Messages in this thread | | | Date | Thu, 20 Dec 2012 11:45:30 +0530 | From | Laxman Dewangan <> | Subject | Re: [PATCH] ARM: tegra: dts: add aliases and DMA requestor for serial controller |
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On Wednesday 19 December 2012 10:30 PM, Stephen Warren wrote: > On 12/18/2012 11:31 PM, Laxman Dewangan wrote: >> Add APB DMA requestor and serial aliases for serial controller. >> There will be two serial driver i.e. 8250 based simple serial driver >> and APB DMA based serial driver for higher baudrate and performace. >> >> The simple serial driver get enabled with compatible nvidia,tegra20-uart >> and APB DMA based driver will get enabled with compatible >> nvidia,tegra20-hsuart. > This patch seems to do two things: > > 1) Add a comment describing how to select the basic or DMA-based driver. > I can see why this is useful. > > 2) Add aliases for the serial ports. I have no idea why this is useful.
Serial aliases are added because we want to get the port number like /dev/ttyTHS0, /d/ttyTHS2 etc. The uarta should be /dev/ttyTHS0 and uartc should be /dev/ttyTHS2. The port number can be found using aliases and of_alias_get_id() in driver file:
port_number = of_alias_get_id(np, "serial");
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