iio: Add hardware consumer buffer support (48b66f8f) · Commits · e / devices / android_kernel_fairphone_FP4

drivers/iio/buffer/Kconfig

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		@@ -29,6 +29,16 @@ config IIO_BUFFER_DMAENGINE

		Should be selected by drivers that want to use this functionality.

		config IIO_BUFFER_HW_CONSUMER
		tristate "Industrial I/O HW buffering"
		help
		Provides a way to bonding when an IIO device has a direct connection
		to another device in hardware. In this case buffers for data transfers
		are handled by hardware.

		Should be selected by drivers that want to use the generic Hw consumer
		interface.

		config IIO_KFIFO_BUF
		tristate "Industrial I/O buffering based on kfifo"
		help

drivers/iio/buffer/Makefile

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		@@ -7,5 +7,6 @@
		obj-$(CONFIG_IIO_BUFFER_CB) += industrialio-buffer-cb.o
		obj-$(CONFIG_IIO_BUFFER_DMA) += industrialio-buffer-dma.o
		obj-$(CONFIG_IIO_BUFFER_DMAENGINE) += industrialio-buffer-dmaengine.o
		obj-$(CONFIG_IIO_BUFFER_HW_CONSUMER) += industrialio-hw-consumer.o
		obj-$(CONFIG_IIO_TRIGGERED_BUFFER) += industrialio-triggered-buffer.o
		obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o

drivers/iio/buffer/industrialio-hw-consumer.c

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		// SPDX-License-Identifier: GPL-2.0
		/*
		* Copyright 2017 Analog Devices Inc.
		* Author: Lars-Peter Clausen <lars@metafoo.de>
		*/

		#include <linux/err.h>
		#include <linux/export.h>
		#include <linux/slab.h>
		#include <linux/module.h>

		#include <linux/iio/iio.h>
		#include <linux/iio/consumer.h>
		#include <linux/iio/hw-consumer.h>
		#include <linux/iio/buffer_impl.h>

		/**
		* struct iio_hw_consumer - IIO hw consumer block
		* @buffers: hardware buffers list head.
		* @channels: IIO provider channels.
		*/
		struct iio_hw_consumer {
		struct list_head buffers;
		struct iio_channel *channels;
		};

		struct hw_consumer_buffer {
		struct list_head head;
		struct iio_dev *indio_dev;
		struct iio_buffer buffer;
		long scan_mask[];
		};

		static struct hw_consumer_buffer *iio_buffer_to_hw_consumer_buffer(
		struct iio_buffer *buffer)
		{
		return container_of(buffer, struct hw_consumer_buffer, buffer);
		}

		static void iio_hw_buf_release(struct iio_buffer *buffer)
		{
		struct hw_consumer_buffer *hw_buf =
		iio_buffer_to_hw_consumer_buffer(buffer);
		kfree(hw_buf);
		}

		static const struct iio_buffer_access_funcs iio_hw_buf_access = {
		.release = &iio_hw_buf_release,
		.modes = INDIO_BUFFER_HARDWARE,
		};

		static struct hw_consumer_buffer *iio_hw_consumer_get_buffer(
		struct iio_hw_consumer hwc, struct iio_dev indio_dev)
		{
		size_t mask_size = BITS_TO_LONGS(indio_dev->masklength) * sizeof(long);
		struct hw_consumer_buffer *buf;

		list_for_each_entry(buf, &hwc->buffers, head) {
		if (buf->indio_dev == indio_dev)
		return buf;
		}

		buf = kzalloc(sizeof(*buf) + mask_size, GFP_KERNEL);
		if (!buf)
		return NULL;

		buf->buffer.access = &iio_hw_buf_access;
		buf->indio_dev = indio_dev;
		buf->buffer.scan_mask = buf->scan_mask;

		iio_buffer_init(&buf->buffer);
		list_add_tail(&buf->head, &hwc->buffers);

		return buf;
		}

		/**
		* iio_hw_consumer_alloc() - Allocate IIO hardware consumer
		* @dev: Pointer to consumer device.
		*
		* Returns a valid iio_hw_consumer on success or a ERR_PTR() on failure.
		*/
		struct iio_hw_consumer iio_hw_consumer_alloc(struct device dev)
		{
		struct hw_consumer_buffer *buf;
		struct iio_hw_consumer *hwc;
		struct iio_channel *chan;
		int ret;

		hwc = kzalloc(sizeof(*hwc), GFP_KERNEL);
		if (!hwc)
		return ERR_PTR(-ENOMEM);

