[PATCH 09/19] drivers: serial: add support for Samsung S5PC110 SoC uart

[Marek Szyprowski]

Hello,

On Thursday, November 19, 2009 12:49 PM Mark Brown wrote:

> On Thu, Nov 19, 2009 at 11:38:41AM +0000, Russell King - ARM Linux wrote:
> 
> > I'm not sure what you're commenting on precisely, but the Samsung code as
> > a whole doesn't use the clk API very well, and I suspect that is starting
> > to cause people to have to pass clock names around.
> 
> That's what I'd thought originally but it's not quite the problem here.
> The issue is that Samsung serial port clock is chosen from a mux and the
> logic to select which of the inputs to that mux should be used is in the
> serial driver.  This means that if the set of parent clocks changes then
> the serial driver needs to be told what they are.
> 
> My suggestion was to push this logic down into the clock API so the
> serial driver just requests a rate and then clock API picks the best
> option from the mux.  As well as being nicer from the clock API point of
> view this would also allow other drivers to use the same logic since
> these muxes are a standard idiom for Samsung SoCs.

What if a device does not operate properly when clocked from one of the
available clock sources (lets say machine specific problem)? There must
be a way of setting which clock(s) should not be considered when calculating
best choice for particular device.

Best regards
--
Marek Szyprowski
Samsung Poland R&D Center