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authorJonathan Cameron <jic23@cam.ac.uk>2009-08-18 18:06:29 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2009-09-15 12:02:25 -0700
commit0a1231dfea57516fb6cf107afdfb625a11a1cc5e (patch)
tree408b9906efb7a667e429c4f571a58d611393c8cb /drivers/staging/iio/adc/max1363_ring.c
parent14cd9a73d97e3c1063fa1b2b02ef32ac8a914e11 (diff)
Staging: IIO: max1363 add software ring buffer support using ring_sw
Changes since V2: * Moved to new registration methodology. Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/staging/iio/adc/max1363_ring.c')
-rw-r--r--drivers/staging/iio/adc/max1363_ring.c241
1 files changed, 241 insertions, 0 deletions
diff --git a/drivers/staging/iio/adc/max1363_ring.c b/drivers/staging/iio/adc/max1363_ring.c
new file mode 100644
index 00000000000..a953eac6fd6
--- /dev/null
+++ b/drivers/staging/iio/adc/max1363_ring.c
@@ -0,0 +1,241 @@
+/*
+ * Copyright (C) 2008 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.
+ *
+ * max1363_ring.c
+ */
+
+#include <linux/interrupt.h>
+#include <linux/gpio.h>
+#include <linux/workqueue.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/sysfs.h>
+#include <linux/list.h>
+#include <linux/i2c.h>
+
+#include "../iio.h"
+#include "../ring_generic.h"
+#include "../ring_sw.h"
+#include "../trigger.h"
+#include "../sysfs.h"
+
+#include "max1363.h"
+
+ssize_t max1363_scan_from_ring(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *dev_info = dev_get_drvdata(dev);
+ struct max1363_state *info = dev_info->dev_data;
+ int i, ret, len = 0;
+ char *ring_data;
+
+ ring_data = kmalloc(info->current_mode->numvals*2, GFP_KERNEL);
+ if (ring_data == NULL) {
+ ret = -ENOMEM;
+ goto error_ret;
+ }
+ ret = dev_info->ring->access.read_last(dev_info->ring, ring_data);
+ if (ret)
+ goto error_free_ring_data;
+ len += sprintf(buf+len, "ring ");
+ for (i = 0; i < info->current_mode->numvals; i++)
+ len += sprintf(buf + len, "%d ",
+ ((int)(ring_data[i*2 + 0] & 0x0F) << 8)
+ + ((int)(ring_data[i*2 + 1])));
+ len += sprintf(buf + len, "\n");
+ kfree(ring_data);
+
+ return len;
+
+error_free_ring_data:
+ kfree(ring_data);
+error_ret:
+ return ret;
+}
+
+/**
+ * max1363_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 max1363_ring_preenable(struct iio_dev *indio_dev)
+{
+ struct max1363_state *st = indio_dev->dev_data;
+ size_t d_size;
+
+ if (indio_dev->ring->access.set_bpd) {
+ d_size = st->current_mode->numvals*2 + sizeof(s64);
+ if (d_size % 8)
+ d_size += 8 - (d_size % 8);
+ indio_dev->ring->access.set_bpd(indio_dev->ring, d_size);
+ }
+
+ return 0;
+}
+
+/**
+ * max1363_ring_postenable() typical ring post enable
+ *
+ * Only not moved into the core for the hardware ring buffer cases
+ * that are more sophisticated.
+ **/
+static int max1363_ring_postenable(struct iio_dev *indio_dev)
+{
+ if (indio_dev->trig == NULL)
+ return 0;
+ return iio_trigger_attach_poll_func(indio_dev->trig,
+ indio_dev->pollfunc);
+}
+
+/**
+ * max1363_ring_predisable() runs just prior to ring buffer being disabled
+ *
+ * Typical predisable function which ensures that no trigger events can
+ * occur before we disable the ring buffer (and hence would have no idea
+ * what to do with them)
+ **/
+static int max1363_ring_predisable(struct iio_dev *indio_dev)
+{
+ if (indio_dev->trig)
+ return iio_trigger_dettach_poll_func(indio_dev->trig,
+ indio_dev->pollfunc);
+ else
+ return 0;
+}
+
+/**
+ * max1363_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.
+ **/
+void max1363_poll_func_th(struct iio_dev *indio_dev)
+{
+ struct max1363_state *st = indio_dev->dev_data;
+
+ schedule_work(&st->poll_work);
+
+ return;
+}
+/**
+ * max1363_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 max1363_poll_bh_to_ring(struct work_struct *work_s)
+{
+ struct max1363_state *st = container_of(work_s, struct max1363_state,
+ poll_work);
+ struct iio_dev *indio_dev = st->indio_dev;
+ struct iio_sw_ring_buffer *ring = iio_to_sw_ring(indio_dev->ring);
+ s64 time_ns;
+ __u8 *rxbuf;
+ int b_sent;
+ size_t d_size;
+
+ /* Ensure the timestamp is 8 byte aligned */
+ d_size = st->current_mode->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 (st->current_mode->numvals == 0)
+ return;
+
+ rxbuf = kmalloc(d_size, GFP_KERNEL);
+ if (rxbuf == NULL)
+ return;
+
+ b_sent = i2c_master_recv(st->client,
+ rxbuf,
+ st->current_mode->numvals*2);
+ if (b_sent < 0)
+ goto done;
+
+ time_ns = iio_get_time_ns();
+
+ memcpy(rxbuf + d_size - sizeof(s64), &time_ns, sizeof(time_ns));
+
+ indio_dev->ring->access.store_to(&ring->buf, rxbuf, time_ns);
+done:
+ kfree(rxbuf);
+ atomic_dec(&st->protect_ring);
+}
+
+
+int max1363_register_ring_funcs_and_init(struct iio_dev *indio_dev)
+{
+ struct max1363_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);
+ indio_dev->pollfunc = kzalloc(sizeof(*indio_dev->pollfunc), GFP_KERNEL);
+ if (indio_dev->pollfunc == NULL) {
+ ret = -ENOMEM;
+ goto error_deallocate_sw_rb;
+ }
+ /* Configure the polling function called on trigger interrupts */
+ indio_dev->pollfunc->poll_func_main = &max1363_poll_func_th;
+ indio_dev->pollfunc->private_data = indio_dev;
+
+ /* Ring buffer functions - here trigger setup related */
+ indio_dev->ring->postenable = &max1363_ring_postenable;
+ indio_dev->ring->preenable = &max1363_ring_preenable;
+ indio_dev->ring->predisable = &max1363_ring_predisable;
+ INIT_WORK(&st->poll_work, &max1363_poll_bh_to_ring);
+
+ /* 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 max1363_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);
+}
+
+void max1363_uninitialize_ring(struct iio_ring_buffer *ring)
+{
+ iio_ring_buffer_unregister(ring);
+};
+
+int max1363_initialize_ring(struct iio_ring_buffer *ring)
+{
+ return iio_ring_buffer_register(ring);
+};