pwm: jz4740: Document known limitations
The JZ4740 PWM implementation doesn't fulfill the (up to now
insufficiently documented) requirements of the PWM API. At least
document them in the driver.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c
index f901e8a..9d444d01 100644
--- a/drivers/pwm/pwm-jz4740.c
+++ b/drivers/pwm/pwm-jz4740.c
@@ -2,6 +2,11 @@
/*
* Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
* JZ4740 platform PWM support
+ *
+ * Limitations:
+ * - The .apply callback doesn't complete the currently running period before
+ * reconfiguring the hardware.
+ * - Each period starts with the inactive part.
*/
#include <linux/clk.h>
