iio: Add helper function for initializing triggered buffers

Add a helper function for executing the common tasks which are usually involved in setting up a simple software ringbuffer. It will allocate the buffer, allocate the pollfunc and register the buffer. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: Add helper function for initializing triggered buffers
Add a helper function for executing the common tasks which are usually involved in setting up a simple software ringbuffer. It will allocate the buffer, allocate the pollfunc and register the buffer. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Lars-Peter Clausen · Greg Kroah-Hartman
1 parent f5b81ddd12
Showing 4 changed files with 133 additions and 0 deletions Side-by-side Diff
drivers/iio/Kconfig
drivers/iio/Makefile
drivers/iio/industrialio-triggered-buffer.c
include/linux/iio/triggered_buffer.h
@@ -30,6 +30,13 @@
 	  no buffer events so it is up to userspace to work out how
 	  often to read from the buffer.
  
+config IIO_TRIGGERED_BUFFER
+	tristate
+	select IIO_TRIGGER
+	select IIO_KFIFO_BUF
+	help
+	  Provides helper functions for setting up triggered buffers.
+
 endif # IIO_BUFFER
  
 config IIO_TRIGGER
@@ -7,6 +7,7 @@
 industrialio-$(CONFIG_IIO_BUFFER) += industrialio-buffer.o
 industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o
  
+obj-$(CONFIG_IIO_TRIGGERED_BUFFER) += industrialio-triggered-buffer.o
 obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
  
