Re: [PATCH] net: phy: motorcomm: Fix the issue in the code regarding the incorrect use of time units

On Tue, Oct 28, 2025 at 01:07:34PM +0100, Andrew Lunn wrote:

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 #define YT8521_CCR_RXC_DLY_EN			BIT(8)
-#define YT8521_CCR_RXC_DLY_1_900_NS		1900
+#define YT8521_CCR_RXC_DLY_1_900_PS		1900

This could be down to interpretation.

#define YT8521_CCR_RXC_DLY_1.900_NS		1900

would be technically correct, but not valid for cpp(1). So the . is
replaced with a _ .

#define YT8521_CCR_RXC_DLY_1900_PS		1900

would also be correct, but that is not what you have in your patch,
you leave the _ in place.

Alright, I didn't realize that 1_950 represents 1.950;
I thought the underscores were used for code neatness,
making numbers like 900 and 1050 the same length, for example:
#define YT8521_RC1R_RGMII_0_900_PS
#define YT8521_RC1R_RGMII_1_050_PS

In that case, is my patch still necessary?

I think it is unnecessary.

If you want, you could add a comment which explains that the _ should
be read as a .  However, this does appear elsewhere in Linux, it is
one of those things you learn with time.

Hang on.

Is the "1900" 1.9ns or 1.9ps ?

If YT8521_CCR_RXC_DLY_1_900_NS means 1.9ns, and the value is in ps,
then surely if it's being renamed to _PS, then it _must_ become
YT8521_CCR_RXC_DLY_1900_NS, because 1.900ps is wrong?

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