[PATCH] ARM: mxs: Change duart device to use amba-pl011

[u.kleine-koenig@pengutronix.de (Uwe Kleine-König)]

Hello Shawn,

On Mon, Dec 27, 2010 at 07:49:40PM +0800, Shawn Guo wrote:
> On Wed, Dec 22, 2010 at 09:25:42PM +0100, Uwe Kleine-K?nig wrote:
> > On Tue, Dec 21, 2010 at 09:12:10PM +0800, Shawn Guo wrote:
> > > The mxs duart is actually an amba-pl011 device. This commit changes
> > > the duart device code to dynamically allocate amba-pl011 device,
> > > so that drivers/serial/amba-pl011.c can be used on mxs.
> > I have problems using this.  The problem I found up to now is that
> > during probe of the device (triggered by mxs_add_duart ->
> > amba_device_register -> amba_put_disable_pclk) the uart clock is
> > disabled.  This happens because initially its usage count is 0 but the
> > clock is enabled by barebox.  clk_enable doesn't hurt, but in the
> > matching clk_disable the usage count drops to zero again and so the
> > clock is disabled in hardware.  After that no further outputs can be
> > seen.
> > 
> I did not see this problem. It's true that the clock is turned off
> in amba_device_register. But later, the clock will be turned on
> again by amba_probe -> amba_get_enable_pclk very soon.
This is only a problem with DEBUG_LL I guess.

Best regards
Uwe

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