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

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

> -----Original Message-----
> From: Andrew Lunn [mailto:andrew@lunn.ch]
> Sent: 15 August 2023 02:17
> To: Sriranjani P <sriranjani.p@samsung.com>
> Cc: davem@davemloft.net; edumazet@google.com; kuba@kernel.org;
> pabeni@redhat.com; robh+dt@kernel.org;
> krzysztof.kozlowski+dt@linaro.org; conor+dt@kernel.org;
> richardcochran@gmail.com; alexandre.torgue@foss.st.com;
> joabreu@synopsys.com; mcoquelin.stm32@gmail.com;
> alim.akhtar@samsung.com; linux-fsd@tesla.com;
> pankaj.dubey@samsung.com; swathi.ks@samsung.com;
> ravi.patel@samsung.com; netdev@vger.kernel.org;
> devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; linux-samsung-
> soc@vger.kernel.org; linux-arm-kernel@lists.infradead.org; Chandrasekar R
> <rcsekar@samsung.com>; Suresh Siddha <ssiddha@tesla.com>
> 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