+1 for compatibility with Linux.

śr., 16 kwi 2025 o 10:04 Xiang Xiao <xiaoxiang781...@gmail.com> napisał(a):

> On Wed, Apr 16, 2025 at 3:53 PM Peter van der Perk <
> peter.vanderp...@nxp.com>
> wrote:
>
> > can_ioctl_data_s is in a 32-bit union.
> >
> >
> https://github.com/apache/nuttx/blob/40c6af6dec0d769ac57f69e89709f9d6310ee0c6/include/net/if.h#L299
> > Making it 64-bit would break that union.
> >
> >
> but lifr_ifru doesn't require its member size to be less than 64-bit, why
> not align can_ioctl_data_s with Linux definition.
>
> Hence back then it was chosen to use kHz instead.
> >
> > Yours sincerely,
> >
> > Peter van der Perk
> >
> > -----Original Message-----
> > From: Carlos Sanchez <carlossanc...@geotab.com.INVALID>
> > Sent: Wednesday, April 16, 2025 9:37 AM
> > To: dev@nuttx.apache.org
> > Subject: CAN ioctl units (WAS: socketcan ioctl(...SIOCSCANBITRATE...)
> > brings the interface up)
> >
> >
> > > > I was going to propose another global CAN change, removing the 1000
> > > > factor from bitrate thus making bitrate calls use units in Hz
> > > > instead of kHz, so we can discuss that and (if agreed) I make the
> > > > change on the same PR to avoid creating so a tiny one.
> >
> > > What's the unit used on Linux? we need to align the interface with
> Linux.
> >
> > Units in linux are Hz, according to
> >
> >
> https://docs.kernel.org/networking/can.html#the-can-network-device-driver-interface
> >
> > One problem with using kHz is Single Wire Can (SAE J2411) uses bitrates
> of
> > 33333 bps (83333 bps in high speed mode) so representing this in kbps
> > causes a timing error which can be significant in some cases.
> >
> > The change would require modifying arbi_bitrate and data_bitrate fields
> on
> > struct can_ioctl_data_s from uint16_t to uint32_t, otherwise usual
> bitrates
> > cannot be represented.
> >
> > Carlos
> >
>

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