From: "Marc LeFevre" <lfx@cypress•com>
To: <linuxppc-embedded@ozlabs•org>
Subject: RTC woes
Date: Tue, 19 Feb 2008 09:34:52 -0700 [thread overview]
Message-ID: <06cb01c87315$5dad6010$f30213ac@isd.cypress.com> (raw)
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Hi:
I'm new to the list. I have an e500-based embedded Linux system running a
2.6.22 kernel. I have a PCF8563T i2c based RTC chip attached to the PPC i2c
bus. In my kernel config file I have selected CONFIG_RTC_INTF_DEV=y and
CONFIG_RTC_DRV_PCF8563=y. I do a mknod for /dev/rtc as c 10 135 (standard
Linux) and link /dev/rtc0 to it.
When I boot, get the following message:
drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
and, of course I cannot access /dev/rtc after booting. I can, however, talk
to the rtc if I use /dev/i2c and a generic i2c read and write utility.
When I look in /proc/devices, I see that rtc has taken major number 254
which puzzles me. RTC should not need a dynamic major number, right? I have
perused the drivers in linux/drivers/rtc and don't find any of them calling
register_chrdev() to get a dynamic major number. So here are my questions:
1) Shouldn't rtc automagically use major/minor 10/135?
2) How can I find where in the source it asks for a dynamic major
number?
3) Does the PPC have some quirks regarding i2c operation that are at
the root of this problem?
BYW, I tried making the rtc device file as c 254 0 to match what's in
/proc/devices and that gives me the same bejavior.
Thanks in advance for any help you can offer.
Marc
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next reply other threads:[~2008-02-19 16:40 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-19 16:34 Marc LeFevre [this message]
2008-02-19 22:30 ` RTC woes Clemens Koller
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