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staging: comedi: comedidev.h: document struct comedi_device 

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ian Abbott 2015-09-21 18:52:50 +01:00 committed by Greg Kroah-Hartman
parent a3ed91f875
commit 9ac5b44fbe
1 changed files with 81 additions and 3 deletions
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84
drivers/staging/comedi/comedidev.h
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@ -287,6 +287,87 @@ struct comedi_driver {
int offset;
};
/**
* struct comedi_device - Working data for a COMEDI device
* @use_count: Number of open file objects.
* @driver: Low-level COMEDI driver attached to this COMEDI device.
* @pacer: Optional pointer to a dynamically allocated acquisition pacer
* control. It is freed automatically after the COMEDI device is
* detached from the low-level driver.
* @private: Optional pointer to private data allocated by the low-level
* driver. It is freed automatically after the COMEDI device is
* detached from the low-level driver.
* @class_dev: Sysfs comediX device.
* @minor: Minor device number of COMEDI char device (0-47).
* @detach_count: Counter incremented every time the COMEDI device is detached.
* Used for checking a previous attachment is still valid.
* @hw_dev: Optional pointer to the low-level hardware &struct device. It is
* required for automatically configured COMEDI devices and optional for
* COMEDI devices configured by the %COMEDI_DEVCONFIG ioctl, although
* the bus-specific COMEDI functions only work if it is set correctly.
* It is also passed to dma_alloc_coherent() for COMEDI subdevices that
* have their 'async_dma_dir' member set to something other than
* %DMA_NONE.
* @board_name: Pointer to a COMEDI board name or a COMEDI driver name. When
* the low-level driver's "attach" handler is called by the handler for
* the %COMEDI_DEVCONFIG ioctl, it either points to a matched board name
* string if the 'num_names' member of the &struct comedi_driver is
* non-zero, otherwise it points to the low-level driver name string.
* When the low-lever driver's "auto_attach" handler is called for an
* automatically configured COMEDI device, it points to the low-level
* driver name string. The low-level driver is free to change it in its
* "attach" or "auto_attach" handler if it wishes.
* @board_ptr: Optional pointer to private, read-only board type information in
* the low-level driver. If the 'num_names' member of the &struct
* comedi_driver is non-zero, the handler for the %COMEDI_DEVCONFIG ioctl
* will point it to a pointer to a matched board name string within the
* driver's private array of static, read-only board type information when
* calling the driver's "attach" handler. The low-level driver is free to
* change it.
* @attached: Flag indicating that the COMEDI device is attached to a low-level
* driver.
* @ioenabled: Flag used to indicate that a PCI device has been enabled and
* its regions requested.
* @spinlock: Generic spin-lock for use by the low-level driver.
* @mutex: Generic mutex for use by the COMEDI core module.
* @attach_lock: &struct rw_semaphore used to guard against the COMEDI device
* being detached while an operation is in progress. The down_write()
* operation is only allowed while @mutex is held and is used when
* changing @attached and @detach_count and calling the low-level driver's
* "detach" handler. The down_read() operation is generally used without
* holding @mutex.
* @refcount: &struct kref reference counter for freeing COMEDI device.
* @n_subdevices: Number of COMEDI subdevices allocated by the low-level
* driver for this device.
* @subdevices: Dynamically allocated array of COMEDI subdevices.
* @mmio: Optional pointer to a remapped MMIO region set by the low-level
* driver.
* @iobase: Optional base of an I/O port region requested by the low-level
* driver.
* @iolen: Length of I/O port region requested at @iobase.
* @irq: Optional IRQ number requested by the low-level driver.
* @read_subdev: Optional pointer to a default COMEDI subdevice operated on by
* the read() file operation. Set by the low-level driver.
* @write_subdev: Optional pointer to a default COMEDI subdevice operated on by
* the write() file operation. Set by the low-level driver.
* @async_queue: Storage for fasync_helper().
* @open: Optional pointer to a function set by the low-level driver to be
* called when @use_count changes from 0 to 1.
* @close: Optional pointer to a function set by the low-level driver to be
* called when @use_count changed from 1 to 0.
*
* This is the main control data structure for a COMEDI device (as far as the
* COMEDI core is concerned). There are two groups of COMEDI devices -
* "legacy" devices that are configured by the handler for the
* %COMEDI_DEVCONFIG ioctl, and automatically configured devices resulting
* from a call to comedi_auto_config() as a result of a bus driver probe in
* a low-level COMEDI driver. The "legacy" COMEDI devices are allocated
* during module initialization if the "comedi_num_legacy_minors" module
* parameter is non-zero and use minor device numbers from 0 to
* comedi_num_legacy_minors minus one. The automatically configured COMEDI
* devices are allocated on demand and use minor device numbers from
* comedi_num_legacy_minors to 47.
*/
struct comedi_device {
int use_count;
struct comedi_driver *driver;
@ -296,9 +377,6 @@ struct comedi_device {
struct device *class_dev;
int minor;
unsigned int detach_count;
/* hw_dev is passed to dma_alloc_coherent when allocating async buffers
* for subdevices that have async_dma_dir set to something other than
* DMA_NONE */
struct device *hw_dev;
const char *board_name;