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path: root/drivers/iio/industrialio-buffer.c
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* iio: Add support for blocking IO on buffersLars-Peter Clausen2013-12-031-1/+22
| | | | | | | | | | Currently the IIO buffer interface only allows non-blocking reads. This patch adds support for blocking IO. In blocking mode the thread will go to sleep if no data is available and will wait for the buffer implementation to signal that new data is available by waking up the buffers waitqueue. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* iio: Add data_available callback for buffersLars-Peter Clausen2013-12-031-1/+9
| | | | | | | | | | | | | This patch adds a new data_available() callback to the iio_buffer_access_funcs struct. The callback is used to indicate whether data is available in the buffer for reading. It is meant to replace the stufftoread flag from the iio_buffer struct. The reasoning for this is that the buffer implementation usually can determine whether data is available rather easily based on its state, on the other hand it can be rather tricky to update the stufftoread flag in a race free way. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* Merge 3.12-rc6 into staging-next.Greg Kroah-Hartman2013-10-191-0/+3
|\ | | | | | | | | | | We want these fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * iio:buffer: Free active scan mask in iio_disable_all_buffers()Lars-Peter Clausen2013-10-151-0/+3
| | | | | | | | | | | | | | | | | | | | Usually the active scan mask is freed in __iio_update_buffers() when the buffer is disabled. But when the device is still sampling when it is removed we'll end up disabling the buffers in iio_disable_all_buffers(). So we also need to free the active scan mask here, otherwise it will be leaked. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* | iio: Remove unused iio_sw_buffer_preenable()Lars-Peter Clausen2013-10-161-18/+0
| | | | | | | | | | | | | | | | | | The functionality implemented by iio_sw_buffer_preenable() is now done directly in the IIO core and previous users of iio_sw_buffer_preenable() have all been updated to not use it anymore. It is unused now and can be remove. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* | iio: Update buffer's bytes per datum after updating the scan maskLars-Peter Clausen2013-10-161-1/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently a IIO device driver needs to make sure to update the buffer's bytes per datum after the scan mask has changed. This is usually done in the preenable callback by invoking iio_sw_buffer_preenable(). This is something that needs to be done and is done for virtually all devices which support buffers (we currently have only one exception). Also this a bit of a layering violation since we have to call the buffer setup ops from the device setup ops. This requires the device driver to know about the internal requirements of the buffer (e.g. whether we need to call the set_bytes_per_datum) callback. And especially with in-kernel buffer consumers, which allows to attach arbitrary buffers to a device, this is something that the driver can't know. Moving this to the core allows us to drop the individual calls to iio_sw_buffer_preenable() from drivers. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Cc: Denis Ciocca <denis.ciocca@st.com> Cc: Marek Vasut <marex@denx.de> Cc: Zubair Lutfullah <zubair.lutfullah@gmail.com> Cc: Jacek Anaszewski <j.anaszewski@samsung.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* | iio:buffer: Ignore noop requests for iio_update_buffers()Lars-Peter Clausen2013-10-121-0/+14
| | | | | | | | | | | | | | | | | | Since the kernel now disables all buffers when a device is unregistered it might happen that a in-kernel consumer tries to disable that buffer again. So ignore requests where the buffer already is in the desired state. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* | iio: Add a helper to free a list of IIO device attributesLars-Peter Clausen2013-10-121-19/+2
| | | | | | | | | | | | | | | | | | | | | | We have the same code to free a IIO device attribute list in multiple place. This patch adds a new helper function to take care of this and replaces the custom instances with a call to the helper function. Note that we do not need to call list_del() for each of the list items since we will never look at any of the list items nor the list itself again. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* | iio:buffer: Add proper locking for iio_update_buffers()Lars-Peter Clausen2013-10-121-3/+26
| | | | | | | | | | | | | | | | | | | | We need to make sure that in-kernel users of iio_update_buffers() do not race against each other or against unregistration of the device. So we need to take both the mlock and the info_exist_lock when calling iio_update_buffers() from a in-kernel consumer. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* | iio: Wakeup poll and blocking reads when the device is unregisteredLars-Peter Clausen2013-10-121-0/+16
| | | | | | | | | | | | | | | | | | Once the device has been unregistered there won't be any new data no matter how long a userspace application waits, so we might as well wake them up and let them know. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* | iio: Return -ENODEV for file operations if the device has been unregisteredLars-Peter Clausen2013-10-121-0/+6
