Re: [PATCH] phy: rockchip: naneng-combphy: Fix TX detect RX termination errata

[Vinod Koul <vkoul@kernel.org>]

On 25-03-26, 15:23, Shawn Lin wrote:
> Some PHY revisions may fail to detect the peer RX's termination
> resistor (RTERM) under certain critical temperature conditions.
> This causes TX detection failures on PCIe links.
> 
> Add a workaround to force the RTERM detection ready signal for
> affected PHY revisions. This ensures reliable TX-to-RX termination
> detection across all operating temperature ranges.
> 
> The fix applies to RK3562, RK3568, RK3576 and RK3588 SoCs which share
> the same PHY IP with this hardware errata.

Missing Fixes tag?

> 
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
> ---
> 
>  drivers/phy/rockchip/phy-rockchip-naneng-combphy.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/drivers/phy/rockchip/phy-rockchip-naneng-combphy.c b/drivers/phy/rockchip/phy-rockchip-naneng-combphy.c
> index b60d6bf..76d4994 100644
> --- a/drivers/phy/rockchip/phy-rockchip-naneng-combphy.c
> +++ b/drivers/phy/rockchip/phy-rockchip-naneng-combphy.c
> @@ -106,6 +106,9 @@
>  #define RK3568_PHYREG18				0x44
>  #define RK3568_PHYREG18_PLL_LOOP		0x32
>  
> +#define RK3568_PHYREG26				0x64
> +#define RK3568_PHYREG26_FORCE_RTERM_DET_RDY	BIT(5)
> +
>  #define RK3568_PHYREG30				0x74
>  #define RK3568_PHYREG30_GATE_TX_PCK_SEL         BIT(7)
>  #define RK3568_PHYREG30_GATE_TX_PCK_DLY_PLL_OFF BIT(7)
> @@ -193,6 +196,7 @@ struct rockchip_combphy_cfg {
>  	unsigned int num_phys;
>  	unsigned int phy_ids[3];
>  	const struct rockchip_combphy_grfcfg *grfcfg;
> +	bool force_rxterm_det_rdy;
>  	int (*combphy_cfg)(struct rockchip_combphy_priv *priv);
>  };
>  
> @@ -264,6 +268,17 @@ static int rockchip_combphy_init(struct phy *phy)
>  
>  	switch (priv->type) {
>  	case PHY_TYPE_PCIE:
> +		/*
> +		 * Hardware Errata: TX fails to detect peer RX termination.

Is there an errata number or links which people can refer to?

> +		 * Some PHY revisions may fail to detect remote RX's RTERM
> +		 * (receiver termination resistor) under certain critical
> +		 * temperature conditions. Set force rterm detect ready to
> +		 * fix it.
> +		 */
> +		if (priv->cfg->force_rxterm_det_rdy)
> +			rockchip_combphy_updatel(priv, RK3568_PHYREG26_FORCE_RTERM_DET_RDY,
> +					RK3568_PHYREG26_FORCE_RTERM_DET_RDY, RK3568_PHYREG26);
> +		fallthrough;
>  	case PHY_TYPE_USB3:
>  	case PHY_TYPE_SATA:
>  	case PHY_TYPE_SGMII:
> @@ -745,6 +760,7 @@ static const struct rockchip_combphy_cfg rk3562_combphy_cfgs = {
>  	},
>  	.grfcfg		= &rk3562_combphy_grfcfgs,
>  	.combphy_cfg	= rk3562_combphy_cfg,
> +	.force_rxterm_det_rdy  = true,
>  };
>  
>  static int rk3568_combphy_cfg(struct rockchip_combphy_priv *priv)
> @@ -962,6 +978,7 @@ static const struct rockchip_combphy_cfg rk3568_combphy_cfgs = {
>  	},
>  	.grfcfg		= &rk3568_combphy_grfcfgs,
>  	.combphy_cfg	= rk3568_combphy_cfg,
> +	.force_rxterm_det_rdy  = true,
>  };
>  
>  static int rk3576_combphy_cfg(struct rockchip_combphy_priv *priv)
> @@ -1231,6 +1248,7 @@ static const struct rockchip_combphy_cfg rk3576_combphy_cfgs = {
>  	},
>  	.grfcfg		= &rk3576_combphy_grfcfgs,
>  	.combphy_cfg	= rk3576_combphy_cfg,
> +	.force_rxterm_det_rdy  = true,
>  };
>  
>  static int rk3588_combphy_cfg(struct rockchip_combphy_priv *priv)
> @@ -1418,6 +1436,7 @@ static const struct rockchip_combphy_cfg rk3588_combphy_cfgs = {
>  	},
>  	.grfcfg		= &rk3588_combphy_grfcfgs,
>  	.combphy_cfg	= rk3588_combphy_cfg,
> +	.force_rxterm_det_rdy  = true,
>  };
>  
>  static const struct of_device_id rockchip_combphy_of_match[] = {
> -- 
> 2.7.4
> 
> 
> -- 
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> linux-phy@lists.infradead.org
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-- 
~Vinod

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