Merge tag 'linux-can-next-for-4.16-20180116' of ssh://gitolite.kernel…

….org/pub/scm/linux/kernel/git/mkl/linux-can-next

Marc Kleine-Budde says:

====================
pull-request: can-next 2018-01-16

this is a pull request for net-next/master consisting of 9 patches.

This is a series of patches, some of them initially by Franklin S Cooper
Jr, which was picked up by Faiz Abbas. Faiz Abbas added some patches
while working on this series, I contributed one as well.

The first two patches add support to CAN device infrastructure to limit
the bitrate of a CAN adapter if the used CAN-transceiver has a certain
maximum bitrate.

The remaining patches improve the m_can driver. They add support for
bitrate limiting to the driver, clean up the driver and add support for
runtime PM.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/can/can-transceiver.txt

@@ -0,0 +1,24 @@
+Generic CAN transceiver Device Tree binding
+------------------------------
+
+CAN transceiver typically limits the max speed in standard CAN and CAN FD
+modes. Typically these limitations are static and the transceivers themselves
+provide no way to detect this limitation at runtime. For this situation,
+the "can-transceiver" node can be used.
+
+Required Properties:
+ max-bitrate:	a positive non 0 value that determines the max
+		speed that CAN/CAN-FD can run. Any other value
+		will be ignored.
+
+Examples:
+
+Based on Texas Instrument's TCAN1042HGV CAN Transceiver
+
+m_can0 {
+	....
+	can-transceiver {
+		max-bitrate = <5000000>;
+	};
+	...
+};

Documentation/devicetree/bindings/net/can/m_can.txt

@@ -43,6 +43,11 @@ Required properties:
 			  Please refer to 2.4.1 Message RAM Configuration in
 			  Bosch M_CAN user manual for details.
 
+Optional Subnode:
+- can-transceiver	: Can-transceiver subnode describing maximum speed
+			  that can be used for CAN/CAN-FD modes. See
+			  Documentation/devicetree/bindings/net/can/can-transceiver.txt
+			  for details.
 Example:
 SoC dtsi:
 m_can1: can@20e8000 {
@@ -63,4 +68,8 @@ Board dts:
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_m_can1>;
 	status = "enabled";
+
+	can-transceiver {
+		max-bitrate = <5000000>;
+	};
 };

drivers/net/can/dev.c

@@ -27,6 +27,7 @@
 #include <linux/can/skb.h>
 #include <linux/can/netlink.h>
 #include <linux/can/led.h>
+#include <linux/of.h>
 #include <net/rtnetlink.h>
 
 #define MOD_DESC "CAN device driver interface"
@@ -814,6 +815,29 @@ int open_candev(struct net_device *dev)
 }
 EXPORT_SYMBOL_GPL(open_candev);
 
+#ifdef CONFIG_OF
+/* Common function that can be used to understand the limitation of
+ * a transceiver when it provides no means to determine these limitations
+ * at runtime.
+ */
+void of_can_transceiver(struct net_device *dev)
+{
+	struct device_node *dn;
+	struct can_priv *priv = netdev_priv(dev);
+	struct device_node *np = dev->dev.parent->of_node;
+	int ret;
+
+	dn = of_get_child_by_name(np, "can-transceiver");
+	if (!dn)
+		return;
+
+	ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max);
+	if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max))
+		netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n");
+}
+EXPORT_SYMBOL_GPL(of_can_transceiver);
+#endif
+
 /*
  * Common close function for cleanup before the device gets closed.
  *
@@ -913,6 +937,13 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 					priv->bitrate_const_cnt);
 		if (err)
 			return err;
+
+		if (priv->bitrate_max && bt.bitrate > priv->bitrate_max) {
+			netdev_err(dev, "arbitration bitrate surpasses transceiver capabilities of %d bps\n",
+				   priv->bitrate_max);
+			return -EINVAL;
+		}
+
 		memcpy(&priv->bittiming, &bt, sizeof(bt));
 
 		if (priv->do_set_bittiming) {
@@ -997,6 +1028,13 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 					priv->data_bitrate_const_cnt);
 		if (err)
 			return err;
+
+		if (priv->bitrate_max && dbt.bitrate > priv->bitrate_max) {
+			netdev_err(dev, "canfd data bitrate surpasses transceiver capabilities of %d bps\n",
+				   priv->bitrate_max);
+			return -EINVAL;
+		}
+
 		memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
 
 		if (priv->do_set_data_bittiming) {
@@ -1064,6 +1102,7 @@ static size_t can_get_size(const struct net_device *dev)
 	if (priv->data_bitrate_const)				/* IFLA_CAN_DATA_BITRATE_CONST */
 		size += nla_total_size(sizeof(*priv->data_bitrate_const) *
 				       priv->data_bitrate_const_cnt);
+	size += sizeof(priv->bitrate_max);			/* IFLA_CAN_BITRATE_MAX */
 
 	return size;
 }
@@ -1121,7 +1160,11 @@ static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
 	     nla_put(skb, IFLA_CAN_DATA_BITRATE_CONST,
 		     sizeof(*priv->data_bitrate_const) *
 		     priv->data_bitrate_const_cnt,
-		     priv->data_bitrate_const))
+		     priv->data_bitrate_const)) ||
+
+	    (nla_put(skb, IFLA_CAN_BITRATE_MAX,
+		     sizeof(priv->bitrate_max),
+		     &priv->bitrate_max))
 	    )
 
 		return -EMSGSIZE;