| | | | | | | | | | | | | | | | | | If the IIO device has been unregistered return -ENODEV for any further file operations like read() and ioctl(). This avoids userspace being able to grab new references to the device. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* | iio: Add reference counting for buffersLars-Peter Clausen2013-10-121-5/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since the buffer is accessed by userspace we can not just free the buffers memory once we are done with it in kernel space. There might still be open file descriptors and userspace still might be accessing the buffer. This patch adds support for reference counting to the IIO buffers. When a buffer is created and initialized its initial reference count is set to 1. Instead of freeing the memory of the buffer the buffer's _free() function will drop that reference again. But only after the last reference to the buffer has been dropped the buffer the buffer's memory will be freed. The IIO device will take a reference to its primary buffer. The patch adds a small helper function for this called iio_device_attach_buffer() which will get a reference to the buffer and assign the buffer to the IIO device. This function must be used instead of assigning the buffer to the device by hand. The reference is only dropped once the IIO device is freed and we can be sure that there are no more open file handles. A reference to a buffer will also be taken whenever the buffer is active to avoid the buffer being freed while data is still being send to it. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* | Merge 3.12-rc2 into staging-next.Greg Kroah-Hartman2013-09-251-2/+28
|\| | | | | | | | | | | | | | | This resolves the merge problem with two iio drivers that Stephen Rothwell pointed out. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * iio: Stop sampling when the device is removedLars-Peter Clausen2013-09-211-0/+19
| | | | | | | | | | | | | | | | Make sure to stop sampling when the device is removed, otherwise it will continue to sample forever. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
| * iio: Fix crash when scan_bytes is computed with active_scan_mask == NULLPeter Meerwald2013-09-211-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | if device has available_scan_masks set and the buffer is enabled without any scan_elements enabled, in a NULL pointer is dereferenced in iio_compute_scan_bytes() [ 18.993713] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 19.002593] pgd = debd4000 [ 19.005432] [00000000] *pgd=9ebc0831, *pte=00000000, *ppte=00000000 [ 19.012329] Internal error: Oops: 17 [#1] PREEMPT ARM [ 19.017639] Modules linked in: [ 19.020843] CPU: 0 Not tainted (3.9.11-00036-g75c888a-dirty #207) [ 19.027587] PC is at _find_first_bit_le+0xc/0x2c [ 19.032440] LR is at iio_compute_scan_bytes+0x2c/0xf4 [ 19.037719] pc : [<c021dc60>] lr : [<c03198d0>] psr: 200d0013 [ 19.037719] sp : debd9ed0 ip : 00000000 fp : 000802bc [ 19.049713] r10: 00000000 r9 : 00000000 r8 : deb67250 [ 19.055206] r7 : 00000000 r6 : 00000000 r5 : 00000000 r4 : deb67000 [ 19.062011] r3 : de96ec00 r2 : 00000000 r1 : 00000004 r0 : 00000000 [ 19.068847] Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user [ 19.076324] Control: 10c5387d Table: 9ebd4019 DAC: 00000015 problem is the rollback code in iio_update_buffers(), old_mask may be NULL (e.g. on first call) I'm not too confident about the fix; works for me... Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* | iio: Pass scan mask as unsigned longPeter Meerwald2013-09-211-2/+2
| | | | | | | | | | Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* | iio: Minor cleanups of industrialio-bufferPeter Meerwald2013-09-181-5/+8
| | | | | | | | | | | | | | | | adding one return value check fix one kerneldoc Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* | iio: iio_push_to_buffers(): Change type of 'data' to const void *Lars-Peter Clausen2013-09-151-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Change the type of the 'data' parameter for iio_push_to_buffers() from 'u8 *' to 'const void *'. Drivers typically use the correct type (e.g. __be16 *) for their data buffer. When passing the buffer to iio_push_to_buffers() it needs to be cast to 'u8 *' for the compiler to not complain (and also having to add __force if we want to keep sparse happy as well). Since the buffer implementation should not care about the data layout (except the size of one sample) using a void pointer is the correct thing to do. Also make it const as the buffer implementations are not supposed to modify it. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* | iio: refactor info mask and ext_info attribute creation.Jonathan Cameron2013-09-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce an enum to specify whether the attribute is separate or shared. Factor out the bitmap handling for loop into a separate function. Tidy up error handling and add a NULL assignment to squish a false positive warning from GCC. Change ext_info shared type from boolean to enum and update in all drivers. Signed-off-by: Jonathan Cameron <jic23@kernel.org> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
* | iio:buffer: Simplify iio_buffer_is_active()Lars-Peter Clausen2013-09-151-20/+11
