[canxl v5 17/17] can: dev: print bitrate error with two decimal digits

[Oliver Hartkopp <socketcan@hartkopp.net>]

Increase the resolution when printing the bitrate error and round-up the
value to 0.01% in the case the resolution would still provide values
which would lead to 0.00%.

Suggested-by: Vincent Mailhol <mailhol@kernel.org>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
---
 drivers/net/can/dev/calc_bittiming.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/net/can/dev/calc_bittiming.c b/drivers/net/can/dev/calc_bittiming.c
index 0b11c4e98172..71c5ba338f8f 100644
--- a/drivers/net/can/dev/calc_bittiming.c
+++ b/drivers/net/can/dev/calc_bittiming.c
@@ -150,23 +150,26 @@ int can_calc_bittiming(const struct net_device *dev, struct can_bittiming *bt,
 		if (bitrate_error == 0 && sample_point_error == 0)
 			break;
 	}
 
 	if (best_bitrate_error) {
-		/* Error in one-tenth of a percent */
-		v64 = (u64)best_bitrate_error * 1000;
+		/* Error in one-hundredth of a percent */
+		v64 = (u64)best_bitrate_error * 10000;
 		do_div(v64, bt->bitrate);
 		bitrate_error = (u32)v64;
+		/* print at least 0.01% when the error is smaller */
+		bitrate_error = max(bitrate_error, 1U);
 		if (bitrate_error > CAN_CALC_MAX_ERROR) {
 			NL_SET_ERR_MSG_FMT(extack,
-					   "bitrate error: %u.%u%% too high",
-					   bitrate_error / 10, bitrate_error % 10);
+					   "bitrate error: %u.%02u%% too high",
+					   bitrate_error / 100,
+					   bitrate_error % 100);
 			return -EINVAL;
 		}
 		NL_SET_ERR_MSG_FMT(extack,
-				   "bitrate error: %u.%u%%",
-				   bitrate_error / 10, bitrate_error % 10);
+				   "bitrate error: %u.%02u%%",
+				   bitrate_error / 100, bitrate_error % 100);
 	}
 
 	/* real sample point */
 	bt->sample_point = can_update_sample_point(btc, sample_point, best_tseg,
 						   &tseg1, &tseg2, NULL);
-- 
2.47.3