Hi Marc, On Saturday 03 November 2018 03:06 PM, Marc Kleine-Budde wrote: > On 11/02/2018 08:26 PM, Faiz Abbas wrote: >> In some subsystems (eg. CAN) the physical layer capabilities are >> the limiting factor in the datarate of the device. Typically, the >> physical layer transceiver does not provide a way to discover this >> limitation at runtime. Thus this information needs to be represented as >> a phy attribute which is read from the device tree. >> >> Therefore, add an optional max_bitrate attribute to the generic phy >> sybsystem. Also add the complementary API which enables the consumer >> to get max_bitrate. >> >> Signed-off-by: Faiz Abbas <faiz_abbas@xxxxxx> > > NACK - We already have such a functionality in the CAN subsystem. > Please have a look at the patches: > > e759c626d826 can: m_can: Support higher speed CAN-FD bitrates > b54f9eea7667 dt-bindings: can: m_can: Document new can transceiver binding > 2290aefa2e90 can: dev: Add support for limiting configured bitrate > 54a7fbcc17bc dt-bindings: can: can-transceiver: Document new binding > I remove the transceiver child node binding documentation in patch 5/6. The existing implementation is pretty limiting as it just has a child node with no associated device. What if a transceiver requires its own configurations before it can start sending/receiving messages (for example, my usecase requires it to pull the standby line low)? I think that can be solved by implementing the transceiver as a phy and exposing a generic get_max_bitrate API. That way, the transceiver device can do all its startup configuration in the phy probe function. In any case, do suggest if you have a better idea on how to implement pull gpio low requirement. Thanks, Faiz
