On 11.06.2022 15:15:51, Max Staudt wrote:
> @Marc, Wolfgang - one SocketCAN design question about bitrate setting at
> the end. I'd appreciate your opinion on my dummy do_set_bittiming().
[...]
> > > +/* Dummy needed to use bitrate_const */
> > > +static int can327_do_set_bittiming(struct net_device *netdev)
> > > +{
> > > + return 0;
> > > +}
> >
> > Is this dummy function really needed? If think that access to
> > can_priv::do_set_bittiming is always garded. Setting it to NULL should
> > be OK. c.f.:
> > https://elixir.bootlin.com/linux/latest/source/drivers/net/can/dev/netlink.c#L198
>
> drivers/net/can/dev/netlink.c - can_changelink():
>
> /* Calculate bittiming parameters based on
> * bittiming_const if set, otherwise pass bitrate
> * directly via do_set_bitrate(). Bail out if neither
> * is given.
> */
> if (!priv->bittiming_const && !priv->do_set_bittiming)
> return -EOPNOTSUPP;
>
> can327 has neither of these two, so I provide a dummy for one.
>
> What should I do instead?
What about this change?
diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index 7633d98e3912..667ddd28fcdc 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c
@@ -176,7 +176,8 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[],
* directly via do_set_bitrate(). Bail out if neither
* is given.
*/
- if (!priv->bittiming_const && !priv->do_set_bittiming)
+ if (!priv->bittiming_const && !priv->do_set_bittiming &&
+ !priv->bitrate_const)
return -EOPNOTSUPP;
memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
If it works I'll make a patch and apply it to net-next/master so that
you can base your series on this.
> While at it, a comment in elm327_init mentioned bittiming_const - that
> was from the pre-bitrate_const (< v4.11) times, and I've now updated it
> to mention bitrate_const instead.
regards,
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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