clocksource: sh_cmt: Add CMT register layout comment

Add a comment about different register layouts
supported by the CMT driver.

Signed-off-by: Magnus Damm <damm@opensource.se>
Acked-by: John Stultz <john.stultz@linaro.org>
Tested-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
This commit is contained in:
Magnus Damm 2012-12-14 14:54:37 +09:00 committed by Simon Horman
parent cccd70455c
commit 118aee4dd9

View File

@ -66,6 +66,21 @@ struct sh_cmt_priv {
unsigned long value);
};
/* Examples of supported CMT timer register layouts and I/O access widths:
*
* "16-bit counter and 16-bit control" as found on sh7263:
* CMSTR 0xfffec000 16-bit
* CMCSR 0xfffec002 16-bit
* CMCNT 0xfffec004 16-bit
* CMCOR 0xfffec006 16-bit
*
* "32-bit counter and 16-bit control" as found on sh7372, sh73a0, r8a7740:
* CMSTR 0xffca0000 16-bit
* CMCSR 0xffca0060 16-bit
* CMCNT 0xffca0064 32-bit
* CMCOR 0xffca0068 32-bit
*/
static unsigned long sh_cmt_read16(void __iomem *base, unsigned long offs)
{
return ioread16(base + (offs << 1));