linux-kernel - Re: [PATCH 2/2] dmaengine: dw-axi-dmac: add reset control support

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Message-ID: <CAOPX745BVB4oVUxz0ZYRRs3_KWT6Y6cGrMdc26v49U66+u0ReA@mail.gmail.com>
Date: Mon, 13 Oct 2025 17:56:33 +0300
From: Artem Shimko <a.shimko.dev@...il.com>
To: Philipp Zabel <p.zabel@...gutronix.de>
Cc: Eugeniy Paltsev <Eugeniy.Paltsev@...opsys.com>, Vinod Koul <vkoul@...nel.org>, 
	dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] dmaengine: dw-axi-dmac: add reset control support

Hi Philipp,

On Mon, Oct 13, 2025 at 11:41 AM Philipp Zabel <p.zabel@...gutronix.de> wrote:
> reset_control_assert/deassert() handle NULL pointers, so you could drop
> the chip->has_resets flag and just
>
>         reset_control_assert(chip->resets);
>
> unconditionally.

Thanks, I'll fix that

> Why is this moved down here?

Reset operations typically require clock signals to be available. By
moving reset after clock
acquisition (devm_clk_get), we ensure that the clock is ready to
operate when reset is performed.

> If it is ok to keep the module in reset, shouldn't the reset control be
> asserted on device remove() as well?

dw_remove() has axi_dma_suspend() function, which is where the reset assertion
occurs via reset_control_assert().

Best regards,
Artem Shimko