|/ | | | | | | | | We can skip having to loop through all the device's buffers to see if a certain buffer is active, if we let the buffer's list head point to itself when the buffer is inactive. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* iio: buffer: cleanup messages in iio_update_buffers()Michał Mirosław2013-05-221-6/+4
| | | | | | | | 1. make messages grepable (in one line) 2. include returned errno in them Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* staging:iio: Add support for multiple buffersJonathan Cameron2012-11-101-117/+263
| | | | | | | | | Route all buffer writes through the demux. Addition or removal of a buffer results in tear down and setup of all the buffers for a given device. Signed-off-by: Jonathan Cameron <jic23@kernel.org> Tested-by: srinivas pandruvada <srinivas.pandruvada@intel.com>
* iio: Use strict_strtouint instead of kstrtoulLars-Peter Clausen2012-10-191-3/+3
| | | | | | | | | strict_strto* has been deprecated in favor of kstrto*. Use strict_strtouint respective strict_strtoint, since that is what the functions we pass the converted values to expect. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* iio: Drop timestamp parameter from buffer store_to callbackLars-Peter Clausen2012-09-081-3/+2
| | | | | | | | | Drop timestamp parameter from buffer store_to callback and subsequently from iio_push_to_buffer. The timestamp parameter is unused and it seems likely that it will stay unused in the future, so it should be safe to remove it. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* iio: whitespace cleanup and removal of semicolon after functionsPeter Meerwald2012-09-031-5/+5
| | | | | Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* Merge tag 'togreg-3.6a' of ↵Greg Kroah-Hartman2012-07-121-7/+36
|\ | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next IIO: One new driver and a couple of nice cleanups.
| * iio: Introduce iio_validate_scan_mask_onehotLars-Peter Clausen2012-07-091-0/+16
| | | | | | | | | | | | | | | | | | | | Add a helper function for validating a scan mask for devices where exactly one channel must be selected during sampling. This is a common case among devices which have scan mask restrictions so it makes sense to provide this function in the core. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
| * iio: Add callback to check whether a scan mask is validLars-Peter Clausen2012-07-091-7/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is useful for cases where the number of valid scan masks grows exponentially, but it is rather easy to check whether a mask is valid or not programmatically. An example of such a case is a device with multiple ADCs where each ADC has a upstream MUX, which allows to select from a number of physical channels. +-------+ +-------+ | | | | --- Channel 1 | ADC 1 |---| MUX 1 | --- ... | | | | --- Channel M +-------+ +-------+ . . . . . . . . . +-------+ +-------+ | | | | --- Channel M * N + 1 | ADC N |---| MUX N | --- ... | | | | --- Channel M * N + M +-------+ +-------+ The number of necessary scan masks for this case is (M+1)**N - 1, on the other hand it is easy to check whether subsets for each ADC of the scanmask have only one bit set. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* | iio: iio_buffer_register: Use correct channel when calculating masklengthLars-Peter Clausen2012-07-081-1/+1
|/ | | | | | | | | | The channel set assigned to the iio device is not necessarily the same has the channel set passed to iio_buffer_register. So to avoid possible complications always work with the channel set pass to iio_buffer_register and ignore the channel set assigned to the iio device. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
* iio: iio_buffer_register: Skip channels with negative scan indexLars-Peter Clausen2012-06-181-0/+3
| | | | | | | | | | | It is not always the case that all channels can be used in buffered mode. This patch allows channels, which can not be used in buffered mode, to set their scan index to a negative number, which will cause iio_buffer_register to ignore the channel. 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: buffer: Fix NULL pointer deref caused by empty scan maskLars-Peter Clausen2012-06-151-0/+4
| | | | | | | | | | | | | | | | iio_scan_mask_match() returns NULL if the passed in scan mask is empty. This will happen if no channel has been selected and buffer is enabled. iio_sw_buffer_preenable() will assign NULL to indio_dev->active_scan_mask in this case. As a result iio_update_demux() will cause a NULL pointer deref, because it expects active_scan_mask to be non-NULL. Since it does not make much sense to start data capture if there is no data to capture this patch updates the code to fail gracefully in iio_scan_mask_match() instead of crashing the kernel. 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: Use dev_to_iio_dev()Lars-Peter Clausen2012-05-141-8/+8
| | | | | | | | | Replace open-coded instances of getting a iio_dev struct from a device struct with dev_to_iio_dev(). 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: Move the core files to drivers/iioJonathan Cameron2012-04-251-0/+755
Take the core support + the kfifo buffer implentation out of staging. Whilst we are far from done in improving this subsystem it is now at a stage where the userspae interfaces (provided by the core) can be considered stable. Drivers will follow over a longer time scale. Signed-off-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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