2021-03-05 00:08:06

by Philippe Schenker

Subject: [PATCH] ARM: dts: colibri-imx6ull: Change drive strength for usdhc2

The current setting reflects about 86 Ohms of source-impedance
on the SDIO signals where the WiFi board is hooked up. PCB traces are
routed with 50 Ohms impedance and there are no serial resistors on
those traces.

This commit changes the source-impedance to 52 Ohms to better match our
hardware design.

The impedances given in this commit message refer to 3.3V operation.

Signed-off-by: Philippe Schenker <[email protected]>

---

arch/arm/boot/dts/imx6ull-colibri.dtsi | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/arm/boot/dts/imx6ull-colibri.dtsi b/arch/arm/boot/dts/imx6ull-colibri.dtsi
index 4436556624d6..0cdbf7b6e728 100644
--- a/arch/arm/boot/dts/imx6ull-colibri.dtsi
+++ b/arch/arm/boot/dts/imx6ull-colibri.dtsi
@@ -522,12 +522,12 @@ MX6UL_PAD_SD1_DATA3__USDHC1_DATA3 0x170b9

pinctrl_usdhc2: usdhc2-grp {
fsl,pins = <
- MX6UL_PAD_CSI_DATA00__USDHC2_DATA0 0x17059
- MX6UL_PAD_CSI_DATA01__USDHC2_DATA1 0x17059
- MX6UL_PAD_CSI_DATA02__USDHC2_DATA2 0x17059
- MX6UL_PAD_CSI_DATA03__USDHC2_DATA3 0x17059
- MX6UL_PAD_CSI_HSYNC__USDHC2_CMD 0x17059
- MX6UL_PAD_CSI_VSYNC__USDHC2_CLK 0x17059
+ MX6UL_PAD_CSI_DATA00__USDHC2_DATA0 0x17069
+ MX6UL_PAD_CSI_DATA01__USDHC2_DATA1 0x17069
+ MX6UL_PAD_CSI_DATA02__USDHC2_DATA2 0x17069
+ MX6UL_PAD_CSI_DATA03__USDHC2_DATA3 0x17069
+ MX6UL_PAD_CSI_HSYNC__USDHC2_CMD 0x17069
+ MX6UL_PAD_CSI_VSYNC__USDHC2_CLK 0x17069

MX6UL_PAD_GPIO1_IO03__OSC32K_32K_OUT 0x10
>;
--
2.30.1

2021-03-08 08:36:49

by Shawn Guo

Subject: Re: [PATCH] ARM: dts: colibri-imx6ull: Change drive strength for usdhc2

On Thu, Mar 04, 2021 at 10:31:39AM +0100, Philippe Schenker wrote:
> The current setting reflects about 86 Ohms of source-impedance
> on the SDIO signals where the WiFi board is hooked up. PCB traces are
> routed with 50 Ohms impedance and there are no serial resistors on
> those traces.
>
> This commit changes the source-impedance to 52 Ohms to better match our
> hardware design.
>
> The impedances given in this commit message refer to 3.3V operation.
>
> Signed-off-by: Philippe Schenker <[email protected]>

Applied, thanks.