Xenomai  3.0.8
Subdevice management services

Subdevice declaration in a driver. More...

Collaboration diagram for Subdevice management services:

Functions

struct a4l_subdevicea4l_alloc_subd (int sizeof_priv, void(*setup)(struct a4l_subdevice *))
 Allocate a subdevice descriptor. More...
 
int a4l_add_subd (struct a4l_device *dev, struct a4l_subdevice *subd)
 Add a subdevice to the driver descriptor. More...
 
struct a4l_subdevicea4l_get_subd (struct a4l_device *dev, int idx)
 Get a pointer to the subdevice descriptor referenced by its registration index. More...
 

Subdevices types

Flags to define the subdevice type

#define A4L_SUBD_UNUSED   (A4L_SUBD_MASK_SPECIAL|0x1)
 Unused subdevice.
 
#define A4L_SUBD_AI   (A4L_SUBD_MASK_READ|0x2)
 Analog input subdevice.
 
#define A4L_SUBD_AO   (A4L_SUBD_MASK_WRITE|0x4)
 Analog output subdevice.
 
#define A4L_SUBD_DI   (A4L_SUBD_MASK_READ|0x8)
 Digital input subdevice.
 
#define A4L_SUBD_DO   (A4L_SUBD_MASK_WRITE|0x10)
 Digital output subdevice.
 
#define A4L_SUBD_DIO   (A4L_SUBD_MASK_SPECIAL|0x20)
 Digital input/output subdevice.
 
#define A4L_SUBD_COUNTER   (A4L_SUBD_MASK_SPECIAL|0x40)
 Counter subdevice.
 
#define A4L_SUBD_TIMER   (A4L_SUBD_MASK_SPECIAL|0x80)
 Timer subdevice.
 
#define A4L_SUBD_MEMORY   (A4L_SUBD_MASK_SPECIAL|0x100)
 Memory, EEPROM, DPRAM.
 
#define A4L_SUBD_CALIB   (A4L_SUBD_MASK_SPECIAL|0x200)
 Calibration subdevice DACs.
 
#define A4L_SUBD_PROC   (A4L_SUBD_MASK_SPECIAL|0x400)
 Processor, DSP.
 
#define A4L_SUBD_SERIAL   (A4L_SUBD_MASK_SPECIAL|0x800)
 Serial IO subdevice.
 
#define A4L_SUBD_TYPES
 Mask which gathers all the types.
 

Subdevice features

Flags to define the subdevice's capabilities

#define A4L_SUBD_CMD   0x1000
 The subdevice can handle command (i.e it can perform asynchronous acquisition)
 
#define A4L_SUBD_MMAP   0x8000
 The subdevice support mmap operations (technically, any driver can do it; however, the developer might want that his driver must be accessed through read / write.
 

Subdevice status

Flags to define the subdevice's status

#define A4L_SUBD_BUSY_NR   0
 The subdevice is busy, a synchronous or an asynchronous acquisition is occuring.
 
#define A4L_SUBD_BUSY   (1 << A4L_SUBD_BUSY_NR)
 The subdevice is busy, a synchronous or an asynchronous acquisition is occuring.
 
#define A4L_SUBD_CLEAN_NR   1
 The subdevice is about to be cleaned in the middle of the detach procedure.
 
#define A4L_SUBD_CLEAN   (1 << A4L_SUBD_CLEAN_NR)
 The subdevice is busy, a synchronous or an asynchronous acquisition is occuring.
 

Detailed Description

Subdevice declaration in a driver.

The subdevice structure is the most complex one in the Analogy driver layer. It contains some description fields to fill and some callbacks to declare.

The description fields are:

The functions callbakcs are:

Once the subdevice is filled, it must be inserted into the driver structure thanks to a4l_add_subd().

Function Documentation

◆ a4l_add_subd()

int a4l_add_subd ( struct a4l_device *  dev,
struct a4l_subdevice subd 
)

Add a subdevice to the driver descriptor.

Once the driver descriptor structure is initialized, the function a4l_add_subd() must be used so to add some subdevices to the driver.

Parameters
[in]devDevice descriptor structure
[in]subdSubdevice descriptor structure
Returns
the index with which the subdevice has been registered, in case of error a negative error code is returned.

References a4l_subdevice::dev, a4l_subdevice::idx, and a4l_subdevice::list.

◆ a4l_alloc_subd()

struct a4l_subdevice* a4l_alloc_subd ( int  sizeof_priv,
void(*)(struct a4l_subdevice *)  setup 
)

Allocate a subdevice descriptor.

This is a helper function so as to get a suitable subdevice descriptor

Parameters
[in]sizeof_privSize of the subdevice's private data
[in]setupSetup function to be called after the allocation
Returns
the index with which the subdevice has been registered, in case of error a negative error code is returned.

References rtdm_malloc().

◆ a4l_get_subd()

struct a4l_subdevice* a4l_get_subd ( struct a4l_device *  dev,
int  idx 
)

Get a pointer to the subdevice descriptor referenced by its registration index.

This function is scarcely useful as all the drivers callbacks get the related subdevice descriptor as first argument. This function is not optimized, it goes through a linked list to get the proper pointer. So it must not be used in real-time context but at initialization / cleanup time (attach / detach).

Parameters
[in]devDevice descriptor structure
[in]idxSubdevice index
Returns
0 on success, otherwise negative error code.