[PATCH v1 0/3] arm64: dts: imx8mm-var-dart: update SoM support

[PATCH v1 0/3] arm64: dts: imx8mm-var-dart: update SoM support

[Stefano Radaelli]

This series updates the Variscite DART-MX8M-MINI SoM device tree to
better reflect the currently supported hardware configuration.

The changes configure SAI3 in synchronous RX mode, add TPM support,
and increase the Ethernet PHY reset deassert delay to improve PHY
detection reliability.

Stefano Radaelli (3):
  arm64: dts: imx8mm-var-dart: configure SAI3 synchronous RX mode
  arm64: dts: imx8mm-var-dart: add TPM support
  arm64: dts: imx8mm-var-dart: increase PHY reset deassert delay

 arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)


base-commit: 46d8fa682d263271f3ef7bf95166b124c19d6c62
-- 
2.47.3

[PATCH v1 1/3] arm64: dts: imx8mm-var-dart: configure SAI3 synchronous RX mode

[Stefano Radaelli]

From: Stefano Radaelli <stefano.r@variscite.com>

Configure SAI3 to operate in synchronous RX mode, so that the trasmit
path uses the receive bit clock and frame sync signals.

Remove the TX_SYNC and TX_BCLK pinmux entries, as these signals are not
used in this configuration.

Co-developed-by: Francesco Ferraro <francesco.f@variscite.com>
Signed-off-by: Francesco Ferraro <francesco.f@variscite.com>
Signed-off-by: Stefano Radaelli <stefano.r@variscite.com>
---
 arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi
index 2324063f8fd9..c7a9eb23e5e8 100644
--- a/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi
@@ -305,6 +305,7 @@ &sai3 {
 	assigned-clock-parents = <&clk IMX8MM_AUDIO_PLL1_OUT>;
 	assigned-clock-rates = <1536000>;
 	fsl,sai-mclk-direction-output;
+	fsl,sai-synchronous-rx;
 	status = "okay";
 };
 
@@ -446,8 +447,6 @@ pinctrl_sai3: sai3grp {
 			MX8MM_IOMUXC_SAI3_RXFS_SAI3_RX_SYNC		0xd6
 			MX8MM_IOMUXC_SAI3_RXC_SAI3_RX_BCLK		0xd6
 			MX8MM_IOMUXC_SAI3_RXD_SAI3_RX_DATA0		0xd6
-			MX8MM_IOMUXC_SAI3_TXFS_SAI3_TX_SYNC		0xd6
-			MX8MM_IOMUXC_SAI3_TXC_SAI3_TX_BCLK		0xd6
 			MX8MM_IOMUXC_SAI3_TXD_SAI3_TX_DATA0		0xd6
 			MX8MM_IOMUXC_SAI3_MCLK_SAI3_MCLK		0xd6
 		>;
-- 
2.47.3

[PATCH v1 2/3] arm64: dts: imx8mm-var-dart: add TPM support

[Stefano Radaelli]

From: Stefano Radaelli <stefano.r@variscite.com>

Add support for the TPM available on the Variscite DART-MX8M-MINI SOM.

Co-developed-by: Nate Drude <nate.d@variscite.com>
Signed-off-by: Nate Drude <nate.d@variscite.com>
Signed-off-by: Stefano Radaelli <stefano.r@variscite.com>
---
 arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi
index c7a9eb23e5e8..9fc0f7e551ca 100644
--- a/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi
@@ -138,6 +138,13 @@ &i2c1 {
 	sda-gpios = <&gpio5 15 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
 	status = "okay";
 
+	st33ktpm2xi2c_som: tpm@2e {
+		compatible = "st,st33ktpm2xi2c", "tcg,tpm-tis-i2c";
+		reg = <0x2e>;
+		label = "tpm";
+		reset-gpios = <&gpio4 31 GPIO_ACTIVE_HIGH>;
+	};
+
 	pmic@4b {
 		compatible = "rohm,bd71847";
 		reg = <0x4b>;
-- 
2.47.3

[PATCH v1 3/3] arm64: dts: imx8mm-var-dart: increase PHY reset deassert delay

[Stefano Radaelli]

From: Stefano Radaelli <stefano.r@variscite.com>

The Ethernet PHY reset signal also controls the regulators supplying
VDDA2P5 and VDD1P0, so releasing reset restores the PHY's 2.5 V and
1.0 V analog supplies.

