On 12/17/2012 11:36 AM, Stephen Warren wrote: > On 12/17/2012 05:10 AM, Laxman Dewangan wrote: >> Nvidia's Tegra has multiple uart controller which supports: >> - APB dma based controller fifo read/write. >> - End Of Data interrupt in incoming data to know whether end >> of frame achieve or not. >> - Hw controlled RTS and CTS flow control to reduce SW overhead. > >> diff --git a/Documentation/devicetree/bindings/serial/nvidia,serial-tegra.txt b/Documentation/devicetree/bindings/serial/nvidia,serial-tegra.txt > >> +NVIDIA Tegra20/Tegra30 high speed (dma based) UART controller driver. >> + >> +Required properties: >> +- compatible : should be "nvidia,tegra20-hsuart", "nvidia,tegra30-hsuart". > > One question that isn't addressed here is: > > Tegra has 5 UARTs. All of them can use the existing 8250.c by specifying > compatible = "nvidia,tegra20-uart". The way it is supposed to work is that the compatible property should list "nvidia,tegra30-hsuart" first, followed by a fallback name that refers to the generic 8250 compatibility. Having the 8250.c driver bind to the more-specific tegra30-hsuart name is wrong. However, the 8250.c driver doesn't > support the DMA features of this driver. This driver is an alternate > driver for the same HW that allows DMA to be used with it, etc. > > Since DT is supposed to describe the HW, modifying the DT to change the > compatible value in order to select a different driver in Linux doesn't > seem correct, or is it? Is there any kind of precedent for how to select > different drivers for the same HW at run-time? I'd wondered about using > the sysfs bind/unbind "methods" from user-space as the driver selection > mechanism... > _______________________________________________ > devicetree-discuss mailing list > devicetree-discuss@xxxxxxxxxxxxxxxx > https://lists.ozlabs.org/listinfo/devicetree-discuss > -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
