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From:   Dylan Hung <dylan_hung@aspeedtech.com>
To:     <robh+dt@kernel.org>, <joel@jms.id.au>, <andrew@aj.id.au>,
        <andrew@lunn.ch>, <hkallweit1@gmail.com>, <linux@armlinux.org.uk>,
        <davem@davemloft.net>, <kuba@kernel.org>, <pabeni@redhat.com>,
        <p.zabel@pengutronix.de>, <devicetree@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-aspeed@lists.ozlabs.org>, <linux-kernel@vger.kernel.org>,
        <netdev@vger.kernel.org>
CC:     <BMC-SW@aspeedtech.com>
Subject: [PATCH v3 2/3] net: mdio: add reset control for Aspeed MDIO
Date:   Fri, 25 Mar 2022 12:14:50 +0800
Message-ID: <20220325041451.894-3-dylan_hung@aspeedtech.com>
In-Reply-To: <20220325041451.894-1-dylan_hung@aspeedtech.com>
References: <20220325041451.894-1-dylan_hung@aspeedtech.com>
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Add reset assertion/deassertion for Aspeed MDIO.  There are 4 MDIO
controllers embedded in Aspeed AST2600 SOC and share one reset control
register SCU50[3].  To work with old DT blobs which don't have the reset
property, devm_reset_control_get_optional_shared is used in this change.

Signed-off-by: Dylan Hung <dylan_hung@aspeedtech.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
---
 drivers/net/mdio/mdio-aspeed.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/net/mdio/mdio-aspeed.c b/drivers/net/mdio/mdio-aspeed.c
index e2273588c75b..1afb58ccc524 100644
--- a/drivers/net/mdio/mdio-aspeed.c
+++ b/drivers/net/mdio/mdio-aspeed.c
@@ -3,6 +3,7 @@
 
 #include <linux/bitfield.h>
 #include <linux/delay.h>
+#include <linux/reset.h>
 #include <linux/iopoll.h>
 #include <linux/mdio.h>
 #include <linux/module.h>
@@ -37,6 +38,7 @@
 
 struct aspeed_mdio {
 	void __iomem *base;
+	struct reset_control *reset;
 };
 
 static int aspeed_mdio_read(struct mii_bus *bus, int addr, int regnum)
@@ -120,6 +122,12 @@ static int aspeed_mdio_probe(struct platform_device *pdev)
 	if (IS_ERR(ctx->base))
 		return PTR_ERR(ctx->base);
 
+	ctx->reset = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
+	if (IS_ERR(ctx->reset))
+		return PTR_ERR(ctx->reset);
+
+	reset_control_deassert(ctx->reset);
+
 	bus->name = DRV_NAME;
 	snprintf(bus->id, MII_BUS_ID_SIZE, "%s%d", pdev->name, pdev->id);
 	bus->parent = &pdev->dev;
@@ -129,6 +137,7 @@ static int aspeed_mdio_probe(struct platform_device *pdev)
 	rc = of_mdiobus_register(bus, pdev->dev.of_node);
 	if (rc) {
 		dev_err(&pdev->dev, "Cannot register MDIO bus!\n");
+		reset_control_assert(ctx->reset);
 		return rc;
 	}
 
@@ -139,7 +148,11 @@ static int aspeed_mdio_probe(struct platform_device *pdev)
 
 static int aspeed_mdio_remove(struct platform_device *pdev)
 {
-	mdiobus_unregister(platform_get_drvdata(pdev));
+	struct mii_bus *bus = (struct mii_bus *)platform_get_drvdata(pdev);
+	struct aspeed_mdio *ctx = bus->priv;
+
+	reset_control_assert(ctx->reset);
+	mdiobus_unregister(bus);
 
 	return 0;
 }
-- 
2.25.1