ramips: mtk_eth_soc: allow multiple resets

Use devm_reset_control_array_get_exclusive to register multiple
reset lines in FE driver. This is required to reattach ESW reset to FE
driver again, based on device tree bindings.

While at that, remove unused fe_priv.rst_ppe field, and add error
message if getting the reset fails.

Fixes: 60fadae62b64 ("ramips: ethernet: ralink: move reset of the esw into the esw instead of fe")

Co-developed-by: Maxim Anisimov <[email protected]>
Signed-off-by: Maxim Anisimov <[email protected]>

[Split out of the bigger commit, provide commit mesage, refactor error
handling]
Signed-off-by: Lech Perczak <[email protected]>

target/linux/ramips/files/drivers/net/ethernet/ralink/mtk_eth_soc.c

@@ -143,12 +143,12 @@ void fe_reset(u32 reset_bits)
 
 void fe_reset_fe(struct fe_priv *priv)
 {
-	if (!priv->rst_fe)
+	if (!priv->resets)
 		return;
 
-	reset_control_assert(priv->rst_fe);
+	reset_control_assert(priv->resets);
 	usleep_range(60, 120);
-	reset_control_deassert(priv->rst_fe);
+	reset_control_deassert(priv->resets);
 	usleep_range(60, 120);
 }
 
@@ -1595,9 +1595,11 @@ static int fe_probe(struct platform_device *pdev)
 
 	priv = netdev_priv(netdev);
 	spin_lock_init(&priv->page_lock);
-	priv->rst_fe = devm_reset_control_get(&pdev->dev, "fe");
-	if (IS_ERR(priv->rst_fe))
-		priv->rst_fe = NULL;
+	priv->resets = devm_reset_control_array_get_exclusive(&pdev->dev);
+	if (IS_ERR(priv->resets)) {
+		dev_err(&pdev->dev, "Failed to get resets for FE and ESW cores: %pe\n", priv->resets);
+		priv->resets = NULL;
+	}
 
 	if (soc->init_data)
 		soc->init_data(soc, netdev);

target/linux/ramips/files/drivers/net/ethernet/ralink/mtk_eth_soc.h

@@ -497,8 +497,7 @@ struct fe_priv {
 	struct work_struct		pending_work;
 	DECLARE_BITMAP(pending_flags, FE_FLAG_MAX);
 
-	struct reset_control		*rst_ppe;
-	struct reset_control		*rst_fe;
+	struct reset_control		*resets;
 	struct mtk_foe_entry		*foe_table;
 	dma_addr_t			foe_table_phys;
 	struct flow_offload __rcu	**foe_flow_table;