[Linux-stm32] [PATCH 1/2] net-next: stmmac: mediatek: add more suuport for RMII

[biao huang]

Hi Andrew,

	Thanks for your comments~

On Thu, 2019-12-12 at 14:25 +0100, Andrew Lunn wrote:

> On Thu, Dec 12, 2019 at 10:41:44AM +0800, Biao Huang wrote:
> > MT2712 SoC can provide the rmii reference clock, and the clock
> > will output from TXC pin only, which means ref_clk pin of external
> > PHY should connect to TXC pin in this case.
> > Add corresponding clock and timing settings.
> 
> Hi Biao
> 
> Subject line has a typo.

will fix in next version.

> 
> > @@ -278,6 +296,7 @@ static int mediatek_dwmac_config_dt(struct mediatek_dwmac_plat_data *plat)
> >  	mac_delay->tx_inv = of_property_read_bool(plat->np, "mediatek,txc-inverse");
> >  	mac_delay->rx_inv = of_property_read_bool(plat->np, "mediatek,rxc-inverse");
> >  	plat->rmii_rxc = of_property_read_bool(plat->np, "mediatek,rmii-rxc");
> > +	plat->rmii_clk_from_mac = of_property_read_bool(plat->np, "mediatek,rmii-clk-from-mac");
> >  
> >  	return 0;
> >  }
> > @@ -287,6 +306,16 @@ static int mediatek_dwmac_clk_init(struct mediatek_dwmac_plat_data *plat)
> >  	const struct mediatek_dwmac_variant *variant = plat->variant;
> >  	int i, num = variant->num_clks;
> >  
> > +	plat->mac_rmii_clk = NULL;
> > +	if (plat->phy_mode == PHY_INTERFACE_MODE_RMII &&
> > +	    plat->rmii_clk_from_mac) {
> > +		plat->mac_rmii_clk = devm_clk_get(plat->dev, "rmii_internal");
> > +		if (IS_ERR(plat->mac_rmii_clk)) {
> > +			dev_err(plat->dev, "Failed to get reference clk from MAC\n");
> > +			return PTR_ERR(plat->mac_rmii_clk);
> > +		}
> > +	}
> 
> Please don't use a binary property. This is a clock, so describe it in
> DT as a clock. Add it to the existing list of clocks.

The clock labeled as "rmii_internal" is needed only in RMII(when MAC
provides reference clock), and useless for RGMII/MII/RMII(when phy
provides reference clock).

So, add a boolean flag to indicate where the RMII reference clock is
from, MAC or PHY, if MAC, enable the "rmii_internal", or disable it.
and this clock already documented in dt-binding in PATCH 2/2.

For power saving, it should not be enabled in default, so can't add it
to the existing list of clocks directly.

Any advice for this special case?

Thanks.

> 
>    Andrew

Biao
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