The vast majority of devicetree bindings for GPIO controllers are
expected to have "flags" cells in their respective GPIO specifiers,
but that's not required by the specification and we want to make sure
to support that.
However, so many drivers and applications initialize gpio_dt_flags_t
values that it's silly to require each and every one of them to check
for the flags value and fall back to the sensible default flags value
of 0 when it does not exist.
Make the API easier to use correctly by returning 0 in the devicetree
core API for accessing flags, whenever there are no flags defined.
Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
This is joint work with Kumar Gala (see signed-off-by).
Add helper macros which abstract the "true names" of each of the four
types of node identifier we intend to support (e.g. DT_ALIAS(),
DT_INST()).
These can be passed to a new DT_PROP() macro which can be used to read
the value of a devicetree property given a node identifier from one of
these four other macros, and the as-a-c-token name of the property.
Add other accessor macros and tests as well.
Add some convenience APIs for writing device drivers based on instance
numbers as well. Drivers can "#define DT_DRV_COMPAT driver_compatible"
at the top of the file, then utilize these DT_INST_* macros to access
various property defines.
For example, the uart_sifive driver can do:
#define DT_DRV_COMPAT sifive_uart0
Then use DT_INST macros like:
.port = DT_INST_REG_ADDR(0),
.sys_clk_freq = DT_INST_PROP(0, clock_frequency),
For convenience working with specific hardware, also add:
<devicetree/gpio.h>
<devicetree/adc.h>
<devicetree/spi.h>
Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
