From abbe13a2ffd99168592fc9d987b2427ac7484d51 Mon Sep 17 00:00:00 2001 From: Wenchao Han Date: Mon, 10 May 2021 07:53:12 -0700 Subject: [PATCH] arm64: dts: qcom: sc7180: Modify SPI_CLK voltage level for trogdor On coachz it could be observed that SPI_CLK voltage level was only 1.4V during active transfers because the drive strength was too weak. The line hadn't finished slewing up by the time we started driving it down again. Using a drive strength of 8 lets us achieve the correct voltage level of 1.8V. Though the worst problems were observed on coachz hardware, let's do this across the board for trogdor devices. Scoping other boards shows that this makes the clk line look nicer on them too and doesn't introduce any problems. Only the clk line is adjusted, not any data lines. Because SPI isn't a DDR protocol we only sample the data lines on either rising or falling edges, not both. That means the clk line needs to toggle twice as fast as data lines so having the higher drive strength is more important there. Signed-off-by: Wenchao Han [dianders: Adjust author real name; adjust commit message] Signed-off-by: Douglas Anderson Link: https://lore.kernel.org/r/20210510075253.1.Ib4c296d6ff9819f26bcaf91e8a08729cc203fed0@changeid Signed-off-by: Bjorn Andersson --- arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi index 5c137aa700c0..c55ea188e560 100644 --- a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi +++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi @@ -978,6 +978,7 @@ ap_spi_fp: &spi10 { &qspi_clk { pinconf { pins = "gpio63"; + drive-strength = <8>; bias-disable; }; }; -- 2.11.0