Re: [PATCH RESEND 0/6 v10] gpio: Add block GPIO

From: Roland Stigge
Date: Mon Dec 17 2012 - 13:02:35 EST


On 12/17/2012 06:37 PM, Wolfgang Grandegger wrote:
> /* Do synchronous data output with a single write access */
> __raw_writel(~mask, pio + PIO_OWDR);
> __raw_writel(mask, pio + PIO_OWER);
> __raw_writel(val, pio + PIO_ODSR);
>
> For caching we would need a storage. Not sure if it's worth compared to
> a context switch into the kernel.

Block GPIO is not only for you in userspace. ;-) You can also implement
efficient n-bit bus I/O in kernel drivers, n-bit-banging. :-) So not
always context switches involved.

Roland
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/