RE: [PATCH v3 2/4] net: stmmac: dwc-qos: Add FSD EQoS support

["Swathi K S" <swathi.ks@xxxxxxxxxxx>]

> -----Original Message-----
> From: Andrew Lunn [mailto:andrew@xxxxxxx]
> Sent: 15 August 2023 02:17
> To: Sriranjani P <sriranjani.p@xxxxxxxxxxx>
> Cc: davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx;
> pabeni@xxxxxxxxxx; robh+dt@xxxxxxxxxx;
> krzysztof.kozlowski+dt@xxxxxxxxxx; conor+dt@xxxxxxxxxx;
> richardcochran@xxxxxxxxx; alexandre.torgue@xxxxxxxxxxx;
> joabreu@xxxxxxxxxxxx; mcoquelin.stm32@xxxxxxxxx;
> alim.akhtar@xxxxxxxxxxx; linux-fsd@xxxxxxxxx;
> pankaj.dubey@xxxxxxxxxxx; swathi.ks@xxxxxxxxxxx;
> ravi.patel@xxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-samsung-
> soc@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; Chandrasekar R
> <rcsekar@xxxxxxxxxxx>; Suresh Siddha <ssiddha@xxxxxxxxx>
> Subject: Re: [PATCH v3 2/4] net: stmmac: dwc-qos: Add FSD EQoS support
> 
> > +static const int rx_clock_skew_val[] = {0x2, 0x0};
> 
> > +static int dwc_eqos_setup_rxclock(struct platform_device *pdev, int
> > +ins_num) {
> > +	struct device_node *np = pdev->dev.of_node;
> > +	struct regmap *syscon;
> > +	unsigned int reg;
> > +
> > +	if (np && of_property_read_bool(np, "fsd-rx-clock-skew")) {
> > +		syscon = syscon_regmap_lookup_by_phandle_args(np,
> > +							      "fsd-rx-clock-
> skew",
> > +							      1, &reg);
> > +		if (IS_ERR(syscon)) {
> > +			dev_err(&pdev->dev,
> > +				"couldn't get the rx-clock-skew syscon!\n");
> > +			return PTR_ERR(syscon);
> > +		}
> > +
> > +		regmap_write(syscon, reg, rx_clock_skew_val[ins_num]);
> 
> Please could you explain what this is doing.

As per customer requirement, we need to provide a delay of 2ns in FSYS in
both TX and RX path and no delay in peric block

> 
>        Andrew

Regards,
Swathi