linux/Documentation/devicetree/bindings/input/touchscreen
Dirk Behme 62f4666968 Input: zforce - make the interrupt GPIO optional
Add support for hardware which uses an I2C Serializer / Deserializer
(SerDes) to communicate with the zFroce touch driver. In this case the
SerDes will be configured as an interrupt controller and the zForce driver
will have no access to poll the GPIO line.

To support this, we add two dedicated new GPIOs in the device tree:
reset-gpios and irq-gpios, with the irq-gpios being optional.

To not break the existing device trees, the index based 'gpios' entries
are still supported, but marked as deprecated.

With this, if the interrupt GPIO is available, either via the old or new
device tree style, the while loop will read and handle the packets as long
as the GPIO indicates that the interrupt is asserted (existing, unchanged
driver behavior).

If the interrupt GPIO isn't available, i.e. not configured via the new
device tree style, we are falling back to one read per ISR invocation
(new behavior to support the SerDes).

Note that the gpiod functions help to handle the optional GPIO:
devm_gpiod_get_index_optional() will return NULL in case the interrupt
GPIO isn't available. And gpiod_get_value_cansleep() does cover this, too,
by returning 0 in this case.

Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Reviewed-by: Heiko Stuebner <heiko.stuebner@bq.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2015-08-03 14:10:10 -07:00
..
auo_pixcir_ts.txt
brcm,iproc-touchscreen.txt
bu21013.txt
chipone_icn8318.txt
edt-ft5x06.txt
egalax-ts.txt
goodix.txt
lpc32xx-tsc.txt
mms114.txt
pixcir_i2c_ts.txt Input: pixcir_i2c_ts - add RESET gpio 2015-07-11 17:28:27 -07:00
sitronix-st1232.txt
stmpe.txt
sun4i.txt
sx8654.txt
ti-tsc-adc.txt
touchscreen.txt
tsc2005.txt
tsc2007.txt
zforce_ts.txt Input: zforce - make the interrupt GPIO optional 2015-08-03 14:10:10 -07:00