Very simple buffered reading. Did not provide a trigger as
the sysfs trigger already meets that requirement.
Signed-off-by: Jonathan Cameron <jic23@xxxxxxxxx>
---
drivers/staging/iio/Kconfig | 5 +
drivers/staging/iio/Makefile | 1 +
drivers/staging/iio/iio_simple_dummy.c | 73 ++++++++-
drivers/staging/iio/iio_simple_dummy.h | 27 ++++
drivers/staging/iio/iio_simple_dummy_buffer.c | 206 +++++++++++++++++++++++++
5 files changed, 303 insertions(+), 9 deletions(-)
diff --git a/drivers/staging/iio/Kconfig b/drivers/staging/iio/Kconfig
index 75128a0..09cf580 100644
--- a/drivers/staging/iio/Kconfig
+++ b/drivers/staging/iio/Kconfig
@@ -89,6 +89,11 @@ config IIO_SIMPLE_DUMMY_EVENTS
help
Add some dummy events to the simple dummy driver.
+config IIO_SIMPLE_DUMMY_BUFFER
+ boolean "Buffered capture support"
+ depends on IIO_KFIFO_BUF
+ help
+ Add buffered data capture to the simple dummy driver.
endif # IIO_SIMPLE_DUMMY
diff --git a/drivers/staging/iio/Makefile b/drivers/staging/iio/Makefile
index 75aacfd..eaa07b0 100644
--- a/drivers/staging/iio/Makefile
+++ b/drivers/staging/iio/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
obj-$(CONFIG_IIO_SIMPLE_DUMMY) += iio_dummy.o
iio_dummy-y := iio_simple_dummy.o
iio_dummy-$(CONFIG_IIO_SIMPLE_DUMMY_EVENTS) += iio_simple_dummy_events.o
+iio_dummy-$(CONFIG_IIO_SIMPLE_DUMMY_BUFFER) += iio_simple_dummy_buffer.o
obj-$(CONFIG_IIO_DUMMY_EVGEN) += iio_dummy_evgen.o
diff --git a/drivers/staging/iio/iio_simple_dummy.c b/drivers/staging/iio/iio_simple_dummy.c
index c5119a0..af0c992 100644
--- a/drivers/staging/iio/iio_simple_dummy.c
+++ b/drivers/staging/iio/iio_simple_dummy.c
@@ -21,6 +21,7 @@
#include "iio.h"
#include "sysfs.h"
+#include "buffer_generic.h"
#include "iio_simple_dummy.h"
/*
@@ -82,7 +83,14 @@ static struct iio_chan_spec iio_dummy_channels[] = {
* when converting to standard units (microvolts)
*/
(1 << IIO_CHAN_INFO_SCALE_SEPARATE),
-
+ /* The ordering of elements in the buffer via an enum */
+ .scan_index = voltage0,
+ .scan_type = { /* Description of storage in buffer */
+ .sign = 'u', /* unsigned */
+ .realbits = 13, /* 13 bits */
+ .storagebits = 16, /* 16 bits used for storage */
+ .shift = 0, /* zero shift */
+ },
#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
/*
* simple event - triggered when value rises above
@@ -110,6 +118,13 @@ static struct iio_chan_spec iio_dummy_channels[] = {
* input channels of type IIO_VOLTAGE.
*/
(1 << IIO_CHAN_INFO_SCALE_SHARED),
+ .scan_index = diffvoltage1m2,
+ .scan_type = { /* Description of storage in buffer */
+ .sign = 's', /* signed */
+ .realbits = 12, /* 12 bits */
+ .storagebits = 16, /* 16 bits used for storage */
+ .shift = 0, /* zero shift */
+ },
},
/* Differential ADC channel in_voltage3-voltage4_raw etc*/
{
@@ -120,13 +135,13 @@ static struct iio_chan_spec iio_dummy_channels[] = {
.channel2 = 4,
.info_mask =
(1 << IIO_CHAN_INFO_SCALE_SHARED),
- },
- /* DAC channel out_voltage0_raw */
- {
- .type = IIO_VOLTAGE,
- .output = 1,
- .indexed = 1,
- .channel = 0,
+ .scan_index = diffvoltage3m4,
+ .scan_type = {
+ .sign = 's',
+ .realbits = 11,
+ .storagebits = 16,
+ .shift = 0,
+ },
},
/*
* 'modified' (i.e. axis specified) acceleration channel
@@ -145,6 +160,25 @@ static struct iio_chan_spec iio_dummy_channels[] = {
* calibration.
*/
(1 << IIO_CHAN_INFO_CALIBBIAS_SEPARATE),
+ .scan_index = accelx,
+ .scan_type = { /* Description of storage in buffer */
+ .sign = 's', /* signed */
+ .realbits = 16, /* 12 bits */
+ .storagebits = 16, /* 16 bits used for storage */
+ .shift = 0, /* zero shift */
+ },
+ },
+ /*
+ * Convenience macro for timestamps. 4 is the index in
+ * the buffer.
