2022-04-07 12:05:06

by Dylan Hung

Subject: [PATCH RESEND v3 2/3] 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 <[email protected]>
Reviewed-by: Philipp Zabel <[email protected]>
---
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

2022-04-11 08:22:46

by Andrew Jeffery

Subject: Re: [PATCH RESEND v3 2/3] net: mdio: add reset control for Aspeed MDIO

On Thu, 7 Apr 2022, at 17:27, Dylan Hung wrote:
> 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 <[email protected]>
> Reviewed-by: Philipp Zabel <[email protected]>
> ---
> 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);

Isn't this unnecessary because you've used the devm_ variant to acquire
the reset?

Andrew

2022-04-11 13:39:27

by Philipp Zabel

Subject: Re: [PATCH RESEND v3 2/3] net: mdio: add reset control for Aspeed MDIO

On Mo, 2022-04-11 at 09:50 +0930, Andrew Jeffery wrote:
>
> On Thu, 7 Apr 2022, at 17:27, Dylan Hung wrote:
> > 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 <[email protected]>
> > Reviewed-by: Philipp Zabel <[email protected]>
> > ---
> >  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);
>
> Isn't this unnecessary because you've used the devm_ variant to acquire
> the reset?

No, this is correct. deassert/assert needs to be balanced, and the
reset_control_deassert() call in aspeed_mdio_probe() is not devres
managed.

regards
Philipp