On Sat, 6 Nov 2021, at 20:32, Chin-Ting Kuo wrote:

Hi Andrew,

quoted

quoted

quoted

-	rc = device_property_read_u32_array(dev, prop, degrees, 2);

+	rc = device_property_read_u32_array(dev, prop, degrees, 4);
 	phase->valid = !rc;
 	if (phase->valid) {
-		phase->in_deg = degrees[0];
-		phase->out_deg = degrees[1];
+		phase->inv_in_deg = degrees[0] ? true : false;
+		phase->in_deg = degrees[1];
+		phase->inv_out_deg = degrees[2] ? true : false;
+		phase->out_deg = degrees[3];

This fundamentally breaks any in-tree users. We can't do this.

In terms of the binding, if negative phase values are something we must do,
we can just extend the value range to include [-359, -1] right?

Yes, agree it and I tried it before. But, it seems that the device tree 
doesn't support
negative value with "-" prefixed and there is no device tree related 
API used to get
the negative value from .dts. Thus, I tried to add an additional flag 
to present
negative value.

Hmm. Still, I don't think we can break the binding this way.

Rob, Ulf, Adrian: What are your thoughts on handling phase offsets in 
[-360, 360] in the binding? Do we append the flag field? Add a separate 
property? I don't think interleaving the flags is desirable, though 
interested in your thoughts.

Andrew