kernel/linux.git/include/linux/iio/buffer_impl.h, branch v6.19.11

Merge tag 'char-misc-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

2025-12-07T02:34:24+00:00

Pull char/misc/IIO driver updates from Greg KH: "Here is the big set of char/misc/iio driver updates for 6.19-rc1. Lots of stuff in here including: - lots of IIO driver updates, cleanups, and additions - large interconnect driver changes as they get converted over to a dynamic system of ids - coresight driver updates - mwave driver updates - binder driver updates and changes - comedi driver fixes now that the fuzzers are being set loose on them - nvmem driver updates - new uio driver addition - lots of other small char/misc driver updates, full details in the shortlog All of these have been in linux-next for a while now" * tag 'char-misc-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (304 commits) char: applicom: fix NULL pointer dereference in ac_ioctl hangcheck-timer: fix coding style spacing hangcheck-timer: Replace %Ld with %lld hangcheck-timer: replace printk(KERN_CRIT) with pr_crit uio: Add SVA support for PCI devices via uio_pci_generic_sva.c dt-bindings: slimbus: fix warning from example intel_th: Fix error handling in intel_th_output_open misc: rp1: Fix an error handling path in rp1_probe() char: xillybus: add WQ_UNBOUND to alloc_workqueue users misc: bh1770glc: use pm_runtime_resume_and_get() in power_state_store misc: cb710: Fix a NULL vs IS_ERR() check in probe() mux: mmio: Add suspend and resume support virt: acrn: split acrn_mmio_dev_res out of acrn_mmiodev greybus: gb-beagleplay: Fix timeout handling in bootloader functions greybus: add WQ_PERCPU to alloc_workqueue users char/mwave: drop typedefs char/mwave: drop printk wrapper char/mwave: remove printk tracing char/mwave: remove unneeded fops char/mwave: remove MWAVE_FUTZ_WITH_OTHER_DEVICES ifdeffery ...

iio: buffer: support getting dma channel from the buffer

2025-10-13T07:38:08+00:00

Add a new buffer accessor .get_dma_dev() in order to get the struct device responsible for actually providing the dma channel. We cannot assume that we can use the parent of the IIO device for mapping the DMA buffer. This becomes important on systems (like the Xilinx/AMD zynqMP Ultrascale) where memory (or part of it) is mapped above the 32 bit range. On such systems and given that a device by default has a dma mask of 32 bits we would then need to rely on bounce buffers (to swiotlb) for mapping memory above the dma mask limit. In the process, add an iio_buffer_get_dma_dev() helper function to get the proper DMA device. Cc: stable@vger.kernel.org Reviewed-by: David Lechner Signed-off-by: Nuno Sá Signed-off-by: Jonathan Cameron

iio: buffer: document store_to() callback may be called in any context

2025-10-13T07:37:24+00:00

Document that the struct iio_buffer_access_funcs.store_to() callback must be safe to call from any context since it is called from iio_push_to_buffer() which may be called from any context. Signed-off-by: David Lechner Signed-off-by: Jonathan Cameron

iio: core: Add new DMABUF interface infrastructure

2024-06-30T10:29:17+00:00

Add the necessary infrastructure to the IIO core to support a new optional DMABUF based interface. With this new interface, DMABUF objects (externally created) can be attached to a IIO buffer, and subsequently used for data transfer. A userspace application can then use this interface to share DMABUF objects between several interfaces, allowing it to transfer data in a zero-copy fashion, for instance between IIO and the USB stack. The userspace application can also memory-map the DMABUF objects, and access the sample data directly. The advantage of doing this vs. the read() interface is that it avoids an extra copy of the data between the kernel and userspace. This is particularly userful for high-speed devices which produce several megabytes or even gigabytes of data per second. As part of the interface, 3 new IOCTLs have been added: IIO_BUFFER_DMABUF_ATTACH_IOCTL(int fd): Attach the DMABUF object identified by the given file descriptor to the buffer. IIO_BUFFER_DMABUF_DETACH_IOCTL(int fd): Detach the DMABUF object identified by the given file descriptor from the buffer. Note that closing the IIO buffer's file descriptor will automatically detach all previously attached DMABUF objects. IIO_BUFFER_DMABUF_ENQUEUE_IOCTL(struct iio_dmabuf *): Request a data transfer to/from the given DMABUF object. Its file descriptor, as well as the transfer size and flags are provided in the "iio_dmabuf" structure. These three IOCTLs have to be performed on the IIO buffer's file descriptor, obtained using the IIO_BUFFER_GET_FD_IOCTL() ioctl. Signed-off-by: Paul Cercueil Co-developed-by: Nuno Sa Signed-off-by: Nuno Sa Link: https://patch.msgid.link/20240620122726.41232-4-paul@crapouillou.net Signed-off-by: Jonathan Cameron