+ */
+ IIO_CHAN_SOFT_TIMESTAMP(4),
+ /* DAC channel out_voltage0_raw */
+ {
+ .type = IIO_VOLTAGE,
+ .output = 1,
+ .indexed = 1,
+ .channel = 0,
},
};
@@ -391,11 +425,29 @@ static int __devinit iio_dummy_probe(int index)
ret = iio_simple_dummy_events_register(indio_dev);
if (ret < 0)
goto error_free_device;
- ret = iio_device_register(indio_dev);
+
+ /* Configure buffered capture support. */
+ ret = iio_simple_dummy_configure_buffer(indio_dev);
if (ret < 0)
goto error_unregister_events;
+ /*
+ * Register the channels with the buffer, but avoid the output
+ * channel being registered by reducing the number of channels by 1.
+ */
+ ret = iio_buffer_register(indio_dev, iio_dummy_channels, 5);
+ if (ret < 0)
+ goto error_unconfigure_buffer;
+
+ ret = iio_device_register(indio_dev);
+ if (ret < 0)
+ goto error_unregister_buffer;
+
return 0;
+error_unregister_buffer:
+ iio_buffer_unregister(indio_dev);
+error_unconfigure_buffer:
+ iio_simple_dummy_unconfigure_buffer(indio_dev);
error_unregister_events:
iio_simple_dummy_events_unregister(indio_dev);
error_free_device:
@@ -429,6 +481,9 @@ static int iio_dummy_remove(int index)
/* Device specific code to power down etc */
+ /* Buffered capture related cleanup */
+ iio_buffer_unregister(indio_dev);
+ iio_simple_dummy_unconfigure_buffer(indio_dev);
ret = iio_simple_dummy_events_unregister(indio_dev);
if (ret)
diff --git a/drivers/staging/iio/iio_simple_dummy.h b/drivers/staging/iio/iio_simple_dummy.h
index 998fd1f..53975d9 100644
--- a/drivers/staging/iio/iio_simple_dummy.h
+++ b/drivers/staging/iio/iio_simple_dummy.h
@@ -78,4 +78,31 @@ iio_simple_dummy_events_unregister(struct iio_dev *indio_dev)
#endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS*/
+/**
+ * enum iio_simple_dummy_scan_elements - scan index enum
+ * @voltage0: the single ended voltage channel
+ * @diffvoltage1m2: first differential channel
+ * @diffvoltage3m4: second differenial channel
+ * @accelx: acceleration channel
+ *
+ * Enum provides convenient numbering for the scan index.
+ */
+enum iio_simple_dummy_scan_elements {
+ voltage0,
+ diffvoltage1m2,
+ diffvoltage3m4,
+ accelx,
+};
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_BUFFER
+int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev);
+void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev);
+#else
+static inline int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev)
+{
+ return 0;
+};
+static inline
+void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev)
+{};
+#endif /* CONFIG_IIO_SIMPLE_DUMMY_BUFFER */
diff --git a/drivers/staging/iio/iio_simple_dummy_buffer.c b/drivers/staging/iio/iio_simple_dummy_buffer.c
new file mode 100644
index 0000000..f0b36d2
--- /dev/null
+++ b/drivers/staging/iio/iio_simple_dummy_buffer.c
@@ -0,0 +1,206 @@
+/**
+ * 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/slab.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/bitmap.h>
+
+#include "iio.h"
+#include "trigger_consumer.h"
+#include "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 occuring,
+ * 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;
+ struct iio_buffer *buffer = indio_dev->buffer;
+ int len = 0;
+ /*
+ * The datasize is obtained from the buffer. It was stored when
+ * the preenable setup function was called.
+ */
+ size_t datasize = buffer->access->get_bytes_per_datum(buffer);
+ u16 *data = kmalloc(datasize, GFP_KERNEL);
+ if (data == NULL)
+ return -ENOMEM;
+
+ if (buffer->scan_count) {
+ /*
+ * 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.
+ * sofware 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 fidliest option by far.
+ * Here lets pretend we have random access. And the values are
+ * in the constant table fakedata.
+ */
+ int i, j;
+ for (i = 0, j = 0; i < buffer->scan_count; i++) {
+ j = find_next_bit(buffer->scan_mask,
+ indio_dev->masklength, j + 1);
+ /* random access read form the 'device' */
+ data[i] = fakedata[j];
+ len += 2;
+ }
+ }
+ /* Store a timestampe at an 8 byte boundary */
+ if (buffer->scan_timestamp)
+ *(s64 *)(((phys_addr_t)data + len
+ + sizeof(s64) - 1) & ~(sizeof(s64) - 1))
+ = iio_get_time_ns();
+ buffer->access->store_to(buffer, (u8 *)data, pf->timestamp);
+
+ kfree(data);
+
+ /*
+ * 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_sw_buffer_preenable:
+ * Generic function for equal sized ring elements + 64 bit timestamp
+ * Assumes that any combination of channels can be enabled.
+ * Typically replaced to implement restrictions on what combinations
+ * can be captured (hardware scan modes).
+ */
+ .preenable = &iio_sw_buffer_preenable,
+ /*
+ * 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(indio_dev);
+ if (buffer == NULL) {
+ ret = -ENOMEM;
+ goto error_ret;
+ }
+
+ indio_dev->buffer = buffer;
+ /* Tell the core how to access the buffer */
+ buffer->access = &kfifo_access_funcs;
+
+ /* Number of bytes per element */
+ buffer->bpe = 2;
+ /* 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.
+ */
+ buffer->setup_ops = &iio_simple_dummy_buffer_setup_ops;
+ buffer->owner = THIS_MODULE;
+
+ /*
+ * 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 top 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 == NULL) {
+ 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);
+}
--
1.7.7
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