Synchronous acquisition API

Data Structures
struct	a4l_instruction
	Structure describing the synchronous instruction. More...
struct	a4l_instruction_list
	Structure describing the list of synchronous instructions. More...

Macros
#define	A4L_INSN_WAIT_MAX   100000
	Maximal wait duration.

Functions
int	a4l_snd_insnlist (a4l_desc_t *dsc, a4l_insnlst_t *arg)
	Perform a list of synchronous acquisition misc operations.
int	a4l_snd_insn (a4l_desc_t *dsc, a4l_insn_t *arg)
	Perform a synchronous acquisition misc operation.

Instruction type
Flags to define the type of instruction
#define	A4L_INSN_READ   (0 | A4L_INSN_MASK_READ)
	Read instruction.
#define	A4L_INSN_WRITE   (1 | A4L_INSN_MASK_WRITE)
	Write instruction.
#define	A4L_INSN_BITS
	"Bits" instruction
#define	A4L_INSN_CONFIG
	Configuration instruction.
#define	A4L_INSN_GTOD
	Get time instruction.
#define	A4L_INSN_WAIT
	Wait instruction.
#define	A4L_INSN_INTTRIG
	Trigger instruction (to start asynchronous acquisition)

Detailed Description

Function Documentation

a4l_snd_insn()

int a4l_snd_insn	(	a4l_desc_t *	dsc,
		a4l_insn_t *	arg
	)

Perform a synchronous acquisition misc operation.

The function a4l_snd_insn() triggers a synchronous acquisition.

Parameters

[in]	dsc	Device descriptor filled by a4l_open() (and optionally a4l_fill_desc())
[in]	arg	Instruction structure

Returns

0 on success. Otherwise:

• -EINVAL is returned if some argument is missing or wrong (Please, type "dmesg" for more info)
• -EFAULT is returned if a user <-> kernel transfer went wrong
• -ENOMEM is returned if the system is out of memory

References a4l_descriptor::fd.

Referenced by a4l_config_subd(), a4l_sync_dio(), a4l_sync_read(), and a4l_sync_write().

a4l_snd_insnlist()

int a4l_snd_insnlist	(	a4l_desc_t *	dsc,
		a4l_insnlst_t *	arg
	)

Perform a list of synchronous acquisition misc operations.

The function a4l_snd_insnlist() is able to send many synchronous instructions on a various set of subdevices, channels, etc.

Parameters

[in]	dsc	Device descriptor filled by a4l_open() (and optionally a4l_fill_desc())
[in]	arg	Instructions list structure

Returns

0 on success. Otherwise:

• -EINVAL is returned if some argument is missing or wrong (Please, type "dmesg" for more info)
• -EFAULT is returned if a user <-> kernel transfer went wrong
• -ENOMEM is returned if the system is out of memory

References a4l_descriptor::fd.

Referenced by a4l_sync_read(), and a4l_sync_write().