tests: drivers: counter: Configurable ticks tolerance

Make ticks tolerance configurable for chips which need a more
relaxed value for testcase which assesses count precision.

Signed-off-by: Raffael Rostagno <[email protected]>

Author: Raffael Rostagno

tests/drivers/counter/counter_basic_api/Kconfig

@@ -7,4 +7,13 @@ config TEST_DRIVER_COUNTER_MCUX_LPC_RTC_HIGHRES
 	help
 	  tests the nxp_lpc_rtc_highres compatible driver
 
+config TEST_DRIVER_COUNTER_TOLERANCE
+	int "Counter ticks tolerance (%)"
+	default 10
+	help
+	  Error tolerance used in counter driver tests.
+	  A number of ticks is estimated and counter is tested against systimer,
+	  to verify accuracy. Tolerance is a percentage of deviation allowed for
+	  the number of expected ticks.
+
 source "Kconfig.zephyr"

tests/drivers/counter/counter_basic_api/src/test_counter.c

@@ -744,8 +744,8 @@ static void test_valid_function_without_alarm(const struct device *dev)
 		ticks_expected = counter_us_to_ticks(dev, wait_for_us);
 	}
 
-	/* Set 10% or 2 ticks tolerance, whichever is greater */
-	ticks_tol = ticks_expected / 10;
+	/* Set percentage or 2 ticks tolerance, whichever is greater */
+	ticks_tol = (ticks_expected * CONFIG_TEST_DRIVER_COUNTER_TOLERANCE) / 100;
 	ticks_tol = ticks_tol < 2 ? 2 : ticks_tol;
 
 	err = counter_start(dev);