Re: [EXTERNAL] Re: [RESEND PATCH] net: ethernet: ti: davinci_mdio: Add workaround for errata i2329

[Ravi Gunasekaran]

Hello Andrew,

On 09/08/22 1:43 am, Andrew Lunn wrote:
> > +static int davinci_mdio_sw_read(struct mii_bus *bus, int phy_id, int phy_reg)
> > +{
> > +	struct davinci_mdio_data *data = bus->priv;
> > +	u32 reg, i;
> > +	int ret;
> > +	u8 ack;
> > +
> > +	if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
> > +		return -EINVAL;
> > +
> > +	ret = pm_runtime_get_sync(data->dev);
> > +	if (ret < 0) {
> > +		pm_runtime_put_noidle(data->dev);
> > +		return ret;
> > +	}
> > +
> > +	davinci_mdio_disable(data);
> > +	davinci_mdio_enable_manual_mode(data);
> > +	davinci_mdio_sw_preamble(data);
> > +
> > +	davinci_mdio_sw_clr_bit(data, MDIO_MDCLK);
> > +	davinci_mdio_sw_set_bit(data, MDIO_OE);
> > +
> > +	 /* Issue clause 22 MII read function {0,1,1,0} */
> > +	davinci_mdio_man_send_pattern(data, C22_BITRANGE, C22_READ_PATTERN);
> > +
> > +	/* Send the device number MSB first */
> > +	davinci_mdio_man_send_pattern(data, PHY_BITRANGE, phy_id);
> > +
> > +	/* Send the register number MSB first */
> > +	davinci_mdio_man_send_pattern(data, PHY_BITRANGE, phy_reg);
> > +
> > +	/* Send turn around cycles */
> > +	davinci_mdio_sw_clr_bit(data, MDIO_OE);
> > +
> > +	davinci_mdio_toggle_man_bit(data, MDIO_MDCLK);
> > +
> > +	ack = davinci_mdio_test_man_bit(data, MDIO_PIN);
> > +	davinci_mdio_toggle_man_bit(data, MDIO_MDCLK);
> > +
> > +	reg = 0;
> > +	if (ack == 0) {
> > +		for (i = MDIO_BITRANGE; i; i = i >> 1) {
> > +			if (davinci_mdio_test_man_bit(data, MDIO_PIN))
> > +				reg |= i;
> > +
> > +			davinci_mdio_toggle_man_bit(data, MDIO_MDCLK);
> > +		}
> > +	} else {
> > +		for (i = MDIO_BITRANGE; i; i = i >> 1)
> > +			davinci_mdio_toggle_man_bit(data, MDIO_MDCLK);
> > +
> > +		reg = 0xFFFF;
> > +	}
> > +
> > +	davinci_mdio_sw_clr_bit(data, MDIO_MDCLK);
> > +	davinci_mdio_sw_set_bit(data, MDIO_MDCLK);
> > +	davinci_mdio_sw_set_bit(data, MDIO_MDCLK);
> > +	davinci_mdio_toggle_man_bit(data, MDIO_MDCLK);
>
> You appear to of re-invented drivers/net/mdio/mdio-bitbang.c
>
> If there is a reason this cannot be used, please at least state it in
> the commit message.
Thanks for reviewing the patch. Since mdiobb_{read,write}() are exported, I can 
invoke these in my mdio read/write implementation. I will rework and send the v2 patch

>      Andrew

--
Regards,
Ravi