From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Ben Dooks <ben.dooks@sifive.com>
Cc: linux-pwm@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, Lee Jones <lee.jones@linaro.org>,
Thierry Reding <thierry.reding@gmail.com>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Greentime Hu <greentime.hu@sifive.com>,
jarkko.nikula@linux.intel.com,
William Salmon <william.salmon@sifive.com>,
Jude Onyenegecha <jude.onyenegecha@sifive.com>
Subject: Re: [PATCH v7 10/10] pwm: dwc: use clock rate in hz to avoid rounding issues
Date: Thu, 16 Feb 2023 22:39:27 +0100 [thread overview]
Message-ID: <20230216213927.r3lvjz6u7d62y4pb@pengutronix.de> (raw)
In-Reply-To: <20221223153820.404565-11-ben.dooks@sifive.com>
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On Fri, Dec 23, 2022 at 03:38:20PM +0000, Ben Dooks wrote:
> As noted, the clock-rate when not a nice multiple of ns is probably
> going to end up with inacurate caculations, as well as on a non pci
Given that such a non-nice ca*l*culation only happens in the of case
that is introduced here, it would be nice to move this patch before the
introduction of the of-support.
> system the rate may change (although we've not put a clock rate
> change notifier in this code yet) so we also add some quick checks
> of the rate when we do any calculations with it.
If the clk rate changes while the PWM is on, this modifies the output.
This is unfortunate and so it justifies adding a call to
clk_rate_exclusive_get() when the PWM is on.
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:[~2023-02-16 21:39 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-23 15:38 [PATCH v7 00/10] Designware PWM driver updates for OF Ben Dooks
2022-12-23 15:38 ` [PATCH v7 01/10] dt-bindings: pwm: Document Synopsys DesignWare snps,pwm-dw-apb-timers-pwm2 Ben Dooks
2022-12-23 15:38 ` [PATCH v7 02/10] pwm: dwc: allow driver to be built with COMPILE_TEST Ben Dooks
2022-12-23 15:38 ` [PATCH v7 03/10] pwm: dwc: change &pci->dev to dev in probe Ben Dooks
2022-12-23 15:38 ` [PATCH v7 04/10] pwm: dwc: move memory alloc to own function Ben Dooks
2023-02-16 21:19 ` Uwe Kleine-König
2022-12-23 15:38 ` [PATCH v7 05/10] pwm: dwc: use devm_pwmchip_add Ben Dooks
2022-12-23 15:38 ` [PATCH v7 06/10] pwm: dwc: split pci out of core driver Ben Dooks
2023-02-16 21:30 ` Uwe Kleine-König
2023-06-13 19:22 ` Ben Dooks
2023-06-14 7:02 ` Uwe Kleine-König
2022-12-23 15:38 ` [PATCH v7 07/10] pwm: dwc: make timer clock configurable Ben Dooks
2023-02-16 21:33 ` Uwe Kleine-König
2022-12-23 15:38 ` [PATCH v7 08/10] pwm: dwc: add of/platform support Ben Dooks
2022-12-23 15:38 ` [PATCH v7 09/10] pwm: dwc: add PWM bit unset in get_state call Ben Dooks
2022-12-23 15:38 ` [PATCH v7 10/10] pwm: dwc: use clock rate in hz to avoid rounding issues Ben Dooks
2023-02-16 21:39 ` Uwe Kleine-König [this message]
2023-06-14 11:17 ` Ben Dooks
2023-01-17 16:39 ` [PATCH v7 00/10] Designware PWM driver updates for OF Ben Dooks
2023-01-17 17:07 ` Uwe Kleine-König
2023-02-17 15:08 ` (subset) " Thierry Reding
2023-03-10 18:21 ` Uwe Kleine-König
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