Hi,
On Sun, Jan 29, 2017 at 02:04:00PM +0200, Guy Shapiro wrote:
> The syscon-poweroff driver powers off the machine by writing a value to
> a register. Both the register and the value are configured via the
> device tree.
>
> I encountered a situation where I need to mask the written value - some
> values of the register must remain unchanged during the power-down.
> (This is required to turn on the i.mx6ul using the RTC. See [1] for more
> details.)
>
> Unfortunately, the property of the register value is currently named
> mask, so we can't just add a "mask" property.
>
> The solutions I could think of:
> 1) Add a new mask property and name it "mask_mask" or something like
> that.
> 2) Create a new "syscon-masked-poweroff" driver that will have value and
> mask properties.
>
> What do you think?
I suggest the we add a value property to the binding [0]
and use the following logic in the driver to keep
compatibility with the old binding:
if (!value) {
/* support for old binding */
val = mask;
mask = 0xFFFFFFFF;
} else if (!mask) {
/* support for just providing value */
mask = 0xFFFFFFFF;
val = value;
}
regmap_update_bits(map, offset, mask, val);
[0] Documentation/devicetree/bindings/power/reset/syscon-poweroff.txt
-- Sebastian
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