[PATCH v3 2/5] pwm: omap-dmtimer: Update description for pwm omap dm timer

Lokesh Vutla
2020-03-12T04:23:14Z

Update the description with a brief about how pwm is generated
using OMAP DM timer and add Limitations for the pwm generations.
Also add link to the Reference Manual.

Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
---
drivers/pwm/pwm-omap-dmtimer.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-omap-dmtimer.c b/drivers/pwm/pwm-omap-dmtimer.c
index e4f5f710bfaa..92aac6c86b95 100644
--- a/drivers/pwm/pwm-omap-dmtimer.c
+++ b/drivers/pwm/pwm-omap-dmtimer.c
@@ -10,7 +10,15 @@
*
* Description:
* This file is the core OMAP support for the generic, Linux
- * PWM driver / controller, using the OMAP's dual-mode timers.
+ * PWM driver / controller, using the OMAP's dual-mode timers
+ * with a timer counter that goes up. When it overflows it gets
+ * reloaded with the load value and the pwm output goes up.
+ * When counter matches with match register, the output goes down.
+ * Reference Manual: http://www.ti.com/lit/ug/spruh73q/spruh73q.pdf
+ *
+ * Limitations:
+ * - When PWM is stopped, timer counter gets stopped immediately. This
+ * doesn't allow the current PWM period to complete and stops abruptly.
*/

#include <linux/clk.h>
--
2.23.0