iio: ping: add parallax ping sensors

Add support for parallax ping and laser ping sensors with just one pin
for trigger and echo signal.

This driver is based on srf04. In contrast to it it's necessary to
change direction of the pin and to request the irq just for the period
when the echo is rising and falling. Because this adds a lot of cases
there is this individual driver for handling this type of sensors.

Add a new configuration variable CONFIG_PING to Kconfig and Makefile.

Julia reported an issue with failing to unlock a mutex in some error
paths.

Signed-off-by: Andreas Klinger <ak@it-klinger.de>
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/iio/proximity/Kconfig b/drivers/iio/proximity/Kconfig
index d53601447da4..37606d400805 100644
--- a/drivers/iio/proximity/Kconfig
+++ b/drivers/iio/proximity/Kconfig
@@ -58,6 +58,21 @@ config MB1232
 	  To compile this driver as a module, choose M here: the
 	  module will be called mb1232.
 
+config PING
+	tristate "Parallax GPIO bitbanged ranger sensors"
+	depends on GPIOLIB
+	help
+	  Say Y here to build a driver for GPIO bitbanged ranger sensors
+	  with just one GPIO for the trigger and echo. This driver can be
+	  used to measure the distance of objects.
+
+	  Actually supported are:
+	  - Parallax PING))) (ultrasonic)
+	  - Parallax LaserPING (time-of-flight)
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ping.
+
 config RFD77402
 	tristate "RFD77402 ToF sensor"
 	depends on I2C