[PATCH 2/4] arch/arm/mach-at91/clock.c: Add missing IS_ERR test

Jean-Christophe PLAGNIOL-VILLARD plagnioj at jcrosoft.com
Tue Jan 25 12:23:47 EST 2011


On 07:12 Tue 25 Jan     , Julia Lawall wrote:
> On Tue, 25 Jan 2011, Jean-Christophe PLAGNIOL-VILLARD wrote:
> 
> > On 23:23 Mon 24 Jan     , Russell King - ARM Linux wrote:
> > > On Tue, Jan 25, 2011 at 10:51:38AM +1300, Ryan Mallon wrote:
> > > > You could, but it would not be helpful. Clock associations are used so
> > > > that _different_ devices can have the same function and map to the
> > > > correct clock. This is used when there are multiple instances of a
> > > > single peripheral. For example, the uart clocks work like this:
> > > > 
> > > > 	at91_clock_associate("usart1_clk", &pdev->dev, "usart");
> > > > 
> > > > so then you can do this in a driver:
> > > > 	
> > > > 	uart_clk = clk_get(&pdev->dev, "usart");
> > > > 
> > > > Rather than:
> > > > 
> > > > 	uart_clk = clk_get(NULL, "usart1_clk");
> > > > 
> > > > The former will find the correct uart clock for the device. Because each
> > > > uart is a separate device the correct clock will be selected for each uart.
> > > > 	
> > > > My point was that there should be no overlap between clk->name and
> > > > clk->function otherwise clk_get will not be able to return the correct
> > > > clock.
> > > 
> > > It would be nice if AT91 could switch over to using clkdev at some
> > > point, which greatly helps with associating struct clk's with their
> > > device/function names - and reduces the amount of "different" code.
> > I working on it that's was one of the reason I move clkdev to drivers
> > as AT91 and AVR32 need to switch
> 
> Shall I just leave the patch as is then?
I'll try to send a patch before chinese new year

Best Regards,
J.



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