[PATCH v2] powercap: intel_rapl_tpmi: Handle PMU registration failure during probe

[Sumeet Pawnikar <sumeet4linux@gmail.com>]

intel_rapl_tpmi_probe() invokes rapl_package_add_pmu() but ignores
its return value, so a PMU registration failure would leave the driver
reporting probe success despite the PMU being absent, with no log
trace.

Since PMU registration is an optional auxiliary feature for perf energy
counters, its failure should not break the primary powercap functionality.
Check the return value and log a warning to ensure graceful degradation.

Fixes: 963a9ad3c589 ("powercap: intel_rapl_tpmi: Enable PMU support")
Signed-off-by: Sumeet Pawnikar <sumeet4linux@gmail.com>
---
v1->v2: 
  * Since PMU registration is an optional auxiliary feature here,
    treat it's failure as a non fatal error and log a warning
    and continue, similar to other RAPL drivers like intel_rapl_msr,
    to ensure graceful degradation (Based on Sashiko feedback:
    https://sashiko.dev/#/patchset/20260515184250.228062-1-sumeet4linux%40gmail.com)
  * Add Fixes tag in changelog.
---
 drivers/powercap/intel_rapl_tpmi.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/powercap/intel_rapl_tpmi.c b/drivers/powercap/intel_rapl_tpmi.c
index 7f41491d9cd1..078a85158ce4 100644
--- a/drivers/powercap/intel_rapl_tpmi.c
+++ b/drivers/powercap/intel_rapl_tpmi.c
@@ -414,7 +414,10 @@ static int intel_rapl_tpmi_probe(struct auxiliary_device *auxdev,
 		goto err;
 	}
 
-	rapl_package_add_pmu(trp->rp);
+	ret = rapl_package_add_pmu(trp->rp);
+	if (ret)
+		dev_warn(&auxdev->dev, "Failed to add RAPL PMU for Package%d, %ld\n",
+			info->package_id, ret);
 
 	auxiliary_set_drvdata(auxdev, trp);
 
-- 
2.43.0