Hi Dylan,
On Mo, 2022-03-21 at 15:01 +0800, Dylan Hung wrote:
> Add reset deassertion for Aspeed MDIO. There are 4 MDIO controllers
> embedded in Aspeed AST2600 SOC and share one reset control register
> SCU50[3]. So devm_reset_control_get_shared is used in this change.
>
> Signed-off-by: Dylan Hung <dylan_hung@xxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> drivers/net/mdio/mdio-aspeed.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/net/mdio/mdio-aspeed.c b/drivers/net/mdio/mdio-
> aspeed.c
> index e2273588c75b..8ac262a12d13 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_shared(&pdev->dev, NULL);
The device tree bindings should have a required reset control property
documented before this is added.
> + if (IS_ERR(ctx->reset))
> + return PTR_ERR(ctx->reset);
> +
> + reset_control_deassert(ctx->reset);
> +
This is missing a corresponding reset_control_assert() in
aspeed_mdio_remove() and in the error path of of_mdiobus_register().
That would allow to assert the reset line again after all MDIO
controllers are unbound.
regards
Philipp
