Messages in this thread | | | From | Linus Walleij <> | Date | Thu, 20 Oct 2016 14:00:06 +0200 | Subject | Re: [PATCH v2 1/4] ACPI / property: Allow holes in reference properties |
| |
On Thu, Sep 29, 2016 at 3:39 PM, Mika Westerberg <mika.westerberg@linux.intel.com> wrote:
> DT allows holes or empty phandles for references. This is used for example > in SPI subsystem where some chip selects are native and others are regular > GPIOs. In ACPI _DSD we currently do not support this but instead the > preceding reference consumes all following integer arguments. > > For example we would like to support something like the below ASL fragment > for SPI: > > Package () { > "cs-gpios", > Package () { > ^GPIO, 19, 0, 0, // GPIO CS0 > 0, // Native CS > ^GPIO, 20, 0, 0, // GPIO CS1 > } > } > > The zero in the middle means "no entry" or NULL reference. To support this > we change acpi_data_get_property_reference() to take firmware node and > num_args as argument and rename it to __acpi_node_get_property_reference(). > The function returns -ENOENT if the given index resolves to "no entry" > reference and -ENODATA when there are no more entries in the property. > > We then add static inline wrapper acpi_node_get_property_reference() that > passes MAX_ACPI_REFERENCE_ARGS as num_args to support the existing > behaviour which some drivers have been relying on. > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Yours, Linus Walleij
| |