Date: Fri, 13 Nov 1998 00:17:48 +0000 From: Nicolas Souchu <nsouch@teaser.fr> To: Ron Klinkien <root@zappa.demon.nl> Cc: freebsd-hackers@FreeBSD.ORG, Marc Bouget <mbouget@club-internet.fr> Subject: Re: i2c projects Message-ID: <19981113001748.14820@breizh.prism.uvsq.fr> In-Reply-To: <19981109211837.A4702@zappa.demon.nl>; from Ron Klinkien on Mon, Nov 09, 1998 at 09:18:37PM %2B0100 References: <19981109211837.A4702@zappa.demon.nl>
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On Mon, Nov 09, 1998 at 09:18:37PM +0100, Ron Klinkien wrote:
>
>
>
>Does anyone have any pointers/src code on how to use
>the i2c drivers with FreeBSD?
>
>I want to build a weather station / home automation project using a FreeBSD running pc,
>and the i2c bus on my video capture card.
Cool. FreeBSD is the good choice.
>
>The i2c driver src and man pages don't give me enough info..
>
>Furthermore I have compiled a kernel with i2c support
>but there are no ii* devices in /dev, and not in MAKEDEV too.
Yes, this is lacking. Waiting for a MAKEDEV update, try:
mknod iic0 c 105 0
mknod smb0 c 106 0
and so on, replacing 0 by 1,2...
>
>Which major/minor numbers to use etc...?
You would have found them in the related drivers:
/sys/dev/iicbus/iic.c
/sys/dev/smbus/smb.c
>
>Regards,
>Ron.
>
iicbus is a powerfull framework that should bring you all what you need with
only few indications about how to use it.
First of all, which video card do you have? A bt848 based card? Perfect,
the drivers are ready to work.
As described in the bktr man page, you'll need in addition to 'device bktr0'
in your /sys/i386/conf/MACHINE file:
controller iicbus0
controller iicbb0
device iic0 at iicbus?
controller smbus0
device smb0 at smbus?
--
Now, you want to write user/kernel code? If you need kernel code which is
uncertain, /sys/dev/iicbus/iic.c will be a good start. Read, copy and
modify it as needed.
For userland code, you'll have to add your devices in /sys/dev/iicbus/iic.c:
{ "iic", IICBUS_DEVICE_CLASS, "MY DEVICE IDENTIFIER", MY_DEVICE_ADDRESS},
like this (for each device on you I2C bus):
/*
* list of known devices
*/
struct iicbus_device iicbus_children[] = {
{ "iicsmb", IICBUS_DRIVER_CLASS, "I2C to SMB bridge" },
{ "iic", IICBUS_DEVICE_CLASS, "MY DEVICE IDENTIFIER", MY_DEVICE_ADDRESS},
{ "iic", IICBUS_DEVICE_CLASS, "PCF8574 I2C to 8 bits parallel i/o", 64},
{ "iic", IICBUS_DEVICE_CLASS, "PCF8584 as slave", PCF_MASTER_ADDRESS },
{ "ic", IICBUS_DEVICE_CLASS, "network interface", PCF_MASTER_ADDRESS },
#if 0
{ "iic", IICBUS_DRIVER_CLASS, "General Call", I2C_GENERAL_CALL },
#endif
{ NULL, 0 }
};
--
Then see /usr/include/machine/iic.h to have the ioctls on /dev/iic?
They are implemented by /sys/dev/iicbus/iic.c
Nicolas.
--
nsouch@teaser.fr / nsouch@freebsd.org
FreeBSD - Turning PCs into workstations - http://www.FreeBSD.org
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