Ulf Hansson wrote:
Linus Walleij wrote:
On Mon, Oct 24, 2011 at 1:48 PM, Ulf Hansson <ulf.hansson@xxxxxxxxxxxxxx> wrote:
[Russell]
The MCIPWR signal controls the external power switch. This is the only
signal for it. This is the only connection for it. There is no other
control form for this power switch.
Then we are only left to use the variant struct I believe. In principle, a
flag in the variant struct, could indicate whether it is OK to disable the
vcore regulator and thus clear the MCIPWR when doing runtime_suspend.
Yep I think the best could be to add some variant named
bool external_card_power; and then document in the kerneldoc that this
means the driver can clear MMCIPWR without risk of cutting the power
to the card.
This should be true for Ux500, U300 and Nomadik (just checked the designs -
they all have external regulators).
Could we assume that all boards which utilizes the ARM PL180 are using
the MMCIPWR register to control power the card? Or should we add a new
amba mmci platform member so this is configurable for each board?
An option could also be if we might want to simplify code to just skip
the entire runtime_suspend|idle|resume function (ie stubb it or
something) for these kind of boards?
What do you prefer?
By the way, there is also another option. In the runtime_suspend
function for ARM PL180 block we can use mmc_power_save_host (and then
also disable vcore etc) and vice verse in runtime_resume with
mmc_power_restore_host.
Of course, these kind of operations takes quite some time to execute and
therefore we use a much bigger timeout than 50 ms (for example 10 s
instead) for ARM PL180.
Just an idea...
So the state save/restore and amba_vcore_disable(adev); should be done
only for those variants.
However this:
clk_disable(host->clk);
We ought to be able to do for *all* variants, provided we can create
pm_runtime_get/put and delay properly to cover all bus traffic
(looks like the patch already does that), plus all the time the card is
signalling busy. The best I can think of is to just return -EBUSY to runtime
PM like this:
if ((readl(base + MMCISTATUS) & (MCI_CMDACTIVE | MCI_TXACTIVE| MCI_RXACTIVE))
return -EBUSY;
Yours,
Linus Walleij
--
To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
