From: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Alexander Stein" <alexander.stein@ew.tq-group.com>
Cc: Sean Young <sean@mess.org>,
linux-media@vger.kernel.org,
Thierry Reding <thierry.reding@gmail.com>,
Florian Fainelli <florian.fainelli@broadcom.com>,
Ray Jui <rjui@broadcom.com>,
Scott Branden <sbranden@broadcom.com>,
Broadcom internal kernel review list
<bcm-kernel-feedback-list@broadcom.com>,
Stefan Wahren <wahrenst@gmx.net>,
linux-pwm@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] pwm: bcm2835: allow pwm driver to be used in atomic context
Date: Sat, 14 Oct 2023 09:51:12 +0300 [thread overview]
Message-ID: <e3e1bca1-bffa-d97a-d4af-27a10c43c064@gmail.com> (raw)
In-Reply-To: <20231013175140.dzlz4grrgngoyxbc@pengutronix.de>
On 13.10.23 г. 20:51 ч., Uwe Kleine-König wrote:
> Hello,
>
> On Fri, Oct 13, 2023 at 01:13:50PM +0200, Alexander Stein wrote:
>> Am Freitag, 13. Oktober 2023, 13:04:48 CEST schrieb Stefan Wahren:
>>> Am 13.10.23 um 12:46 schrieb Sean Young:
>>>> clk_get_rate() may do a mutex lock. Since the clock rate cannot change on
>>>> an rpi, simply fetch it once.
>>>
>>> does it mean you checked all possible SoCs (BCM2835, BCM2836, BCM2837,
>>> BCM2711, BCM2712) for this change?
>>>
>>> Is it impossible that the real clock can never be influenced by turbo
>>> mode like SPI?
>>
>> Assuming the clock can change, which I would, then a clock notifier seems
>> appropriate. See [1] for an example.
>
> I'm not a fan. If the clock changes, the output also changes. With a
> clock notifier you can soften the issue and reconfigure to something
> similar as the original wave form, but a glitch happens for sure.
>
Right, but without notifier, everything rate related after the change
will be wrong
Ivo
next prev parent reply other threads:[~2023-10-14 6:51 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1697193646.git.sean@mess.org>
2023-10-13 10:46 ` [PATCH v2 1/3] pwm: make it possible to apply pwm changes in atomic context Sean Young
2023-10-13 11:51 ` Thierry Reding
2023-10-13 14:58 ` Sean Young
2023-10-13 15:34 ` Thierry Reding
2023-10-13 18:04 ` Uwe Kleine-König
2023-10-14 8:31 ` Sean Young
2023-10-13 10:46 ` [PATCH v2 2/3] pwm: bcm2835: allow pwm driver to be used " Sean Young
2023-10-13 11:04 ` Stefan Wahren
2023-10-13 11:13 ` Alexander Stein
2023-10-13 11:44 ` Stefan Wahren
2023-10-13 17:51 ` Uwe Kleine-König
2023-10-14 6:51 ` Ivaylo Dimitrov [this message]
2023-10-14 8:47 ` Uwe Kleine-König
2023-10-13 10:46 ` [PATCH v2 3/3] media: pwm-ir-tx: trigger edges from hrtimer interrupt context Sean Young
2023-10-15 6:31 ` Ivaylo Dimitrov
2023-10-15 21:25 ` Sean Young
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