--- /dev/null
+/*
+ * Copyright (C) 2010 Michael Hennerich, Analog Devices Inc.
+ * Copyright (C) 2008-2010 Jonathan Cameron
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * ad799x_ring.c
+ */
+
+#include <linux/interrupt.h>
+#include <linux/workqueue.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/sysfs.h>
+#include <linux/list.h>
+#include <linux/i2c.h>
+#include <linux/bitops.h>
+
+#include "../iio.h"
+#include "../ring_generic.h"
+#include "../ring_sw.h"
+#include "../trigger.h"
+#include "../sysfs.h"
+
+#include "ad799x.h"
+
+int ad799x_single_channel_from_ring(struct ad799x_state *st, long mask)
+{
+ struct iio_ring_buffer *ring = st->indio_dev->ring;
+ int count = 0, ret;
+ u16 *ring_data;
+
+ if (!(ring->scan_mask & mask)) {
+ ret = -EBUSY;
+ goto error_ret;
+ }
+
+ ring_data = kmalloc(ring->access.get_bytes_per_datum(ring), GFP_KERNEL);
+ if (ring_data == NULL) {
+ ret = -ENOMEM;
+ goto error_ret;
+ }
+ ret = ring->access.read_last(ring, (u8 *) ring_data);
+ if (ret)
+ goto error_free_ring_data;
+ /* Need a count of channels prior to this one */
+ mask >>= 1;
+ while (mask) {
+ if (mask & ring->scan_mask)
+ count++;
+ mask >>= 1;
+ }
+
+ ret = be16_to_cpu(ring_data[count]);
+
+error_free_ring_data:
+ kfree(ring_data);
+error_ret:
+ return ret;
+}
+
+/**
+ * ad799x_ring_preenable() setup the parameters of the ring before enabling
+ *
+ * The complex nature of the setting of the nuber of bytes per datum is due
+ * to this driver currently ensuring that the timestamp is stored at an 8
+ * byte boundary.
+ **/
+static int ad799x_ring_preenable(struct iio_dev *indio_dev)
+{
+ struct iio_ring_buffer *ring = indio_dev->ring;
+ struct ad799x_state *st = indio_dev->dev_data;
+ size_t d_size;
+ unsigned long numvals;
+
+ /*
+ * Need to figure out the current mode based upon the requested
+ * scan mask in iio_dev
+ */
+
+ if (st->id == ad7997 || st->id == ad7998)
+ ad799x_set_scan_mode(st, ring->scan_mask);
+
+ numvals = ring->scan_count;
+
+ if (ring->access.set_bytes_per_datum) {
+ d_size = numvals*2 + sizeof(s64);
+ if (d_size % 8)
+ d_size += 8 - (d_size % 8);
+ ring->access.set_bytes_per_datum(ring, d_size);
+ }
+
+ return 0;
+}
+
+/**
+ * ad799x_poll_func_th() th of trigger launched polling to ring buffer
+ *
+ * As sampling only occurs on i2c comms occuring, leave timestamping until
+ * then. Some triggers will generate their own time stamp. Currently
+ * there is no way of notifying them when no one cares.
+ **/
+static void ad799x_poll_func_th(struct iio_dev *indio_dev, s64 time)
+{
+ struct ad799x_state *st = indio_dev->dev_data;
+
+ schedule_work(&st->poll_work);
+
+ return;
+}
+/**
+ * ad799x_poll_bh_to_ring() bh of trigger launched polling to ring buffer
+ * @work_s: the work struct through which this was scheduled
+ *
+ * Currently there is no option in this driver to disable the saving of
+ * timestamps within the ring.
+ * I think the one copy of this at a time was to avoid problems if the
+ * trigger was set far too high and the reads then locked up the computer.
