From: Heiko Stuebner <heiko@sntech.de>
To: Nicolas Frattaroli <frattaroli.nicolas@gmail.com>,
Liam Girdwood <lgirdwood@gmail.com>,
Mark Brown <broonie@kernel.org>, Jaroslav Kysela <perex@perex.cz>,
Takashi Iwai <tiwai@suse.com>,
Philipp Zabel <p.zabel@pengutronix.de>,
Nicolas Frattaroli <frattaroli.nicolas@gmail.com>
Cc: linux-rockchip@lists.infradead.org, alsa-devel@alsa-project.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4] ASoC: rockchip: i2s-tdm: Strip out direct CRU use
Date: Sat, 16 Oct 2021 17:50:22 +0200 [thread overview]
Message-ID: <1782571.1Dz21PRzoM@phil> (raw)
In-Reply-To: <20211016105354.116513-2-frattaroli.nicolas@gmail.com>
Am Samstag, 16. Oktober 2021, 12:53:50 CEST schrieb Nicolas Frattaroli:
> In cases where both rx and tx lrck are synced to the same source,
> the resets for rx and tx need to be triggered simultaneously,
> according to the downstream driver.
>
> As there is no reset API to atomically bulk (de)assert two resets
> at once, what the driver did was implement half a reset controller
> specific to Rockchip, which tried to write the registers for the
> resets within one write ideally or several writes within an irqsave
> section.
>
> This of course violates abstractions quite badly. The driver should
> not write to the CRU's registers directly.
>
> In practice, for the cases I tested the driver with, which is audio
> playback, replacing the synchronised asserts with just individual
> ones does not seem to make any difference.
>
> If it turns out that this breaks something in the future, it should
> be fixed through the specification and implementation of an atomic
> bulk reset API, not with a CRU hack.
>
> Signed-off-by: Nicolas Frattaroli <frattaroli.nicolas@gmail.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
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next prev parent reply other threads:[~2021-10-16 15:50 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-16 10:53 [PATCH 0/4] Getting rid of the reset controller in i2s-tdm Nicolas Frattaroli
2021-10-16 10:53 ` [PATCH 1/4] ASoC: rockchip: i2s-tdm: Strip out direct CRU use Nicolas Frattaroli
2021-10-16 15:50 ` Heiko Stuebner [this message]
2021-10-16 10:53 ` [PATCH 2/4] ASoC: dt-bindings: rockchip: i2s-tdm: Drop rockchip, cru property Nicolas Frattaroli
2021-10-16 15:47 ` Heiko Stuebner
2021-10-16 10:53 ` [PATCH 3/4] arm64: dts: rockchip: Add i2s1 on rk356x Nicolas Frattaroli
2021-10-16 10:53 ` [PATCH 4/4] arm64: dts: rockchip: Add analog audio on Quartz64 Nicolas Frattaroli
2021-10-17 11:36 ` (subset) [PATCH 0/4] Getting rid of the reset controller in i2s-tdm Mark Brown
2021-10-17 11:45 ` Mark Brown
2021-10-17 12:36 ` Heiko Stuebner
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