Messages in this thread | | | Subject | Re: [PATCH 1/4] can: dev: Add support for limiting configured bitrate | From | Sergei Shtylyov <> | Date | Thu, 20 Jul 2017 12:52:12 +0300 |
| |
Hello!
On 7/20/2017 2:36 AM, Franklin S Cooper Jr wrote:
> Various CAN or CAN-FD IP may be able to run at a faster rate than > what the transceiver the CAN node is connected to. This can lead to > unexpected errors. However, CAN transceivers typically have fixed > limitations and provide no means to discover these limitations at > runtime. Therefore, add support for a fixed-transceiver node that > can be reused by other CAN peripheral drivers to determine for both > CAN and CAN-FD what the max bitrate that can be used. If the user > tries to configure CAN to pass these maximum bitrates it will throw > an error. > > Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com> > --- > drivers/net/can/dev.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/can/dev.h | 5 +++++ > 2 files changed, 53 insertions(+) > > diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c > index 365a8cc..fbab87d 100644 > --- a/drivers/net/can/dev.c > +++ b/drivers/net/can/dev.c [...] > @@ -814,6 +830,38 @@ int open_candev(struct net_device *dev) > } > EXPORT_SYMBOL_GPL(open_candev); > > +#ifdef CONFIG_OF > +void of_transceiver_is_fixed(struct net_device *dev)
Strange name for a *void* function... Also, I think 'struct net_device *' variables are typically called 'ndev'.
> +{ > + struct device_node *dn; > + struct can_priv *priv = netdev_priv(dev); > + u32 max_frequency; > + struct device_node *np; > + > + np = dev->dev.parent->of_node; > + > + /* New binding */ > + dn = of_get_child_by_name(np, "fixed-transceiver"); > + if (!dn) > + return; > + > + of_property_read_u32(dn, "max-arbitration-speed", &max_frequency);
In case this function fails, 'max_frequency' will have no value -- you'd better initialize it...
> + > + if (max_frequency > 0) > + priv->max_trans_arbitration_speed = max_frequency; > + else > + priv->max_trans_arbitration_speed = -1; > + > + of_property_read_u32(dn, "max-data-speed", &max_frequency);
Again, when that function fails, the variable will keep the value from the previous call...
[...]
MBR, Sergei
| |