[PATCH] I2C: Clarify the usage of i2c-dev.h

Upon suggestion by Nils Roeder, here is an update to the i2c
documentation to clarify which header files user-space applications
relying on the i2c-dev interface should include.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Jean Delvare 2005-06-25 11:37:40 +02:00 committed by Greg Kroah-Hartman
parent a68e2f4895
commit 1d772e2587
1 changed files with 7 additions and 4 deletions

View File

@ -14,9 +14,12 @@ C example
=========
So let's say you want to access an i2c adapter from a C program. The
first thing to do is `#include <linux/i2c.h>" and "#include <linux/i2c-dev.h>.
Yes, I know, you should never include kernel header files, but until glibc
knows about i2c, there is not much choice.
first thing to do is "#include <linux/i2c-dev.h>". Please note that
there are two files named "i2c-dev.h" out there, one is distributed
with the Linux kernel and is meant to be included from kernel
driver code, the other one is distributed with lm_sensors and is
meant to be included from user-space programs. You obviously want
the second one here.
Now, you have to decide which adapter you want to access. You should
inspect /sys/class/i2c-dev/ to decide this. Adapter numbers are assigned
@ -78,7 +81,7 @@ Full interface description
==========================
The following IOCTLs are defined and fully supported
(see also i2c-dev.h and i2c.h):
(see also i2c-dev.h):
ioctl(file,I2C_SLAVE,long addr)
Change slave address. The address is passed in the 7 lower bits of the