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Commit 12a6075c authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
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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: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Reviewed-by: default avatarRamesh Shanmugasundaram <Ramesh.shanmugasundaram@bp.renesas.com>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent d140199a

drivers/net/can/dev.c

+48 −1
Original line number Diff line number Diff line
@@ -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);

}

include/linux/can/dev.h

+4 −0
Original line number Diff line number Diff line
@@ -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,

include/uapi/linux/can/netlink.h

+5 −0
Original line number Diff line number Diff line
@@ -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 */