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From: Lokesh Vutla <lokeshvutla@ti.com>
To: "Thierry Reding" <thierry.reding@gmail.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Tony Lindgren <tony@atomide.com>,
	Linux OMAP Mailing List <linux-omap@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <linux-pwm@vger.kernel.org>,
	Sekhar Nori <nsekhar@ti.com>, Vignesh R <vigneshr@ti.com>,
	Lokesh Vutla <lokeshvutla@ti.com>
Subject: [PATCH v3 2/5] pwm: omap-dmtimer: Update description for pwm omap dm timer
Date: Thu, 12 Mar 2020 09:52:07 +0530	[thread overview]
Message-ID: <20200312042210.17344-3-lokeshvutla@ti.com> (raw)
In-Reply-To: <20200312042210.17344-1-lokeshvutla@ti.com>

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


WARNING: multiple messages have this Message-ID (diff)
From: Lokesh Vutla <lokeshvutla@ti.com>
To: "Thierry Reding" <thierry.reding@gmail.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Tony Lindgren <tony@atomide.com>,
	Linux OMAP Mailing List <linux-omap@vger.kernel.org>,
	linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
	Sekhar Nori <nsekhar@ti.com>, Vignesh R <vigneshr@ti.com>,
	Lokesh Vutla <lokeshvutla@ti.com>
Subject: [PATCH v3 2/5] pwm: omap-dmtimer: Update description for pwm omap dm timer
Date: Thu, 12 Mar 2020 09:52:07 +0530	[thread overview]
Message-ID: <20200312042210.17344-3-lokeshvutla@ti.com> (raw)
In-Reply-To: <20200312042210.17344-1-lokeshvutla@ti.com>

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

  parent reply	other threads:[~2020-03-12  4:23 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-12  4:22 [PATCH v3 0/5] pwm: omap-dmtimer: Allow for dynamic pwm period updates Lokesh Vutla
2020-03-12  4:22 ` Lokesh Vutla
2020-03-12  4:22 ` [PATCH v3 1/5] pwm: omap-dmtimer: Drop unused header file Lokesh Vutla
2020-03-12  4:22   ` Lokesh Vutla
2020-03-12  6:35   ` Uwe Kleine-König
2020-03-12  4:22 ` Lokesh Vutla [this message]
2020-03-12  4:22   ` [PATCH v3 2/5] pwm: omap-dmtimer: Update description for pwm omap dm timer Lokesh Vutla
2020-03-12  6:35   ` Uwe Kleine-König
2020-03-12  4:22 ` [PATCH v3 3/5] pwm: omap-dmtimer: Fix pwm enabling sequence Lokesh Vutla
2020-03-12  4:22   ` Lokesh Vutla
2020-03-12  4:22 ` [PATCH v3 4/5] pwm: omap-dmtimer: Do not disable pwm before changing period/duty_cycle Lokesh Vutla
2020-03-12  4:22   ` Lokesh Vutla
2020-03-12  6:40   ` Uwe Kleine-König
2020-03-12  8:05     ` Lokesh Vutla
2020-03-12  8:05       ` Lokesh Vutla
2020-03-12  8:47       ` Uwe Kleine-König
2020-03-12 10:44         ` Lokesh Vutla
2020-03-12 10:44           ` Lokesh Vutla
2020-03-12 14:21           ` Richard Cochran
2020-03-12 17:14             ` Lokesh Vutla
2020-03-18  4:40           ` Lokesh Vutla
2020-03-18  4:40             ` Lokesh Vutla
2020-03-30 14:14     ` Thierry Reding
2020-03-30 19:16       ` Uwe Kleine-König
2020-03-31 20:45         ` Thierry Reding
2020-04-01  8:22           ` Uwe Kleine-König
2020-04-01 10:22             ` Lokesh Vutla
2020-04-01 10:22               ` Lokesh Vutla
2020-04-01 11:47               ` Uwe Kleine-König
2020-04-01 18:39                 ` Thierry Reding
2020-04-01 20:36                   ` Uwe Kleine-König
2020-04-01 18:28             ` Thierry Reding
2020-04-01 20:31               ` Uwe Kleine-König
2020-04-01 21:37                 ` Thierry Reding
2020-04-02 14:02                   ` Uwe Kleine-König
2020-04-03  8:51                     ` Lokesh Vutla
2020-04-03  8:51                       ` Lokesh Vutla
2020-04-03 13:59                       ` Uwe Kleine-König
2020-03-31 15:29       ` Lokesh Vutla
2020-03-31 15:29         ` Lokesh Vutla
2020-03-31 20:10         ` Thierry Reding
2020-04-01 10:15           ` Lokesh Vutla
2020-03-12  4:22 ` [PATCH v3 5/5] pwm: omap-dmtimer: Implement .apply callback Lokesh Vutla
2020-03-12  4:22   ` Lokesh Vutla
2020-03-13 15:31   ` Tony Lindgren
2020-03-23 11:30 ` [PATCH v3 0/5] pwm: omap-dmtimer: Allow for dynamic pwm period updates Lokesh Vutla
2020-03-23 11:30   ` Lokesh Vutla
2020-03-30 14:04   ` Thierry Reding

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