On 07/20/2017 04:52 AM, Sergei Shtylyov wrote:

Hello!

On 7/20/2017 2:36 AM, Franklin S Cooper Jr wrote:

quoted

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 <redacted>
---
  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

[...]

quoted

@@ -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...

Ok I see what you mean since I'm not actually returning anything. I'll
go with of_can_transceiver_fixed based on your comment also Oliver's
suggestion.

   Also, I think 'struct net_device *' variables are typically called
'ndev'.

All other functions within this file uses struct net_device *dev. So I'm
just following the style currently used.

quoted

+{
+    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...

Thanks for catching this. Will fix.

quoted

+
+    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...

Will fix.

[...]

MBR, Sergei

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html