Re: [PATCH] arm64: dts: ti: k3-am65: Add support for UHS-I modes in MMCSD1 subsystem

[Nishanth Menon <nm@ti.com>]

On 16:13-20210407, Aswath Govindraju wrote:
> UHS-I speed modes are supported in AM65 S.R. 2.0 SoC[1].
> 
> Add support by removing the no-1-8-v tag and including the voltage
> regulator device tree nodes for power cycling.
> 
> [1] - https://www.ti.com/lit/ug/spruid7e/spruid7e.pdf, section 12.3.6.1.1
> 
> Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>

> ---
> 
> test logs:
> https://pastebin.ubuntu.com/p/vpYbY9QWh8/
> 
Thanks, but I dont plan on queuing this for 5.13-rc1 (my PR is already
out). but it does trigger an interesting discussion..

>  arch/arm64/boot/dts/ti/k3-am65-main.dtsi      |  1 -
>  .../arm64/boot/dts/ti/k3-am654-base-board.dts | 33 +++++++++++++++++++
>  2 files changed, 33 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/ti/k3-am65-main.dtsi b/arch/arm64/boot/dts/ti/k3-am65-main.dtsi
> index cb340d1b401f..632f32fce4a1 100644
> --- a/arch/arm64/boot/dts/ti/k3-am65-main.dtsi
> +++ b/arch/arm64/boot/dts/ti/k3-am65-main.dtsi
> @@ -301,7 +301,6 @@
>  		ti,otap-del-sel = <0x2>;
>  		ti,trm-icp = <0x8>;
>  		dma-coherent;
> -		no-1-8-v;
>  	};
>  

Jan - this will break your IOT SR1.0 boards, no? with all the SR1.0,
2.0, 2.1 coming along, the plan for TI was to support older revs via
overlays hoping that older boards will eventually get replaced or die
out of lack of use.. but you do have production on 1.0 -> so would you
rather handle this in overlay OR IOT boards dts introduce no-1-8-v
property?


-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D