drivers: net: cpsw: disable coalesce when rx_coalesce_usecs is zero

instead of return error on zero rx_coalesce_usecs, disable coalesce

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/cpsw.c

@@ -884,14 +884,16 @@ static int cpsw_set_coalesce(struct net_device *ndev,
 	u32 addnl_dvdr = 1;
 	u32 coal_intvl = 0;
 
-	if (!coal->rx_coalesce_usecs)
-		return -EINVAL;
-
 	coal_intvl = coal->rx_coalesce_usecs;
 
 	int_ctrl =  readl(&priv->wr_regs->int_control);
 	prescale = priv->bus_freq_mhz * 4;
 
+	if (!coal->rx_coalesce_usecs) {
+		int_ctrl &= ~(CPSW_INTPRESCALE_MASK | CPSW_INTPACEEN);
+		goto update_return;
+	}
+
 	if (coal_intvl < CPSW_CMINTMIN_INTVL)
 		coal_intvl = CPSW_CMINTMIN_INTVL;
 
@@ -919,6 +921,8 @@ static int cpsw_set_coalesce(struct net_device *ndev,
 	int_ctrl |= CPSW_INTPACEEN;
 	int_ctrl &= (~CPSW_INTPRESCALE_MASK);
 	int_ctrl |= (prescale & CPSW_INTPRESCALE_MASK);
+
+update_return:
 	writel(int_ctrl, &priv->wr_regs->int_control);
 
 	cpsw_notice(priv, timer, "Set coalesce to %d usecs.\n", coal_intvl);