diff mbox series

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

Message ID 20200312042210.17344-3-lokeshvutla@ti.com (mailing list archive)
State New, archived
Headers show
Series pwm: omap-dmtimer: Allow for dynamic pwm period updates | expand

Commit Message

Lokesh Vutla March 12, 2020, 4:22 a.m. UTC 
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(-)

Comments

Uwe Kleine-König March 12, 2020, 6:35 a.m. UTC | #1 
On Thu, Mar 12, 2020 at 09:52:07AM +0530, Lokesh Vutla wrote:
> 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>

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Thanks
Uwe
diff mbox series

Patch

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>