Make it possible to name the producer side of a GPIO line using
a "gpio-line-names" property array, modeled on the
"clock-output-names" property from the clock bindings.
This naming is especially useful for:
- Debugging: lines are named after function, not just opaque
offset numbers.
- Exploration: systems where some or all GPIO lines are available
to end users, such as prototyping, one-off's "makerspace usecases"
users are helped by the names of the GPIO lines when tinkering.
This usecase has been surfacing recently.
The gpio-line-names attribute is completely optional.
Example output from lsgpio on a patched Snowball tree:
GPIO chip: gpiochip6, "8000e180.gpio", 32 GPIO lines
line 0: unnamed unused
line 1: "AP_GPIO161" "extkb3" [kernel]
line 2: "AP_GPIO162" "extkb4" [kernel]
line 3: "ACCELEROMETER_INT1_RDY" unused [kernel]
line 4: "ACCELEROMETER_INT2" unused
line 5: "MAG_DRDY" unused [kernel]
line 6: "GYRO_DRDY" unused [kernel]
line 7: "RSTn_MLC" unused
line 8: "RSTn_SLC" unused
line 9: "GYRO_INT" unused
line 10: "UART_WAKE" unused
line 11: "GBF_RESET" unused
line 12: unnamed unused
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Amit Kucheria <amit.kucheria@linaro.org>
Cc: David Mandala <david.mandala@linaro.org>
Cc: Lee Campbell <leecam@google.com>
Cc: devicetree@vger.kernel.org
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Michael Welling <mwelling@ieee.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
fd9c55315d