From 12a6075cabc0d9ffbc0366b44daa22f278606312 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Tue, 10 Jan 2017 18:52:06 +0100 Subject: can: dev: add CAN interface termination API This patch adds a netlink interface to configure the CAN bus termination of CAN interfaces. Inside the driver an array of supported termination values is defined: const u16 drvname_termination[] = { 60, 120, CAN_TERMINATION_DISABLED }; struct drvname_priv *priv; priv = netdev_priv(dev); priv->termination_const = drvname_termination; priv->termination_const_cnt = ARRAY_SIZE(drvname_termination); priv->termination = CAN_TERMINATION_DISABLED; And the funtion to set the value has to be defined: priv->do_set_termination = drvname_set_termination; Signed-off-by: Oliver Hartkopp Reviewed-by: Ramesh Shanmugasundaram Signed-off-by: Marc Kleine-Budde --- drivers/net/can/dev.c | 49 +++++++++++++++++++++++++++++++++++++++- include/linux/can/dev.h | 4 ++++ include/uapi/linux/can/netlink.h | 5 ++++ 3 files changed, 57 insertions(+), 1 deletion(-) diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c index 8d6208c0b400..fefe2cd17721 100644 --- a/drivers/net/can/dev.c +++ b/drivers/net/can/dev.c @@ -958,6 +958,30 @@ static int can_changelink(struct net_device *dev, } } + if (data[IFLA_CAN_TERMINATION]) { + const u16 termval = nla_get_u16(data[IFLA_CAN_TERMINATION]); + const unsigned int num_term = priv->termination_const_cnt; + unsigned int i; + + if (!priv->do_set_termination) + return -EOPNOTSUPP; + + /* check whether given value is supported by the interface */ + for (i = 0; i < num_term; i++) { + if (termval == priv->termination_const[i]) + break; + } + if (i >= num_term) + return -EINVAL; + + /* Finally, set the termination value */ + err = priv->do_set_termination(dev, termval); + if (err) + return err; + + priv->termination = termval; + } + return 0; } @@ -980,6 +1004,11 @@ static size_t can_get_size(const struct net_device *dev) size += nla_total_size(sizeof(struct can_bittiming)); if (priv->data_bittiming_const) /* IFLA_CAN_DATA_BITTIMING_CONST */ size += nla_total_size(sizeof(struct can_bittiming_const)); + if (priv->termination_const) { + size += nla_total_size(sizeof(priv->termination)); /* IFLA_CAN_TERMINATION */ + size += nla_total_size(sizeof(*priv->termination_const) * /* IFLA_CAN_TERMINATION_CONST */ + priv->termination_const_cnt); + } return size; } @@ -1018,7 +1047,15 @@ static int can_fill_info(struct sk_buff *skb, const struct net_device *dev) (priv->data_bittiming_const && nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST, sizeof(*priv->data_bittiming_const), - priv->data_bittiming_const))) + priv->data_bittiming_const)) || + + (priv->termination_const && + (nla_put_u16(skb, IFLA_CAN_TERMINATION, priv->termination) || + nla_put(skb, IFLA_CAN_TERMINATION_CONST, + sizeof(*priv->termination_const) * + priv->termination_const_cnt, + priv->termination_const)))) + return -EMSGSIZE; return 0; @@ -1073,6 +1110,16 @@ static struct rtnl_link_ops can_link_ops __read_mostly = { */ int register_candev(struct net_device *dev) { + struct can_priv *priv = netdev_priv(dev); + + /* Ensure termination_const, termination_const_cnt and + * do_set_termination consistency. All must be either set or + * unset. + */ + if ((!priv->termination_const != !priv->termination_const_cnt) || + (!priv->termination_const != !priv->do_set_termination)) + return -EINVAL; + dev->rtnl_link_ops = &can_link_ops; return register_netdev(dev); } diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h index 5f5270941ba0..f6a57f322f00 100644 --- a/include/linux/can/dev.h +++ b/include/linux/can/dev.h @@ -38,6 +38,9 @@ struct can_priv { struct can_bittiming bittiming, data_bittiming; const struct can_bittiming_const *bittiming_const, *data_bittiming_const; + const u16 *termination_const; + unsigned int termination_const_cnt; + u16 termination; struct can_clock clock; enum can_state state; @@ -53,6 +56,7 @@ struct can_priv { int (*do_set_bittiming)(struct net_device *dev); int (*do_set_data_bittiming)(struct net_device *dev); int (*do_set_mode)(struct net_device *dev, enum can_mode mode); + int (*do_set_termination)(struct net_device *dev, u16 term); int (*do_get_state)(const struct net_device *dev, enum can_state *state); int (*do_get_berr_counter)(const struct net_device *dev, diff --git a/include/uapi/linux/can/netlink.h b/include/uapi/linux/can/netlink.h index 94ffe0c83ce7..7414771926fb 100644 --- a/include/uapi/linux/can/netlink.h +++ b/include/uapi/linux/can/netlink.h @@ -127,9 +127,14 @@ enum { IFLA_CAN_BERR_COUNTER, IFLA_CAN_DATA_BITTIMING, IFLA_CAN_DATA_BITTIMING_CONST, + IFLA_CAN_TERMINATION, + IFLA_CAN_TERMINATION_CONST, __IFLA_CAN_MAX }; #define IFLA_CAN_MAX (__IFLA_CAN_MAX - 1) +/* u16 termination range: 1..65535 Ohms */ +#define CAN_TERMINATION_DISABLED 0 + #endif /* !_UAPI_CAN_NETLINK_H */ -- cgit v1.2.3