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authorCristina Opriceana <cristina.opriceana@gmail.com>2015-10-09 16:31:28 +0300
committerJonathan Cameron <jic23@kernel.org>2015-10-25 12:33:01 +0000
commit415f792447572ef1949a3cef5119bbce8cc66373 (patch)
tree343fd0cd479ed2962d02bca228e153f845efebe9 /drivers/iio/dummy/iio_simple_dummy_buffer.c
parentf0b1643581b376ebd97a0068cbc3d146d6abdff1 (diff)
iio: Move IIO Dummy Driver out of staging
This patch moves the reference IIO dummy driver from drivers/staging/iio into a separate folder, drivers/iio/dummy and adds the proper Kconfig and Makefile for it. A new config menu entry called IIO dummy driver has also been added in the Industrial I/O support menu, corresponding to this driver. Signed-off-by: Cristina Opriceana <cristina.opriceana@gmail.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'drivers/iio/dummy/iio_simple_dummy_buffer.c')
-rw-r--r--drivers/iio/dummy/iio_simple_dummy_buffer.c192
1 files changed, 192 insertions, 0 deletions
diff --git a/drivers/iio/dummy/iio_simple_dummy_buffer.c b/drivers/iio/dummy/iio_simple_dummy_buffer.c
new file mode 100644
index 000000000000..00ed7745f3c5
--- /dev/null
+++ b/drivers/iio/dummy/iio_simple_dummy_buffer.c
@@ -0,0 +1,192 @@
+/**
+ * Copyright (c) 2011 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.
+ *
+ * Buffer handling elements of industrial I/O reference driver.
+ * Uses the kfifo buffer.
+ *
+ * To test without hardware use the sysfs trigger.
+ */
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/bitmap.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/kfifo_buf.h>
+
+#include "iio_simple_dummy.h"
+
+/* Some fake data */
+
+static const s16 fakedata[] = {
+ [voltage0] = 7,
+ [diffvoltage1m2] = -33,
+ [diffvoltage3m4] = -2,
+ [accelx] = 344,
+};
+
+/**
+ * iio_simple_dummy_trigger_h() - the trigger handler function
+ * @irq: the interrupt number
+ * @p: private data - always a pointer to the poll func.
+ *
+ * This is the guts of buffered capture. On a trigger event occurring,
+ * if the pollfunc is attached then this handler is called as a threaded
+ * interrupt (and hence may sleep). It is responsible for grabbing data
+ * from the device and pushing it into the associated buffer.
+ */
+static irqreturn_t iio_simple_dummy_trigger_h(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ int len = 0;
+ u16 *data;
+
+ data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
+ if (!data)
+ goto done;
+
+ if (!bitmap_empty(indio_dev->active_scan_mask, indio_dev->masklength)) {
+ /*
+ * Three common options here:
+ * hardware scans: certain combinations of channels make
+ * up a fast read. The capture will consist of all of them.
+ * Hence we just call the grab data function and fill the
+ * buffer without processing.
+ * software scans: can be considered to be random access
+ * so efficient reading is just a case of minimal bus
+ * transactions.
+ * software culled hardware scans:
+ * occasionally a driver may process the nearest hardware
+ * scan to avoid storing elements that are not desired. This
+ * is the fiddliest option by far.
+ * Here let's pretend we have random access. And the values are
+ * in the constant table fakedata.
+ */
+ int i, j;
+
+ for (i = 0, j = 0;
+ i < bitmap_weight(indio_dev->active_scan_mask,
+ indio_dev->masklength);
+ i++, j++) {
+ j = find_next_bit(indio_dev->active_scan_mask,
+ indio_dev->masklength, j);
+ /* random access read from the 'device' */
+ data[i] = fakedata[j];
+ len += 2;
+ }
+ }
+
+ iio_push_to_buffers_with_timestamp(indio_dev, data, iio_get_time_ns());
+
+ kfree(data);
+
+done:
+ /*
+ * Tell the core we are done with this trigger and ready for the
+ * next one.
+ */
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+static const struct iio_buffer_setup_ops iio_simple_dummy_buffer_setup_ops = {
+ /*
+ * iio_triggered_buffer_postenable:
+ * Generic function that simply attaches the pollfunc to the trigger.
+ * Replace this to mess with hardware state before we attach the
+ * trigger.
+ */
+ .postenable = &iio_triggered_buffer_postenable,
+ /*
+ * iio_triggered_buffer_predisable:
+ * Generic function that simple detaches the pollfunc from the trigger.
+ * Replace this to put hardware state back again after the trigger is
+ * detached but before userspace knows we have disabled the ring.
+ */
+ .predisable = &iio_triggered_buffer_predisable,
+};
+
+int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev)
+{
+ int ret;
+ struct iio_buffer *buffer;
+
+ /* Allocate a buffer to use - here a kfifo */
+ buffer = iio_kfifo_allocate();
+ if (!buffer) {
+ ret = -ENOMEM;
+ goto error_ret;
+ }
+
+ iio_device_attach_buffer(indio_dev, buffer);
+
+ /* Enable timestamps by default */
+ buffer->scan_timestamp = true;
+
+ /*
+ * Tell the core what device type specific functions should
+ * be run on either side of buffer capture enable / disable.
+ */
+ indio_dev->setup_ops = &iio_simple_dummy_buffer_setup_ops;
+
+ /*
+ * Configure a polling function.
+ * When a trigger event with this polling function connected
+ * occurs, this function is run. Typically this grabs data
+ * from the device.
+ *
+ * NULL for the bottom half. This is normally implemented only if we
+ * either want to ping a capture now pin (no sleeping) or grab
+ * a timestamp as close as possible to a data ready trigger firing.
+ *
+ * IRQF_ONESHOT ensures irqs are masked such that only one instance
+ * of the handler can run at a time.
+ *
+ * "iio_simple_dummy_consumer%d" formatting string for the irq 'name'
+ * as seen under /proc/interrupts. Remaining parameters as per printk.
+ */
+ indio_dev->pollfunc = iio_alloc_pollfunc(NULL,
+ &iio_simple_dummy_trigger_h,
+ IRQF_ONESHOT,
+ indio_dev,
+ "iio_simple_dummy_consumer%d",
+ indio_dev->id);
+
+ if (!indio_dev->pollfunc) {
+ ret = -ENOMEM;
+ goto error_free_buffer;
+ }
+
+ /*
+ * Notify the core that this device is capable of buffered capture
+ * driven by a trigger.
+ */
+ indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
+
+ return 0;
+
+error_free_buffer:
+ iio_kfifo_free(indio_dev->buffer);
+error_ret:
+ return ret;
+}
+
+/**
+ * iio_simple_dummy_unconfigure_buffer() - release buffer resources
+ * @indo_dev: device instance state
+ */
+void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev)
+{
+ iio_dealloc_pollfunc(indio_dev->pollfunc);
+ iio_kfifo_free(indio_dev->buffer);
+}