Subject: Re: [PATCH net-next 1/5] net: txgbe: Identify PHY and SFP module

From: Andrew Lunn <[email-masked]>
Date: Tue, 8 Nov 2022 21:52:51 +0100

> +/**
> + *  txgbe_identify_sfp_module - Identifies SFP modules
> + *  @hw: pointer to hardware structure
> + *
> + *  Searches for and identifies the SFP module and assigns appropriate PHY type.
> + **/
> +static int txgbe_identify_sfp_module(struct txgbe_hw *hw)
> +{
> +	u8 oui_bytes[3] = {0, 0, 0};
> +	u8 comp_codes_10g = 0;
> +	u8 comp_codes_1g = 0;
> +	int status = -EFAULT;
> +	u32 vendor_oui = 0;
> +	u8 identifier = 0;
> +	u8 cable_tech = 0;
> +	u8 cable_spec = 0;
> +
> +	/* LAN ID is needed for I2C access */
> +	txgbe_init_i2c(hw);
> +
> +	status = txgbe_read_i2c_eeprom(hw, TXGBE_SFF_IDENTIFIER, &identifier);
> +	if (status != 0)
> +		goto err_read_i2c_eeprom;
> +
> +	if (identifier != TXGBE_SFF_IDENTIFIER_SFP) {
> +		hw->phy.type = txgbe_phy_sfp_unsupported;
> +		status = -ENODEV;
> +	} else {
> +		status = txgbe_read_i2c_eeprom(hw, TXGBE_SFF_1GBE_COMP_CODES,
> +					       &comp_codes_1g);
> +		if (status != 0)
> +			goto err_read_i2c_eeprom;
> +
> +		status = txgbe_read_i2c_eeprom(hw, TXGBE_SFF_10GBE_COMP_CODES,
> +					       &comp_codes_10g);
> +		if (status != 0)
> +			goto err_read_i2c_eeprom;
> +
> +		status = txgbe_read_i2c_eeprom(hw, TXGBE_SFF_CABLE_TECHNOLOGY,
> +					       &cable_tech);
> +		if (status != 0)
> +			goto err_read_i2c_eeprom;
> +
> +		 /* ID Module
> +		  * =========
> +		  * 1   SFP_DA_CORE
> +		  * 2   SFP_SR/LR_CORE
> +		  * 3   SFP_act_lmt_DA_CORE
> +		  * 4   SFP_1g_cu_CORE
> +		  * 5   SFP_1g_sx_CORE
> +		  * 6   SFP_1g_lx_CORE
> +		  */

So it looks like you have Linux driving the SFP, not firmware. In that
case, please throw all this code away. Implement a standard Linux I2C
bus master driver, and make use of driver/net/phy/sfp*.[ch].

    Andrew