On 7/12/2010 1:37 PM, Russell King - ARM Linux wrote:

On Mon, Jul 12, 2010 at 09:37:43AM +0530, Viresh KUMAR wrote:

quoted

quoted

This issue is different from the issue i raised which was common to
all amba devices. This is just for this GPIO driver, we need to enable clk
before using any gpio pin.

PL061 does not have any other clock signal other than PCLK, the APB (AMBA
peripheral bus) clock.  This clock needs to be running to access any
register in an APB peripheral.  The primecell drivers and AMBA support
is currently implemented with the assumtion that this clock is
permanently running.

If you need to enable a clock before using any GPIO pin, and it's not the
APB clock, then that's a platform extension that is outside of the PL061
domain, and probably also affects alternate functions of the GPIO pins as
well.  That means the PL061 code shouldn't manage that clock signal as it
won't know what's going on with the alternate functions.

Russell,

I agree that this clock is outside of GPIO's domain, but this is how it
is done for all other amba and non amba devices too, like pl011, pl022,
etc. There also we are handling platform specific clocks in drivers only.

Am i missing something??

viresh.