Re: [PATCH net-next v3 2/2] net: mdio: mdio-i2c: Add support for single-byte SMBus operations

[Paolo Abeni <pabeni@redhat.com>]

On 3/14/25 5:23 PM, Maxime Chevallier wrote:
> diff --git a/drivers/net/mdio/mdio-i2c.c b/drivers/net/mdio/mdio-i2c.c
> index da2001ea1f99..202f486e71f1 100644
> --- a/drivers/net/mdio/mdio-i2c.c
> +++ b/drivers/net/mdio/mdio-i2c.c
> @@ -106,6 +106,62 @@ static int i2c_mii_write_default_c22(struct mii_bus *bus, int phy_id, int reg,
>  	return i2c_mii_write_default_c45(bus, phy_id, -1, reg, val);
>  }
>  
> +static int smbus_byte_mii_read_default_c22(struct mii_bus *bus, int phy_id,
> +					   int reg)
> +{
> +	struct i2c_adapter *i2c = bus->priv;
> +	union i2c_smbus_data smbus_data;
> +	int val = 0, ret;
> +
> +	if (!i2c_mii_valid_phy_id(phy_id))
> +		return 0;
> +
> +	ret = i2c_smbus_xfer(i2c, i2c_mii_phy_addr(phy_id), 0,
> +			     I2C_SMBUS_READ, reg,
> +			     I2C_SMBUS_BYTE_DATA, &smbus_data);
> +	if (ret < 0)
> +		return ret;
> +
> +	val = ((smbus_data.byte & 0xff) << 8);

External brackets not needed.

> +
> +	ret = i2c_smbus_xfer(i2c, i2c_mii_phy_addr(phy_id), 0,
> +			     I2C_SMBUS_READ, reg,
> +			     I2C_SMBUS_BYTE_DATA, &smbus_data);
> +	if (ret < 0)
> +		return ret;
> +
> +	val |= (smbus_data.byte & 0xff);

same here.

> +
> +	return val;
> +}
> +
> +static int smbus_byte_mii_write_default_c22(struct mii_bus *bus, int phy_id,
> +					    int reg, u16 val)
> +{
> +	struct i2c_adapter *i2c = bus->priv;
> +	union i2c_smbus_data smbus_data;
> +	int ret;
> +
> +	if (!i2c_mii_valid_phy_id(phy_id))
> +		return 0;
> +
> +	smbus_data.byte = ((val & 0xff00) >> 8);

and here.

> +
> +	ret = i2c_smbus_xfer(i2c, i2c_mii_phy_addr(phy_id), 0,
> +			     I2C_SMBUS_WRITE, reg,
> +			     I2C_SMBUS_BYTE_DATA, &smbus_data);
> +	if (ret < 0)
> +		return ret;
> +
> +	smbus_data.byte = val & 0xff;

I would not have noted the above if even this one carried additional
brackets...

Cheers,

Paolo