		INIT_LIST_HEAD(&hwc->buffers);

		hwc->channels = iio_channel_get_all(dev);
		if (IS_ERR(hwc->channels)) {
		ret = PTR_ERR(hwc->channels);
		goto err_free_hwc;
		}

		chan = &hwc->channels[0];
		while (chan->indio_dev) {
		buf = iio_hw_consumer_get_buffer(hwc, chan->indio_dev);
		if (!buf) {
		ret = -ENOMEM;
		goto err_put_buffers;
		}
		set_bit(chan->channel->scan_index, buf->buffer.scan_mask);
		chan++;
		}

		return hwc;

		err_put_buffers:
		list_for_each_entry(buf, &hwc->buffers, head)
		iio_buffer_put(&buf->buffer);
		iio_channel_release_all(hwc->channels);
		err_free_hwc:
		kfree(hwc);
		return ERR_PTR(ret);
		}
		EXPORT_SYMBOL_GPL(iio_hw_consumer_alloc);

		/**
		* iio_hw_consumer_free() - Free IIO hardware consumer
		* @hwc: hw consumer to free.
		*/
		void iio_hw_consumer_free(struct iio_hw_consumer *hwc)
		{
		struct hw_consumer_buffer buf, n;

		iio_channel_release_all(hwc->channels);
		list_for_each_entry_safe(buf, n, &hwc->buffers, head)
		iio_buffer_put(&buf->buffer);
		kfree(hwc);
		}
		EXPORT_SYMBOL_GPL(iio_hw_consumer_free);

		/**
		* iio_hw_consumer_enable() - Enable IIO hardware consumer
		* @hwc: iio_hw_consumer to enable.
		*
		* Returns 0 on success.
		*/
		int iio_hw_consumer_enable(struct iio_hw_consumer *hwc)
		{
		struct hw_consumer_buffer *buf;
		int ret;

		list_for_each_entry(buf, &hwc->buffers, head) {
		ret = iio_update_buffers(buf->indio_dev, &buf->buffer, NULL);
		if (ret)
		goto err_disable_buffers;
		}

		return 0;

		err_disable_buffers:
		list_for_each_entry_continue_reverse(buf, &hwc->buffers, head)
		iio_update_buffers(buf->indio_dev, NULL, &buf->buffer);
		return ret;
		}
		EXPORT_SYMBOL_GPL(iio_hw_consumer_enable);

		/**
		* iio_hw_consumer_disable() - Disable IIO hardware consumer
		* @hwc: iio_hw_consumer to disable.
		*/
		void iio_hw_consumer_disable(struct iio_hw_consumer *hwc)
		{
		struct hw_consumer_buffer *buf;

		list_for_each_entry(buf, &hwc->buffers, head)
		iio_update_buffers(buf->indio_dev, NULL, &buf->buffer);
		}
		EXPORT_SYMBOL_GPL(iio_hw_consumer_disable);

		MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
		MODULE_DESCRIPTION("Hardware consumer buffer the IIO framework");
		MODULE_LICENSE("GPL v2");

include/linux/iio/hw-consumer.h

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		/* SPDX-License-Identifier: GPL-2.0 */
		/*
		* Industrial I/O in kernel hardware consumer interface
		*
		* Copyright 2017 Analog Devices Inc.
		* Author: Lars-Peter Clausen <lars@metafoo.de>
		*/

		#ifndef LINUX_IIO_HW_CONSUMER_H
		#define LINUX_IIO_HW_CONSUMER_H

		struct iio_hw_consumer;

		struct iio_hw_consumer iio_hw_consumer_alloc(struct device dev);
		void iio_hw_consumer_free(struct iio_hw_consumer *hwc);
		int iio_hw_consumer_enable(struct iio_hw_consumer *hwc);
		void iio_hw_consumer_disable(struct iio_hw_consumer *hwc);

		#endif