core/accelerometer/accelero_device.c File Reference

#include "sceptre.h"
#include "device.h"
#include "accelero.h"
#include <stdlib.h>

Go to the source code of this file.

Functions
int	accelero_dev_open (struct _reent *p_reent, const char *p_name, int flags, int mode)
_ssize_t	accelero_dev_read (struct _reent *p_reent, int file, void *p_dst, size_t dst_size)
_ssize_t	accelero_dev_close (struct _reent *p_reent, int file)
Variables
device_table_entry_t	accelero_device

---

Detailed Description

Accelerometer device driver implementation.

Definition in file accelero_device.c.

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Function Documentation

_ssize_t accelero_dev_close	(	struct _reent *	p_reent,
		int	file
	)

Close function for the accelerometer device driver.

This function gets called when you do something like this after obtaining a valid FILE handle with fopen():

fclose(p_accelerometer);

Returns:

Always 0.

Definition at line 125 of file accelero_device.c.

int accelero_dev_open	(	struct _reent *	p_reent,
		const char *	p_name,
		int	flags,
		int	mode
	)

Open function for the accelerometer device driver.

This function gets called when you do something like this:

FILE *p_accelerometer = fopen("/accelero/","rw");

Note the forward slashes surrounding the "file" name. Everything that follows the string "/accelero/" is passed to this function in p_name, i.e.

FILE *p_accelerometer = fopen("/accelero/1000000","rw");

will pass "1000000" (adc clock frequency) in p_name to this function.

Parameters:

	p_reent	Pointer to a structure that will receive the return value.
	p_name	Pointer to the name of the file to open.
	flags	Flags.
	mode	Mode.

Returns:

Valid handle (never fails).

Definition at line 72 of file accelero_device.c.

_ssize_t accelero_dev_read	(	struct _reent *	p_reent,
		int	file,
		void *	p_dst,
		size_t	dst_size
	)

Read function for the accelerometer device driver.

This function gets called when you do something like this after obtaining a valid FILE handle with fopen():

float data[3]; fread(data,sizeof(float),3,p_accelerometer);

Parameters:

	p_reent	Pointer to a structure that will receive the return value.
	file	Handle of the file to read from.
	p_dst	Address to write the data to.
	dst_size	Number of bytes to read.

Returns:

The number of bytes read on success, -1 otherwise.

Definition at line 98 of file accelero_device.c.

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Variable Documentation

device_table_entry_t accelero_device

Initial value:

{
  "accelero",             
  SCEPTRE_ACCELEROMETER,  
  accelero_dev_open,      
  accelero_dev_close,     
  accelero_dev_read,      
  NULL,                   
  NULL,                   
  NULL                    
}

A pointer to this structure has to be registered in the device_table_list.

Definition at line 39 of file accelero_device.c.