Re: [PATCH v2] arm64: dts: rockchip: Explicitly request UFS reset pin on RK3576

[Quentin Schulz <quentin.schulz@cherry.de>]

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@2a2d0000: [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@2a2d0000: [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@cherry.de>

Thanks!
Quentin