iio: Don't silently expect attribute types

2022-11-23T19:44:04+00:00

The iio_triggered_buffer_setup_ext() and the devm_iio_kfifo_buffer_setup_ext() were changed by commit 15097c7a1adc ("iio: buffer: wrap all buffer attributes into iio_dev_attr") to silently expect that all attributes given in buffer_attrs array are device-attributes. This expectation was not forced by the API - and some drivers did register attributes created by IIO_CONST_ATTR(). When using IIO_CONST_ATTRs the added attribute "wrapping" does not copy the pointer to stored string constant and when the sysfs file is read the kernel will access to invalid location. Change the function signatures to expect an array of iio_dev_attrs to avoid similar errors in the future. Merge conflict resolved whilst applying due to patch crossing with two new drivers (kx022a accelerometer and ad4130 ADC). Signed-off-by: Matti Vaittinen Tested-by: Claudiu Beznea Link: https://lore.kernel.org/r/63f54787a684eb1232f1c5d275a09c786987fe4a.1664782676.git.mazziesaccount@gmail.com Signed-off-by: Jonathan Cameron

iio: Add output buffer support

2021-10-19T07:30:44+00:00

Currently IIO only supports buffer mode for capture devices like ADCs. Add support for buffered mode for output devices like DACs. The output buffer implementation is analogous to the input buffer implementation. Instead of using read() to get data from the buffer write() is used to copy data into the buffer. poll() with POLLOUT will wakeup if there is space available. Drivers can remove data from a buffer using iio_pop_from_buffer(), the function can e.g. called from a trigger handler to write the data to hardware. A buffer can only be either a output buffer or an input, but not both. So, for a device that has an ADC and DAC path, this will mean 2 IIO buffers (one for each direction). The direction of the buffer is decided by the new direction field of the iio_buffer struct and should be set after allocating and before registering it. Co-developed-by: Lars-Peter Clausen Signed-off-by: Lars-Peter Clausen Co-developed-by: Alexandru Ardelean Signed-off-by: Alexandru Ardelean Signed-off-by: Mihail Chindris Link: https://lore.kernel.org/r/20211007080035.2531-2-mihail.chindris@analog.com Signed-off-by: Jonathan Cameron

iio: buffer: add ioctl() to support opening extra buffers for IIO device

2021-03-11T20:47:05+00:00

With this change, an ioctl() call is added to open a character device for a buffer. The ioctl() number is 'i' 0x91, which follows the IIO_GET_EVENT_FD_IOCTL ioctl. The ioctl() will return an FD for the requested buffer index. The indexes are the same from the /sys/iio/devices/iio:deviceX/bufferY (i.e. the Y variable). Since there doesn't seem to be a sane way to return the FD for buffer0 to be the same FD for the /dev/iio:deviceX, this ioctl() will return another FD for buffer0 (or the first buffer). This duplicate FD will be able to access the same buffer object (for buffer0) as accessing directly the /dev/iio:deviceX chardev. Also, there is no IIO_BUFFER_GET_BUFFER_COUNT ioctl() implemented, as the index for each buffer (and the count) can be deduced from the '/sys/bus/iio/devices/iio:deviceX/bufferY' folders (i.e the number of bufferY folders). Used following C code to test this: ------------------------------------------------------------------- #include #include #include #include #include #define IIO_BUFFER_GET_FD_IOCTL _IOWR('i', 0x91, int) int main(int argc, char *argv[]) { int fd; int fd1; int ret; if ((fd = open("/dev/iio:device0", O_RDWR))<0) { fprintf(stderr, "Error open() %d errno %d\n",fd, errno); return -1; } fprintf(stderr, "Using FD %d\n", fd); fd1 = atoi(argv[1]); ret = ioctl(fd, IIO_BUFFER_GET_FD_IOCTL, &fd1); if (ret < 0) { fprintf(stderr, "Error for buffer %d ioctl() %d errno %d\n", fd1, ret, errno); close(fd); return -1; } fprintf(stderr, "Got FD %d\n", fd1); close(fd1); close(fd); return 0; } ------------------------------------------------------------------- Results are: ------------------------------------------------------------------- # ./test 0 Using FD 3 Got FD 4 # ./test 1 Using FD 3 Got FD 4 # ./test 2 Using FD 3 Got FD 4 # ./test 3 Using FD 3 Got FD 4 # ls /sys/bus/iio/devices/iio\:device0 buffer buffer0 buffer1 buffer2 buffer3 dev in_voltage_sampling_frequency in_voltage_scale in_voltage_scale_available name of_node power scan_elements subsystem uevent ------------------------------------------------------------------- iio:device0 has some fake kfifo buffers attached to an IIO device. Signed-off-by: Alexandru Ardelean Link: https://lore.kernel.org/r/20210215104043.91251-21-alexandru.ardelean@analog.com Signed-off-by: Jonathan Cameron