The existing 100 ms reset deassertion delay is not sufficient for
reliable PHY detection. The TI DP83867 requires 200 ms of stabilization
after power-up before MDIO register access.

Increase the reset deassertion delay to 200 ms to ensure reliable PHY
detection across repeated boots.

Co-developed-by: Nate Drude <nate.d@variscite.com>
Signed-off-by: Nate Drude <nate.d@variscite.com>
Signed-off-by: Stefano Radaelli <stefano.r@variscite.com>
---
 arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi
index 9fc0f7e551ca..fcd937d8d29a 100644
--- a/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi
@@ -123,7 +123,7 @@ ethphy0: ethernet-phy@0 {
 			reg = <0>;
 			reset-gpios = <&gpio1 9 GPIO_ACTIVE_LOW>;
 			reset-assert-us = <10000>;
-			reset-deassert-us = <100000>;
+			reset-deassert-us = <200000>;
 			vddio-supply = <&reg_phy_vddio>;
 		};
 	};
-- 
2.47.3

Re: [PATCH v1 2/3] arm64: dts: imx8mm-var-dart: add TPM support

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] arm64: dts: incorrect polarity for TPM reset gpio
- [Medium] arm64: dts: missing pinctrl for TPM reset gpio
--

commit b6842f762ba714e622e3da081d4b664400c4462d
Author: Stefano Radaelli <stefano.r@variscite.com>

arm64: dts: imx8mm-var-dart: add TPM support

Add support for the TPM available on the Variscite DART-MX8M-MINI SOM.

> diff --git a/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi
> index c7a9eb23e5e88..9fc0f7e551ca7 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mm-var-dart.dtsi

[ ... ]

> @@ -138,6 +138,13 @@ &i2c1 {
>  	sda-gpios = <&gpio5 15 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
>  	status = "okay";
>  
> +	st33ktpm2xi2c_som: tpm@2e {
> +		compatible = "st,st33ktpm2xi2c", "tcg,tpm-tis-i2c";
> +		reg = <0x2e>;
> +		label = "tpm";
> +		reset-gpios = <&gpio4 31 GPIO_ACTIVE_HIGH>;

[Severity: Medium]
Will this reset line work without a corresponding pinctrl configuration?

The node requests &gpio4 31 (pad SAI3_TXFS) as its reset line but lacks a
pinctrl-0 property to configure the pad's multiplexer to GPIO mode.

Since the i.MX pinctrl driver does not implement .gpio_request_enable(),
the GPIO subsystem cannot automatically reconfigure the pad when requested.

Does this leave the pad in its default or bootloader-assigned state,
causing software toggling of the GPIO to silently fail and breaking
the hardware reset capability?

[Severity: High]
Is the reset GPIO polarity correct for the ST33K TPM hardware?

The STMicroelectronics ST33K TPM hardware reset line is active-low
(RST_N), but the reset-gpios property specifies GPIO_ACTIVE_HIGH.

When the driver attempts to release the device from reset by logically
de-asserting the GPIO, won't gpiolib drive the physical line LOW (0V)?

Driving the active-low hardware pin LOW will hold the TPM in reset
permanently, causing device initialization to fail entirely. Should this
be configured as GPIO_ACTIVE_LOW instead?

> +	};
> +
>  	pmic@4b {
>  		compatible = "rohm,bd71847";
>  		reg = <0x4b>;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/cover.1789657399.git.stefano.r@variscite.com?part=2