pwm: Let pwm_set_waveform_might_sleep() return 0 instead of 1 after rounding up

While telling the caller of pwm_set_waveform_might_sleep() if the
request was completed by rounding down only or (some) rounding up gives
additional information, it makes usage this function needlessly hard and
the additional information is not used. A prove for that is that
currently both users of this function just pass the returned value up to
their caller even though a positive value isn't intended there.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/528cc3bbd9e35dea8646b1bcc0fbfe6c498bb4ed.1746010245.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

Author: ukleinek

drivers/pwm/core.c

@@ -411,9 +411,8 @@ static int __pwm_set_waveform(struct pwm_device *pwm,
  * possible/needed. In the above example requesting .period_length_ns = 94 and
  * @exact = true, you get the hardware configured with period = 93.5 ns.
  *
- * Returns: 0 on success, 1 if was rounded up (if !@exact), -EDOM if setting
- * failed due to the exact waveform not being possible (if @exact), or a
- * different negative errno on failure.
+ * Returns: 0 on success, -EDOM if setting failed due to the exact waveform not
+ * being possible (if @exact), or a different negative errno on failure.
  * Context: May sleep.
  */
 int pwm_set_waveform_might_sleep(struct pwm_device *pwm,
@@ -442,14 +441,17 @@ int pwm_set_waveform_might_sleep(struct pwm_device *pwm,
 	}
 
 	/*
-	 * map err == 1 to -EDOM for exact requests. Also make sure that -EDOM is
-	 * only returned in exactly that case. Note that __pwm_set_waveform()
-	 * should never return -EDOM which justifies the unlikely().
+	 * map err == 1 to -EDOM for exact requests and 0 for !exact ones. Also
+	 * make sure that -EDOM is only returned in exactly that case. Note that
+	 * __pwm_set_waveform() should never return -EDOM which justifies the
+	 * unlikely().
 	 */
 	if (unlikely(err == -EDOM))
 		err = -EINVAL;
 	else if (exact && err == 1)
 		err = -EDOM;
+	else if (err == 1)
+		err = 0;
 
 	return err;
 }