iio: buffer: introduce support for attaching more IIO buffers

2021-03-11T20:47:05+00:00

With this change, calling iio_device_attach_buffer() will actually attach more buffers. Right now this doesn't do any validation of whether a buffer is attached twice; maybe that can be added later (if needed). Attaching a buffer more than once should yield noticeably bad results. The first buffer is the legacy buffer, so a reference is kept to it. At this point, accessing the data for the extra buffers (that are added after the first one) isn't possible yet. The iio_device_attach_buffer() is also changed to return an error code, which for now is -ENOMEM if the array could not be realloc-ed for more buffers. To adapt to this new change iio_device_attach_buffer() is called last in all place where it's called. The realloc failure is a bit difficult to handle during un-managed calls when unwinding, so it's better to have this as the last error in the setup_buffer calls. At this point, no driver should call iio_device_attach_buffer() directly, it should call one of the {devm_}iio_triggered_buffer_setup() or devm_iio_kfifo_buffer_setup() or devm_iio_dmaengine_buffer_setup() functions. This makes iio_device_attach_buffer() a bit easier to handle. Signed-off-by: Alexandru Ardelean Link: https://lore.kernel.org/r/20210215104043.91251-20-alexandru.ardelean@analog.com Signed-off-by: Jonathan Cameron

iio: buffer: wrap all buffer attributes into iio_dev_attr

2021-03-11T20:47:04+00:00

This change wraps all buffer attributes into iio_dev_attr objects, and assigns a reference to the IIO buffer they belong to. With the addition of multiple IIO buffers per one IIO device, we need a way to know which IIO buffer is being enabled/disabled/controlled. We know that all buffer attributes are device_attributes. So we can wrap them with a iio_dev_attr types. In the iio_dev_attr type, we can also hold a reference to an IIO buffer. So, we end up being able to allocate wrapped attributes for all buffer attributes (even the one from other drivers). The neat part with this mechanism, is that we don't need to add any extra cleanup, because these attributes are being added to a dynamic list that will get cleaned up via iio_free_chan_devattr_list(). With this change, the 'buffer->scan_el_dev_attr_list' list is being renamed to 'buffer->buffer_attr_list', effectively merging (or finalizing the merge) of the buffer/ & scan_elements/ attributes internally. Accessing these new buffer attributes can now be done via 'to_iio_dev_attr(attr)->buffer' inside the show/store handlers. Signed-off-by: Alexandru Ardelean Link: https://lore.kernel.org/r/20210215104043.91251-15-alexandru.ardelean@analog.com Signed-off-by: Jonathan Cameron

iio: core: merge buffer/ & scan_elements/ attributes

2021-03-11T20:47:03+00:00

With this change, we create a new directory for the IIO device called buffer0, under which both the old buffer/ and scan_elements/ are stored. This is done to simplify the addition of multiple IIO buffers per IIO device. Otherwise we would need to add a bufferX/ and scan_elementsX/ directory for each IIO buffer. With the current way of storing attribute groups, we can't have directories stored under each other (i.e. scan_elements/ under buffer/), so the best approach moving forward is to merge their attributes. The old/legacy buffer/ & scan_elements/ groups are not stored on the opaque IIO device object. This way the IIO buffer can have just a single attribute_group object, saving a bit of memory when adding multiple IIO buffers. Signed-off-by: Alexandru Ardelean Link: https://lore.kernel.org/r/20210215104043.91251-13-alexandru.ardelean@analog.com Signed-off-by: Jonathan Cameron