It allows to set the bitrate via ip tool, as it happens for the other
CAN device drivers. It still remains possible to set the bitrate via
slcand or slcan_attach utilities. In case the ip tool is used, the
driver will send the serial command to the adapter.
The struct can_bittiming_const and struct can_priv::clock.freq has been
set with empirical values that allow you to get a correct bit timing, so
that the slc_do_set_bittiming() can be called.
Signed-off-by: Dario Binacchi <dario.binacchi@xxxxxxxxxxxxxxxxxxxx>
---
DTS properties could be used to set the can.clock.freq and the
can.bittiming_const variables. This way the parameters could be changed
based on the type of the adapter.
drivers/net/can/slcan.c | 54 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 53 insertions(+), 1 deletion(-)
diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c
index dbd4ebdfa024..f1bf32b70c4d 100644
--- a/drivers/net/can/slcan.c
+++ b/drivers/net/can/slcan.c
@@ -105,6 +105,18 @@ struct slcan {
static struct net_device **slcan_devs;
static DEFINE_SPINLOCK(slcan_lock);
+static const struct can_bittiming_const slcan_bittiming_const = {
+ .name = KBUILD_MODNAME,
+ .tseg1_min = 2,
+ .tseg1_max = 256,
+ .tseg2_min = 1,
+ .tseg2_max = 128,
+ .sjw_max = 128,
+ .brp_min = 1,
+ .brp_max = 256,
+ .brp_inc = 1,
+};
+
/************************************************************************
* SLCAN ENCAPSULATION FORMAT *
************************************************************************/
@@ -435,6 +447,7 @@ static int slc_close(struct net_device *dev)
netif_stop_queue(dev);
close_candev(dev);
sl->can.state = CAN_STATE_STOPPED;
+ sl->can.bittiming.bitrate = 0;
sl->rcount = 0;
sl->xleft = 0;
spin_unlock_bh(&sl->lock);
@@ -456,7 +469,9 @@ static int slc_open(struct net_device *dev)
* can.bittiming.bitrate is 0, causing open_candev() to fail.
* So let's set to a fake value.
*/
- sl->can.bittiming.bitrate = -1;
+ if (sl->can.bittiming.bitrate == 0)
+ sl->can.bittiming.bitrate = -1UL;
+
err = open_candev(dev);
if (err) {
netdev_err(dev, "failed to open can device\n");
@@ -554,6 +569,40 @@ static void slc_sync(void)
}
}
+static int slc_do_set_bittiming(struct net_device *dev)
+{
+ struct slcan *sl = netdev_priv(dev);
+ unsigned char cmd[SLC_MTU];
+ int i, s = -1, err;
+ unsigned int bitrates[] = {
+ 10000, 20000, 50000, 100000,
+ 125000, 250000, 500000, 800000,
+ 1000000,
+ };
+
+ for (i = 0; i < ARRAY_SIZE(bitrates); i++) {
+ if (sl->can.bittiming.bitrate == bitrates[i]) {
+ s = i;
+ break;
+ }
+ }
+
+ if (s < 0) {
+ netdev_err(dev, "invalid bitrate\n");
+ return -EINVAL;
+ }
+
+ snprintf(cmd, sizeof(cmd), "C\rS%d\r", s);
+ err = slcan_transmit_cmd(sl, cmd);
+ if (err) {
+ sl->can.bittiming.bitrate = 0;
+ netdev_err(sl->dev,
+ "failed to send bitrate command 'C\\rS%d\\r'\n", s);
+ }
+
+ return err;
+}
+
/* Find a free SLCAN channel, and link in this `tty' line. */
static struct slcan *slc_alloc(void)
{
@@ -583,6 +632,9 @@ static struct slcan *slc_alloc(void)
/* Initialize channel control data */
sl->magic = SLCAN_MAGIC;
sl->dev = dev;
+ sl->can.clock.freq = 24 * 1000 * 1000;
+ sl->can.bittiming_const = &slcan_bittiming_const;
+ sl->can.do_set_bittiming = slc_do_set_bittiming;
spin_lock_init(&sl->lock);
INIT_WORK(&sl->tx_work, slcan_transmit);
init_waitqueue_head(&sl->xcmd_wait);
--
2.32.0
