diff --git a/drivers/net/dsa/qca/ar9331.c b/drivers/net/dsa/qca/ar9331.c index ca2ad77b71f1..6686192e1883 100644 --- a/drivers/net/dsa/qca/ar9331.c +++ b/drivers/net/dsa/qca/ar9331.c @@ -837,16 +837,24 @@ static int ar9331_mdio_write(void *ctx, u32 reg, u32 val) return 0; } - ret = __ar9331_mdio_write(sbus, AR9331_SW_MDIO_PHY_MODE_REG, reg, val); - if (ret < 0) - goto error; - + /* In case of this switch we work with 32bit registers on top of 16bit + * bus. Some registers (for example access to forwarding database) have + * trigger bit on the first 16bit half of request, the result and + * configuration of request in the second half. + * To make it work properly, we should do the second part of transfer + * before the first one is done. + */ ret = __ar9331_mdio_write(sbus, AR9331_SW_MDIO_PHY_MODE_REG, reg + 2, val >> 16); if (ret < 0) goto error; + ret = __ar9331_mdio_write(sbus, AR9331_SW_MDIO_PHY_MODE_REG, reg, val); + if (ret < 0) + goto error; + return 0; + error: dev_err_ratelimited(&sbus->dev, "Bus error. Failed to write register.\n"); return ret;