Re: [PATCH 7/8] arm64: dts: ti: k3-am64-sk: Disable MMC1 internal pulls

"Mendez, Judith" <[email protected]> Mon, 3 Aug 2026 17:26:11 -0500
Newsgroups dev.linux.lists.sashiko-reviews,org.kernel.vger.linux-devicetree
Message-ID <[email protected]>
Hi all,

Addressing Sashiko review.

On 7/29/2026 3:13 PM, [email protected] wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] Unintended removal of pulldown and incorrect receiver state for `MMC1_CLK`.
> --
> 
> --- Patch [7]: [PATCH 7/8] arm64: dts: ti: k3-am64-sk: Disable MMC1 internal pulls ---
> commit 3a83d1bd44a1ef684b5bd29a93a2127e82509201
> Author: Judith Mendez <[email protected]>
> 
> arm64: dts: ti: k3-am64-sk: Disable MMC1 internal pulls
> 
> This commit drops internal pullups on MMC data and CMD pins to prevent violating
> minimum pull resistance specifications, as external pullups are already present
> on the board. It also removes the CD pullup to reduce power consumption.
> 
>> diff --git a/arch/arm64/boot/dts/ti/k3-am642-sk.dts b/arch/arm64/boot/dts/ti/k3-am642-sk.dts
>> --- a/arch/arm64/boot/dts/ti/k3-am642-sk.dts
>> +++ b/arch/arm64/boot/dts/ti/k3-am642-sk.dts
>> @@ -198,13 +198,13 @@ &main_pmx0 {
>>   	main_mmc1_pins_default: main-mmc1-default-pins {
>>   		bootph-all;
>>   		pinctrl-single,pins = <
>> -			AM64X_IOPAD(0x0298, PIN_INPUT_PULLUP, 0) /* (D19) MMC1_SDCD */
>> -			AM64X_IOPAD(0x0294, PIN_INPUT_PULLUP, 0) /* (J19) MMC1_CMD */
>> -			AM64X_IOPAD(0x028c, PIN_INPUT_PULLDOWN, 0) /* (L20) MMC1_CLK */
>> +			AM64X_IOPAD(0x0298, PIN_INPUT, 0) /* (D19) MMC1_SDCD */
>> +			AM64X_IOPAD(0x0294, PIN_INPUT, 0) /* (J19) MMC1_CMD */
>> +			AM64X_IOPAD(0x028c, PIN_INPUT, 0) /* (L20) MMC1_CLK */
> 
> [Severity: Medium]
> The commit message mentions removing internal pullups because of external
> pullups on the board, but MMC1_CLK in main_mmc1_pins_default was configured
> with PIN_INPUT_PULLDOWN. Does this blanket change unintentionally leave the clock
> pin floating when the MMC controller tri-states the clock line (for example,
> during idle or suspend)?

MMC1_CLK has a 49.9K external pulldown, so there should be no issue
dropping the internal pulldown.

> 
> Additionally, keeping this as PIN_INPUT leaves the receiver enabled. If the
> clock line floats without a pulldown, could the floating voltage cause the input
> receiver to rapidly toggle and increase power consumption? Should this pin be
> configured as OUTPUT-only instead?

I think I missed one patch for setting MMC1_CLK pin as output for am64x,
will check and add patch in respin.

~ Judith