On Wed, Oct 9, 2013 at 7:42 AM, Shawn Guo <shawn.guo@xxxxxxxxxx> wrote:
> It's naturally expected that when there are multiple phandle entries
> specified in pinctrl-* property, these entries will be applied
> sequentially. And this is how Linux kernel works. So let's define
> this behavior in the binding doc.
NAK this this a Linux kernel implementation detail. Sherman Yin
fixed this up so the drivers does not have to imply any sequence
semantic for this.
Study commit 03b054e9696c3cbd3d5905ec96da15acd0a2fe8d
"pinctrl: Pass all configs to driver on pin_config_set()"
It is perfectly legal for a driver to accumulate the settings into
e.g. a single register write if it can, e.g.:
u32 val = 0;
for (i = 0; i < num_configs; i++) {
switch() {
FOO:
val |= 1;
break;
BAR:
val |= 2:
break;
BAZ:
val |=4;
break;
};
writel(val, base+pinreg);
I.e. the driver may choose to apply configs sequentially, but that is
not at all necessary.
Yours,
Linus Walleij
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