Hi Stephen, On 01/21/16 00:13, Stephen Warren wrote: > On 01/19/2016 06:12 AM, Ralf Ramsauer wrote: >> This patch enables the APB DMA high speed UARTs of the Jetson TK1. > >> diff --git a/arch/arm/boot/dts/tegra124-jetson-tk1.dts >> b/arch/arm/boot/dts/tegra124-jetson-tk1.dts > >> + /* First high speed UART */ >> + serial@0,70006000 { >> + compatible = "nvidia,tegra124-hsuart", "nvidia,tegra30-hsuart"; >> + status = "okay"; >> + }; > > It would be nice if the comment described the HW connectivity, i.e. > which signals the UART was connected to on the board, just like the > comments for other IO controllers already enabled in the DT file. I'd > suggest replacing the comment above with: > > /* Expansion BR_UART1_RXD/_TXD */ I'll be more verbose with commenting in the next round > >> + /* Second high speed UART */ >> + serial@0,70006040 { >> + compatible = "nvidia,tegra124-hsuart", "nvidia,tegra30-hsuart"; >> + status = "okay"; >> + }; > > ... and that commetn with: > > /* Expansion UART2_RXD/_TXD/_RTS/_CTS */ Ack > >> + >> + /* Third high speed UART */ >> + serial@0,70006200 { >> + compatible = "nvidia,tegra124-hsuart", "nvidia,tegra30-hsuart"; >> + status = "okay"; >> + }; > > That UART doesn't seem to be used at all according to the schematics > and pinmux spreadsheet. Do you have any reference to the contrary > aside from the L4T DT file? I believe it shouldn't be enabled. Just checked it, and yes, you're absolutely right. I used the L4T device tree as reference. Can't tell you why, but it appears that they activated all uarts. This is a short excerpt of Nvidias official DT: serial@70006000 { compatible = "nvidia,tegra114-hsuart"; status = "okay"; }; serial@70006040 { compatible = "nvidia,tegra114-hsuart"; status = "okay"; }; serial@70006200 { compatible = "nvidia,tegra114-hsuart"; status = "okay"; }; serial@70006300 { compatible = "nvidia,tegra20-uart", "nvidia,tegra114-hsuart"; console-port; sqa-automation-port; status = "okay"; }; This is a short excerpt of /proc/iomem of a Jetson TK1 running latest stock L4T linux: 70006000-7000603f : /serial@70006000 70006040-7000607f : /serial@70006040 70006200-7000623f : /serial@70006200 70006300-7000631f : serial Let me doublecheck that again - in fact only two of three high speed UARTs are actually exposed to the expansion header. (besides the strange fact, that nvidia seems to have all uarts enabled...) According to [1]: uart1 - expansion connector uart2 - expansion connector uart3 - ??? uart4 - DB9 RS232 connector I'll check this in a few days again. Thanks for review, Stephen! Ralf [1] http://developer.download.nvidia.com/embedded/jetson/TK1/2014-03-24/JetsonTK1_ModuleSpecification_PM375_V1.0.pdf -- Ralf Ramsauer GPG: 0x8F10049B -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html