[PATCH net-next 10/20] can: rockchip_canfd: rkcanfd_register_done(): add warning for erratum 5

[Marc Kleine-Budde <mkl@pengutronix.de>]

Tests on the rk3568v2 and rk3568v3 show that a reduced "baudclk" (e.g.
80MHz, compared to the standard 300MHz) significantly increases the
possibility of incorrect FIFO counters, i.e. erratum 5.

Print an info message if the clock is below the known good value of
300MHz.

Tested-by: Alibek Omarov <a1ba.omarov@gmail.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patch.msgid.link/20240904-rockchip-canfd-v5-10-8ae22bcb27cc@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/rockchip/rockchip_canfd-core.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-core.c b/drivers/net/can/rockchip/rockchip_canfd-core.c
index 40911bb63623..d6c0f2fe8d2b 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-core.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-core.c
@@ -738,6 +738,13 @@ static void rkcanfd_register_done(const struct rkcanfd_priv *priv)
 		    FIELD_GET(RKCANFD_REG_RTL_VERSION_MAJOR, dev_id),
 		    FIELD_GET(RKCANFD_REG_RTL_VERSION_MINOR, dev_id),
 		    priv->devtype_data.quirks);
+
+	if (priv->devtype_data.quirks & RKCANFD_QUIRK_RK3568_ERRATUM_5 &&
+	    priv->can.clock.freq < RKCANFD_ERRATUM_5_SYSCLOCK_HZ_MIN)
+		netdev_info(priv->ndev,
+			    "Erratum 5: CAN clock frequency (%luMHz) lower than known good (%luMHz), expect degraded performance\n",
+			    priv->can.clock.freq / MEGA,
+			    RKCANFD_ERRATUM_5_SYSCLOCK_HZ_MIN / MEGA);
 }
 
 static int rkcanfd_register(struct rkcanfd_priv *priv)
-- 
2.45.2