OPP: debugfs: Use performance level if available to distinguish between rates

Some OPP tables have entries with same rate and different performance
level. For these entries, using only the rate as the debugfs directory name
causes below error:

debugfs: 'opp:5000000' already exists in 'soc@0-1c00000.pci'

Fix it by appending the performance level to the dir name if available.

Reported-by: Bjorn Andersson <andersson@kernel.org>
Closes: https://lore.kernel.org/linux-arm-msm/75lzykd37zdvrks5i2bb4zb2yzjtm25kv3hegmikndkbr772mz@w2ykff3ny45u/
Fixes: 05db359 ("OPP: Add support to find OPP for a set of keys")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

Author: Mani-Sadhasivam

drivers/opp/debugfs.c

@@ -130,22 +130,24 @@ void opp_debug_create_one(struct dev_pm_opp *opp, struct opp_table *opp_table)
 {
 	struct dentry *pdentry = opp_table->dentry;
 	struct dentry *d;
-	unsigned long id;
-	char name[25];	/* 20 chars for 64 bit value + 5 (opp:\0) */
+	char name[36];	/* "opp:"(4) + u64(20) + "-" (1) + u32(10) + NULL(1) */
 
 	/*
 	 * Get directory name for OPP.
 	 *
-	 * - Normally rate is unique to each OPP, use it to get unique opp-name.
+	 * - Normally rate is unique to each OPP, use it to get unique opp-name,
+	 *   together with performance level if available.
 	 * - For some devices rate isn't available or there are multiple, use
 	 *   index instead for them.
 	 */
-	if (likely(opp_table->clk_count == 1 && opp->rates[0]))
-		id = opp->rates[0];
-	else
-		id = _get_opp_count(opp_table);
-
-	snprintf(name, sizeof(name), "opp:%lu", id);
+	if (likely(opp_table->clk_count == 1 && opp->rates[0])) {
+		if (opp->level == OPP_LEVEL_UNSET)
+			snprintf(name, sizeof(name), "opp:%lu", opp->rates[0]);
+		else
+			snprintf(name, sizeof(name), "opp:%lu-%u", opp->rates[0], opp->level);
+	} else {
+		snprintf(name, sizeof(name), "opp:%u", _get_opp_count(opp_table));
+	}
 
 	/* Create per-opp directory */
 	d = debugfs_create_dir(name, pdentry);