[PATCH v3 4/6] ARM: dts: imx6q{dl}: fix the wrong RTS/CTS pad name

[Lothar Waßmann]

Hi,

Russell King - ARM Linux writes:
> On Sun, Jul 07, 2013 at 01:51:14PM +0200, Lothar Waßmann wrote:
> > Hi,
> > 
> > Shawn Guo writes:
> > > On Fri, Jul 05, 2013 at 02:12:30PM +0800, Huang Shijie wrote:
> > > > There is something wrong with the RTS/CTS pads:
> > > >   The RTS pad is assigned with the CTS's value;
> > > >   while the CTS pad is assigned with the RTS's value.
> > > > 
> > > 
> > > So basically, you are saying that select_input should be set up for CTS
> > > rather than RTS.  It seems that the people who generated the macro got
> > > the wrong input from developer.
> > > 
> > programming 'select_input' only makes sense for inputs, not outputs.
> > Since CTS is an output signal, select_input only makes sense for the
> > RTS function of the pads.
> 
> Note: If you are a DTE, then RTS is an output, CTS is an input.  If you
> are a DCE, then RTS is an input and CTS is an output (normally on a
> standard UART, you just swap the wiring for RTS and CTS but really that's
> all that is going on.)  So swapping them in software should be acceptable
> too, provided you're not having to disable any auto flow control facilities.
>
Freescale had decided to implement their UARTs on the i.MX SoCs as DCE
and later added a bit to switch between DCE and DTE mode. That's where
all the confusion comes from.


Lothar Waßmann
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