kernel/linux.git/include/linux/iio/buffer_impl.h, branch v6.6.132

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

iio: buffer: remove 'scan_el_attrs' attribute group from buffer struct

2020-04-19T15:56:34+00:00

This field doesn't seem used. It seems that only 'buffer->attrs' was ever used to extend sysfs attributes for an IIO buffer. Moving forward, it may not make sense to keep it. This patch removes the field and it's initialization code. Since we want to rework IIO buffer, to be able to add more buffers per IIO device, we will merge [somehow] the 'buffer' & 'scan_elements' groups, and we will continue to add the attributes to the 'buffer' group. Removing it here, will also make the rework here a bit smaller, since this code will not be present. Signed-off-by: Alexandru Ardelean Signed-off-by: Jonathan Cameron

iio: buffer: drop left-over 'stufftoread' field

2020-04-19T15:56:21+00:00

This seems like a left-over from a7348347ba8a4 ("staging:iio: Add polling of events on the ring access chrdev."). Then it was moved into the sca3000 driver around 9dd4694dafbd8 ("iio: staging: sca3000: hide stufftoread logic"), and that one seemed to be the only user of this. Then it eventually was no longer used after 152a6a884ae1 ("staging:iio:accel:sca3000 move to hybrid hard / soft buffer design.") Signed-off-by: Alexandru Ardelean Signed-off-by: Jonathan Cameron

iio: buffer: rename 'read_first_n' callback to 'read'

2019-12-29T15:20:09+00:00

It is implied that 'read' will read the first n bytes and not e.g. bytes only from offsets within the buffer that are a prime number. This change is non-functional, mostly just a rename. A secondary intent with this patch is to make room later to add a write callback. Signed-off-by: Lars-Peter Clausen Signed-off-by: Alexandru Ardelean Signed-off-by: Jonathan Cameron

iio:buffer: make length types match kfifo types

2018-03-30T10:14:32+00:00

Currently, we use int for buffer length and bytes_per_datum. However, kfifo uses unsigned int for length and size_t for element size. We need to make sure these matches or we will have bugs related to overflow (in the range between INT_MAX and UINT_MAX for length, for example). In addition, set_bytes_per_datum uses size_t while bytes_per_datum is an int, which would cause bugs for large values of bytes_per_datum. Change buffer length to use unsigned int and bytes_per_datum to use size_t. Signed-off-by: Martin Kelly Cc: Signed-off-by: Jonathan Cameron