+ **/
+static void ad799x_poll_bh_to_ring(struct work_struct *work_s)
+{
+ struct ad799x_state *st = container_of(work_s, struct ad799x_state,
+ poll_work);
+ struct iio_dev *indio_dev = st->indio_dev;
+ struct iio_ring_buffer *ring = indio_dev->ring;
+ struct iio_sw_ring_buffer *ring_sw = iio_to_sw_ring(indio_dev->ring);
+ s64 time_ns;
+ __u8 *rxbuf;
+ int b_sent;
+ size_t d_size;
+ u8 cmd;
+
+ unsigned long numvals = ring->scan_count;
+
+ /* Ensure the timestamp is 8 byte aligned */
+ d_size = numvals*2 + sizeof(s64);
+
+ if (d_size % sizeof(s64))
+ d_size += sizeof(s64) - (d_size % sizeof(s64));
+
+ /* Ensure only one copy of this function running at a time */
+ if (atomic_inc_return(&st->protect_ring) > 1)
+ return;
+
+ /* Monitor mode prevents reading. Whilst not currently implemented
+ * might as well have this test in here in the meantime as it does
+ * no harm.
+ */
+ if (numvals == 0)
+ return;
+
+ rxbuf = kmalloc(d_size, GFP_KERNEL);
+ if (rxbuf == NULL)
+ return;
+
+ switch (st->id) {
+ case ad7991:
+ case ad7995:
+ case ad7999:
+ cmd = st->config | (ring->scan_mask << AD799X_CHANNEL_SHIFT);
+ break;
+ case ad7992:
+ case ad7993:
+ case ad7994:
+ cmd = (ring->scan_mask << AD799X_CHANNEL_SHIFT) |
+ AD7998_CONV_RES_REG;
+ break;
+ case ad7997:
+ case ad7998:
+ cmd = AD7997_8_READ_SEQUENCE | AD7998_CONV_RES_REG;
+ break;
+ default:
+ cmd = 0;
+ }
+
+ b_sent = i2c_smbus_read_i2c_block_data(st->client,
+ cmd, numvals*2, rxbuf);
+ if (b_sent < 0)
+ goto done;
+
+ time_ns = iio_get_time_ns();
+
+ memcpy(rxbuf + d_size - sizeof(s64), &time_ns, sizeof(time_ns));
+
+ ring->access.store_to(&ring_sw->buf, rxbuf, time_ns);
+done:
+ kfree(rxbuf);
+ atomic_dec(&st->protect_ring);
+}
+
+
+int ad799x_register_ring_funcs_and_init(struct iio_dev *indio_dev)
+{
+ struct ad799x_state *st = indio_dev->dev_data;
+ int ret = 0;
+
+ indio_dev->ring = iio_sw_rb_allocate(indio_dev);
+ if (!indio_dev->ring) {
+ ret = -ENOMEM;
+ goto error_ret;
+ }
+ /* Effectively select the ring buffer implementation */
+ iio_ring_sw_register_funcs(&st->indio_dev->ring->access);
+ ret = iio_alloc_pollfunc(indio_dev, NULL, &ad799x_poll_func_th);
+ if (ret)
+ goto error_deallocate_sw_rb;
+
+ /* Ring buffer functions - here trigger setup related */
+
+ indio_dev->ring->preenable = &ad799x_ring_preenable;
+ indio_dev->ring->postenable = &iio_triggered_ring_postenable;
+ indio_dev->ring->predisable = &iio_triggered_ring_predisable;
+
+ INIT_WORK(&st->poll_work, &ad799x_poll_bh_to_ring);
+
+ indio_dev->ring->scan_el_attrs = st->chip_info->scan_attrs;
+
+ /* Flag that polled ring buffering is possible */
+ indio_dev->modes |= INDIO_RING_TRIGGERED;
+ return 0;
+error_deallocate_sw_rb:
+ iio_sw_rb_free(indio_dev->ring);
+error_ret:
+ return ret;
+}
+
+void ad799x_ring_cleanup(struct iio_dev *indio_dev)
+{
+ /* ensure that the trigger has been detached */
+ if (indio_dev->trig) {
+ iio_put_trigger(indio_dev->trig);
+ iio_trigger_dettach_poll_func(indio_dev->trig,
+ indio_dev->pollfunc);
+ }
+ kfree(indio_dev->pollfunc);
+ iio_sw_rb_free(indio_dev->ring);
+}
projects / mv-sheeva.git / blobdiff