From: pratikmanvar09@gmail.com
To: francesco@dolcini.it
Cc: festevam@gmail.com, jun.li@nxp.com, kernel@pengutronix.de,
linux-arm-kernel@lists.infradead.org, linux-imx@nxp.com,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
oe-kbuild-all@lists.linux.dev, pratik.manvar@ifm.com,
pratikmanvar09@gmail.com, s.hauer@pengutronix.de,
shawnguo@kernel.org, thierry.reding@gmail.com,
u.kleine-koenig@pengutronix.de, xiaoning.wang@nxp.com
Subject: Re: [PATCH v3] pwm: imx27: workaround of the pwm output bug
Date: Tue, 5 Mar 2024 14:57:29 +0530 [thread overview]
Message-ID: <65e6e58d.050a0220.6580e.7a57@mx.google.com> (raw)
In-Reply-To: <20240103110200.1018-1-pratikmanvar09@gmail.com>
Hello Francesco,
Sorry for the abysmal delay.
Thanks for your review and suggestions.
>Hello Pratik,
>
>On Wed, Jan 03, 2024 at 04:32:00PM +0530, pratikmanvar09@gmail.com wrote:
>> From: Clark Wang <xiaoning.wang@nxp.com>
>>
>> This fixes the pwm output bug when decrease the duty cycle.
>> This is a limited workaround for the PWM IP issue TKT0577206.
>>
>> Root cause:
>> When the SAR FIFO is empty, the new write value will be directly applied
>> to SAR even the current period is not over.
>> If the new SAR value is less than the old one, and the counter is
>> greater than the new SAR value, the current period will not filp the
>> level. This will result in a pulse with a duty cycle of 100%.
>>
>> Workaround:
>> Add an old value SAR write before updating the new duty cycle to SAR.
>> This will keep the new value is always in a not empty fifo, and can be
>> wait to update after a period finished.
>>
>> Limitation:
>> This workaround can only solve this issue when the PWM period is longer
>> than 2us(or <500KHz).
>>
>> Reviewed-by: Jun Li <jun.li@nxp.com>
>> Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
>> Link: https://github.com/nxp-imx/linux-imx/commit/16181cc4eee61d87cbaba0e5a479990507816317
>> Tested-by: Pratik Manvar <pratik.manvar@ifm.com>
>> Signed-off-by: Pratik Manvar <pratik.manvar@ifm.com>
>
>A very similar patch was already send in 2021 [1], did it had review
>comments not addressed? Please have a look.
>
>In general please refrain from sending a new patch version every other
>day, while every Linux kernel subsystem has different rules and a
>difference pace of development, in this specific case sending a v3 just
>adding your signed-off-by without allowing a little bit of time to wait
>for more feedback is just not sane.
Ok, I will keep this in mind. Thanks!
>
>[1] https://lore.kernel.org/all/?q=dfn%3Adrivers%2Fpwm%2Fpwm-imx27.c+AND+b%3A%22Clark+Wang%22
Ok, I did not check this. I will look into this. Thanks!
Thanks & Regards,
Pratik Manvar
next prev parent reply other threads:[~2024-03-05 9:27 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-29 6:30 [PATCH] pwm: imx27: workaround of the pwm output bug pratikmanvar09
2023-12-30 2:01 ` kernel test robot
2024-01-03 6:34 ` [PATCH v2] " pratikmanvar09
2024-01-03 11:00 ` Stefan Wahren
2024-02-04 6:36 ` pratikmanvar09
2024-02-04 10:02 ` Stefan Wahren
2024-03-05 9:24 ` pratikmanvar09
2024-01-03 10:34 ` [PATCH] " Francesco Dolcini
2024-01-03 11:02 ` [PATCH v3] " pratikmanvar09
2024-01-03 12:20 ` Francesco Dolcini
2024-01-24 11:48 ` Stefan Wahren
2024-01-25 21:28 ` Uwe Kleine-König
2024-03-05 9:27 ` pratikmanvar09 [this message]
2024-01-03 12:18 ` [PATCH] " Uwe Kleine-König
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=65e6e58d.050a0220.6580e.7a57@mx.google.com \
--to=pratikmanvar09@gmail.com \
--cc=festevam@gmail.com \
--cc=francesco@dolcini.it \
--cc=jun.li@nxp.com \
--cc=kernel@pengutronix.de \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-imx@nxp.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pwm@vger.kernel.org \
--cc=oe-kbuild-all@lists.linux.dev \
--cc=pratik.manvar@ifm.com \
--cc=s.hauer@pengutronix.de \
--cc=shawnguo@kernel.org \
--cc=thierry.reding@gmail.com \
--cc=u.kleine-koenig@pengutronix.de \
--cc=xiaoning.wang@nxp.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).