 obj-y += adc/
+ /*
+ * Copyright (c) 2012 Analog Devices, Inc.
+ *  Author: Lars-Peter Clausen <lars@metafoo.de>
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/kfifo_buf.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+
+static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
+	.preenable = &iio_sw_buffer_preenable,
+	.postenable = &iio_triggered_buffer_postenable,
+	.predisable = &iio_triggered_buffer_predisable,
+};
+
+/**
+ * iio_triggered_buffer_setup() - Setup triggered buffer and pollfunc
+ * @indio_dev:		IIO device structure
+ * @pollfunc_bh:	Function which will be used as pollfunc bottom half
+ * @pollfunc_th:	Function which will be used as pollfunc top half
+ * @setup_ops:		Buffer setup functions to use for this device.
+ *			If NULL the default setup functions for triggered
+ *			buffers will be used.
+ *
+ * This function combines some common tasks which will normally be performed
+ * when setting up a triggered buffer. It will allocate the buffer and the
+ * pollfunc, as well as register the buffer with the IIO core.
+ *
+ * Before calling this function the indio_dev structure should already be
+ * completely initialized, but not yet registered. In practice this means that
+ * this function should be called right before iio_device_register().
+ *
+ * To free the resources allocated by this function call
+ * iio_triggered_buffer_cleanup().
+ */
+int iio_triggered_buffer_setup(struct iio_dev *indio_dev,
+	irqreturn_t (*pollfunc_bh)(int irq, void *p),
+	irqreturn_t (*pollfunc_th)(int irq, void *p),
+	const struct iio_buffer_setup_ops *setup_ops)
+{
+	int ret;
+
+	indio_dev->buffer = iio_kfifo_allocate(indio_dev);
+	if (!indio_dev->buffer) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	indio_dev->pollfunc = iio_alloc_pollfunc(pollfunc_bh,
+						 pollfunc_th,
+						 IRQF_ONESHOT,
+						 indio_dev,
+						 "%s_consumer%d",
+						 indio_dev->name,
+						 indio_dev->id);
+	if (indio_dev->pollfunc == NULL) {
+		ret = -ENOMEM;
+		goto error_kfifo_free;
+	}
+
+	/* Ring buffer functions - here trigger setup related */
+	if (setup_ops)
+		indio_dev->setup_ops = setup_ops;
+	else
+		indio_dev->setup_ops = &iio_triggered_buffer_setup_ops;
+
+	/* Flag that polled ring buffering is possible */
+	indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
+
+	ret = iio_buffer_register(indio_dev,
+				  indio_dev->channels,
+				  indio_dev->num_channels);
+	if (ret)
+		goto error_dealloc_pollfunc;
+
+	return 0;
+
+error_dealloc_pollfunc:
+	iio_dealloc_pollfunc(indio_dev->pollfunc);
+error_kfifo_free:
+	iio_kfifo_free(indio_dev->buffer);
+error_ret:
+	return ret;
+}
+EXPORT_SYMBOL(iio_triggered_buffer_setup);
+
+/**
+ * iio_triggered_buffer_cleanup() - Free resources allocated by iio_triggered_buffer_setup()
+ * @indio_dev: IIO device structure
+ */
+void iio_triggered_buffer_cleanup(struct iio_dev *indio_dev)
+{
+	iio_buffer_unregister(indio_dev);
+	iio_dealloc_pollfunc(indio_dev->pollfunc);
+	iio_kfifo_free(indio_dev->buffer);
+}
+EXPORT_SYMBOL(iio_triggered_buffer_cleanup);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("IIO helper functions for setting up triggered buffers");
+MODULE_LICENSE("GPL");
+#ifndef _LINUX_IIO_TRIGGERED_BUFFER_H_
+#define _LINUX_IIO_TRIGGERED_BUFFER_H_
+
+#include <linux/interrupt.h>
+
+struct iio_dev;
+struct iio_buffer_setup_ops;
+
+int iio_triggered_buffer_setup(struct iio_dev *indio_dev,
+	irqreturn_t (*pollfunc_bh)(int irq, void *p),
+	irqreturn_t (*pollfunc_th)(int irq, void *p),
+	const struct iio_buffer_setup_ops *setup_ops);
+void iio_triggered_buffer_cleanup(struct iio_dev *indio_dev);
+
+#endif
...	...	@@ -30,6 +30,13 @@
30	30	no buffer events so it is up to userspace to work out how
31	31	often to read from the buffer.
32	32
	33	+config IIO_TRIGGERED_BUFFER
	34	+ tristate
	35	+ select IIO_TRIGGER
	36	+ select IIO_KFIFO_BUF
	37	+ help
	38	+ Provides helper functions for setting up triggered buffers.
	39	+
33	40	endif # IIO_BUFFER
34	41
35	42	config IIO_TRIGGER
...	...	@@ -7,6 +7,7 @@
7	7	industrialio-$(CONFIG_IIO_BUFFER) += industrialio-buffer.o
8	8	industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o
9	9
	10	+obj-$(CONFIG_IIO_TRIGGERED_BUFFER) += industrialio-triggered-buffer.o
10	11	obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
11	12
12	13	obj-y += adc/
	1	+ /*
