net: mdio: add reset control for Aspeed MDIO

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>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/mdio/mdio-aspeed.c b/drivers/net/mdio/mdio-aspeed.c
index 7aa4982..944d005 100644 (file)
--- 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>
@@ -41,6 +42,7 @@
 
 struct aspeed_mdio {
        void __iomem *base;
+       struct reset_control *reset;
 };
 
 static int aspeed_mdio_op(struct mii_bus *bus, u8 st, u8 op, u8 phyad, u8 regad,
@@ -174,6 +176,12 @@ 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;
@@ -184,6 +192,7 @@ 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;
        }
 
@@ -194,7 +203,11 @@ 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;
 }