 * handler running there is currently no way for the interrupt
+	 * to clear.
+	 */
+}
+
+/* Whilst this makes a lot of calls to iio_sw_ring functions - it is to device
+ * specific to be rolled into the core.
+ */
+static void adis16400_trigger_bh_to_ring(struct work_struct *work_s)
+{
+	struct adis16400_state *st
+		= container_of(work_s, struct adis16400_state,
+			       work_trigger_to_ring);
+
+	int i = 0;
+	s16 *data;
+	size_t datasize = st->indio_dev
+		->ring->access.get_bpd(st->indio_dev->ring);
+
+	data = kmalloc(datasize , GFP_KERNEL);
+	if (data == NULL) {
+		dev_err(&st->us->dev, "memory alloc failed in ring bh");
+		return;
+	}
+
+	if (st->indio_dev->scan_count)
+		if (adis16400_spi_read_burst(&st->indio_dev->dev, st->rx) >= 0)
+			for (; i < st->indio_dev->scan_count; i++) {
+				data[i] = combine_8_to_16(st->rx[i*2+1],
+							  st->rx[i*2]);
+			}
+
+	/* Guaranteed to be aligned with 8 byte boundary */
+	if (st->indio_dev->scan_timestamp)
+		*((s64 *)(data + ((i + 3)/4)*4)) = st->last_timestamp;
+
+	st->indio_dev->ring->access.store_to(st->indio_dev->ring,
+					    (u8 *)data,
+					    st->last_timestamp);
+
+	iio_trigger_notify_done(st->indio_dev->trig);
+	kfree(data);
+
+	return;
+}
+/* in these circumstances is it better to go with unaligned packing and
+ * deal with the cost?*/
+static int adis16400_data_rdy_ring_preenable(struct iio_dev *indio_dev)
+{
+	size_t size;
+	dev_dbg(&indio_dev->dev, "%s\n", __func__);
+	/* Check if there are any scan elements enabled, if not fail*/
+	if (!(indio_dev->scan_count || indio_dev->scan_timestamp))
+		return -EINVAL;
+
+	if (indio_dev->ring->access.set_bpd) {
+		if (indio_dev->scan_timestamp)
+			if (indio_dev->scan_count) /* Timestamp and data */
+				size = 6*sizeof(s64);
+			else /* Timestamp only  */
+				size = sizeof(s64);
+		else /* Data only */
+			size = indio_dev->scan_count*sizeof(s16);
+		indio_dev->ring->access.set_bpd(indio_dev->ring, size);
+	}
+
+	return 0;
+}
+
+static int adis16400_data_rdy_ring_postenable(struct iio_dev *indio_dev)
+{
+	return indio_dev->trig
+		? iio_trigger_attach_poll_func(indio_dev->trig,
+					       indio_dev->pollfunc)
+		: 0;
+}
+
+static int adis16400_data_rdy_ring_predisable(struct iio_dev *indio_dev)
+{
+	return indio_dev->trig
+		? iio_trigger_dettach_poll_func(indio_dev->trig,
+						indio_dev->pollfunc)
+		: 0;
+}
+
+void adis16400_unconfigure_ring(struct iio_dev *indio_dev)
+{
+	kfree(indio_dev->pollfunc);
+	iio_sw_rb_free(indio_dev->ring);
+}
+
+int adis16400_configure_ring(struct iio_dev *indio_dev)
+{
+	int ret = 0;
+	struct adis16400_state *st = indio_dev->dev_data;
+	struct iio_ring_buffer *ring;
+	INIT_WORK(&st->work_trigger_to_ring, adis16400_trigger_bh_to_ring);
+	/* Set default scan mode */
+
+	iio_scan_mask_set(indio_dev, iio_scan_el_supply.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_gyro_x.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_gyro_y.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_gyro_z.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_accel_x.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_accel_y.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_accel_z.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_magn_x.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_magn_y.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_magn_z.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_temp.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_adc_0.number);
+	indio_dev->scan_timestamp = true;
+
+	indio_dev->scan_el_attrs = &adis16400_scan_el_group;
+
+	ring = iio_sw_rb_allocate(indio_dev);
+	if (!ring) {
+		ret = -ENOMEM;
+		return ret;
+	}
+	indio_dev->ring = ring;
+	/* Effectively select the ring buffer implementation */
+	iio_ring_sw_register_funcs(&ring->access);
+	ring->preenable = &adis16400_data_rdy_ring_preenable;
+	ring->postenable = &adis16400_data_rdy_ring_postenable;
+	ring->predisable = &adis16400_data_rdy_ring_predisable;
+	ring->owner = THIS_MODULE;
+
+	indio_dev->pollfunc = kzalloc(sizeof(*indio_dev->pollfunc), GFP_KERNEL);
+	if (indio_dev->pollfunc == NULL) {
+		ret = -ENOMEM;
+		goto error_iio_sw_rb_free;;
+	}
+	indio_dev->pollfunc->poll_func_main = &adis16400_poll_func_th;
+	indio_dev->pollfunc->private_data = indio_dev;
+	indio_dev->modes |= INDIO_RING_TRIGGERED;
+	return 0;
+
+error_iio_sw_rb_free:
+	iio_sw_rb_free(indio_dev->ring);
+	return ret;
+}
+
+int adis16400_initialize_ring(struct iio_ring_buffer *ring)
+{
+	return iio_ring_buffer_register(ring, 0);
+}
+
+void adis16400_uninitialize_ring(struct iio_ring_buffer *ring)
+{
+	iio_ring_buffer_unregister(ring);
+}