can: bittiming: factor out can_sjw_set_default() and can_sjw_check()

Factor out the functionality of assigning a SJW default value into
can_sjw_set_default() and the checking the SJW limits into
can_sjw_check().

This functions will be improved and called from a different function
in the following patches.

Link: https://lore.kernel.org/all/20230202110854.2318594-11-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/dev/bittiming.c b/drivers/net/can/dev/bittiming.c
index 0b0b8c767c5bc3e965b3f70a038eb5f9eaeae288..101de1b3bf307ead29c1cf07e765b3b5ba1e783e 100644 (file)
--- a/drivers/net/can/dev/bittiming.c
+++ b/drivers/net/can/dev/bittiming.c
@@ -6,6 +6,24 @@
 
 #include <linux/can/dev.h>
 
+void can_sjw_set_default(struct can_bittiming *bt)
+{
+       if (bt->sjw)
+               return;
+
+       /* If user space provides no sjw, use 1 as default */
+       bt->sjw = 1;
+}
+
+int can_sjw_check(const struct net_device *dev, const struct can_bittiming *bt,
+                 const struct can_bittiming_const *btc, struct netlink_ext_ack *extack)
+{
+       if (bt->sjw > btc->sjw_max)
+               return -ERANGE;
+
+       return 0;
+}
+
 /* Checks the validity of the specified bit-timing parameters prop_seg,
  * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
  * prescaler value brp. You can find more information in the header
@@ -18,12 +36,16 @@ static int can_fixup_bittiming(const struct net_device *dev, struct can_bittimin
        const struct can_priv *priv = netdev_priv(dev);
        unsigned int tseg1;
        u64 brp64;
+       int err;
+
+       can_sjw_set_default(bt);
+
+       err = can_sjw_check(dev, bt, btc, extack);
+       if (err)
+               return err;
 
        tseg1 = bt->prop_seg + bt->phase_seg1;
-       if (!bt->sjw)
-               bt->sjw = 1;
-       if (bt->sjw > btc->sjw_max ||
-           tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
+       if (tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
            bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
                return -ERANGE;
 

diff --git a/include/linux/can/bittiming.h b/include/linux/can/bittiming.h
index 53d693ae5397376e2a9a0357000c27a0531cc34d..6cb2ae308e3fe87405ed5cbf1694d9f6f0b09bae 100644 (file)
--- a/include/linux/can/bittiming.h
+++ b/include/linux/can/bittiming.h
@@ -138,6 +138,11 @@ can_calc_tdco(struct can_tdc *tdc, const struct can_tdc_const *tdc_const,
 }
 #endif /* CONFIG_CAN_CALC_BITTIMING */
 
+void can_sjw_set_default(struct can_bittiming *bt);
+
+int can_sjw_check(const struct net_device *dev, const struct can_bittiming *bt,
+                 const struct can_bittiming_const *btc, struct netlink_ext_ack *extack);
+
 int can_get_bittiming(const struct net_device *dev, struct can_bittiming *bt,
                      const struct can_bittiming_const *btc,
                      const u32 *bitrate_const,