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can: dev: add CAN interface termination API

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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 <socketcan@hartkopp.net>
Reviewed-by: Ramesh Shanmugasundaram <Ramesh.shanmugasundaram@bp.renesas.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Oliver Hartkopp 2017-01-10 18:52:06 +01:00 committed by Marc Kleine-Budde
parent d140199af5
commit 12a6075cab
3 changed files with 57 additions and 1 deletions
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49
drivers/net/can/dev.c
View file

@ -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);
}

4
include/linux/can/dev.h
View file

@ -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,

5
include/uapi/linux/can/netlink.h
View file

@ -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 */