arch/arm/mach-omap2/omap5/fdt.c: ft_fixup_clocks: use clock-output-names property as fallback (kernel 5.19+)

Clock names has been updated in kernel 5.19+ with the removal of
non-standard node names [1]. Due to this change, ft_opp_clock_fixups()
doesn't work anymore since ft_fixup_clocks() is looking to the clock
name and ft_opp_clock_fixups() error out with the following message:

  ft_fixup_clocks failed for DSP voltage domain: <valid offset/length>

We can't use the new clock name since several clock are using the same
generic name "clock". ft_opp_clock_fixups() is looking at the clocks
node in cm_core_aon@0:

/sys/firmware/devicetree/base/ocp/interconnect@4a000000/segment@0/target-module@5000/cm_core_aon@0/clocks
  ...
  clock@120
  clock@160
  clock@1a0
  clock@1e0
  clock@210
  clock@234
  clock@284
  clock@2a8
  clock@2d8

When fdt_subnode_offset() fail, we can look at clock-output-names
property as fallback since it contain the previous clock name.

libfdt doesn't provide any support to replace fdt_subnode_offset() by
a new function looking for clock-output-names property instead of the
node name. So we have to implement it in arch/arm/mach-omap2/omap5/fdt.c
for now.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e4920169e7a2a839836d3a0d8cda1bae8caa3056

Cc: Suman Anna <s-anna@ti.com>
Cc: Tom Rini <trini@konsulko.com>
Cc: Andrew Davis <afd@ti.com>
Signed-off-by: Romain Naour <romain.naour@skf.com>

1 files changed, 33 insertions, 4 deletions

diff --git a/arch/arm/mach-omap2/omap5/fdt.c b/arch/arm/mach-omap2/omap5/fdt.c
index a8c301c6c28..0ca02e664c4 100644
--- a/arch/arm/mach-omap2/omap5/fdt.c
+++ b/arch/arm/mach-omap2/omap5/fdt.c
@@ -206,9 +206,28 @@ u32 dra7_opp_gpu_clk_rates[NUM_OPPS][OPP_GPU_CLK_NUM] = {
 	{1064000000, 532000000}, /* OPP_HIGH */
 };
 
+static int fdt_clock_output_name_eq_(const void *fdt, int offset,
+				     const char *s, int len)
+{
+	int olen;
+	const char *p = fdt_getprop(fdt, offset, "clock-output-names", &olen);
+
+	if (!p)
+		/* short match */
+		return 0;
+
+	if (memcmp(p, s, len) != 0)
+		return 0;
+
+	if (p[len] == '\0')
+		return 1;
+	else
+		return 0;
+}
+
 static int ft_fixup_clocks(void *fdt, const char **names, u32 *rates, int num)
 {
-	int offs, node_offs, ret, i;
+	int offs, node_offs, subnode, ret, i;
 	uint32_t phandle;
 
 	offs = fdt_path_offset(fdt, "/ocp/interconnect@4a000000/segment@0/target-module@5000/cm_core_aon@0/clocks");
@@ -223,9 +242,19 @@ static int ft_fixup_clocks(void *fdt, const char **names, u32 *rates, int num)
 	for (i = 0; i < num; i++) {
 		node_offs = fdt_subnode_offset(fdt, offs, names[i]);
 		if (node_offs < 0) {
-			debug("Could not find clock sub-node %s: %s\n",
-			      names[i], fdt_strerror(node_offs));
-			return offs;
+			for (subnode = fdt_first_subnode(fdt, offs);
+			     subnode >= 0;
+			     subnode = fdt_next_subnode(fdt, subnode)) {
+				ret = fdt_clock_output_name_eq_(fdt, subnode, names[i],
+								strlen(names[i]));
+				if (ret)
+					node_offs = subnode;
+			}
+			if (node_offs < 0) {
+				debug("Could not find clock sub-node %s: %s\n",
+				      names[i], fdt_strerror(node_offs));
+				return offs;
+			}
 		}
 
 		phandle = fdt_get_phandle(fdt, node_offs);