Date: Mon, 24 Mar 2008 16:00:03 +0000 From: Bruce M Simpson <bms@incunabulum.net> To: nsouch@FreeBSD.org, FreeBSD stable <freebsd-stable@freebsd.org> Subject: lpbb broken in 6.x? Message-ID: <47E7D003.3070009@incunabulum.net>
next in thread | raw e-mail | index | archive | help
Hi,
Just for giggles, I decided to solder up the circuit in lpbb(4) and try
to use it to talk to a 24LC64 EEPROM with its i2c address set to 0.
(Yes, I am using 74LS05s specifically for this circuit.)
Imagine my surprise and dismay, when I try to test out the i2c bus using
this tool:
http://www.ricin.com/freebsd/kbtv/kbtv-1.1.3/saa/saa/support/scan_i2c.c
...and keep seeing this on the console, presumably whenever scan_i2c
issues an iic(4) ioctl:
lpbb0: can't allocate ppbus
I made sure that no other devices were attached to ppbus0. Voltages on
the port and the bus looked sane... SCL and SDA stable below 0.1V,
nothing floating, good solid +5V on the supply rail using a 7805
regulator on a 9V battery to avoid any nasty current surprises -- I
haven't fried my laptop's LPT port.
Initially I had ppi loaded as well, I booted a clean kernel and loaded
lpbb from the loader:
Mar 24 15:40:39 empiric kernel: lpbb0: <Parallel I2C bit-banging
interface> on ppbus0
Mar 24 15:40:39 empiric kernel: iicbb0: <I2C bit-banging driver> on lpbb0
Mar 24 15:40:39 empiric kernel: iicbus0: <Philips I2C bus> on iicbb0
master-only
Mar 24 15:41:10 empiric kernel: iic0: <I2C generic I/O> on iicbus0
Mar 24 15:41:10 empiric kernel: iic1: <I2C generic I/O> on iicbus0
Not sure why iic attaches twice to the iicbus created by lpbb.
However, I still got the same message when I re-ran scan_i2c:
Mar 24 15:41:19 empiric kernel: lpbb0: can't allocate ppbus
Mar 24 15:41:55 empiric last message repeated 1020 times
There are real uses for this code, so I'm wondering, what's wrong with lpbb?
Does lpbb explicitly require hints to be told where to attach?
IMO it shouldn't, it already seems to attach to the first ppbus instance
in the system.
If I get free time otherwise, I'll try to investigate further.
cheers
BMS
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?47E7D003.3070009>