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can-calc-bit-timing: import bit timing calculation algorithm from v3.18 

add missing can_fixup_bittiming()

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
pull/372/head
Marc Kleine-Budde 2022-03-19 14:28:18 +01:00
parent c1f5dc53ec
commit b777ce2e6d
2 changed files with 43 additions and 2 deletions
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41
calc-bit-timing/can-calc-bit-timing-v3_18.c
View File

@ -36,7 +36,6 @@
* registers of the CAN controller. You can find more information
* in the header file linux/can/netlink.h.
*/
static int can_update_spt(const struct can_bittiming_const *btc,
int sampl_pt, int tseg, int *tseg1, int *tseg2)
{
@ -153,3 +152,43 @@ static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
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
* file linux/can/netlink.h.
*/
static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
const struct can_bittiming_const *btc)
{
struct can_priv *priv = netdev_priv(dev);
int tseg1, alltseg;
u64 brp64;
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 ||
bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
return -ERANGE;
brp64 = (u64)priv->clock.freq * (u64)bt->tq;
if (btc->brp_inc > 1)
do_div(brp64, btc->brp_inc);
brp64 += 500000000UL - 1;
do_div(brp64, 1000000000UL); /* the practicable BRP */
if (btc->brp_inc > 1)
brp64 *= btc->brp_inc;
bt->brp = (u32)brp64;
if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
return -EINVAL;
alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
return 0;
}

4
calc-bit-timing/can-calc-bit-timing.c
View File

@ -1186,9 +1186,11 @@ static const unsigned int common_data_bitrates[] = {
#define can_update_spt can_update_spt_v3_18
#define can_calc_bittiming can_calc_bittiming_v3_18
#define can_fixup_bittiming can_fixup_bittiming_v3_18
#include "can-calc-bit-timing-v3_18.c"
#undef can_update_spt
#undef can_calc_bittiming
#undef can_fixup_bittiming
#define can_update_sample_point can_update_sample_point_v4_8
#define can_calc_bittiming can_calc_bittiming_v4_8
@ -1244,7 +1246,7 @@ static const struct alg alg_list[] = {
.name = "v4.8",
}, {
.calc_bittiming = can_calc_bittiming_v3_18,
.fixup_bittiming = can_fixup_bittiming,
.fixup_bittiming = can_fixup_bittiming_v3_18,
.name = "v3.18",
}, {
.calc_bittiming = can_calc_bittiming_v2_6_31,