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Message-ID: <9e51b504-e0f0-4d17-baa2-387339507c86@cherry.de>
Date: Tue, 20 Jan 2026 13:59:15 +0100
From: Quentin Schulz <quentin.schulz@...rry.de>
To: Alexey Charkov <alchark@...il.com>, Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
<conor+dt@...nel.org>, Heiko Stuebner <heiko@...ech.de>,
"Martin K. Petersen" <martin.petersen@...cle.com>,
Shawn Lin <shawn.lin@...k-chips.com>, Manivannan Sadhasivam <mani@...nel.org>
Cc: devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org,
stable@...r.kernel.org
Subject: Re: [PATCH v2] arm64: dts: rockchip: Explicitly request UFS reset pin
on RK3576
Hi Alexey,
On 1/20/26 1:53 PM, Alexey Charkov wrote:
> Rockchip RK3576 UFS controller uses a dedicated pin to reset the connected
> UFS device, which can operate either in a hardware controlled mode or as a
> GPIO pin.
>
> Power-on default is GPIO mode, but the boot ROM reconfigures it to a
> hardware controlled mode if it uses UFS to load the next boot stage.
>
> Given that existing bindings (and rk3576.dtsi) expect a GPIO-controlled
> device reset, request the required pin config explicitly.
>
> This doesn't appear to affect Linux, but it does affect U-boot:
>
> Before:
> => md.l 0x2604b398
> 2604b398: 00000011 00000000 00000000 00000000 ................
> < ... snip ... >
> => ufs init
> ufshcd-rockchip ufshc@...d0000: [RX, TX]: gear=[3, 3], lane[2, 2], pwr[FASTAUTO_MODE, FASTAUTO_MODE], rate = 2
> => md.l 0x2604b398
> 2604b398: 00000011 00000000 00000000 00000000 ................
>
> After:
> => md.l 0x2604b398
> 2604b398: 00000011 00000000 00000000 00000000 ................
> < ... snip ...>
> => ufs init
> ufshcd-rockchip ufshc@...d0000: [RX, TX]: gear=[3, 3], lane[2, 2], pwr[FASTAUTO_MODE, FASTAUTO_MODE], rate = 2
> => md.l 0x2604b398
> 2604b398: 00000010 00000000 00000000 00000000 ................
>
> (0x2604b398 is the respective pin mux register, with its BIT0 driving the
> mode of UFS_RST: unset = GPIO, set = hardware controlled UFS_RST)
>
> This helps ensure that GPIO-driven device reset actually fires when the
> system requests it, not when whatever black box magic inside the UFSHC
> decides to reset the flash chip.
>
Would have liked a mention on why pull-down in the commit log.
In any case,
Reviewed-by: Quentin Schulz <quentin.schulz@...rry.de>
Thanks!
Quentin
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