Messages in this thread | | | Subject | Re: [PATCH 1/6] phy: Add max_bitrate attribute & phy_get_max_bitrate() | From | Faiz Abbas <> | Date | Mon, 5 Nov 2018 11:57:41 +0530 |
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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@ti.com> > > 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
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