From: Thierry Reding <thierry.reding@gmail.com>
To: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: linux-kernel@vger.kernel.org,
Nicolas Ferre <nicolas.ferre@atmel.com>,
Bo Shen <voice.shen@atmel.com>,
linux-pwm@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] PWM: atmel: fix incorrect CDTY value after enabling or disabling
Date: Mon, 25 Aug 2014 12:15:23 +0200 [thread overview]
Message-ID: <20140825101522.GA16960@ulmo.nvidia.com> (raw)
In-Reply-To: <1394823931-2815-1-git-send-email-alexandre.belloni@free-electrons.com>
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On Fri, Mar 14, 2014 at 08:05:31PM +0100, Alexandre Belloni wrote:
> pwm-leds calls .config() and .disable() in a row. This exhibits that it may
> happen that the channel gets disabled before CDTY has been updated with CUPD.
> The issue gets quite worse with long periods.
> So, ensure by reading ISR that at least one period has past before disabling the
> channel.
>
> The other issue is that it may happen that CUPD is not flushed before enabling
> the channel so it will update CDTY/CPRD just after one period. So we always set
> CUPD, even when the channel is not enabled.
>
> Tested on at91sam9g45 and sama5d31ek.
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> ---
> drivers/pwm/pwm-atmel.c | 46 +++++++++++++++++++++++++++++-----------------
> 1 file changed, 29 insertions(+), 17 deletions(-)
Hi Alexandre,
going through the list of unapplied patches I came across this old
patch. It was never reviewed nor acked by anyone and you didn't ping me,
so I always assumed it must no longer be required. Is that so?
Thierry
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WARNING: multiple messages have this Message-ID (diff)
From: thierry.reding@gmail.com (Thierry Reding)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] PWM: atmel: fix incorrect CDTY value after enabling or disabling
Date: Mon, 25 Aug 2014 12:15:23 +0200 [thread overview]
Message-ID: <20140825101522.GA16960@ulmo.nvidia.com> (raw)
In-Reply-To: <1394823931-2815-1-git-send-email-alexandre.belloni@free-electrons.com>
On Fri, Mar 14, 2014 at 08:05:31PM +0100, Alexandre Belloni wrote:
> pwm-leds calls .config() and .disable() in a row. This exhibits that it may
> happen that the channel gets disabled before CDTY has been updated with CUPD.
> The issue gets quite worse with long periods.
> So, ensure by reading ISR that at least one period has past before disabling the
> channel.
>
> The other issue is that it may happen that CUPD is not flushed before enabling
> the channel so it will update CDTY/CPRD just after one period. So we always set
> CUPD, even when the channel is not enabled.
>
> Tested on at91sam9g45 and sama5d31ek.
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> ---
> drivers/pwm/pwm-atmel.c | 46 +++++++++++++++++++++++++++++-----------------
> 1 file changed, 29 insertions(+), 17 deletions(-)
Hi Alexandre,
going through the list of unapplied patches I came across this old
patch. It was never reviewed nor acked by anyone and you didn't ping me,
so I always assumed it must no longer be required. Is that so?
Thierry
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next prev parent reply other threads:[~2014-08-25 10:15 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-14 19:05 [PATCH] PWM: atmel: fix incorrect CDTY value after enabling or disabling Alexandre Belloni
2014-03-14 19:05 ` Alexandre Belloni
2014-08-25 10:15 ` Thierry Reding [this message]
2014-08-25 10:15 ` Thierry Reding
2014-08-25 11:54 ` Alexandre Belloni
2014-08-25 11:54 ` Alexandre Belloni
2014-08-25 12:35 ` Thierry Reding
2014-08-25 12:35 ` Thierry Reding
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