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	id 1wr4vb-00FtYG-NS; Tue, 04 Aug 2026 04:30:51 +0200
Date: Tue, 4 Aug 2026 04:30:51 +0200
From: Andrew Lunn <andrew@lunn.ch>
To: Artem Shimko <a.shimko.dev@gmail.com>
Cc: netdev@vger.kernel.org, Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	"David S . Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Maxime Chevallier <maxime.chevallier@bootlin.com>,
	linux-kernel@vger.kernel.org, devicetree@vger.kernel.org
Subject: Re: [PATCH net-next v5 3/3] net: phy: add DAPU Telecom DAP8211R(I)
 Gigabit Ethernet PHY driver
Message-ID: <239a7699-bbda-4fab-bfa0-604b1d8806a9@lunn.ch>
References: <20260803101734.270821-1-a.shimko.dev@gmail.com>
 <20260803101734.270821-4-a.shimko.dev@gmail.com>
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In-Reply-To: <20260803101734.270821-4-a.shimko.dev@gmail.com>

> +/* Initial RGMII RX delay per hardware specification: 0 * 150ps == 0.00ns */
> +#define DAP8211R_INITIAL_RX_DEL_VAL	0
> +/* Initial RGMII TX delay per hardware specification: 1 * 150ps == 0.15ns*/
> +#define DAP8211R_INITIAL_TX_DEL_VAL	1
> +/* Default RGMII delay: 13 * 150 == 1.95ns */
> +#define DAP8211R_DEFAULT_DEL_SEL	0xD


> +static int dap8211r_config_init(struct phy_device *phydev)
> +{
> +	u16 set = 0;
> +	int ret, val;
> +	s32 rx_internal_delay = DAP8211R_INITIAL_RX_DEL_VAL;
> +	s32 tx_internal_delay = DAP8211R_INITIAL_TX_DEL_VAL;
> +
> +	if (!phy_interface_is_rgmii(phydev))
> +		return 0;
> +
> +	if (phydev->interface != PHY_INTERFACE_MODE_RGMII_TXID)
> +		rx_internal_delay = phy_get_internal_delay(phydev, dap8211r_internal_delay,
> +							   DAP8211R_DELAY_SIZE, true);
> +
> +	if (phydev->interface != PHY_INTERFACE_MODE_RGMII_RXID)
> +		tx_internal_delay = phy_get_internal_delay(phydev, dap8211r_internal_delay,
> +							   DAP8211R_DELAY_SIZE, false);
> +
> +	switch (phydev->interface) {
> +	case PHY_INTERFACE_MODE_RGMII:
> +		if (rx_internal_delay < 0)
> +			rx_internal_delay = DAP8211R_INITIAL_RX_DEL_VAL;
> +
> +		if (tx_internal_delay < 0)
> +			tx_internal_delay = DAP8211R_INITIAL_TX_DEL_VAL;
> +		break;

Why 0.00 for one and 0.15ns for the other? PHY_INTERFACE_MODE_RGMII
means no delays.

	Andrew