• Peter Rosin's avatar
    hwmon: (jc42) optionally try to disable the SMBUS timeout · 68615eb0
    Peter Rosin authored
    With a nxp,se97 chip on an atmel sama5d31 board, the I2C adapter driver
    is not always capable of avoiding the 25-35 ms timeout as specified by
    the SMBUS protocol. This may cause silent corruption of the last bit of
    any transfer, e.g. a one is read instead of a zero if the sensor chip
    times out. This also affects the eeprom half of the nxp-se97 chip, where
    this silent corruption was originally noticed. Other I2C adapters probably
    suffer similar issues, e.g. bit-banging comes to mind as risky...
    The SMBUS register in the nxp chip is not a standard Jedec register, but
    it is not special to the nxp chips either, at least the atmel chips
    have the same mechanism. Therefore, do not special case this on the
    manufacturer, it is opt-in via the device property anyway.
    Cc: stable@vger.kernel.org # 4.9+
    Signed-off-by: default avatarPeter Rosin <peda@axentia.se>
    Acked-by: default avatarRob Herring <robh@kernel.org>
    Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
jc42.txt 984 Bytes