[Bug 149] New: lm4857 not i2c address compliant

bugzilla-daemon at bugzilla.openmoko.org bugzilla-daemon at bugzilla.openmoko.org
Mon Jan 22 10:59:10 CET 2007


           Summary: lm4857 not i2c address compliant
           Product: OpenMoko
           Version: current svn head
          Platform: Neo1973
        OS/Version: Linux
            Status: NEW
          Severity: major
          Priority: P2
         Component: kernel
        AssignedTo: laforge at openmoko.org
        ReportedBy: graeme.gregory at wolfsonmicro.com

While doing the driver for the wm8753 I needed to turn on the lm5857 amp chip
which required talking to it through I2C bus.

I have found the two addresses the chip can use (0x7C, 0x7D) are not i2c
compliant as they are in the reserved range according to the i2c spec. This
means the i2c driver in the kernel rejects this address when trying to create an
i2c connection to this chip.

The code at 652-657 in i2c-core.c is responsible for this checking.

	/* Make sure the address is valid */
	if (addr < 0x03 || addr > 0x77) {
		dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
		return -EINVAL;

I have had to comment out this check in order to make use of this chip.

I think this causes problems for neo1973 audio support to enter mainline ASoC as
I guess kernel core will never accept this change.

------- You are receiving this mail because: -------
You reported the bug, or are watching the reporter.

More information about the buglog mailing list