Re: [PATCH v2 1/2] hwmon: (jc42) optionally try to disable the SMBUS timeout

Rob Herring
2017-11-28T15:01:46Z

On Mon, Nov 27, 2017 at 05:31:00PM +0100, Peter Rosin wrote:
> 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.
>
> Signed-off-by: Peter Rosin <peda@axentia.se>
> ---
> Documentation/devicetree/bindings/hwmon/jc42.txt | 4 ++++

Acked-by: Rob Herring <robh@kernel.org>

> drivers/hwmon/jc42.c | 21 +++++++++++++++++++++
> 2 files changed, 25 insertions(+)