Re: [PATCH 5/7] powerpc/85xx: p2020: Define just one machine description

On Monday 26 September 2022 10:02:47 Christophe Leroy wrote:

quoted

+static int __init p2020_probe(void)
  {
-	if (of_machine_is_compatible("fsl,P2020RDB-PC"))
-		return 1;
-	return 0;
+	struct device_node *p2020_cpu;
+
+	/*
+	 * There is no common compatible string for all P2020 boards.
+	 * The only common thing is "PowerPC,P2020@0" cpu node.
+	 * So check for P2020 board via this cpu node.
+	 */
+	p2020_cpu = of_find_node_by_path("/cpus/PowerPC,P2020@0");
+	if (!p2020_cpu)
+		return 0;

This looks odd. I though all probe were using the compatible, and in 
fact I have a series in preparation that drops all 
of_machine_is_compatible() checks in probe functions and do it in the 
caller instead, after adding a .compatible string in the machine 
description.

Is there really no compatible that can be used for all p2020 ?

Really. There is none. I have looked into all available P2020 DTB files
(either externals passed by bootloader or kernel in-tree) and there is
no common compatible string. The only "common" thing is cpu node, how I
implemented it int this patch series.

And same issue is with boards with P101x and P102x DTB files.