	2	+ * Copyright (c) 2012 Analog Devices, Inc.
	3	+ * Author: Lars-Peter Clausen <lars@metafoo.de>
	4	+ *
	5	+ * This program is free software; you can redistribute it and/or modify it
	6	+ * under the terms of the GNU General Public License version 2 as published by
	7	+ * the Free Software Foundation.
	8	+ */
	9	+
	10	+#include <linux/kernel.h>
	11	+#include <linux/export.h>
	12	+#include <linux/module.h>
	13	+#include <linux/iio/iio.h>
	14	+#include <linux/iio/buffer.h>
	15	+#include <linux/iio/kfifo_buf.h>
	16	+#include <linux/iio/triggered_buffer.h>
	17	+#include <linux/iio/trigger_consumer.h>
	18	+
	19	+static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
	20	+ .preenable = &iio_sw_buffer_preenable,
	21	+ .postenable = &iio_triggered_buffer_postenable,
	22	+ .predisable = &iio_triggered_buffer_predisable,
	23	+};
	24	+
	25	+/**
	26	+ * iio_triggered_buffer_setup() - Setup triggered buffer and pollfunc
	27	+ * @indio_dev: IIO device structure
	28	+ * @pollfunc_bh: Function which will be used as pollfunc bottom half
	29	+ * @pollfunc_th: Function which will be used as pollfunc top half
	30	+ * @setup_ops: Buffer setup functions to use for this device.
	31	+ * If NULL the default setup functions for triggered
	32	+ * buffers will be used.
	33	+ *
	34	+ * This function combines some common tasks which will normally be performed
	35	+ * when setting up a triggered buffer. It will allocate the buffer and the
	36	+ * pollfunc, as well as register the buffer with the IIO core.
	37	+ *
	38	+ * Before calling this function the indio_dev structure should already be
	39	+ * completely initialized, but not yet registered. In practice this means that
	40	+ * this function should be called right before iio_device_register().
	41	+ *
	42	+ * To free the resources allocated by this function call
	43	+ * iio_triggered_buffer_cleanup().
	44	+ */
	45	+int iio_triggered_buffer_setup(struct iio_dev *indio_dev,
	46	+ irqreturn_t (pollfunc_bh)(int irq, void p),
	47	+ irqreturn_t (pollfunc_th)(int irq, void p),
	48	+ const struct iio_buffer_setup_ops *setup_ops)
	49	+{
	50	+ int ret;
	51	+
	52	+ indio_dev->buffer = iio_kfifo_allocate(indio_dev);
	53	+ if (!indio_dev->buffer) {
	54	+ ret = -ENOMEM;
	55	+ goto error_ret;
	56	+ }
	57	+
	58	+ indio_dev->pollfunc = iio_alloc_pollfunc(pollfunc_bh,
	59	+ pollfunc_th,
	60	+ IRQF_ONESHOT,
	61	+ indio_dev,
	62	+ "%s_consumer%d",
	63	+ indio_dev->name,
	64	+ indio_dev->id);
	65	+ if (indio_dev->pollfunc == NULL) {
	66	+ ret = -ENOMEM;
	67	+ goto error_kfifo_free;
	68	+ }
	69	+
	70	+ /* Ring buffer functions - here trigger setup related */
	71	+ if (setup_ops)
	72	+ indio_dev->setup_ops = setup_ops;
	73	+ else
	74	+ indio_dev->setup_ops = &iio_triggered_buffer_setup_ops;
	75	+
	76	+ /* Flag that polled ring buffering is possible */
	77	+ indio_dev->modes \|= INDIO_BUFFER_TRIGGERED;
	78	+
	79	+ ret = iio_buffer_register(indio_dev,
	80	+ indio_dev->channels,
	81	+ indio_dev->num_channels);
	82	+ if (ret)
	83	+ goto error_dealloc_pollfunc;
	84	+
	85	+ return 0;
	86	+
	87	+error_dealloc_pollfunc:
	88	+ iio_dealloc_pollfunc(indio_dev->pollfunc);
	89	+error_kfifo_free:
	90	+ iio_kfifo_free(indio_dev->buffer);
	91	+error_ret:
	92	+ return ret;
	93	+}
	94	+EXPORT_SYMBOL(iio_triggered_buffer_setup);
	95	+
	96	+/**
	97	+ * iio_triggered_buffer_cleanup() - Free resources allocated by iio_triggered_buffer_setup()
	98	+ * @indio_dev: IIO device structure
	99	+ */
	100	+void iio_triggered_buffer_cleanup(struct iio_dev *indio_dev)
	101	+{
	102	+ iio_buffer_unregister(indio_dev);
	103	+ iio_dealloc_pollfunc(indio_dev->pollfunc);
	104	+ iio_kfifo_free(indio_dev->buffer);
	105	+}
	106	+EXPORT_SYMBOL(iio_triggered_buffer_cleanup);
	107	+
	108	+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
	109	+MODULE_DESCRIPTION("IIO helper functions for setting up triggered buffers");
	110	+MODULE_LICENSE("GPL");
	1	+#ifndef _LINUX_IIO_TRIGGERED_BUFFER_H_
	2	+#define _LINUX_IIO_TRIGGERED_BUFFER_H_
	3	+
	4	+#include <linux/interrupt.h>
	5	+
	6	+struct iio_dev;
	7	+struct iio_buffer_setup_ops;
	8	+
	9	+int iio_triggered_buffer_setup(struct iio_dev *indio_dev,
	10	+ irqreturn_t (pollfunc_bh)(int irq, void p),
	11	+ irqreturn_t (pollfunc_th)(int irq, void p),
	12	+ const struct iio_buffer_setup_ops *setup_ops);
	13	+void iio_triggered_buffer_cleanup(struct iio_dev *indio_dev);
	14	+
	15	+#endif