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    SubjectRe: [PATCH: 2.6.11-rc5] i2c chips: add adt7461 support to lm90 driver
    Hi James,

    > > Add ADT7461 (temperature sensor) support to LM90 driver.
    > >
    > > Signed-off-by: James Chapman <jchapman@katalix.com>
    >
    > Applied, thanks.

    I had Greg drop this patch because it doesn't seem to be correct to me.
    The patch assumes that the ADT7461 is 100% compatible with the ADM1032.
    The datasheets mentions that, but only in the default confiuration of
    the chip. If I read it correctly, the ADT7461 can also be switched to an
    extended temperature range mode, where the register formats are
    different. In this mode, the chip is NOT compatible with the ADM1032 and
    needs specific handling.

    I wonder how the limits are affected by the extended mode. The datasheet
    doesn't give much details about this. I would assume that they are
    affected too though, or it wouldn't make much sense.

    I also see that the ADT7461 datasheet explicitely says that temperature
    measurements below 0 return 0 and over 127 return 127, in compatibility
    mode. Then we probably should not allow limits to be set outside of this
    range, as it might fool the user into thinking that the device can
    actually measure this. The ADM1032 datasheet isn't as clear on the
    topic, so I'm not sure what should be done for this one.

    Please modify your patch so that it works properly for both modes. I do
    not request that you implement mode change, nor even that you support
    extended range mode if you don't need it. But I want you to ensure that
    the driver will behave properly on an ADT7461 found in this
    non-compatible range. This might be as easy as to not recognize the chip
    as supported if found in that mode, providing you don't care about the
    extended range.

    I would also like you do update the documentation located on top of the
    lm90 driver source file. I listed all supported chips with links to
    datasheet and some additional per-chip information. The ADT7461
    definitely needs something similar. Then please update Kconfig to
    mention the new chip.

    I would also appreciate a patch to lm_sensors' sensors-detect script for
    the ADT7461, and possibly a patch for libsensors and sensors as well,
    unless you are not interested in these (in which case you would need to
    explicitely mention in Kconfig that the ADT7461 has no user-space
    support at the moment).

    Thanks,
    --
    Jean Delvare
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