raimps: mtk_eth_soc: drop rst_esw from ESW driver

The ESW core needs to be reset together with FE core, so after the
relevant reset controller lines are moved under FE, drop rst_esw and all
related code, which would not execute anyway, because rst_esw would be
NULL. While at that, ensure that if reset line for EPHY cannot be
claimed, a proper error message is reported.

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

Co-developed-by: Maxim Anisimov <maxim.anisimov.ua@gmail.com>
Signed-off-by: Maxim Anisimov <maxim.anisimov.ua@gmail.com>

[Split out of the bigger commit, provide commit mesage, refactor error
handling]
Signed-off-by: Lech Perczak <lech.perczak@gmail.com>

target/linux/ramips/files/drivers/net/ethernet/ralink/esw_rt3050.c

@@ -237,7 +237,6 @@ struct rt305x_esw {
 	int			led_frequency;
 	struct esw_vlan vlans[RT305X_ESW_NUM_VLANS];
 	struct esw_port ports[RT305X_ESW_NUM_PORTS];
-	struct reset_control	*rst_esw;
 	struct reset_control	*rst_ephy;
 
 };
@@ -261,18 +260,6 @@ static inline void esw_rmw_raw(struct rt305x_esw *esw, unsigned reg,
 	__raw_writel(t | val, esw->base + reg);
 }
 
-static void esw_reset(struct rt305x_esw *esw)
-{
-	if (!esw->rst_esw)
-		return;
-
-	reset_control_assert(esw->rst_esw);
-	usleep_range(60, 120);
-	reset_control_deassert(esw->rst_esw);
-	/* the esw takes long to reset otherwise the board hang */
-	msleep(10);
-}
-
 static void esw_reset_ephy(struct rt305x_esw *esw)
 {
 	if (!esw->rst_ephy)
@@ -466,8 +453,6 @@ static void esw_hw_init(struct rt305x_esw *esw)
 	u8 port_disable = 0;
 	u8 port_map = RT305X_ESW_PMAP_LLLLLL;
 
-	esw_reset(esw);
-
 	/* vodoo from original driver */
 	esw_w32(esw, 0xC8A07850, RT305X_ESW_REG_FCT0);
 	esw_w32(esw, 0x00000000, RT305X_ESW_REG_SGC2);
@@ -1441,12 +1426,11 @@ static int esw_probe(struct platform_device *pdev)
 	if (reg_init)
 		esw->reg_led_source = be32_to_cpu(*reg_init);
 
-	esw->rst_esw = devm_reset_control_get(&pdev->dev, "esw");
-	if (IS_ERR(esw->rst_esw))
-		esw->rst_esw = NULL;
-	esw->rst_ephy = devm_reset_control_get(&pdev->dev, "ephy");
-	if (IS_ERR(esw->rst_ephy))
+	esw->rst_ephy = devm_reset_control_get_exclusive(&pdev->dev, "ephy");
+	if (IS_ERR(esw->rst_ephy)) {
+		dev_err(esw->dev, "failed to get EPHY reset: %pe\n", esw->rst_ephy);
 		esw->rst_ephy = NULL;
+	}
 
 	spin_lock_init(&esw->reg_rw_lock);
 	platform_set_drvdata(pdev, esw);