From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Claudiu Beznea <claudiu.beznea@microchip.com>,
Thierry Reding <thierry.reding@gmail.com>,
Lee Jones <lee.jones@linaro.org>
Cc: linux-pwm@vger.kernel.org,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Nicolas Ferre <nicolas.ferre@microchip.com>,
Ludovic Desroches <ludovic.desroches@microchip.com>,
kernel@pengutronix.de, linux-arm-kernel@lists.infradead.org
Subject: overflow and wrong timeout errors in pwm-atmel
Date: Wed, 21 Apr 2021 13:03:36 +0200 [thread overview]
Message-ID: <20210421110336.bd5s6e2kjxqilddi@pengutronix.de> (raw)
In-Reply-To: <20210421092606.1634092-1-u.kleine-koenig@pengutronix.de>
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On Wed, Apr 21, 2021 at 11:26:08AM +0200, Uwe Kleine-König wrote:
> With these three patches PWM_DEBUG is now happy. (At least I couldn't
> trigger a warning any more. I think there are still a few problems with
> integer overflows.)
BTW, setting the period to 138350580899 (with a clock rate of 133333333
Hz) results in setting period=0 because
state->period * clkrate =
138350580899 * 133333333 =
40254751 (discarded from 18446744073749806367).
Another problem I just noticed is: The driver configures a period of 4s
just fine (i.e. without an overflow). But waiting for a new period to
start (e.g. in atmel_pwm_disable()) aborts after 2s.
So in the area of big period states there are still a few things to
improve.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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next prev parent reply other threads:[~2021-04-21 11:03 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-20 9:51 [PATCH 1/2] pwm: atmel: Fix duty cycle calculation in .get_state() Uwe Kleine-König
2021-04-20 9:51 ` Uwe Kleine-König
2021-04-20 9:51 ` [PATCH 2/2] pwm: atmel: Improve duty cycle calculation in .apply() Uwe Kleine-König
2021-04-20 9:51 ` Uwe Kleine-König
2021-04-23 17:07 ` Thierry Reding
2021-04-23 17:07 ` Thierry Reding
2021-04-21 9:26 ` [PATCH] pwm: atmel: rework tracking updates pending in hardware Uwe Kleine-König
2021-04-21 9:26 ` Uwe Kleine-König
2021-04-21 11:03 ` Uwe Kleine-König [this message]
2021-04-21 13:48 ` overflow and wrong timeout errors in pwm-atmel Uwe Kleine-König
2021-04-21 13:48 ` Uwe Kleine-König
2021-04-21 14:18 ` Alexandre Belloni
2021-04-21 14:18 ` Alexandre Belloni
2021-04-21 15:26 ` Uwe Kleine-König
2021-04-21 15:26 ` Uwe Kleine-König
2021-07-05 7:55 ` [PATCH] pwm: atmel: rework tracking updates pending in hardware Uwe Kleine-König
2021-07-05 7:55 ` Uwe Kleine-König
2021-04-23 17:07 ` [PATCH 1/2] pwm: atmel: Fix duty cycle calculation in .get_state() Thierry Reding
2021-04-23 17:07 ` Thierry Reding
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