[PATCH net-next v6 3/5] net: ftgmac100: Add RGMII delay support for AST2600

[Jacky Chou <jacky_chou@aspeedtech.com>]

> > > > Therefore, we calculate the delay stage from the
> > > > rx-internal-delay-ps of MAC2/3 to add 26. If the stage is equel to
> > > > or bigger than 32, the delay stage will be mask 0x1f to get the correct
> setting.
> > >
> > > Please return -EINVAL. Asking for more than 7.75ns is clearly broken.
> >
> > ...
> > 	tx_delay_index = DIV_ROUND_CLOSEST(rgmii_tx_delay,
> rgmii_delay_unit);
> > 	if (tx_delay_index >= 32) {
> > 		dev_err(dev, "The %u ps of TX delay is out of range\n",
> > 			rgmii_tx_delay);
> > 		return -EINVAL;
> > 	}
> >
> > 	rx_delay_index = DIV_ROUND_CLOSEST(rgmii_rx_delay,
> rgmii_delay_unit);
> > 	if (rx_delay_index >= 32) {
> > 		dev_err(dev, "The %u ps of RX delay is out of range\n",
> > 			rgmii_rx_delay);
> > 		return -EINVAL;
> > 	}
> > ...
> >
> > These codes will calculate the ns delay to MAC delay index.
> > (rgmii_delay_unit is 250 ps on MAC2/3) If set tx delay to 8 ns on MAC2
> > or MAC3, it will get index is 32.
> > It is over the delay configuration range, here will return -EINVAL.
> 
> So is the comment wrong? No masking is actually done?
> 

Yes. I will update the comment in next version.
Thank you for reminding me.

Thanks,
Jacky