Re: [PATCH RFC net-next 8/9] net: stmmac: qcom-ethqos: support external PCS

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

Hi Ayaan,

On 9/23/26 03:07, Mohd Ayaan Anwar wrote:
> Select the XPCS instance initialized by stmmac when firmware provides
> a pcs-handle. Reject interfaces that are not supported by the selected
> PCS.
> 
> Signed-off-by: Mohd Ayaan Anwar <mohd.anwar@oss.qualcomm.com>
> ---
>  .../net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c  | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
> index ac7d6d3e205a1ab5b391def879d6f1033a0961b6..a99a78880c0fb7858e90b6212b37ebfc7fccaf84 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
> @@ -7,6 +7,8 @@
>  #include <linux/platform_device.h>
>  #include <linux/phy.h>
>  #include <linux/phy/phy.h>
> +#include <linux/pcs/pcs-xpcs.h>
> +#include <linux/property.h>
>  
>  #include "stmmac.h"
>  #include "stmmac_platform.h"
> @@ -681,6 +683,21 @@ static void ethqos_ptp_clk_freq_config(struct stmmac_priv *priv)
>  	netdev_dbg(priv->dev, "PTP rate %lu\n", plat_dat->clk_ptp_rate);
>  }
>  
> +static struct phylink_pcs *
> +qcom_ethqos_select_pcs(struct stmmac_priv *priv, phy_interface_t interface)
> +{
> +	struct phylink_pcs *pcs;
> +
> +	if (!priv->hw->xpcs)
> +		return ERR_PTR(-ENODEV);

If there's no device (i.e. no PCS), then you should return NULL.

> +
> +	pcs = xpcs_to_phylink_pcs(priv->hw->xpcs);
> +	if (!test_bit(interface, pcs->supported_interfaces))
> +		return ERR_PTR(-EOPNOTSUPP);

phylink already checks if the interface is in pcs->supported_interfaces,
no need to do it here :)

Thanks,

Maxime