core/thermometer/thermo_device.c File Reference

#include "sceptre.h"
#include "device.h"
#include "ds18b20.h"

Go to the source code of this file.

Functions
int	thermo_open (struct _reent *p_reent, const char *p_name, int flags, int mode)
_ssize_t	thermo_read (struct _reent *p_reent, int file, void *p_dst, size_t dst_size)
_ssize_t	thermo_write (struct _reent *p_reent, int file, const void *p_src, size_t src_size)
Variables
device_table_entry_t	thermo_device

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Detailed Description

Thermometer device driver.

Definition in file thermo_device.c.

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Function Documentation

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

Open function for the thermometer device driver.

This function gets called when you do something like this:

FILE *p_thermometer = fopen("/thermo/","rw");

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

FILE *p_thermometer = fopen("/thermo/alarm","rw");

will pass "alarm" 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:

A valid handle on success, -1 otherwise.

Definition at line 71 of file thermo_device.c.

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

Read function for the thermometer device driver.

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

uint8_t data[9]; fread(data,sizeof(uint8_t),9,p_thermometer);

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 105 of file thermo_device.c.

_ssize_t thermo_write	(	struct _reent *	p_reent,
		int	file,
		const void *	p_src,
		size_t	src_size
	)

Write function for the thermometer device driver.

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

uint32_t data = 0x12345678; fwrite(&data,sizeof(uint32_t),1,p_thermometer);

Parameters:

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

Returns:

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

Definition at line 131 of file thermo_device.c.

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Variable Documentation

device_table_entry_t thermo_device

Initial value:

{
  "thermo",             
  SCEPTRE_THERMOMETER,  
  thermo_open,          
  NULL,                 
  thermo_read,          
  thermo_write,         
  NULL,                 
  NULL                  
}

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

Definition at line 38 of file thermo_device.c.