[PATCH v2] net: mdio: mux-meson-gxl: set 28th bit in eth_reg2

[Neil Armstrong]

On 31/03/2025 09:44, Christian Hewitt wrote:
> From: Da Xue <da at libre.computer>
> 
> This bit is necessary to enable packets on the interface. Without this
> bit set, ethernet behaves as if it is working, but no activity occurs.
> 
> The vendor SDK sets this bit along with the PHY_ID bits. U-boot also
> sets this bit, but if u-boot is not compiled with networking support
> the interface will not work.
> 
> Fixes: 9a24e1ff4326 ("net: mdio: add amlogic gxl mdio mux support");
> Signed-off-by: Da Xue <da at libre.computer>
> Signed-off-by: Christian Hewitt <christianshewitt at gmail.com>
> ---
> Resending on behalf of Da Xue who has email sending issues.
> Changes since v1 [0]:
> - Remove blank line between Fixes and SoB tags
> - Submit without mail server mangling the patch
> - Minor tweaks to subject line and commit message
> - CC to stable at vger.kernel.org
> 
> [0] https://patchwork.kernel.org/project/linux-amlogic/patch/CACqvRUbx-KsrMwCHYQS6eGXBohynD8Q1CQx=8=9VhqZi13BCQQ@mail.gmail.com/
> 
>   drivers/net/mdio/mdio-mux-meson-gxl.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/mdio/mdio-mux-meson-gxl.c b/drivers/net/mdio/mdio-mux-meson-gxl.c
> index 00c66240136b..fc5883387718 100644
> --- a/drivers/net/mdio/mdio-mux-meson-gxl.c
> +++ b/drivers/net/mdio/mdio-mux-meson-gxl.c
> @@ -17,6 +17,7 @@
>   #define  REG2_LEDACT		GENMASK(23, 22)
>   #define  REG2_LEDLINK		GENMASK(25, 24)
>   #define  REG2_DIV4SEL		BIT(27)
> +#define  REG2_RESERVED_28	BIT(28)
>   #define  REG2_ADCBYPASS		BIT(30)
>   #define  REG2_CLKINSEL		BIT(31)
>   #define ETH_REG3		0x4
> @@ -65,7 +66,7 @@ static void gxl_enable_internal_mdio(struct gxl_mdio_mux *priv)
>   	 * The only constraint is that it must match the one in
>   	 * drivers/net/phy/meson-gxl.c to properly match the PHY.
>   	 */
> -	writel(FIELD_PREP(REG2_PHYID, EPHY_GXL_ID),
> +	writel(REG2_RESERVED_28 | FIELD_PREP(REG2_PHYID, EPHY_GXL_ID),
>   	       priv->regs + ETH_REG2);
>   
>   	/* Enable the internal phy */

Reviewed-by: Neil Armstrong <neil.armstrong at linaro.org>