Subject: Re: [PATCH RFC 10/26] phy: add I2C mdio bus

From: Florian Fainelli <[email-masked]>
Date: Tue, 08 Dec 2015 10:15:08 -0800

On 07/12/15 09:38, Russell King wrote:
> Add an I2C MDIO bus bridge library, to allow phylib to access PHYs which
> are connected to an I2C bus instead of the more conventional MDIO bus.
> Such PHYs can be found in SFP adapters and SFF modules.
> 
> Signed-off-by: Russell King <[email-masked]>
> ---
[snip]
> +static int i2c_mii_read(struct mii_bus *bus, int phy_id, int reg)
> +{
> +	struct i2c_adapter *i2c = bus->priv;
> +	struct i2c_msg msgs[2];
> +	u8 data[2], dev_addr = reg;
> +	int bus_addr, ret;
> +
> +	bus_addr = 0x40 + phy_id;
> +	if (bus_addr == 0x50 || bus_addr == 0x51)
> +		return 0xffff;

These could deserve a local definition for these specific addresses so
we know why there is such logic here.

> +
> +	msgs[0].addr = bus_addr;
> +	msgs[0].flags = 0;
> +	msgs[0].len = 1;
> +	msgs[0].buf = &dev_addr;
> +	msgs[1].addr = bus_addr;
> +	msgs[1].flags = I2C_M_RD;
> +	msgs[1].len = sizeof(data);
> +	msgs[1].buf = data;
> +
> +	ret = i2c_transfer(i2c, msgs, ARRAY_SIZE(msgs));
> +	if (ret != ARRAY_SIZE(msgs))
> +		return 0xffff;
> +
> +	return data[0] << 8 | data[1];
> +}
> +
> +static int i2c_mii_write(struct mii_bus *bus, int phy_id, int reg, u16 val)
> +{
> +	struct i2c_adapter *i2c = bus->priv;
> +	struct i2c_msg msg;
> +	int bus_addr, ret;
> +	u8 data[3];
> +
> +	bus_addr = 0x40 + phy_id;
> +	if (bus_addr == 0x50 || bus_addr == 0x51)
> +		return 0;

Same here.
-- 
Florian